Assessing integrated phosphorus management practices on crop performance and soil–plant phosphorus dynamics under pearl millet–chickpea system in alkaline Fluvisol

Integrated phosphorus (P) management encompassing both conventional and organic sources is a sustainable option to save synthetic fertilizers without compromising crop productivity. Thus, a three 3-year field (2019–2021) experiment has been conducted to assess the impact of six integrated P-management modules on crop productivity and soil–plant P dynamics under pearl millet–chickpea system in the alkaline Fluvisol of Kanpur. The results showed productivity of both the crops increased over the years irrespective of treatments and highest chickpea equivalent pearl millet yield was recorded in 100% recommended dose of P (3.90 t ha⁻¹). Nitrate reductase (61 and 26% in pearl millet and chickpea, respectively) and total chlorophyll had significant jump in 60% recommended dose of P + farm yard manure (5 t ha⁻¹) over control. Soluble P fraction surged by 45% (pearl millet) and 18% (chickpea) in 60% recommended dose of P +crop residue (50%)+ P solubilising bacteria over control with efficient utilization of non-labile inorganic P fractions in both the crops. Higher physiological and internal P use efficiency in control plot indicates efficient use of above ground P under deficiency in both the crops. Correlation study showed grain yield was not significantly interlinked with soil inorganic P fractions in both the crops. Improved physio-chemical condition of soil along continual nutrient and labile carbon availability lead to significant leap in dehydrogenase (27% in pearl millet and 17% in chickpea) and alkaline phosphatase (27% in pearl millet and 31% in chickpea) in 60% recommended dose of P +crop residue (50%)+ P solubilising bacteria over completely fertilized plots in the end of 3 years. In nutshell, it can be inferred that application of 60% recommended dose of P +crop residue (50%)+ P solubilising bacteria along could be an excellent alternative to conventional practices (100% recommended dose of P) certifying higher P-availability and P-use efficacy.

1 Introduction

Pearl millet [Pennisetum glaucum (L.) R. Br.]–chickpea (Cicer arietinum L.) sequence is an important cropping system in the semi-arid tracts of India (Bana et al., 2023). In India, pearl millet grows in an area of ~7 Mha with production of 97.85 lakh tones and peculiar characters like resistance toward biotic stresses, minimum input requirement, early maturity with high yield, and adaptability to climatic anomalies making the same extremely suitable in the IGP [Ministry of Agriculture Farmers Welfare (MoAFW), 2023; Satyavathi et al., 2021]. In addition, nutritional attributes such as gluten free high protein (8–19%), with low fat (3–8%), richness in mineral nutrients (potassium, magnesium, iron and zinc), vitamins (niacin and thiamine), high fiber, essential amino acids, and polyunsaturated fatty acids (74%) rightly categorize pearl millet as ‘nutri-cereal' with countless health benefits (Satyavathi et al., 2021). As per input availability, several crops such as wheat, mustard, and sorghum can perfectly fit with pearl millet in cropping sequences, but combination with legumes such as chickpea might have been the best fit as it thrives perfectly in the residual soil moisture, restores soil fertility, and ensures profitability to the growers (Bana et al., 2023). Chickpea is the most popular pulse crop in India with an area and production of ~11 Mha and 13.75 Million tons, respectively [Ministry of Agriculture Farmers Welfare (MoAFW), 2023]. Like pearl millet, distinctive characters such as low carbon and water footprint with nominal greenhouse gas (GHG) emission, ability to sequester atmospheric nitrogen (N) through biological nitrogen fixation (BNF), adaptability in the problem soils and resilience toward climate change classify chickpea as a climate smart crop (Dutta et al., 2022). Chickpea grains are packed with proteins (18–22%), vitamins (A, B, C, and K), unsaturated fatty acids (omega-6 and omega-9), minerals (calcium, phosphorus, and micronutrients), dietary fiber (7.4–12.2%), and low fat (<4%) with positive pharmacological impacts on human health (Koul et al., 2022). Hence, based on the facts, pearl millet–chickpea system can be a potential alternative against intensive cereal based systems. Even so, the desired results from any system will not be achieved without balanced P-fertilization which was known as the ‘king-pin' of Indian agriculture (Dey et al., 2017).

After N, the most important element for plant growth is phosphorus (P), involved in several biochemical activities such as root growth, energy transformation, seed production, synthesis of nucleic acid, translocation of photosynthates, and BNF (Mitran et al., 2018). However, reports suggest a large part (80%) of India is low or medium in available P and unable to cater P-demand to the crops (Dey et al., 2017). Furthermore, the critical limit for pearl millet in alluvial and black soil was 4.8 and 7.7 ppm, respectively, indicating the need of balanced P-fertilization for achieving targeted yield (Dey et al., 2017). In India, the demand for phosphate fertilizer is mostly contended through imported di-ammonium phosphate (DAP) (~53 lakh tons in 2022–23) posing enormous burden on economy (Open Government Data, 2024). So, sustainable efforts must be made to curtail the dependency on DAP and look for eco-friendly alternatives such as P-rich organic amendments for supplying the available P without compromising yield.

Over-reliance on synthetic fertilizers may not be a viable option for long run as it has major loop holes such as (i) exacerbating cost, (ii) environmental pollution due to unsystematic application, (iii) increasing gap between rate of application and anticipated production, (iv) meager domestic supply, (v) multi-nutrient deficiencies and depletion in soil fertility (Mahajan et al., 2008). While, on the other side integrated phosphorus management (IPsM) combining both synthetic and organic sources not only have minimal environmental pay-offs but also improve P-use efficiency (PUE) and system productivity (Mahajan et al., 2008). In soil, P availability strongly determined by soil constituents (sesquioxides, carbonates of Ca and Mg), clay minerology, pH, moisture, management practices and dynamics between soil P-pools (Hazra et al., 2021). Mengel et al. (2001), delineated soil P pools into four main fractions, namely, (1). sparingly soluble, (2). strongly adsorbed, (3). Occluded, and (4). organic. In the alkaline or calcareous soil, Ca-phosphate is the dominant fraction and changes into more non-labile (Ca₈-P or Ca₁₀-P) forms depending on soil Ca concentration and pH (Mengel et al., 2001). Majority of soil P is present as organic form, but underscoring the dynamic changes of inorganic P (Pi) is utmost important as it directly linked with plant availability (McLaughlin et al., 2011). Organic amendments such as poultry manure (PM), farm yard manure (FYM), and crop residue (CR) along phosphorus solubilising bacteria (PSB) have appreciable impact on Pi-fractions as decomposition of the organic amendments releases different acids which improve P-solubilisation, mobilization, and reduce P-fixation eventually improving PUE (Touhami et al., 2020). Inorganic P-fractions also influenced positively under IPsM as findings suggest significant increase in available P pools (soluble-P and Ca₂-P) under integrated practices in rice–wheat system (Dutta et al., 2024). In addition, plants under organically amended plots utilize Ca₁₀-P more efficiently than completely fertilized plots with lower amount of occluded P in the former than the later (Bhattacharyya et al., 2015; Liu et al., 2017). Therefore, it will be really interesting to see the dynamics of Pi-fractions under IPsM particularly in pearl millet–chickpea system. Optimistic impact of IPsM on growth attributes, productivity, available P, and microbial activity in crops such as rice (Ahmed et al., 2018), wheat (Ding et al., 2020), maize (Venkatesh et al., 2019), mustard (Kumawat et al., 2014), and legumes (Dotaniya et al., 2022) has been documented. So, in the present circumstances, it is highly pertinent to take our research studies beyond growth attributes and discover the complex interaction between grain yields with soil Pi-fractions as information about the complex interlink between grain yield and Pi-fractions was absent under pearl millet–chickpea system.

Therefore, a three 3-year field experiment was carried out encompassing different IPsM modules in pearl millet–chickpea system to assess the effect on growth attributes, soil vis-à-vis plant P availability, and interlink with crop productivity. The main hypotheses of this study were (i) integration of synthetics with organic amendment (IPsM) has optimistic impact on growth, productivity, and P availability, (ii) influence of IPsM would be more effective in bioavailable Pi fractions (soluble-P, Ca₂-P) than sole chemical fertilization, and (iii) grain yield do have strong linkage with Pi-fractions along with other growth attributes.

2 Materials and methods

2.1 Description of the experimental site

A field experiment has been taken up for three 3 years (2019–2022) in the main research block (plot no. 10/5) of ICAR-Indian Institute of Pulses Research, Kanpur. Weather of the experimental site was typically hot summer with cool winters, and weather parameters during the experimental period are presented in Figure 1. Taxonomically, soil of the experimental area belongs to order ‘Fluvisol' (USDA-NRCS, 1999) with sandy loam texture and moderately alkaline pH (8.1). Soil was non-saline (EC: 0.25 ds m⁻¹), low in organic carbon (0.36%) (Walkley and Black, 1934), available K (211 kg ha⁻¹) (Jackson, 1973), and medium in available N (184.5 kg ha⁻¹) (Subbaiah and Asija, 1956) and available P (15.4 kg ha⁻¹) (Olsen, 1954).

Figure 1

Figure 1. Weather events during the experimental period [2019–2020: (A); 2020–21: (B); 2021–22: (C)].

