Abstract

Dry weight (DW) production of ‘Hawkeye’ soybeans (Glycine max (L.) Merrill) was highly correlated with leaf area index (LAI) accumulation. Those plant population-arrangement combinations favoring a rapid attainment of high LAI (i.e., high plant populations and narrow row spacings) were those also having the greatest DW accumulation. However, the rate of DW production in soybeans was shown previously to be a function of LAI only up to a particular LAI. Further, maximum seed yield occurred at less than maximum LAI and at generally lower populations and narrower row spacings. Highest seed yield occurred in 10-inch rows with 104,544 plants per acre, while DW was maximized in 5-inch rows with 209,088 plants per acre. LAI and DW produced at stage 9 were not good predictors of seed yield.

Plants produced at highest densities were taller, more sparsely branched, lodged more, and set fewer pods and seed than those plants at lower densities. Thus, the seed yield reduction resulting suggested more severe plant competition at higher plant densities. Plant spacing and population had a small effect on protein and oil content.

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