A review of soybean yield when double-cropped after wheat

Abstract

Soybean (Glycine Max L.) planted after wheat (Triticum aestivum L.) harvest in same season (double cropped [DC]) has the potential to increase productivity and sustainability. The objectives of this synthesis review were to (i) quantify attainable yield for DC soybean benchmarking against full-season (FS) soybean; (ii) determine and build probabilistic response models on the effect of previous wheat productivity on DC soybean yields; and (iii) detect and rank factors influencing DC soybean yields via a decision inference tree analysis. A global database on DC soybean studies collected from 1976 to 2017 was divided into three data sets: (i) FS and DC soybean (n = 141 data points); (ii) wheat and DC soybean (n = 463); and (iii) production factors and DC soybean (n = 547). Analysis showed that the yield gap between FS and DC soybeans increased from -31 to 1160 kg ha-1 as FS yield improved from 1500 to 3000 kg ha-1. Even though the proportion of the variation accounted for wheat yields in the DC soybean/wheat yield ratio was low (R2 = 0.15), the probability of soybean yield being equal to wheat yield was 0, 20, 30, and 55% for wheat yields of ≥6. Inference tree analysis indicated that the major factor impacting success of the DC system was wheat yield followed by soybean planting date and maturity group.