2.2 Crop husbandry practices and treatment details

The experiment consists of a total of six treatments with four replications, and details are presented in Table 1. The experiment was set up in randomized block design, and size of every experimental plot was 8 m × 5.5 m. Pearl millet hybrid “MP 7288” was sown under flat beds with 45 cm (row) × 10 cm (plant) spacing in the first fortnight of July ever year. Similarly, chickpea cv. “IPC 11-112” was sown every year in the 3rd week of October in 30 cm × 10 cm spacing. Seed rate of pearl millet and chickpea was 3 and 75 kg ha⁻¹, respectively. After harvesting of pearl millet, plots were plowed, harrowed, and planked before sowing of chickpea. The recommended fertilizer dose of pear millet (N: P₂O₅: K₂O: 60:40:40 in kg ha⁻¹) and chickpea was (N: P₂O₅: K₂O: 20:60:40 in kg ha⁻¹) followed every year (in T₂). In both the crops based on respective treatment, the calculated dose of P (except T₁) and K was applied as basal, while in chickpea 100% of recommended dose of nitrogen (RDN) was applied as a starter dose. In case of pearl millet, the entire RDN was divided in two where 50% of RDN was applied as basal and rest amount was applied 30 days after sowing. Supplementation of N, P, and K in the crops was done through urea (N: 46%), DAP (18% N and 46% P₂O₅), and muriate of potash (MOP: 63% K₂O). In the respective IPsM plots, well-decomposed FYM (N: P: K: 0.55:0.3:0.55) (in T₃ at 5 tons ha⁻¹), PM (N: P: K: 2: 1.8:2.6) (in T₄ at 1 tons ha⁻¹), and CR (N: P: K: 0.50:0.25:1.2) (in T₅ and T₆) were applied 15 days prior to sowing of kharif crop (pearl millet) and mixed thoroughly. Wheat residue was collected from an ongoing experiment and applied based on 50% (3 t ha⁻¹) of the stover yield in T₅ and T₆ same as other organic manures in pearl millet. Before sowing, chickpea seeds were treated with Rhizobium leguminosarum (20 g Kg⁻¹ of seed) and a subsection of chickpea and pearl millet seeds were treated with PSB (Bacillus polymyxa sp.) (for T₆) with same dose such as Rhizobium sp. Two manual weeding in both the crops were done 30 days and 60 days after sowing. No plant protection measures were taken in any crop, and both the crops were irrigated as per recommended package practices following check basin method.

Table 1

Table 1. Treatment details followed in pearl millet–chickpea cropping system.

2.3 Plant and soil sampling

In both the crops, three plants were sampled from two rows in every plots at full vegetative stage just before flowering for the estimation of growth attributes. Plot-wise harvesting of the pearl millet was done when the leaves became yellow and grains became hard. Manually, the cobs were separated from the stalk using a sickle, and yield was recorded on plot basis (tons ha⁻¹) after it attains physiological maturity (<14% moisture content). Chickpea was harvested when leaves started falling, stem became completely brown, and pods produce rattling sound. Similar to pearl millet, plot-wise harvesting was followed and before threshing harvested plants were sundried to achieve 10% moisture content. Chickpea equivalent pearl millet yield was calculated based on procedure by Nath et al. (2023), and minimum support price of the pearl millet and chickpea was obtained from Government of India (GOI, 2025). Plant samples of both the crops (grain and stover) from the respective plots were collected, cleaned, oven-dried (65°C), grinded, and packed in paper bags for determination of nutrient (N, P, and K) concentration.

Post-harvest soil samples from the individual plots (total 18 plots) were collected following standard soil sampling procedure for the analysis of inorganic P (Pi) fractions and microbial parameters. After collecting soil samples, any visible dirt or foreign material was removed. Then, the samples were air-dried, grounded, passed through 1 mm sieve, and packed in clean poly packets. The soil samples were divided into two halves as one section was kept in ambient condition for estimation of different Pi-fractions, while the rest portion was kept at refrigerator (4°C) for determining microbial parameters.

2.4 Estimation of growth attributes, nutrient utilization index, and P-use efficiency

Total along with Chlorophyll A, B, nitrate reductase (NR), and relative leaf water content (RLWC) was recorded in the peak vegetative stage in both the crops in every year. For chlorophyll A and B, 100 mg fresh leaf samples were collected and extracted using dimethyl sulfoxide (DMSO). The leaf samples were incubated in an oven for 2.30 h at 50°C, and the optical density (OD) of the supernatant was measured at 645 and 663 nm (Hiscox and Israelstam, 1979). The final calculation was done based on formula given by Arnon (1949) and expressed as mg per gram of fresh leaf. The formula for calculating chlorophyll A (Formula 1), chlorophyll B (Formula 2), and total content (Formula 3) was given underneath. For NR, 100 mg fresh plant samples were incubated with 3 ml of each phosphate buffer, potassium nitrate, and propanol at 30°C for 60 min. After incubation, 1 ml of each aliquot, sulphanilamide, and 0.025% N-(1-naphthyl)-ethylenediamine dihydrochloride (NEDD) and final OD was measured at 540 nm. The amount of NR can be calculated by multiplying OD with 406.8 and expressed in nano-mole ${\text{NO}}_2^{-}$ g⁻¹ of fresh weight h⁻¹ (Cazetta and Villela, 2004).

$\begin{array}{l}\text{Chlorophyll A }=(12.21\text{ O}{\text{D}}_{663}-2.81\text{ O}{\text{D}}_{645})\\ \times \text{ V}/\text{W }\times 1,000& (1)\end{array}$

$\begin{array}{l}\text{Chlorophyll B }=20.13\text{ O}{\text{D}}_{645}-5.03\text{ O}{\text{D}}_{663}\\ \times \text{ V}/\text{W }\times 1,000& (2)\end{array}$

$\begin{array}{l}\text{Total chlorophyll }=20.2\text{ O}{\text{D}}_{645}+8.02\text{ O}{\text{D}}_{663}\\ \times \text{ V}/\text{W }\times 1,000& (3)\end{array}$

V = Volume of extract; W = weight of sample

RLWC was calculated based on difference between fresh weight (W₁), turgid weight (W₂), and dry weight (W₃) (Formula 4) (Weatherley and Slatyer, 1957).

$\begin{array}{ll}\text{RLWC }(\text{\%})=({\text{W}}_1-{\text{W}}_3/{\text{W}}_2-{\text{W}}_3)\times 100& (4)\end{array}$

Total N, P, and K were analyzed in the plant samples (grain and straw) by micro-Kjeldahl, vanado-molybdic yellow color method, and flame photometer, respectively (Jackson, 1973). Nutrient uptake in the grain and straw was calculated by multiplying the content of individual nutrient (%) with respective yield (Singh et al., 2018). Nutrient utilization in both the crops has been expressed by nutrient harvest index (NHI) (Formula 5), physiological P-efficiency (PE_P) (Formula 6), and internal P-utilization efficiency (IUE_P) (Formula 7) (Singh et al., 2018). Agronomic P use efficiency (AgP_e) and agro-physiological P use efficiency (AgPP_e) have been calculated as per Formulas 8 and 9, respectively (Babu et al., 2013).

$\begin{array}{l}\text{NHI}(\text{\%})=\text{ Uptake in grain }(\text{kg h}{\text{a}}^{-1})/\\ \text{ Total uptake }(\text{kgh}{\text{a}}^{-1})\times 100& (5)\end{array}$

$\begin{array}{ll}\text{P}{\text{E}}_{\text{P}}(\text{kg k}{\text{g}}^{-1})=\text{ Total dry matter}/\text{Total P}-\text{uptake}& (6)\end{array}$

$\begin{array}{ll}\text{IU}{\text{E}}_{\text{P}}(\text{kg k}{\text{g}}^{-1})=\text{ Grain yield}/\text{Total P}-\text{uptake}& (7)\end{array}$

$\begin{array}{l}{\text{AgP}}_{\text{e}}({\text{kg kg}}^{-1})=(\text{Grain yield in respective treatment }-\\ \text{ Grain Yield in control plots})/\text{Units of}\\ \text{ P}-\text{applied in the respective treatment}& (8)\end{array}$

$\begin{array}{l}{\text{AgPP}}_{\text{e}}({\text{kg kg}}^{-1})=(\text{Grain yield in respective treatment }-\\ \text{ Grain Yield in control plots})/\\ (\text{Total uptake in respective treatment }-\\ \text{ Total uptake in control plots})& (9)\end{array}$

