Original Research ARTICLE
Monitoring Crop Status in the Continental United States Using the SMAP Level 4 Carbon Product
- 1Geosciences, University of Montana, United States
- 2Numerical Terradynamic Simulation Group, University of Montana, United States
- 3Numberical Terradynamic Simulation Group, University of Montana, United States
- 4Aula Dei Experimental Station (EEAD), Spain
Accurate monitoring of crop condition is critical to detect anomalies that may threaten the economic viability of agriculture and to understand how crops respond to climatic variability. Retrievals of soil moisture and vegetation information from satellite-based remote sensing products offer an opportunity for continuous and affordable crop condition monitoring. This study compared weekly anomalies in accumulated gross primary production (GPP) from the SMAP Level-4 Carbon (L4C) product to anomalies calculated from a state-scale weekly crop condition index (CCI) and also to crop yield anomalies calculated from county-level yield data reported at the end of the season. We focused on barley, spring wheat, corn, and soybeans cultivated in the continental United States from 2000 to 2018. We found that consistencies between SMAP L4C GPP anomalies and both crop condition and yield anomalies increased as crops developed from the emergence stage (r: 0.4-0.7) and matured (r: 0.6-0.9), and that the agreement was better in drier regions (r: 0.4-0.9) than in wetter regions (r: < 0-0.4). The L4C provides weekly GPP estimates at a 1-km scale, permitting the evaluation and tracking of anomalies in crop status at higher spatial detail than metrics based on the state-level CCI or county-level crop yields. We demonstrate that the L4C GPP product can be used operationally to monitor crop condition with the potential to become an important tool to inform decision-making and research.
Keywords: Agriculture, drought, crop yield, l4C, SMAP, Crop condition, GPP
Received: 21 Aug 2020;
Accepted: 19 Nov 2020.
Copyright: © 2020 Wurster Jr, Maneta, Kimball, Endsley and Beguería. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Mr. Patrick M. Wurster Jr, University of Montana, Geosciences, Missoula, United States, email@example.com