| Contents Notes |
"Yearling beef manure was applied in three rates and three frequencies to 57 experimental plots located within a 9.3 ha field near Grand Junction, Colorado. The basic management practices investigated were irrigation and manure loading frequency, irrigation efficiency, and manure loading rates. Climatological conditions, soil moisture, evapotranspiration, groundwater outflows, and the furrow irrigation system performance were measured in the field plots. The soil was sampled and tested for nitrate-nitrogen (NO3-N), total Kjeldahl-nitrogen (TKN), ammonium-nitrogen (NH4-N), total organic carbon (TOC) and the common salinity constituents. Vacuum extractors below the soil root zone in 10 plots were used to measure and sample the water percolating downward. Crop N-uptake was evaluated by periodic analysis of plant samples. A soil-plant-water-N simulation model reported in the literature was used to evaluate the field data and predict the conditions in the field plots. Model simulations were run for a wide range of typical Grand Junction conditions to evaluate the effect of irrigation and manure utilization practices on NOs-N contamination of groundwater. The results indicate the time required to reach a steady-state condition and the quantitative effects of irrigation efficiencies, irrigation frequency, manure loading rates, manure loading frequency, and initial soil organic matter content." |