2.5 Estimation of soil inorganic phosphorus fractions and microbial parameters

The original Pi-fractionation scheme was adapted from Kuo (1996) and further modified to include di and octa-Ca bound P-fractions (Smillie and Syers, 1972). In this scheme, total seven fractions can be extracted. These are 1. soluble-P (Sol-P), 2. di-calcium P (Ca₂-P), 3. octa-calcium P (Ca₈-P), 4. aluminum bound P (Al-P), 5. iron bound P (Fe-P), 6. occluded-P (Occl-P), and 7. deca-calcium P (Ca₁₀-P). In a 50 ml centrifuge tube, 0.5 g soil sample was taken and pre-caution has been taken to avoid soil loss in every step. Irrespective of fraction, in every step, 25 ml extracting agent was added. Fraction-1 (sol-P) and Fraction-2 (Ca₂-P) were extracted using 1M ammonium chloride (NH₄Cl) and 0.25 M sodium bicarbonate (NaHCO₃) (pH 7.5), respectively. However, the respective shaking time for sol-P and Ca₂-P was 30 min and 60 min. Fraction-3 (Ca₈-P) also known as sparingly soluble P was extracted with ammonium acetate (C₂H₇NO₂) (shaking time: 60 min and pH 4.2) for 1 h, and further soil samples were washed with 95% methanol (25 ml) for 15 min. Although the fourth and fifth fraction (Al-P and Fe-P) are considered non-available but in extremely depleted conditions plant can use them. Ammonium fluoride (NH₄F-0.5M) (shaking time: 60 min and pH: 8.2) and 0.1 M sodium hydroxide (0.1 M NaOH) (shaking time: 17 h) were taken for extracting Al-P and Fe-P, respectively. Occluded-P (Fraction-6) was basically trapped inside soil constituents or bound on the outer surface of Al hydroxides. Most common method for extracting Occ-P is CDB (sodium citrate [Na₃C₆H₅O₇.2H₂O] + sodium dithionate [Na₂S₂O₄ + NaHCO₃]) method. The last fraction (Ca₁₀-P) which resembles similar chemical structure with as hydroxyl apatite [Ca₁₀(PO₄)₆.(OH)₂] was extracted with 0.25 M H₂SO₄ (shaking time: 60 min). After decanting the extracting agent, soil samples from fraction 4 to 7 were washed with 25 ml saturated sodium chloride solution and pooled. The P-concentration was measured by the blue color method (Murphy and Riley, 1962).

Chloroform fumigation followed by extraction using 0.5 M potassium sulfate (K₂SO₄) was followed for determination of soil microbial biomass C (SMBC) (Jenkinson and Powlson, 1976). Standard protocol by Eivazi and Tabatabai (1977) has been followed for quantifying alkaline phosphatase using p-nitrophenyl phosphate as a substrate. Klein et al. (1971) method was followed for the estimation of dehydrogenase activity in the samples using 2,3,5-tri-phenyl tetrazolium chloride (TTC) as a substrate.

2.6 Statistical analysis

Experimental datasets were subjected to Duncan's multiple range test (DMRT) (significance level: p ≤ 0.05) to test the significant difference between the treatments using SPSS (version: 20) software (Gomez and Gomez, 1984). Pearson's correlation coefficient (r) was carried out using Microsoft Excel^TM 2010 with the Data Analysis Tool pack.

3 Results

3.1 Impact of IPsM on crop productivity and growth attributes

Irrespective of years, the pearl millet productivity was recorded significantly higher in plots under 100% recommended dose of P (P_100%). In all the three 3 years (from 2019 to 2022), the productivity of pearl millet was >10% in P_100% over P _control, whereas integrated plots were all statistically at par specifically in the third year of experimentation. In case of chickpea, the results were more variable, and in general, the performance of P_60%+CR+B was considerably better over others irrespective of years. In 2021–22, the productivity of chickpea was statistically at par in P_60%+CR+B with P_100%, and yield gain was ~10% in P_60%+CR+B over P-devoid plots (P_control) (Table 2). The significant difference in stover yield between the P-management practices was only recorded in the first year (2019–20) under pearl millet with highest recorded stover yield in P_60%+CR (7.01 t ha⁻¹). In case of chickpea, stover yield increased over the year's and varies between 2.59 and 2.89 t ha⁻¹ in the final year (2021–22). Highest stover yield in chickpea was recorded in P_60%+CR+B in first (2.53 t ha⁻¹) and third year (2.89 t ha⁻¹), while plots under P_60%+PM have registered maximum stover yield in 2020–21 (2.76 t ha⁻¹) (Table 2). In terms of chickpea equivalent yield of pearl millet (CEY), there was no surprising variation in the first year (2019–20), but in second (2020–21) and third year (2021–22), maximum value was recorded in P_60%+CR+B (3.32 t ha⁻¹) and P_100% (3.90 t ha⁻¹), respectively The trend of CEY in 2021–22 was as follows: P_100% > P_60%+CR+B > P_60%+FYM > P_60%+CR= P_60%+PM> P_Control (p < 0.05) (Table 2). Nitrate reductase (NR) content varies from 25.07 to 64.58 nM NO₂ gFW⁻¹h⁻¹ in pearl millet and 53.42 to 72.29 nM NO₂ gFW⁻¹h⁻¹ in chickpea, and in both the crop, crops under P_60%+FYM recorded significantly higher NR over others. There was no significant variation of chlorophyll A content in pearl millet, but highest chlorophyll B (0.69 mg g⁻¹ leaf) and total chlorophyll (3.35 mg g⁻¹ leaf) content was found in P_60%+PM and P_60%+FYM, respectively. In chickpea, highest total chlorophyll was found in P_60%+CR (2.98 mg g⁻¹ leaf), although it was statistically with par with rest of treatment except P_Control. Values of RLWC vary from 66.27 to 80.36% in pearl millet and 61.92 to 71.23% in chickpea (Table 3).

Table 2

Table 2. Grain yield of pearl millet, chickpea, and chickpea equivalent yield of pearl millet under phosphorus management practices.

Table 3

Table 3. Growth attributing properties of pear millet and chickpea as influenced by integrated phosphorus management (IPsM) practices (pooled data of three 3 years).

3.2 Impact of IPsM on nutrient concentration, uptake, nutrient harvest index, and P-use efficiency

Pooled values of grain N-concentration vary between 1.56–1.78% and 2.05–2.17% in pearl millet and chickpea, respectively. There was no significant difference in stover N-concentration in any crop. In pearl millet, grain P content was 9% and 17% higher in P_60%+CR+B (0.33%) as compared to P_100% and P_Control, respectively. Irrespective of year, grain P and stover P content ranged from 0.316% to 0.379% and 0.157% to 0.193% in chickpea, respectively. Grain-K in pearl millet and stover-K in chickpea was highest in P_60% + CR (0.651%) and P_60% + PM (1.72%), respectively (Figure 2). Over the years, the uptake of N, P, and K increased in both the crops. Highest N-uptake in pearl millet was recorded in P_100% in all the three 3 years (69.98 and 74.92 kg ha⁻¹ in 2020–21 and 2021–22, respectively), but there was no statistical difference in stover N-uptake in any year. Nitrogen harvest index (NHI) did not differ markedly over the years, and plots under 100% RDP were statistically at par with P_60%+CR+B in every year (p < 0.05) in pearl millet (Table 4). N-uptake in chickpea grain and stover varies from 27.17 to 45.83 kg ha⁻¹ and 6.48 to 12.79 kg ha⁻¹ over the years, but NHI became non-significant irrespective of year (p < 0.05) (Table 4). In all the years, maximum P-uptake was recorded in P_60%+CR+B with 4–8% elevation over conventional practice (P_100%) in pearl millet. In chickpea, P-uptake varies from 4.21 to 8.25 kg ha⁻¹ and plots under P_60%+PM recorded 4% and 25% higher grain P-uptake over P_100% and P_Control, respectively. Phosphorus harvest index (PHI) did not differ between the treatments irrespective of year except in 2019–20 under pear millet where PHI increased significantly in P_60%+CR+B (51.17%) over P_60%+FYM (47.26%) and P_100% (48.25%) (p < 0.05) (Table 5). Similar to NHI, potassium harvest index (KHI) did not differ significantly between the treatments, while K-uptake in grain varies from 17.94 to 21.22 kg ha⁻¹ and 20.99 to 25.16 kg ha⁻¹ in 2019–20 and 2020–21, respectively. Grain K-uptake in chickpea was recorded highest in P_60%+CR+B in 2019–20 (18.99 kg ha⁻¹) and 2020–21 (20.55 kg ha⁻¹) but not in 2021–22 (P_100% with 28.15 kg ha⁻¹) (Table 6). Irrespective of year and crop, highest physiological P-use efficiency (PE_P) was found in plots without P (P_control) (Table 7). As compared to P_100% and P_60%+CR+B, respective increment in PEp values under control was 13–16% and 16–19% in pearl millet and chickpea, respectively. Internal P-utilization efficiency (IUE_P) was also following similar pattern like PEp (Table 7). Maximum noted agronomic P-use efficiency (AgPe) was 24.37 kg kg⁻¹ in 2020–21 under P_60%+CR+B which was +39% over P_100%, but in the next year both became statistically at par in pearl millet (Table 7). In chickpea, impact of organic amendments on AgPe was more prominent and it was surged by 16–70% in P_60%+CR+B over P_100% within the period of study (2019–22) (Table 7). Agro-physiological P-use efficiency (AgPPe) was highest under conventional practice (P_100%) in each year, and over the years (2019 to 2022), it has increased by 18.6% in pearl millet. In case of chickpea, AgPPe varies from 66.38 to 98.83 kg kg⁻¹, 62.54 to 100.34 kg kg⁻¹, and 57.56 to 96.68 kg kg⁻¹ in 2019–20, 2020–21, and 2021–22, respectively (Table 7).

Figure 2

Figure 2. Nutrient concentration in grain and stover in pearl millet (A) and chickpea (B) (pooled data of three 3 years) under integrated nutrient management practices. ^#Values followed by different upper case letters (a–c) are significantly different between treatments at p ≤ 0.05.

