Crop rotations in the Rolling Pampas: Characterization, spatial pattern and its potential controls

Abstract

One of the most important decisions made by farmers every year involves land allocation to different crops. Accurate information on crop sequences over large areas is a key prerequisite to address social concerns as soybean monoculture, to map good agronomic practices and to assess farmers' adaptive capacity among others. Here we aimed to characterize crop sequences and describe the crop rotation patterns in an area of the Rolling Pampas in Argentina. We performed annual supervised classifications for the 2010/2011 to 2016/2017 growing seasons using high resolution satellite images and in situ data. Classification's accuracies were always higher than 85%. Analysis of crop sequences showed that the most common practice was alternating periods of continuous planting of early soybean with periods where maize and/or wheat were included in the rotation. In addition, during the period analyzed nearly 10% of the study area exhibited continuous soybean monoculture, and 6% of the area showed a strict crop rotation of maize, soybean, and wheat-soybean double crop. Changes in early soybean planted area were significantly associated (p < 0.1) to its previous year's international price, and were probably affected by political economy regulations. The inclusion of maize or wheat in the rotation was more frequently observed at larger cadastral units, while soybean monoculture was more frequent in smaller cadastral units. This suggests that farmers’ capitalization may be associated to different crop rotation decisions through a different long term planning capacity.