Fifteen years of wheat yield, N uptake, and soil nitrate–N dynamics in a biosolids-amended agroecosystem

• Published in: Agriculture, ecosystems & environment ecosystems & environment, 2010-10, Vol.139 (1), p.116-120
• Main Authors: Barbarick, K.A., Ippolito, J.A., McDaniel, J.
• Format: Article
• Language: English
• Subjects: agroecosystems; Agronomy. Soil science and plant productions; Argiustolls; Biological and medical sciences; biosolids; Carbon monoxide; correlation; dryland farming; Dynamics; fallow; fertilizer rates; Fertilizing; Fundamental and applied biological sciences. Psychology; General agroecology; General agroecology. Agricultural and farming systems. Agricultural development. Rural area planning. Landscaping; General agronomy. Plant production; Generalities. Agricultural and farming systems. Agricultural development; grain yield; Grains; linear models; Linear regression; nitrate nitrogen; nitrogen; nitrogen fertilizers; nutrient uptake; Paleustolls; Planar regression; planare regression; regression analysis; sandy loam soils; sewage sludge; Slopes; Soil (material); soil amendments; soil nutrient dynamics; summer; Three dimensional; Triticum aestivum; Uptakes; Wheat; winter wheat; Winter-wheat summer fallow
• ISSN: 0167-8809; 1873-2305
• DOI: 10.1016/j.agee.2010.07.007

▶ Planar (3D) model is superior to linear model for comparing cumulative wheat grain yield and N uptake to biosolids or N fertilizer rates. ▶ With smaller grain yields, larger accumulation of soil nitrate–N occurs. Understanding N dynamics in biosolids-amended agroecosystems can help avoid over-application and the potential for environmental degradation. We investigated 15-years of biosolids application to dryland-wheat ( Triticum aestivum L.) grown on Weld loam soils (fine, montmorillonitic, mesic Aridic Paleustolls) located about 25 km east of Brighton, CO, USA, questioning what is the relationship between cumulative grain yield and N uptake (N removal) and biosolids or N fertilizer rates and how many times biosolids or N fertilizer are applied? How are wheat-grain production and N uptake intertwined with residual soil NO 3–N? We found that biosolids or N fertilizer rates plus the number of applications of each material produced planar-regression (3D) models with 15-years of grain yield and N uptake data (all R 2 > 0.93). To evaluate how yield or N uptake impacted residual soil NO 3–N, we completed linear regressions on yield, N uptake, and soil NO 3–N. We then correlated the slopes where P < 0.10 for the yield and soil NO 3–N and the N uptake and soil NO 3–N. A significant negative relationship was found for biosolids application for each of these comparisons while the N fertilizer results were inconsistent. For the biosolids treatments, as yield or N uptake increased, residual soil NO 3–N decreased. Our findings show that planar-regression models could aid biosolids beneficial-use management programs when considering agroecosystem N dynamics.