Table 4

Table 4. Nitrogen (N) uptake (kg ha⁻¹) and N-harvest index (NHI) (%) of pearl millet and chickpea under integrated phosphorus management practices.

Table 5

Table 5. Phosphorus (P) uptake (kg ha⁻¹) and P-harvest index (PHI) (%) of pearl millet and chickpea under integrated phosphorus management practices.

Table 6

Table 6. Potassium (K) uptake (kg ha⁻¹) and K-harvest index (KHI) (%) of pearl millet and chickpea under phosphorus management practices.

Table 7

Table 7. Physiological P-efficiency (PE_P) (kg kg⁻¹) and internal P-utilization efficiency (IUE_P) (kg kg⁻¹), agronomic P-use efficiency, and agro-physiological P-use efficiency of pearl millet and chickpea under phosphorus management practices.

3.3 Impact of IPsM on Inorganic P (Pi) fractions and microbial parameters

Labile P pools consisting of soluble-P and Ca₂-P were recorded highest in P_60%+CR (13.13 ppm) and P_60%+PM (13 ppm), respectively, in pearl millet. Substantial impact of integrated dose with P_60%+PM can be seen in labile P pools as sol-P (38%) and Ca₂-P (47%) increased significantly as compared to 100% RDP. Influence of IPsM was not really marked on non-labile P fractions such as Ca₈-P and occluded-P (Occ-P). Application of CR+ PSB with 60% RDP led to highest Fe-P (15.75 ppm) and Al-P (26.22 ppm) over control in pearl millet. A significant surge can be apprehended in P_60%+CR+B over P_100% by 12% for Al-P and 32% for Fe-P, respectively. The most stable Pi-fraction, i.e., deca-calcium P (Ca₁₀-P), is as follows: P_Control> P_100%> P_60%+CR= P_60%+PM> P_60%+FYM > P_60%+CR+B (Table 8). Microbial activity had a significant boost in integrated P-managed plots which can be visible from the experimental findings in pearl millet. The maximum activity of soil microbial biomass carbon (SMBC) and dehydrogenase (DHA) could be recorded in P_60%+CR+B with 15% and 28% surge over P_100%. Alkaline phosphatase is a key enzyme which solubilise non-labile P decreased by 31% and 43% in P_100% and P_Control, respectively, over P_60%+CR+B under pearl millet (Figure 3A).

Table 8

Table 8. Dynamics of soil P-fraction (in ppm) in pearl millet and chickpea under phosphorus management practices in 0–15 cm.

Figure 3

Figure 3. Dynamics of microbial parameters in pearl millet (A) and chickpea (B) under integrated phosphorus management system. SMBC, soil microbial biomass carbon; DHA, dehydrogenase; Alk-P, alkaline phosphatase. ^#Values followed by different upper case letters (a–e) are significantly different between treatments at p ≤ 0.05.

There was no significant variation among the treatments in soluble P content. The range of Ca₂-P varied from 17.95 ppm (P_60%+CR) to 33.83 ppm (P_60%+PM) in chickpea. In addition, irrespective of integrated management strategies, all treatments except P_Control became non-significant with respect to Ca₈-P content (p < 0.05). A slight variation can be observed as Al-P content was maximum in P_100% by 27% over P_60%+CR (16.44 ppm), but a complete opposite pattern can be found in Fe-P where both the P_60%+PM (18.25 ppm) and P_60%+CR (17.6 ppm) were statistically at par and Fe-P was recorded 24 and 27% higher over P_100% in chickpea. Occluded-P content ranged from 15.50 to 23.94 ppm, and plots under PM, CR, and CR + PSB were statistically at par. Similar to pearl millet, control plots (P_Control) had the highest Ca₁₀-P and amount decreased in the integrated P-managed plots in chickpea (Table 8). Plots under P_60%+PM quantified highest SMBC (180.35 μg g⁻¹ of soil) but at par with P_60%+FYM and significantly higher over P_100% (+26%) and P_Control (+55%) in chickpea (p < 0.05). Both the enzymes viz. DHA and alkaline phosphatase were highest in P_60%+CR+B but at par with P_60%+CR. As compared to conventional practices (P_100%), the surge in DHA and alkaline phosphatase activity in P_60%+CR+B was 16 and 27%, respectively, under chickpea (Figure 3B).

3.4 Correlation of grain yield with Pi fractions

In pearl millet, there was no significant relationship between grain yield and inorganic (Pi) fractions but in chickpea grain yield was negatively correlated with Ca₈-P (−0.899 at p < 0.05) and Ca₁₀-P (−0.827 at p < 0.05) (Tables 9, 10). In pearl millet, soluble P was strongly interrelated with Ca₂-P (0.864 at p < 0.05) and Ca₈-P (0.953 at p < 0.01) and negatively with Ca₁₀-P (−0.904 at p < 0.05) (Table 9). The negative correlation between soluble P and Occluded-P (−0.919 at p < 0.01) and Ca₁₀-P (−0.852 at p < 0.05) could be visible in chickpea (Table 10).

Table 9

Table 9. Correlation analysis of grain yield of pearl millet with soil inorganic phosphorus (Pi)-fractions under integrated phosphorus management system.

Table 10

Table 10. Correlation analysis of grain yield of chickpea with soil inorganic phosphorus (Pi)-fractions under integrated phosphorus management system.

4 Discussion

4.1 Impact of IPsM on growth attributes, nutrient concentration, and yield

The positive sides of IPsM can be reflected in different growth attributes such as pigment (chlorophyll A, B, and total) level and NR activity in both the crops. Applications of organic amendments such as FYM, PM, and CR had positively modified the physio-chemical parameters in soil and improved the availability of nutrients resulting better plant growth similar to conventional practices (Thumar et al., 2016). Synchronized nutrient availability in the integrated plots promoted higher cellular activity such as cell division and expansion ensuing better plant growth (Hashim et al., 2015). Nitrate reductase (NR) is a crucial enzyme for BNF particularly in the peak vegetative stage of legumes (chickpea) and the activity reduces with time (Banerjee et al., 2024). Higher NR activity in the integrated plots was due to balanced supply of N and molybdenum (Mo) from the organic sources fostering physiological activities and production of amino compounds with efficient N-assimilation (Márquez-Quiroz et al., 2014). As noted in result, the impact of IPsM on chlorophyll content (A, B, and total) was really apparent, and previous study by Ansari and Mahmood (2017) also cited similar findings in pigeonpea. Apart from major nutrients, especially steady K availability under IPsM upscaled photosynthetic activity, root growth and stomatal regulation resulting in higher chlorophyll content over sole chemically fertilized plots (Dodd, 2003). Favorable soil microenvironment with pronounced microbial activity, water availability, and continuous access of essential nutrients uplifted the growth attributes in both the crops under integrated plots over control or conventional practices (Varatharajan et al., 2022). Although the impact of IPsM on RLWC was not significant in chickpea but, in pearl millet application of organic amendments improves the water holding capacity of the soil ensuring optimum water availability as opposed to control plots (Saha and Ghosh, 2013). In addition, under integrated plots, availability of P along with better soil physical health accentuates root growth leading to greater water availability from the subsurface depths in pearl millet (Kumar et al., 2006). In pearl millet, discernible result regarding N content under grain and stover was missing; however, a slight edge in grain N-content can be detected in 100% RDP as deciphered in earlier studies by Hassan et al. (2018) and Sheoran et al. (2024). Combining application of synthetic fertilizers (DAP and MOP) along with organic amendments not only saves fertilizers from leaching and fixation but also maintains an equilibrium in the soil solution which can be reflected in higher grain P (in chickpea) and stover K (in pearl millet) (Murphy, 2015). In addition, formation of proliferated dense roots, better soil health, and physiological activity in plants under IPsM enhanced the nutrient uptake (Dhaliwal et al., 2023). In case of chickpea, previous results from Dewangan et al. (2017) and Dotaniya et al. (2022) logged beneficial impact of integrated P-management on nutrient concentration in above ground plant parts. Both grain and stover yield has been recorded maximum in conventional practice (100% RDP) as pearl millet is an input dependent fertilizer responsive crop (Sher et al., 2023). Slower nutrient release from the organic amendments along with sub-optimal P-dose under IPsM plots might have hampered pearl millet growth in the early stage which could be reflected in productivity (Rani et al., 2022). However, the yield benefits of IPsM could be apparent under P_60% + CR + PSB in chickpea as stated by Tanwar et al. (2010) in Rajasthan and Thakur et al. (2023) in Madhya Pradesh, India. Multiple advantages of crop residue on soil chemical properties (high CEC, optimum pH, essential nutrients), physical properties (high water holding capacity, low bulk density), and biological properties benefited overall crop performance as presented in the experimental findings (Jat et al., 2018). Development of new tissue, positive sides on morphological and physiological traits, and better crop health led to higher chickpea productivity in integrated plots over control or farmers practices (Thakur et al., 2023). In addition, the positive impact on grain yield particularly in chickpea has also been justified by higher P concentration and leaf chlorophyll content under IPsM (Li et al., 2019; Paramesh et al., 2020).

