Early high‐moisture wheat harvest improves double‐crop system: II. Soybean growth and yield

Abstract

Double cropping soybean [Glycine max (L.) Merr.] after winter wheat (Triticum aestivum L.) increases total food production without additional land. However, double‐crop soybean usually yields less than full‐season soybean, mainly due to late planting. We evaluated double‐crop soybean growth and yield as affected by early planting immediately after high‐moisture wheat harvest across 20 site‐years in five Mid‐Atlantic states during 2015–2017. At each site, six soybean cultivars from relative maturity group (rMG) 3.1–5.9 were planted at three to five dates in a 4‐ to 14‐d interval. Soybean growth, measured by normalized difference vegetation index (NDVI) across the growing season, was affected only by planting date. Although NDVI peaked near the R5 stage, it took 9–27 more days to reach the peak NDVI (0.84–0.98) for early‐planted soybean than for late‐planted soybean. Relative yield declined with planting dates, which explained 41–81% of the relative yield variability. The yield loss from delayed planting was greater in the north (33–80%; Pennsylvania, Maryland, and Delaware) than in the south (20–27%; Virginia, North Carolina) due to longer delay in planting and shorter growing season in the north. Soybean NDVI from the R1–R6 stages was associated with yield, with the strongest association (R2 = .55–.57) at the R2 and R3 stages. The area under the NDVI curve (AUNDVIC) was also strongly associated (R2 = .77) with relative yield, indicating an excellent tool for explaining double‐crop soybean yield loss due to poor growth. High‐moisture wheat harvest facilitated soybean planting 4–21 d earlier, which increased growth and yield.

Early high‐moisture wheat harvest improves double‐crop system: I. Wheat yield and quality

“…Harvesting wheat soon after maturity can substantially reduce the risk of yield and quality losses (Clarke & De Pauw, 1983; Farrer et al., 2006; Johnson et al., 1980; McNeill et al., 2009; Pool et al., 1958). In addition, earlier wheat harvest results greater double‐crop soybean yields due to earlier soybean planting (Parvej et al., 2020).…”

“…Double‐crop soybean growth and yield as affected by planting dates immediately after early high‐moisture wheat harvest was discussed by Parvej et al. (2020).…”

Identifying plant traits to increase wheat yield under irrigated conditions

“…Notably, significant genotypic variations (ranging from 500 to 840-degree days) have been observed for the length of the grain filling period among wheat genotypes [ 16 , 55 , 57 ]. However, it is important to consider the implications of modifying the growth period of a crop plant, as it may result in the loss of the optimal sowing window for the subsequent crop after wheat, such as in wheat-soybean double cropping [ 58 ].…”