Temporal variations in plant and soil characteristics following strip-till manure application

Abstract

Utilizing manure as a cost-effective plant nutrient source under dryland farming is often undermined by transportation and application costs of large quantities of manure. Reducing application quantities by applying manure only to the strip-till (ST) zone also may help reduce possible eutrophication and nitrate contamination of ground and surface water. A 3-yr study conducted at New Mexico State University’s Agricultural Science Center at Tucumcari, NM USA, compared the effectiveness of a one-time application of manure in the ST zone using dryland sorghum (Sorghum bicolor L.) as the test crop in four randomized complete blocks each year. Treatments were an ST control and manure rates [11 (Low (L)) and 22 (High (H)) Mg ha⁻¹] in combination with application techniques [surface (S) and 15\u202fcm incorporation by ST (I)]. Significant treatment X year interactions existed (P\u202f≤\u202f0.05) for sorghum biomass yield, tissue N and P, water-use efficiency (WUE) and the majority of residual soil characteristics with the H\u202f+\u202fI treatment consistently having greater results compared to the other treatments every year. The WUE for control, L\u202f+\u202fS, L\u202f+\u202fI, H\u202f+\u202fS, and H\u202f+\u202fI were 8.9, 9.9, 10.3, 11.7, and 13.9\u202fkg ha⁻¹\u202fmm⁻¹, respectively, three years after the single manure application (P\u202f<\u202f0.01, SEM\u202f=\u202f0.674). Despite having the higher biomass yield and tissue N and P concentrations, H\u202f+\u202fI continued to show high residual soil N and P, even three years after the single manure application. Consequently, significant agricultural benefits from a one-time application of manure continued to be evident beyond a three-year period. Due to predominant semi-arid dryland conditions, the N and P runoff losses were not evident in this study.