4.2 Impact of IPsM on nutrient utilization, uptake, and P-use efficiency

As presented in the experimental datasets, IPsM had non-significant impact on NHI as mentioned in previous research studies by Varatharajan et al. (2019) in pigeonpea and Gupta et al. (2020) in wheat. Higher N and P uptake in grain as opposed to total uptake caused non-significant change in NHI which could be further explained by law of diminishing return (Gupta et al., 2020). Fulfillment of nutrient demand without manure addition in both the crops might have caused higher PE_P in plots with no-P, as opposed to P-added plots (Kumar et al., 2017). Earlier study in pigeonpea and sunflower by Babu et al. (2013) and wheat by Randhawa et al. (2021) matches with present finding as increasing nutrient dose had inversely proportional relation with PE_P. Similar to PE_P, the results suggest decreasing IUE_P with increasing P-dose was due to trivial impact on crop biomass even on change in P-uptake leading to P-build up in tissue (Venkatesh et al., 2019). Moreover, higher PE_P in control plots against P-fertilized plots also indicates inherent ability of crops to utilize P-present in above ground parts more economically under P-deficient conditions (Venkatesh et al., 2019). As discussed in the earlier section, concentration of different nutrients in grain and stover has been tuned up positively under integrated plots which were reflected in uptake also. However, in pearl millet, the striking difference between IPsM plots (T₃-T₆) and conventional practice (T₂) on nutrient uptake was missing due to significant jump in productivity in the former plots than the later. The influence of organic amendments PM, FYM, or CR was more apparent in post-rainy season crop (chickpea). Irrespective of crop, higher nutrient uptake were due to: (i). supply of micronutrients from decomposing organic amendments (ii). organic acid mediated solubilisation of native/locked nutrients (iii). averting nutrient loss by chelation (iv). altered root CEC and rhizospheric modifications (Jakhar et al., 2018; Kumar et al., 2021). Agro-physiological P-use efficiency (AgPP_e) decreased with increasing synthetic fertilizer supplementation, but agronomic P-use efficiency (AgP_e) followed completely opposite trend. Similar to PE_p, integrated P-application was able to meet the crop demand with lower AgPP_e over 100% RDP (Kumar et al., 2017). Interestingly, application of crop residue (P_60%+CR) alone immobilizes bio-available P for the crops resulting significantly lower AgPP_e, but the negative impact gets canceled with co-application with PSB, i.e., T₆ (60% RDP+CR+PSB). Continuous P supply in the integrated plots by synthetic fertilizers in the early stage and later on by the decomposing crop residue improved growth, yield attributes, and productivity leading to higher AgPe as compared to fully fertilized plots as noted in other crops such as wheat (Randhawa et al., 2021), rice (Kaur et al., 2023), and lentil (Kumar et al., 2022).

4.3 Impact of IPsM on soil inorganic P (Pi) fractions, microbial activity, and correlation of Pi-fractions with grain yield

Application of organic amendments has consequential impact on labile P-pools (sol-P and Ca₂-P). Crop residues upon decomposition produce different organic acids (humic acid and fulvic acid) which compete for the same sorption site such as P, making it available for the crops (Mitran et al., 2016). Furthermore, the decomposition and solubilisation of P enhanced significantly upon PSB application. Literature did highlight the direct and indirect impact of organic manures and compost on transforming non-labile Pi into labile Pi. These present experimental records were in line with meta-analysis study by Wei et al. (2022) which showed performance of poultry manure was highly efficient in promoting Pi-fractions among others. Blocking the adsorption sites, acid dissolution of complex non-labile fraction, promoting microbial activity, organic C mediated organic P (Po) transformation, and rhizospheric P-transformation are some of the important mechanism behind organic amendment mediated Pi-transformation (Qin et al., 2020). As pearl millet is an input-intensive crop, therefore, continuous cropping lead to depletion of Ca₈-P in the control plots which could be evident from the experimental findings, while recorded spike in Ca₈-P content in the control plot under chickpea was due to low enzymatic activity under the same which was evident in this experimental result too. Apart from organic acid-mediated P-transformation, productions of carbon-di-oxide (CO₂) during decomposition of residue or manures augment the levels of Fe-P and Al-P in soil facilitating higher P-availability to the standing crop (Bhattacharyya et al., 2005). Similarly, decomposed products of manures such as organic acids prevent re-precipitation of soluble P fractions onto amorphous sesquioxides contributing higher plant available P (Ghosh et al., 2021). Similar to earlier study by Bhattacharyya et al. (2015) and Dutta et al. (2024), the improvement in occluded-P in the integrated plots (P_60%+CR: pearl millet and in P_60%+FYM: chickpea) was resultant of dissolution of trapped P via acidifying agents or protecting solubilised from further entrapment. Low biomass development in the plants under control plots leads to low P-uptake causing build-up of Ca₁₀-P was recorded in control plots under both the crops.

Affirmative impact of organic amendments on microbial parameters (SMBC, DHA, and alkaline phosphatase) was quite evident in this study peculiarly in IPsM plots. SMBC is considered to be an active pool of SOC largely affected by the management-induced changes. Addition of manures (PM) and crop residue increased labile C and nutrient level in the soil resulting exponential increase in SMBC (Rajput et al., 2019; Padbhushan et al., 2021). In addition, application of manures in company with synthetics improves the overall soil quality revamping overall microbial growth and biomass (Dutta et al., 2024). In line with SMBC, rapid availability of mineralisable materials from the decaying residues, intra- and extracellular enzyme content, and metabolic growth could have resulted in remarkable surge in DHA content over conventional plots in both the crops (Nath et al., 2015; Patra et al., 2020). The significant jump in alkaline phosphatase activity in the under integrated plots (T₅ and T₆ majorly) was caused due to the following reasons: 1. adequate availability of food (labile C) from the decaying residues promoted hydrolysis of organic P moieties (esters of phosphoric acid) leads to higher phosphatase activity and 2. continuous availability of P from the amendments fuel up microbial activity conjointly higher phosphatase activity in soil (Kharche et al., 2013; Li et al., 2021; Kumari et al., 2024).

Strong interlinkage among sol-P, Ca₂-P, and Ca₈-P indicates dynamic inter-conversion between the fractions particularly under cereal–legume system (Shen et al., 2004). Ghosh et al. (2021) through long-term study showed strong correlation between soil Pi fractions (saloid bound P, Al-P, occ-P) with maize grain yield but absent in this short time scale of experiment. The results showed significant negative interaction with grain yield with Ca₁₀-P which was quite obvious as the former constitute the most stable and unavailable form of inorganic P.

5 Conclusion

Inclusion of organic amendments such as PM, FYM, and CR along with sub-optimal synthetic fertilizer (DAP) has influential impact on growth attributes, nutrient utilization, P-use efficiency, Pi-fractions, and lastly on yield under pearl millet–chickpea system. Round the season nutrient availability, positive regulation in soil health under integrated condition with boost in microbial activity improved NR, chlorophyll content, and eventually nutrient uptake in both crops. Chickpea equivalent yield of pearl millet was highest in 100% RDP (3.90 t ha⁻¹) which was almost at par with P_60%+CR+B (3.73 t ha⁻¹). Similarly, P_60%+CR+B resulted ~50% higher agronomic P-use efficiency over conventional practices (100% RDP), but the results were less evident in input-intensive pearl millet. Higher values of NHI, PE_p, and IUE_p in control plot suggest invariable nutrient uptake with biomass gain in both the crops. In addition, the presence of more soluble-P and Ca₂-P in the integrated plots ensures higher bio-available P than conventional practices with more efficacious use of sesquioxides bound P fractions. However, the strong inter-linkage between grain yields with P-fractions was missing in both crops which further indicate the need of long run studies. Finally, progressive shift in grain yield especially in chickpea confirmed the 60% recommended P-dose + CR (50%) + PSB was better over conventional practices with higher P-use efficacy and P-availability.

Data availability statement

The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author.

Author contributions

AD: Conceptualization, Data curation, Formal analysis, Investigation, Supervision, Writing – original draft. KKH: Conceptualization, Investigation, Writing – original draft. CN: Conceptualization, Investigation, Supervision, Writing – review & editing. NK: Supervision, Writing – review & editing. RS: Writing – review & editing. CP: Supervision, Writing – review & editing. AP: Formal analysis, Writing – review & editing.

Funding

The author(s) declare that financial support was received for the research and/or publication of this article. As mentioned in the MS, no monetary support has been provided by the institute for funding related to APC. Only funds for conducting research activities have been provided by the concerned institute (ICAR-IIPR, Kanpur). The manuscript was part of three years institute funded project entitled Soil phosphorus dynamics and its release kinetics under pulse based cropping system for sustainable P management in a Fluvisol with project code no. IXX15222.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Generative AI statement

The author(s) declare that no Gen AI was used in the creation of this manuscript.

