AUTHOR=Li Likun , Duan Ruichuan , Li Runzhao , Zou Yan , Liu Jiawen , Chen Fajun , Xing Guangnan 

TITLE=Impacts of corn intercropping with soybean, peanut and millet through different planting patterns on population dynamics and community diversity of insects under fertilizer reduction

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.936039

DOI=10.3389/fpls.2022.936039

ISSN=1664-462X

ABSTRACT=In order to explore a more scientific and reasonable way to planting corn, and simultaneously reduce the over usage of chemical fertilizers and pesticides, the impacts of corn respectively intercropping with soybean, peanut and millet through five planting patterns, including three intercropping patterns (2 corn rows to 2, 3 and 4 rows of soybean/peanut or 2, 4 and 6 millet rows, respectively) and two monoculture patterns of corn and soybean, peanut or millet under normal (600 kg/ha) and reduced (375 kg/ha) levels of NPK (N: P2O5: K2O=15: 15: 15) fertilization on the population abundance and community diversity of insects, and leaf nutrients, induced plant hormones JA and SA were studied in 2018 and 2019. The results showed that the insect community indexes of species number (S), diversity index (H) and uniformity index (E) generally increased under intercropping and were significantly higher than those under corn monoculture. And under intercropping, the number of natural-enemy insect species on corn plants was significantly higher than that under corn monoculture. That is, intercropping may decrease the population of Asiatic corn borer by increasing S, H, E and NEI. Moreover, intercropping type and fertilizer level both significantly affected the nutrient contents in corn leaves. Compared with normal fertilizer level, fertilizer reduction significantly reduced the foliar contents of amino acids, soluble protein and soluble sugar in corn plants. In addition, corn-soybean and corn-peanut intercropping significantly increased the three nutrients contents in corn leaves compared with corn monoculture. In terms of corn nutrients, intercropping could compensate for the effects of fertilizer reduction. The foliar content of JA in corn-soybean intercropping was significantly higher than that in corn monoculture. Under corn-soybean and corn-peanut intercropping, SA was significantly lower than that under corn monoculture. It was concluded that intercropping not fertilizer reduction can significantly increase insect community diversity, and significantly reduce the population abundances of the key species of insect pests on corn plants, and both can enhance the induced JA defense of corn plants, finally improve the plant resistance of corn against insect pest’s occurrence.