Predicting nitrogen mineralization from dairy manure and broadleaf residue in a semiarid cropping system

Abstract

Approximately 37% of US milk production occurs in semiarid regions providing an opportunity to recycle manure nutrients through a variety of cropping systems. Accurate prediction of nitrogen (N) mineralization is critical to determine manure application suitability in intensive irrigated agriculture as many crops in the region have quality parameters that are sensitive to N. Research was conducted in southcentral Idaho to evaluate N mineralization via a buried bag methodology to develop a predictive N‐mineralization model. The study was arranged in a randomized complete block design with manure application rates of 18, 36, and 52 Mg ha−1 (dry wt. basis) both annually and biennially with synthetic fertilizer and untreated check treatments. The crop rotation included small‐grain and broadleaf crops. In the final year of the study, preplant soil organic carbon (SOM), TN, and NO3‐N concentrations were positively linearly correlated with manure application rate. Nearly five‐times as much N was mineralized annually in the 0 to 30 cm depth as compared to the 30 to 60 cm depth. Increased rates of N mineralization for each kg of added N occurred in years when residue from broadleaf crops (slope = 0.17) was applied as compared to years with manure only application (slope = 0.07). Stepwise modelling determined that the most predictive model for seasonal N mineralization (R2 = 0.79) included manure N, residue N, soil organic matter, and electrical conductivity. These results allow preplant N mineralization estimation and will prove critical for managing manure in semiarid regions for agronomic, economic, and environmentally sound crop production.This article is protected by copyright. All rights reserved

Barley residue biomass, nutrient content, and relationships with grain yield

“…As a result of this, Idaho produces the largest amount of barley (33%) in the United States with irrigated state yields that are some of the highest in the country approaching 6.0 Mg ha −1 (USDA-NASS, 2023b). Other crops grown in rotations in the region, particularly potato (Solanum tuberosum L.) and sugar beet (Beta vulgaris L.), retain high nutrient concentrations in the aboveground biomass that is recycled back into the soil in subsequent growing seasons (Leytem et al, 2023). Soil nutrient content can also be elevated due to the low-rainfall semiarid environment which limits runoff, soil formation characteristics associated with the Snake River Plain, and residuals from previous nutrient applications (Rogers, Dari, & Schroeder, 2019).…”