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References

Ahmed, K., Qadir, G., Nawaz, M. Q., Saqib, A. I., Rizwan, M., Zaka, M. A., et al. (2018). Integrated phosphorus management improves production of rice-wheat cropping-system under salt affected conditions. Int. J. Plant Prod. 12, 25–32. doi: 10.1007/s42106-017-0003-x

Crossref Full Text | Google Scholar

Ansari, R. A., and Mahmood, I. (2017). Optimization of organic and bio-organic fertilizers on soil properties and growth of pigeon pea. Sci. Hortic. 226, 1–9. doi: 10.1016/j.scienta.2017.07.033

Crossref Full Text | Google Scholar

Arnon, D. I. (1949). Copper enzymes in isolated chloroplasts. Polyphenoloxidase in beta vulgaris. Plant Physio. 24:1. doi: 10.1104/pp.24.1.1

PubMed Abstract | Crossref Full Text | Google Scholar

Babu, S., Rana, D. S., Prasad, D., and Pal, S. (2013). Effect of sunflower stover and nutrients management on productivity, nutrient economy and phosphorus use efficiencies of pigeonpea (Cajanus cajan)-sunflower (Helianthus annuus) cropping system. Ind. J. Agric. Sci. 83, 203–209. doi: 10.59797/ija.v58i1.4164

Crossref Full Text | Google Scholar

Bana, R. S., Faiz, M. A., Sangwan, S., Choudhary, A. K., Bamboriya, S. D., Godara, S., et al. (2023). Triple-zero tillage and system intensification lead to enhanced productivity, micronutrient biofortification and moisture-stress tolerance ability in chickpea in a pearlmillet-chickpea cropping system of semi-arid climate. Sci. Rep. 13:10226. doi: 10.1038/s41598-023-36044-0

PubMed Abstract | Crossref Full Text | Google Scholar

Banerjee, P., Venugopalan, V. K., Nath, R., Gaber, A., and Hossain, A. (2024). Dynamics of growth, physiology, radiation interception, production, and quality of autumn black gram (Vigna mungo (L.) Hepper) as influenced by nutrient scheduling. PLos ONE 19:e0304466. doi: 10.1371/journal.pone.0304466

PubMed Abstract | Crossref Full Text | Google Scholar

Bhattacharyya, P., Chakrabarti, K., Chakraborty, A., and Nayak, D. C. (2005). Effect of municipal solid waste compost on phosphorous content of rice straw and grain under submerged condition. Arch. Agron. Soil Sci. 51, 363–370. doi: 10.1080/03650340500201634

Crossref Full Text | Google Scholar

Bhattacharyya, P., Nayak, A. K., Shahid, M., Tripathi, R., Mohanty, S., Kumar, A., et al. (2015). Effects of 42-year long-term fertilizer management on soil phosphorus availability, fractionation, adsorption-desorption isotherm and plant uptake in flooded tropical rice. Crop J. 3, 387–395. doi: 10.1016/j.cj.2015.03.009

Crossref Full Text | Google Scholar

Cazetta, J. O., and Villela, L. C. V. (2004). Nitrate reductase activity in leaves and stems of tanner grass (Brachiaria radicans Napper). Sci. Agric. 61, 640–648. doi: 10.1590/S0103-90162004000600012

Crossref Full Text | Google Scholar

Dewangan, S., Singh, R. P., Singh, M. K., and Singh, S. (2017). Effect of integrated nutrient management and drought mitigating practices on performance of rainfed chickpea (Cicer arietinum). Ind. J. Agric. Sci. 87, 301–305. doi: 10.56093/ijas.v87i3.68596

Crossref Full Text | Google Scholar

Dey, P., Santhi, R., Maragatham, S., and Sellamuthu, K. M. (2017). Status of phosphorus and potassium in the Indian soils vis-à-vis world soils. Ind. J. Fertil. 13, 44–59.

Google Scholar

Dhaliwal, S. S., Sharma, V., Shukla, A. K., Verma, V., Kaur, M., Singh, P., et al. (2023). Effect of addition of organic manures on basmati yield, nutrient content and soil fertility status in north-western India. Heliyon 9:e14514. doi: 10.1016/j.heliyon.2023.e14514

PubMed Abstract | Crossref Full Text | Google Scholar

Ding, Z., Kheir, A. M., Ali, M. G., Ali, O. A., Abdelaal, A. I., Lin, X. E., et al. (2020). The integrated effect of salinity, organic amendments, phosphorus fertilizers, and deficit irrigation on soil properties, phosphorus fractionation and wheat productivity. Sci. Rep. 10:2736. doi: 10.1038/s41598-020-59650-8

PubMed Abstract | Crossref Full Text | Google Scholar

Dodd, I. C. (2003). Hormonal interactions and stomatal responses. J. Plant Growth Regul. 22, 32–46. doi: 10.1007/s00344-003-0023-x

Crossref Full Text | Google Scholar

Dotaniya, C. K., Lakaria, B. L., Sharma, Y., Meena, B. P., Aher, S. B., Shirale, A. O., et al. (2022). Performance of chickpea (Cicer arietinum L.) in maize-chickpea sequence under various integrated nutrient modules in a Vertisol of Central India. PLos ONE 17:e0262652. doi: 10.1371/journal.pone.0262652

PubMed Abstract | Crossref Full Text | Google Scholar

Dutta, A., Hazra, K. K., Nath, C. P., Kumar, N., Singh, S. S., Praharaj, C. S., et al. (2024). Long-term impact of legume-inclusive diversification and nutrient management practices on phosphorus dynamics in alkaline Fluvisol. Sci. Rep. 14:65. doi: 10.1038/s41598-023-49616-x

PubMed Abstract | Crossref Full Text | Google Scholar

Dutta, A., Trivedi, A., Nath, C. P., Gupta, D. S., and Hazra, K. K. (2022). A comprehensive review on grain legumes as climate-smart crops: challenges and prospects. Environ. Chall. 7:100479. doi: 10.1016/j.envc.2022.100479

Crossref Full Text | Google Scholar

Eivazi, F., and Tabatabai, M. A. (1977). Phosphatases in soils. Soil Biol. Biochem. 9, 167–172. doi: 10.1016/0038-0717(77)90070-0

Crossref Full Text | Google Scholar

Ghosh, D., Mandal, M., and Pattanayak, S. K. (2021). Long term effect of integrated nutrient management on dynamics of phosphorous in an acid inceptisols of tropical India. Commu. Soil Sci. Plant Anal. 52, 2289–2303. doi: 10.1080/00103624.2021.1924186

Crossref Full Text | Google Scholar

GOI (2025). Directorate of Economics and Statistics, Department of Agriculture, Cooperation and Farmers Welfare, Ministry of Agriculture and Farmers Welfare, Government of India (GOI). Available online at: https://desagri.gov.in/statistics-type/latest-minimum-support-price-mspstatement/2018-19 (accessed January 20, 2025).

Google Scholar

Gomez, K. A., and Gomez, A. A. (1984). Statistical Procedures for Agricultural Research. New York, NY: John Wiley & sons.

Google Scholar

Gupta, G., Dhar, S., Dass, A., Sharma, V. K., Shukla, L., Singh, R., et al. (2020). Assessment of bio-inoculants-mediated nutrient management in terms of productivity, profitability and nutrient harvest index of pigeon pea-wheat cropping system in India. J. Plant Nutr. 43, 2911–2928. doi: 10.1080/01904167.2020.1806302

Crossref Full Text | Google Scholar

Hashim, M., Dhar, S., Vyas, A. K., Pramesh, V., and Kumar, B. (2015). Integrated nutrient management in maize (Zea mays)-wheat (Triticum aestivum) cropping system. Ind. J. Agron. 60, 352–359. doi: 10.59797/ija.v60i3.4484

Crossref Full Text | Google Scholar

Hassan, A., Malik, A., Ahmad, S., Asif, M., Mir, S. A., Bashir, O., et al. (2018). Yield and Nitrogen content of wheat (Triticum aestivum) as affected by FYM and urea in cold arid region of India. Int. J. Curr. Microbiol. App. Sci. 7, 328–332. doi: 10.20546/ijcmas.2018.702.043

PubMed Abstract | Crossref Full Text | Google Scholar

Hazra, K. K., Swain, D. K., and Singh, S. S. (2021). The potential of crop residue recycling for sustainable phosphorus management in non-flooded rice-lentil system in alkaline soil. Soil Tillage Res. 213:105147. doi: 10.1016/j.still.2021.105147

Crossref Full Text | Google Scholar

Hiscox, J. D., and Israelstam, G. F. (1979). A method for the extraction of chlorophyll from leaf tissue without maceration. Can. J. Bot. 57, 1332–1334. doi: 10.1139/b79-163

Crossref Full Text | Google Scholar

Jackson, M. L. (1973). Soil Chemical Analysis. New Delhi, India: Pentice Hall of India Pvt. Ltd.

Google Scholar

Jakhar, R. R., Shekhawat, P. S., Yadav, R. S., Kumawat, A., and Singh, S. P. (2018). Integrated nutrient management in pearlmillet (Pennisetum glaucum) in north-western Rajasthan. Ind. J. Agron. 63, 192–196. doi: 10.59797/ija.v63i2.5404

Crossref Full Text | Google Scholar

Jat, R. D., Jat, H. S., Nanwal, R. K., Yadav, A. K., Bana, A., Choudhary, K. M., et al. (2018). Conservation agriculture and precision nutrient management practices in maize-wheat system: effects on crop and water productivity and economic profitability. Field Crops Res. 222, 111–120. doi: 10.1016/j.fcr.2018.03.025

Crossref Full Text | Google Scholar

Jenkinson, D. S., and Powlson, D. S. (1976). The effects of biocidal treatments on metabolism in soil-V: a method for measuring soil biomass. Soil Biol. Biochem. 8, 209–213. doi: 10.1016/0038-0717(76)90005-5

Crossref Full Text | Google Scholar

Kaur, P., Saini, K. S., Sharma, S., Kaur, J., Bhatt, R., Alamri, S., et al. (2023). Increasing the efficiency of the rice-wheat cropping system through integrated nutrient management. Sustainability 15:12694. doi: 10.3390/su151712694

Crossref Full Text | Google Scholar

Kharche, V. K., Patil, S. R., Kulkarni, A. A., Patil, V. S., and Katkar, R. N. (2013). Long-term integrated nutrient management for enhancing soil quality and crop productivity under intensive cropping system on vertisols. J. Ind. Soc. Soil Sci. 61, 323–332.

