Effects of delayed soil and foliar N fertilization on yield and N2 fixation of soybean

Abstract

Summary Field experiments were conducted to determine the effects of the amount, time and method of fertilizer N application on the efficiency of N uptake, N 2 fixation and yield of soybean.Soil and foliar fertilizer N, applied during the pod-filling stage were absorbed by plants with equal and high efficiency, compared to an appreciably lower utilization efficiency for N applied before seedling emergence. These results reveal that the soybean roots were active in N uptake during these late stages of growth. Nitrogen fertilization during pod-filling resulted in significant yield increases over the control treatment which received an early application of 20 Kg N/ha. Seed yield increases were, however, more pronounced than total dry matter yield, and virtually all of the late-applied N was translocated into the pods. Nitrogen fixation in soybean was not influenced by the application of 40 kg N/ha to plants as soil or foliar N during the pod-filling stage. However, 80 kg N/ha supplied during pod-filling as 40 kg soil plus 40 kg foliar N/ha significantly reduced the amount of N 2 fixed.The results obtained in these studies suggest that inadequate N supply during pod-filling limited soybean yields, and that by the judicious application of fertilizer N during the late stages of growth, it was possible to enhance soybean yields without necessarily inhibiting N 2 fixation.

Genetic Gain × Management Interactions in Soybean: II. Nitrogen Utilization

“…Mean monthly air temperature, total monthly precipitation, and 30 yr averages kg ha -1 (Wilcox et al, 1979) and of 17.2 kg ha -1 (Specht and Williams, 1984) but less than the report of 30 kg ha ) for MG III cultivars. Our MG III yield increases (12 to 16%) from N were consistent with previous reports of 5 to 37% from N applications (Afza et al, 1987;Bhangoo and Albritton, 1976;Ferguson et al, 2000;Harper, 1974;Osborne and Riedell, 2006;Salvagiotti et al, 2009;Wesley et al, 1998).…”

“…This is because soil N and BNF may not fully meet the N requirement of soybean under high yielding conditions. Nitrogen application to soybean before planting (Bhangoo and Albritton, 1976;Ferguson et al, 2000;Osborne and Riedell 2006;Salvagiotti et al, 2009) and during mid to late reproductive development (Afza et al, 1987;Harper, 1974;Salvagiotti et al, 2009;Wesley et al, 1998) has been shown to increase yields from 2 to 26%.…”

Exogenous Application of Tryptophan and Indole Acetic Acid (Iaa) to Induce Root Nodule Formation and Increase Soybean Yield in Acid, Neutral and Alkaline Soil

“…Sampling for observation of root nodules and plant dry weight was performed at R 1 growth stage (maximum vegetative phase) and at R 8 growth stage (fully maturated pods) for plant yield (Hidayat, 1985, Kamal, 2000. Fertilizer N was applied at a dose of 20 kgha -1 N before planting as a starter (Afza et al 1987), while P and K fertilizer were given prior to planting at a dose equivalent to 75 kgha -1 P 2 O 5 and 100 kgha -1 K 2 O (Pasaribu and Suprapto, 1985). Calcium (Ca) and magnesium (Mg) were given in the form of dolomite with the dose of 200 kg ha -1 (Jutono, 1985).…”

THE INFLUENCE OF RATE AND TIME OF MINERAL N APPLICATION ON YIELD AND N2 FIXATION BY FIELD BEAN

“…neither study usedl5N dilution methods to measure N2 frxation. Rennie and Kemp (1984) (Minchin et al 1981;Jensen 1986;Afza et al 1987 (Thomas et al 1967 (Table 1) and difference in total plant N (Fig. 1) Fig.2).…”