Irrigation, Row Width, and Plant Population in Relation to Growth Characteristics of Two Soybean Varieties¹

Abstract

Soybean (Glycine max (L.) Merrill) yields in the past have varied considerably from year to year in the southeastern United States. Many factors are important in soybean production, but water stress at critical growth periods appears to be one of the most frequently limiting factors. Soybeans were grown on a Lucedale fine sandy loam soil to determine the effects of three soil water regimes at two row widths and three plant population levels on water use, rate of plant growth, and bean yield of two varieties. Water use rates by soybeans were influenced more by soil water regime than by row width or variety. Average rates during the season ranged from 0.05 to 0.84 cm/day, depending on the amount of available water in the soil. Variety had the greatest influence on plant height. Final plant heights ranged from 10 to 15 cm greater for ‘Bragg’ than for ‘Hampton 266.’ Heights were increased by irrigation and plant population level, but were not affected by row width. Average bean yields were influenced more by irrigation or variety than by row width or plant population. Average bean yields by soil water regimes were 2,020, 2,420, and 2,490 kg/ha for no irrigation, intermediate, and high irrigation, respectively. Bragg averaged 2,420 kg/ha and Hampton 266 averaged 2,150 kg/ha. Row width and plant population showed little influence on average bean yields.

Soybean Yield Formation: What Controls It and How It Can Be Improved

“…The period from 10 days before R1 to 10 days after R1 is the critical period. Drought stress occurring at the start of linear seed filling (R6) can also reduce seed number, but the main effect of drought initiated at this time or later is on reduced seed size (Sionit and Kramer, 1977;De Souza et al, 1997;Brevedan and Egli, 2003;Doss and Thurlow, 1974). In cases where drought stress is similar at different developmental periods, yield loss is generally twice as great for the R1-R6 vs. R6-R7 periods (Kadhem et al, 1985;Korte et al, 1983b;Shaw and Laing, 1966;Eck et al, 1987;Brown et al, 1985;Hoogenboom et al, 1987;Korte et al, 1983b).…”

Redução na dose do herbicida aplicado em pós-emergência associada a espaçamento reduzido da cultura de soja para controle de Brachiaria plantaginea

“…Uma dessas práticas de manejo está relacionada à diminuição no espaçamento entre linhas, o que possibilita distribuição mais uniforme das plantas (Ikeda, 1992); maior interceptação de radiação (Board & Harville, 1992); competição precoce com plantas daninhas (Johnson, 1987); menor evaporação de água (Doss & Thurlow, 1974); e maior fixação dos órgãos reprodutivos e maior altura de inserção dos legumes (Costa & Pendleton, 1979).…”

Polímeros hidroretentores na cultura da soja em condições de solo argiloso na região norte do Rio Grande do Sul

“…Dentre os estresses abió-ticos que ocorrem na cultura, o déficit hídrico é o evento de maior relevância (Doss & Thurlow, 1974;Sionit & Kramer, 1977). Onde a falta de água causa a abscisão das flores, impede a antese, afeta a massa de grãos e consequentemente a produção (Fageria, 1989).…”