Nitrogen Management in No‐Tillage Grain Sorghum Production: I. Rate and Time of Application

• Published in: Agronomy journal Vol. 92; no. 2; pp. 321 - 328
• Main Authors: Khosla, Raj, Alley, Mark M., Davis, Paul H.
• Format: Journal Article
• Language: English
• Published: Madison American Society of Agronomy 01.03.2000
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Nitrogen fertilization; Nitrogen, phosphorus, potassium fertilizations; Soil-plant relationships. Soil fertility. Fertilization. Amendments; Nitrogen fertilization; Monocotyledones; Intervention day; Inorganic fertilizer; Cereal crop; Dose activity relation; Sorghum bicolor; Loamy soil; Gramineae; Placement; Dicotyledones; Angiospermae; Ultisols; Starter fertilizer; Treatment efficiency; Nitrogen; Glycine max; Grain legume; Leguminosae; Crop rotation; Nutrient; Application method; Spermatophyta; Yield component; Triticum aestivum
• ISSN: 0002-1962; 1435-0645
• DOI: 10.2134/agronj2000.922321x

Grain sorghum [Sorghum bicolor (L.) Moench] is grown in rotation with wheat (Triticum aestivum L.) and soybean [Glycine max (L.) Merr.] in the mid‐Atlantic. Sufficient data on N fertilization of sorghum are not available for this region. Our objective was to evaluate the influence of multi‐rate N fertilization on dryland sorghum. Treatments consisted of factorial combinations of four starter‐band N rates (11, 34, 56, and 78 kg N ha−1) and four sidedress N rates (0, 45, 90, and 134 kg N ha−1). A broadcast treatment of 67 kg N ha−1 at planting was also included. Starter‐band was applied 5 cm to the side and below the seed. Sidedress was applied 35 days after emergence at the eight‐leaf growth stage. Grain yield ranged from 1.7 to 11.9 Mg ha−1 over eight site‐years and was responsive and nonresponsive to N applications on four sites each. Nonresponsiveness was either due to high levels (>85 kg N ha−1) of residual soil mineral N, or severe water stress conditions. Our results indicate that production of sorghum on soils testing high in mineral N (50 kg N ha−1 in the surface 0.3 m) at planting should not receive any starter‐band N in conjunction with sidedress N application of 130 kg N ha−1 for optimum economic return to N fertilization. For soils testing low in mineral N, 40 kg N ha−1 starter‐band in conjunction with 130 kg N ha−1 sidedress N should optimize the sorghum yields in most situations.