Tillage And Beef Cattle Manure Effects On Soil Nitrogen In A Dryland Rotation

Minimum tillage practices used in dryland cropping systems that reduce soil water evaporation and erosion may also decrease efficiency of manure nutrient utilization. We initiated a study in 1997 to investigate the effects of surface-applied stockpiled and composted beef cattle (Bos taurus) manure on soil N and sorghum [Sorghum bicolor (L.) Moench] and wheat (Triticum aestivum L.) yields and N-uptake within a wheat-sorghum-fallow dryland crop rotation. Paired terraces with no-tillage (NT) and stubble-mulch tillage (ST) systems were main plots of a single rotation phase. Stockpiled manure, composted manure, or commercial fertilizer (urea + ammonium phosphate) were applied prior to sorghum planting to supply estimated Nand P requirements of sorghum and wheat for a 3- year period. Phosphorus-based manure or compost treatments also received supplemental urea. Unfertilized treatment checks were included for yield and nutrient comparisons. Sorghum grain yield in 1999 exhibited a significant (P \u3c 0.05) response to tillage and fertilizer treatments. Plots receiving urea had 22% greater yield and 16% greater N-uptake than manure and compost amended plots. Moreover, manure and compost sorghum yields were no different or slightly lower than those of the unfertilized plots. Wheat was a good scavenger of residual N accumulated throughout the fallow period although grain yield was not affected by N treatments and tillage. Residual NO3--N after harvest and N-uptake were significantly greater under ST as compared with NT. Tillage may be required to maintain higher mineralization rates and permit a more efficient use of manure N

Mixed Crop-Livestock Systems in Semiarid Regions

The initial chapters of the monograph address the principles that underlie all dryland farming, and are the basis for the following chapters that address dryland farming issues around the worl

Linking soil microbial community structure to potential carbon mineralization: A continental scale assessment of reduced tillage

Potential carbon mineralization (Cmin) is a commonly used indicator of soil health, with greater Cmin values interpreted as healthier soil. While Cmin values are typically greater in agricultural soils managed with minimal physical disturbance, the mechanisms driving the increases remain poorly understood. This study assessed bacterial and archaeal community structure and potential microbial drivers of Cmin in soils maintained under various degrees of physical disturbance. Potential carbon mineralization, 16S rRNA sequences, and soil characterization data were collected as part of the North American Project to Evaluate Soil Health Measurements (NAPESHM). Results showed that type of cropping system, intensity of physical disturbance, and soil pH influenced microbial sensitivity to physical disturbance. Furthermore, 28% of amplicon sequence variants (ASVs), which were important in modeling Cmin, were enriched under soils managed with minimal physical disturbance. Sequences identified as enriched under minimal disturbance and important for modeling Cmin, were linked to organisms which could produce extracellular polymeric substances and contained metabolic strategies suited for tolerating environmental stressors. Understanding how physical disturbance shapes microbial communities across climates and inherent soil properties and drives changes in Cmin provides the context necessary to evaluate management impacts on standardized measures of soil microbial activity.This article is published as Rieke, Elizabeth L., Shannon B. Cappellazzi, Michael Cope, Daniel Liptzin, G. Mac Bean, Kelsey LH Greub, Charlotte E. Norris et al. "Linking soil microbial community structure to potential carbon mineralization: A continental scale assessment of reduced tillage." Soil Biology and Biochemistry 168 (2022): 108618. Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted