Prospective crop yield and income return based on a retrospective analysis of a long-term rainfed agriculture experiment in Nebraska

Nebraska, US, is projected to face increased winter and spring precipitation, and drier summers as the climate changes over the next 20 to 30 years. Agricultural adaptations and adjustments would be critical to mitigate the adverse impact of climate change and achieve global food security. Focusing on the projected climatic change projections for Nebraska, our objective is to analyze data from a long-term (31 years; 1986–2016) rainfed agriculture experiment to determine how past years, that had similar conditions to the projected future climate - wetter winter (WW), wetter spring (WS), and dry summer (DS), responded to these conditions and attempt to describe the near-future (upcoming 20–30 years) corn and soybean yield, and income returns in northeast Nebraska. First, we used a meteorological drought index, to determine years with projected future climate (6 years with WW, 4 years with WS, and 4 years with DS) and 9 all normal (AN) seasons years during the study period. Second, we performed a linear mixed-model analysis of variance to compare treatment (tillage: no-till, disk-till and plow-till; crop rotation: continuous-corn, corn-soybean; Nitrogen rates: 0–160 kg-N/ha) interaction and their effect on crop yield between projected future climate (WW, WS and DS) years and AN years. Finally, we used partial budgeting to calculate change in income and income risk across imposed management practices. Results indicate that corn years with WW, WS, and DS seasons showed yield reductions of 9.1%, 10.9%, and 38.6% compared to an average AN season corn yield, which was 11.3 Mg/ha. Compared to the average AN season yield of 3.6 Mg/ha, soybean yields were + 1.4%, −3.3%, and − 31.8% for WW, WS, and DS, respectively. These yield differences did not significantly affect average corn and soybean income return in WW and WS years compared to the AN years (900 $/ha). However, total income returns in DS seasons regardless of pre-season conditions was about 40% of income return in AN seasons from CS (900 $/ha) and CC (800 $/ha), respectively. Soybean yield and income returns were more stable than corn, which resulted in the corn-soybean rotation system always being higher in yields and being more profitable. Our recommended management practice of disk tillage and corn-soybean rotation with 80 kg-N/ha could result in highest and stable income returns in near-future. Such long-term crop experimental studies can serve as an important complement to crop-model studies to get improved insight into future crop yield and income returns.