Yield‐Soil Water Relationships in Sorghum‐Soybean Cropping Systems with Different Fertilizer Regimes

Abstract

Crop rotation of soybean [Glycine max (L.) Merr.] with grain sorghum [Sorghum bicolor (L.) Moench], and application of N fertilizer or manure generally increases grain sorghum yield. Little is known about rotation and fertilization effects on soybean yield in the Great Plains. Grain yields were measured from 1981 to 1987 in a cropping experiment started in 1980 on a Sharpsburg silty clay loam (fine, montmorillonitic, mesic Typic Argiudoll). The cropping treatments included continuous soybean, continuous grain sorghum, and grain sorghum‐soybean rotation. Fertilizer treatments consisted of control, manure (15.8 Mg dry matter ha−1 yr−11) and N (45 kg ha−1 for soybean and 90 kg N ha−1 for sorghum). Volumetric soil water content was determined with a neutron probe in 1985, 1986, and 1987. Soil water content was unaffected by fertilizer treatment. Water content in the upper 30 cm was generally greatest with continuous grain sorghum and least with continuous soybean. Soil water depletion to 120 cm in September was 10 to 36 mm greater with soybean than with grain sorghum. Crop rotation increased soybean yield, but N application did not. Manure application reduced soybean yield in 1986, but had no effect in the other years. Rotation and fertilization increased sorghum grain yield. The soybean yield advantage from crop rotation decreased as 1 April to 31 May rainfall increased. Cropping‐system induced differences in soil water content early in the growing season may be partly responsible for higher soybean yield with crop rotation.

Soybean yield and nodulation response to crop history and inoculation

“…The experiment was imposed on plots contained in a long-term rotation study established in 1980 (Roder et al, 1988(Roder et al, , 1989. The experimental factors studied were crop history, soybean inoculation, and manure application.…”

“…Crop rotation with maize (Zea mays L.) and sorghum have been documented to increase succeeding soybean crop yields by 5 to 16% (Roder et al, 1989;Peterson and Varvel, 1989).…”

Adubação nitrogenada na cultura do milho

“…No entanto, pesquisas que utilizam 15 N têm sugerido que a maior parte do N da fitomassa das leguminosas tem como destino o solo (Harris & Hesterman, 1990), ficando acumulado na forma de N orgânico. A quantidade e distribuição de N inorgânico, principalmente NO 3 -, que permanece no perfil do solo, é resultante do fertilizante utilizado, do regime de temperatura e umidade do solo e da aplicação de doses de N maiores do que as necessá-rias para atingir produtividades ótimas (Roder et al, 1989;Teixeira et al, 1994;Torbert et al, 1996;Barrios et al, 1998).…”

Simulating Soil Moisture under Different Tillage Practices, Cropping Systems and Organic Fertilizers Using CropSyst Model, in Matuu Division, Kenya

“…According to Roder (1989) rotation of legumes and cereals, with their different root systems optimizes the network of root channels in soil to deeper soil depths. This leads to increased water penetration, water-holding capacity and available water for crop use.…”