Google Scholar

Klein, D. A., Loh, T. C., and Goulding, R. L. (1971). A rapid procedure to evaluate the dehydrogenase activity of soils low in organic matter. Soil Biol. Biochem. 3, 385–387. doi: 10.1016/0038-0717(71)90049-6

Crossref Full Text | Google Scholar

Koul, B., Sharma, K., Sehgal, V., Yadav, D., Mishra, M., Bharadwaj, C., et al. (2022). Chickpea (Cicer arietinum L.) biology and biotechnology: from domestication to biofortification and biopharming. Plants 11:2926. doi: 10.3390/plants11212926

PubMed Abstract | Crossref Full Text | Google Scholar

Kumar, B., Dhar, S., Paul, S., Paramesh, V., Dass, A., Upadhyay, P. K., et al. (2021). Microbial biomass carbon, activity of soil enzymes, nutrient availability, root growth, and total biomass production in wheat cultivars under variable irrigation and nutrient management. Agronomy 11:669. doi: 10.3390/agronomy11040669

Crossref Full Text | Google Scholar

Kumar, S., Saha, B., Saha, S., Das, A., Poddar, P., Prabhakar, M., et al. (2017). Integrated nutrient management for enhanced yield, nutrients uptake and their use efficiency in rice under intensive rice-wheat cropping system. Int. J. Curr. Microbiol. Appl. Sci. 6, 1958–1972. doi: 10.20546/ijcmas.2017.610.236

PubMed Abstract | Crossref Full Text | Google Scholar

Kumar, S., Sharma, S. K., Thakral, S. K., Bhardwaj, K. K., Jhariya, M. K., Meena, R. S., et al. (2022). Integrated nutrient management improves the productivity and nutrient use efficiency of lens culinaris medik. Sustainability 14:1284. doi: 10.3390/su14031284

PubMed Abstract | Crossref Full Text | Google Scholar

Kumar, S. K., Shivani, S., Mishra, S., and Singh, V. P. (2006). Effect of tillage and irrigation on soil-water-plant relationship and productivity of winter maize (Zea mays) in north Bihar. Ind. J. Agric. Sci. 76, 526–530.

Google Scholar

Kumari, M., Sheoran, S., Prakash, D., Yadav, D. B., Yadav, P. K., Jat, M. K., et al. (2024). Long-term application of organic manures and chemical fertilizers improve the organic carbon and microbiological properties of soil under pearl millet-wheat cropping system in North-Western India. Heliyon 10:e25333. doi: 10.1016/j.heliyon.2024.e25333

PubMed Abstract | Crossref Full Text | Google Scholar

Kumawat, A., Pareek, B. L., Yadav, R. S., and Rathore, P. S. (2014). Effect of integrated nutrient management on growth, yield, quality and nutrient uptake of Indian mustard (Brassica juncea) in arid zone of Rajasthan. Ind. J. Agron. 59, 119–123.

Google Scholar

Kuo, S. (1996). “Phosphorus,” in Methods of Soil Analysis: Chemical Methods Part 3, ed. D. L. Sparks (Madison, WI: SSSA No. 5. ASA-CSSA-SSSA).

Google Scholar

Li, F., Peng, Y., Zhang, D., Yang, G., Fang, K., Wang, G., et al. (2019). Leaf area rather than photosynthetic rate determines the response of ecosystem productivity to experimental warming in an alpine steppe. J. Geophys. Res. Biogeo. 124, 2277–2287. doi: 10.1029/2019JG005193

Crossref Full Text | Google Scholar

Li, J., Xie, T., Zhu, H., Zhou, J., Li, C., Xiong, W., et al. (2021). Alkaline phosphatase activity mediates soil organic phosphorus mineralization in a subalpine forest ecosystem. Geoderma 404:115376. doi: 10.1016/j.geoderma.2021.115376

Crossref Full Text | Google Scholar

Liu, J., Yang, J., Cade-Menun, B. J., Hu, Y., Li, J., Peng, C., et al. (2017). Molecular speciation and transformation of soil legacy phosphorus with and without long-term phosphorus fertilization: insights from bulk and microprobe spectroscopy. Sci. Rep. 7:15354. doi: 10.1038/s41598-017-13498-7

PubMed Abstract | Crossref Full Text | Google Scholar

Mahajan, A., Bhagat, R. M., and Gupta, R. D. (2008). Integrated nutrient management in sustainable rice-wheat cropping system for food security in India. SAARC J. Agric. 6, 29–32.

Google Scholar

Márquez-Quiroz, C., López-Espinosa, S. T., Sánchez-Chávez, E., la García-Bañuelos, M. L., Cruz-Lázaro, D., and Reyes-Carrillo, J. L. (2014). Effect of vermicompost tea on yield and nitrate reductase enzyme activity in saladette tomato. J. Soil Sci Plant Nutri. 14, 223–231. doi: 10.4067/S0718-95162014005000018

PubMed Abstract | Crossref Full Text | Google Scholar

McLaughlin, M. J., McBeath, T. M., Smernik, R., Stacey, S. P., Ajiboye, B., Guppy, C., et al. (2011). The chemical nature of P accumulation in agricultural soils-implications for fertiliser management and design: an Australian perspective. Plant Soil 349, 69–87. doi: 10.1007/s11104-011-0907-7

Crossref Full Text | Google Scholar

Mengel, K., Kirkby, E. A., Kosegarten, H., and Appel, T. (2001). “Phosphorus,” in Principles of Plant Nutrition, eds. K. Mengel, E. A. Kirkby, H. Kosegarten and T. Appel (Dordrecht: Springer). doi: 10.1007/978-94-010-1009-2

Crossref Full Text | Google Scholar

Ministry of Agriculture and Farmers Welfare (MoAFW) (2023). Second advance estimates of production of food grains for 2022–23. Department of Agriculture and Farmers Welfare. Ministry of Agriculture and Farmers Welfare, Govt. of India. Available online at: https://agriwelfare.gov.in/en/Agricultural_Statistics_at_a_Glance (accessed December 30, 2024).

Google Scholar

Mitran, T., Mani, P. K., Basak, N., Mazumder, D., and Roy, M. (2016). Long-term manuring and fertilization influence soil inorganic phosphorus transformation vis-a-vis rice yield in a rice-wheat cropping system. Arch. Agron. Soil Sci. 62, 1–18. doi: 10.1080/03650340.2015.1036747

Crossref Full Text | Google Scholar

Mitran, T., Meena, R. S., Lal, R., Layek, J., Kumar, S., Datta, R., et al. (2018). “Role of soil phosphorus on legume production,” in Legumes for Soil Health and Sustainable Management, eds. R. S. Meena, A. Das, G. S. Yadav, R. Lal (Singapore: Springer). doi: 10.1007/978-981-13-0253-4_15

Crossref Full Text | Google Scholar

Murphy, B. W. (2015). Impact of soil organic matter on soil properties-a review with emphasis on Australian soils. Soil Res. 53, 605–635. doi: 10.1071/SR14246

Crossref Full Text | Google Scholar

Murphy, J., and Riley, J. P. (1962). A modified single solution method for the determination of phosphate in natural waters. Anal. Chim. Acta. 27, 31–36. doi: 10.1016/S0003-2670(00)88444-5

PubMed Abstract | Crossref Full Text | Google Scholar

Nath, C. P., Dutta, A., Hazra, K. K., Praharaj, C. S., Kumar, N., Singh, S. S., et al. (2023). Long-term impact of pulses and organic amendments inclusion in cropping system on soil physical and chemical properties. Sci. Rep. 13:6508. doi: 10.1038/s41598-023-33255-3

PubMed Abstract | Crossref Full Text | Google Scholar

Nath, D. J., Gogoi, D., Buragohain, S., Gayan, A., Devi, Y. B., Bhattacharyya, B., et al. (2015). Effect of integrated nutrient management on soil enzymes, microbial biomass carbon and soil chemical properties after eight years of rice (Oryza sativa) cultivation in an Aeric Endoaquept. J. Ind. Soc. Soil Sci. 63, 406–413. doi: 10.5958/0974-0228.2015.00054.7

Crossref Full Text | Google Scholar

Olsen, S. R. (1954). Estimation of Available Phosphorus in Soils by Extraction with Sodium Bicarbonate (No. 939). Washington, DC: US Department of Agriculture.

Google Scholar

Open Government Data (2024). Open Government Data (OGD), platform India, A digital India initiative. Available online at: https://www.data.gov.in/keywords/DAP (accessed January 10, 2025).

