Maximization of soybean exploration. IV. Effects of spacing, density and stem cutting height on the production of hay and grains from regrowth

Abstract

The effects of row spacing, density and height of the cut on production of hay and grains from regrowth of soybean (Glycine max (L.) Merrill) cv. Cristalina were evaluated. A complete randomized block design in a factorial scheme (3 x 3 x 3) was used. The three plant densities (300,000, 500,000 and 700,000 plants/ha) were arranged in three row spacings (30 cm, 45 cm and 60 cm), and three cutting heights (25 cm, 35 cm and without cutting) with three replicates. The cuttings were made 60 days after sowing. The experiment was set up in the agricultural year of 1983/84, sowing being done in October, 18th. The soil was a clayey texture Dystrophic Dusky Latossol, coming from the experimental field of the Escola Superior de Agricultura de Lavras (ESAL), in Lavras, MG, Brazil, at the latitude 21^o14'S and longitude 45^o00'W. Smaller row spacings (30 cm and 45 cm) allowed significant increases in fresh matter, dry matter, hay, grain, straw and total matter yield. Hay and grain yield from regrowth of soybean were inversely related. However, the yield of plants cut 35 cm above soil level were similar to the uncut control, corresponding to 85% of the control yield and with hay mean yields of 1,463 kg/ha. Cutting the plants decreased plant height, weight of 100 seeds, lodging index and hay and total matter yield. The density of 700,000 plants/ha had significant increases in fresh matter, dry matter and hay yield. However, there was no significant difference between the yield of grains, straw and total matter in all densities studied.