Nitrogen Fertilization of Wheat Double‐Cropped Following Grain Sorghum in a No‐Tillage System

Abstract

Utilization of wheat (Triticum aestivum L. em Thell.) as a cash crop or cover crop in a double‐cropping system is desirable to prevent excessive soil erosion on loess‐derived soils in the southern USA. Fall and spring N application to winter wheat double‐cropped following grain sorghum (Sorghum bicolor L.) was evaluated on a Grenada silt loam (fine‐silty, mixed, thermic Glossic Fragiudalf). The experimental design was a randomized complete block with a split‐plot arrangement of treatments. Rates of N applied at planting; (0, 34, and 67 kg ha−1) were the main plots, with N rates applied in the spring (0, 34, 67, 101 and 134 kg ha−1) the sub‐plots. Fall N (Nf) increased both yield and plant height. Spring N (Ns) had a. greater effect on yield and plant height than Nf. Yields increased from 0.83 to 2.61 Mg ha−1) by increasing Ns from 0 to 134 kg ha−1) without Ns. Yields increased from 1.50 to 2.67 Mg ha−1) by increasing Na from 0 to 67 kg ha−1 with 67 kg ha −1>/ Nf. Yield variation was expressed by Y = 0.822 + 0.0098 Nf + 0.0248 Ns − 8.5 × 10−5) N2s + 1.45 × 10−5 NfNs − 7.41 × 10−7 NfN2s. Plant height increased from 56 to 85 cm by increasing Ns from 0 to 134 kg ha−1 without Nf, but increased from 67 to 80 cm by increasing Ns from 0 to 67 kg ha−1 with 67 kg ha−1 Nf One‐hundred‐kernel weight decreased from 2.35 to 2.11 g by increasing Ns from 34 to 134 kg ha‐1. Grain N increased from 19.9 to 23.2 g kg‐1 by increasing Ns from 34 to 134 kg ha−1.

Seeding and Nitrogen Rates Required to Optimize Winter Wheat Yields following Grain Sorghum and Soybean

“…In all 3 yr, the applied N rate required to maximize grain N was greater than the N rate required to optimize grain yields. Several studies report increased grain N as applied N increased (Kelley 1995; Woodard and Bly, 1998; Hargrove et al, 1983; Howard and Lessman, 1991; Zebarth and Sheard, 1992; Knowles et al, 1993). Kelley (1995) and Woodard and Bly (1998) also reported higher N rates required to optimize grain N than N rates required to maximize grain yield.…”

Some Physico-chemical characteristics of soils influenced by Taal Volcano in reference to soil productivity

“…Crop production was related to the natural soil fertility. The practice of growing several crops on the same piece of land is an old strategy for crop production among fanners in the tropics and it is traditionally adopted by subsistence farmers primarily to increase the diversity of their agricultural products and maximize the use of land resources (Gomez and Gomez 1983;Horwith 1985;Howard and Lessman 1991). Stud- Table 4.…”