Google Scholar

Padbhushan, R., Sharma, S., Kumar, U., Rana, D. S., Kohli, A., Kaviraj, M., et al. (2021). Meta-analysis approach to measure the effect of integrated nutrient management on crop performance, microbial activity, and carbon stocks in Indian soils. Front. Environ. Sci. 9:724702. doi: 10.3389/fenvs.2021.724702

Crossref Full Text | Google Scholar

Paramesh, V., Dhar, S., Dass, A., Kumar, B., Kumar, A., El-Ansary, D. O., et al. (2020). Role of integrated nutrient management and agronomic fortification of zinc on yield, nutrient uptake and quality of wheat. Sustainability 12:3513. doi: 10.3390/su12093513

Crossref Full Text | Google Scholar

Patra, A., Sharma, V. K., Purakayastha, T. J., Barman, M., Kumar, S., Chobhe, K. A., et al. (2020). Effect of long-term integrated nutrient management (INM) practices on soil nutrients availability and enzymatic activity under acidic Inceptisol of North-Eastern region of India. Commu. Soil Sci. Plant Anal. 51, 1137–1149. doi: 10.1080/00103624.2020.1751185

Crossref Full Text | Google Scholar

Qin, X., Guo, S., Zhai, L., Pan, J., Khoshnevisan, B., Wu, S., et al. (2020). How long-term excessive manure application affects soil phosphorous species and risk of phosphorous loss in fluvo-aquic soil. Env. Pollut. 266:115304. doi: 10.1016/j.envpol.2020.115304

PubMed Abstract | Crossref Full Text | Google Scholar

Rajput, R., Pokhriya, P., Panwar, P., Arunachalam, A., and Arunachalam, K. (2019). Soil nutrients, microbial biomass, and crop response to organic amendments in rice cropping system in the shiwaliks of Indian Himalayas. Int. J. Recycl Org. Waste Agricult. 8, 73–85. doi: 10.1007/s40093-018-0230-x

Crossref Full Text | Google Scholar

Randhawa, M. K., Dhaliwal, S. S., Sharma, V., Toor, A. S., Sharma, S., Kaur, M., et al. (2021). Nutrient use efficiency as a strong indicator of nutritional security and builders of soil nutrient status through integrated nutrient management technology in a rice-wheat system in northwestern India. Sustainability 13:4551. doi: 10.3390/su13084551

Crossref Full Text | Google Scholar

Rani, M., Goyal, V., Dey, P., Malik, K., and Yadav, R. (2022). Soil test based balanced fertilization (10 years) for improving soil nutrient status and use efficiency under pearl millet-wheat cropping system. Int. J. Plant Prod. 16, 723–739. doi: 10.1007/s42106-022-00211-6

Crossref Full Text | Google Scholar

Saha, R., and Ghosh, P. K. (2013). Soil organic carbon stock, moisture availability and crop yield as influenced by residue management and tillage practices in maize-mustard cropping system under hill agro-ecosystem. Natl. Acad. Sci. Lett. 36, 461–468. doi: 10.1007/s40009-013-0158-7

Crossref Full Text | Google Scholar

Satyavathi, C. T., Ambawat, S., Khandelwal, V., and Srivastava, R. K. (2021). Pearl millet: a climate-resilient nutricereal for mitigating hidden hunger and provide nutritional security. Front. Plant Sci. 12:659938. doi: 10.3389/fpls.2021.659938

PubMed Abstract | Crossref Full Text | Google Scholar

Shen, J., Li, R., Zhang, F., Fan, J., Tang, C., Rengel, Z., et al. (2004). Crop yields, soil fertility and phosphorus fractions in response to long-term fertilization under the rice monoculture system on a calcareous soil. Field Crops Res. 86, 225–238. doi: 10.1016/j.fcr.2003.08.013

Crossref Full Text | Google Scholar

Sheoran, S., Prakash, D., Raj, D., Mor, V. S., Yadav, P. K., Gupta, R. K., et al. (2024). Long-term organic and N fertilization influence the quality and productivity of pearl millet under pearl millet-wheat sequence in north India. Sci. Rep. 14:19503. doi: 10.1038/s41598-024-70009-1

PubMed Abstract | Crossref Full Text | Google Scholar

Sher, A., Akbar, Z. A., Sattar, A., Ul-Allah, S., Ijaz, M., Calone, R., et al. (2023). Balanced NPK nutrition improves forage productivity and quality of pearl millet grown in semi-arid regions of Pakistan. J. Soil Sci. Plant Nutr. 23, 6542–6550. doi: 10.1007/s42729-023-01509-8

Crossref Full Text | Google Scholar

Singh, U., Praharaj, C. S., Singh, S. S., Hazra, K. K., and Kumar, N. (2018). Effect of crop establishment practices on the performance of component cultivars under pigeonpea (Cajanus cajan)-wheat (Triticum aestivum) cropping system in IGP. Ind. J. Agric. Sci. 88, 691–697. doi: 10.56093/ijas.v88i5.80050

Crossref Full Text | Google Scholar

Smillie, G. W., and Syers, J. K. (1972). Calcium fluoride formation during extraction of calcareous soils with fluoride: II. Implications to the Bray P-1 test. Soil Sci. Soc. Am. J. 36, 25–30. doi: 10.2136/sssaj1972.03615995003600010005x

Crossref Full Text | Google Scholar

Subbaiah, V. V., and Asija, G. K. (1956). A rapid procedure for estimation of available nitrogen in soil. Curr. Sci. 25, 259–260.

Google Scholar

Tanwar, S. P. S., Rokadia, P., and Singh, A. K. (2010). Productivity, nutrient balance and economics of kabuli chickpea (Cicer kabulium) as influenced by integrated nutrient management. Ind. J. Agron. 55, 51–55. doi: 10.59797/ija.v55i1.4715

Crossref Full Text | Google Scholar

Thakur, R. K., Bisen, N. K., Shrivastava, A. K., Rai, S. K., and Sarvade, S. (2023). Impact of integrated nutrient management on crop productivity and soil fertility under rice (Oryza sativa)-chickpea (Cicer arietinum) cropping system in Chhattisgarh plain agro-climatic zone. Ind. J. Agron. 68, 9–13. doi: 10.59797/ija.v68i1.195

Crossref Full Text | Google Scholar

Thumar, C. M., Dhdhat, M. S., Chaudhari, N. N., Hadiya, N. J., and Ahir, N. B. (2016). Growth, yield attributes, yield and economics of summer pearl millet (Pennisetum glaucum L.) as influenced by integrated nutrient management. Int. J. Agric. Sci. 8, 3344–3346.

Google Scholar

Touhami, D., McDowell, R. W., and Condron, L. M. (2020). Role of organic anions and phosphatase enzymes in phosphorus acquisition in the rhizospheres of legumes and grasses grown in a low phosphorus pasture soil. Plants 9:1185. doi: 10.3390/plants9091185

PubMed Abstract | Crossref Full Text | Google Scholar

USDA-NRCS (1999). Soil Taxonomy, Agricultural Handbook No. 436, 2nd Edn. Classification System of Soils. Czech Republic: USDA, ÚHÚL.

Google Scholar

Varatharajan, T., Choudhary, A. K., Pooniya, V., Dass, A., Rana, D. S., Rana, K. S., et al. (2019). Effect of integrated crop management practices on root-shoot characteristics, yield and nutrient harvest index of pigeon pea (Cajanus cajan) under irrigated north Indian Plains. Ind. J. Agron. 64, 270–274. doi: 10.59797/ija.v64i2.5267

Crossref Full Text | Google Scholar

Varatharajan, T., Dass, A., Choudhary, A. K., Sudhishri, S., Pooniya, V., Das, T. K., et al. (2022). Integrated management enhances crop physiology and final yield in maize intercropped with blackgram in semiarid South Asia. Front. Plant Sci. 13:975569. doi: 10.3389/fpls.2022.975569

PubMed Abstract | Crossref Full Text | Google Scholar

Venkatesh, M. S., Hazra, K. K., Ghosh, P. K., and Mishra, J. P. (2019). Integrated phosphorus management in maize-chickpea rotation in moderately-alkaline Inceptisol in Kanpur, India: an agronomic and economic evaluation. Field Crops Res. 233, 21–32. doi: 10.1016/j.fcr.2019.01.001

Crossref Full Text | Google Scholar

Walkley, A., and Black, I. A. (1934). An examination of the degtjareff method for determining soil organic matter, and a proposed modification of the chromic acid titration method. Soil Sci. 37, 29–38. doi: 10.1097/00010694-193401000-00003

Crossref Full Text | Google Scholar

Weatherley, P. E., and Slatyer, R. O. (1957). Relationship between relative turgidity and diffusion pressure deficit in leaves. Nature 179, 1085–1086. doi: 10.1038/1791085a0

Crossref Full Text | Google Scholar

Wei, L., Chen, S., Cui, J., Ping, H., Yuan, C., Chen, Q., et al. (2022). A meta-analysis of arable soil phosphorus pools response to manure application as influenced by manure types, soil properties, and climate. J. Environ. Manage. 313:115006. doi: 10.1016/j.jenvman.2022.115006

PubMed Abstract | Crossref Full Text | Google Scholar