Effects of Wastewater Irrigation and Plant and Row Spacing on Soybean Yield and Development1
- M. J. Cordonnier and
- T. J. Johnston2
Considerable research has demonstrated that soybean [Glycine max (L.) Merr.] yields can be increased with the addition of supplemental water during reproductive stages, but little information is available concerning the use of municipal wastewater as the water source. Variables included in this field study were: three water regimes-municipal wastewater, well water and no water; two row spacings-51 and 76 cm; two in-row spacings-20 and 32 plants/m and two cultivars-Nebsoy and Harcor. Soybeans planted on a Miami silt loam soil (fine-loamy, mixed, mesic Typic Hapludalf) received a total of 9.8 cm of wastewater or well water as overhead spray irrigation in 1979 and 9.4 cm in 1980. Data were collected on seed yield, agronomic characteristics, dry matter production, leaf photosynthesis, and leaf chemical analysis. Seed yields were significantly different for water treatments in 1979 with 2,430, 2,580, and 2,790 kg ha−1 for no water, well water and wastewater, respectively. Yields generally increased as plant population increased with the greatest yield for both cultivars occurring at the highest plant population (645,500 plants ha−1). Irrigated plants were 4 to 5 cm taller, matured 5 to 6 days later, had larger seeds and lodge slightly more than nonirrigated plants. The two cultivars responded differently to the wastewater, with Harcor exhibiting a better response than Nebsoy. The 1980 growing season was wetter than normal and there was little or no yield response to irrigation. Under the conditions of soil type, climate and wastewater quality found during this experiment, wastewater was generally superior to well water in increasing yields.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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