Nitrogen and Phosphorus Fertilizer and Residual Response in Cotton–Sorghum and Cotton–Cotton Sequences

Abstract

Nitrogen and P fertilizer response for cotton (Gossypium hirsutum L.) and sorghum [Sorghum bicolor (L.) Moench] in a reduced tillage rotation system in the Southern High Plains has not been well studied. During 2000 to 2003, an irrigated study of cotton–sorghum rotation vs. continuous cotton evaluated the crop rotation effects on cotton lint yield and assessed N and P fertilizer and residual fertilizer response for the two systems. Preplant soil samples were collected each spring to determine fertilizer rates. Cotton lint yields and cottonseed N were not affected by rotation with sorghum compared with continuous cotton. Nitrogen fertilizer response was observed in lint yields from 2001 to 2003 in cotton following sorghum, but not in continuous cotton. No P fertilizer or soil residual P response in cotton lint yields was found, regardless of rotation. Grain sorghum yields responded to N fertilizer in 2 yr. No grain sorghum response was observed to P fertilizer, but in 1 yr a yield response to residual P fertilizer relative to zero‐P plots was noted. Seed N uptake was greater in sorghum than in cotton. Nitrogen fertility level increased seed N in sorghum and in cotton following sorghum. Infrequent crop response to P fertilizer was not unexpected, especially when Mehlich‐3 soil P in zero‐P subplots was near the 95% sufficiency level of 20 mg P kg−1. The main finding of this study is that N fertilizer response was more consistent for cotton following sorghum than in a continuous cotton system. In refining N fertilizer recommendations, N debits may be needed for N immobilization in sorghum residue. Nitrogen credit may be appropriate from leaf litter for crops following cotton and for NO3–N in irrigation water.

Broiler Litter Fertilization and Cropping System Impacts on Soil Properties

“…This could be related to more N removal by grain corn than seed cotton or greater N immobilization for decomposing corn plant residue than cotton. Our results are in agreement with Booker et al (2007), who reported less soil NO 3 –N when cotton followed sorghum than when cotton followed cotton.…”

Cotton Yield Responses to Fertilizer Nitrogen Rates in a Cotton‐Corn Rotation

“…Brown et al (1985) and Touchton et al (1995) reported an increase in N rate requirement for cotton grown after wheat ( Triticum aestivum L). A recent study by Booker et al (2007) supported these previous findings when they observed greater lint yield response to N fertilizer in cotton following sorghum. They attributed this response to lower N available for the subsequent cotton crop, suggesting that it is also important to account for N debits due to N immobilization in residue to refine N fertilization recommendations for crops in rotation systems.…”

“…Present knowledge of cotton responses to residual N (Boquet et al, 1995; McConnell et al, 1993) suggest yields should increase following high corn N rates. Although, in the present study, the N fertilizer applied to corn would be expected to provide varying levels of residual N to the following cotton crop, lint yield responses to residual N were complicated by various factors that contributed to inconsistent and smaller yield increases than reported previously (Boquet et al, 1995; Booker et al, 2007). As demonstrated by the yield responses to corn N rate with the very low rates of fertilizer N (0 and 28 kg ha −1 ), residual N increased cotton lint yield by about 340 kg ha −1 on Commerce SL and 160 kg ha −1 on Gigger SL (Table 5), which are substantial yield responses to corn N rate.…”

“…However, the absence of additional response to increased fertilizer N rate following corn N rates of 224 and 280 kg N ha −1 may also be partly related to excess production of corn biomass, stimulated by these excessive corn N rates. Booker et al(2007), Dabney et al (2001), and Varco et al (1999) reported that substantial amounts of biomass produced by previous crops immobilized N and increased the amount of fertilizer N required for optimal cotton yields. Results shown in Fig.…”

Nitrogen, Phosphorus, and Potassium Effects on Grain Sorghum Production and Stalk Rot Following Alfalfa and Birdsfoot Trefoil

“…On a very low soil-P vertisol in India, first-year fertilization increased sorghum yield from near zero grain to 3.5 Mg ha −1 with P rates increasing from none to 40 kg P ha −1 and the residual carried over to following years (Sahrawat et al, 1995). Booker et al (2007) also found that residual P fertilizer could result in a grain sorghum yield increase compared with zero P applications, even with no response to direct P fertilization.…”