Evaluation Of Algorithm Thresholds For Crop Canopy Sensor-Based In-Season Nitrogen Application In Corn, Brian T. Krienke

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Nitrogen fertilizer is frequently the most limiting nutrient in corn production. Typically most nitrogen is applied before planting. Since nitrogen can leave the soil system fairly easily, the result can be an inefficient use of nitrogen fertilizer. Previous research has shown increased efficiency with no reduction in yield by applying nitrogen later in the season when the crop is actively growing, with rates regulated spatially through the use of active crop canopy sensors. This study evaluated the potential for N cutoff thresholds using a sufficiency index as the threshold value for areas with poor stand or an unrecoverable N deficiency. …

Effects Of Species, Water, And Nitrogen On Competition Among Three Prairie Grasses, Jerry L. Weatherford, Randall W. Myster

The Prairie Naturalist

We conducted an experiment to investigate effects of species, water (W), and nitrogen (N) on competition among little bluestem (Schizachyrium scoparium), sideoats grama (Bouteloua curtipendula), and indiangrass (Sorghastrum nutans). All biomass parameters and the root:shoot ratio of little bluestem were reduced by the presence off 1 of 2 other species, and its shoot biomass and total biomass were both increased by addition of N. Root and shoot biomass of sideoats grama were reduced by the presence of indiangrass and its total biomass was reduced by the presence of itself, whereas its shoot biomass was increased by addition of W at …

Dried Distillers Grain With Solubles In Laying Hen And Pullet Rations, Mahmoud K. Masa'deh

Department of Animal Science: Dissertations, Theses, and Student Research

The objective of this dissertation was to test different inclusion rates of dried distillers grains with solubles (DDGS) with or without enzyme supplementation. Study one was conducted to test DDGS at 0, 5, 10, 15, 20, or 25% on egg production parameter (24 through76 wk). As DDGS increased, egg wt. decreased during Phase I. However; no difference in egg wt. was observed during Phase II. Yolk color linearly increased with increasing DDGS level. Nitrogen and P retention increased as DDGS increased. Nitrogen and P excretion decreased with increasing DDGS. Study two was conducted to test DDGS inclusion of 0, 2.5, …

What Is The Potential Of Substituting Legumes For Synthetic Nitrogen In Warm Season Perennial Grasses Used For Stocker Cattle Grazing?, J. Biermacher, John A. Guretzky, Ryan Reuter, Maru Kering, Twain Butler, Job Springer, James Rogers, John Blanton, Joe Bouton

Department of Agronomy and Horticulture: Faculty Publications

Stocker cattle grazing warm season perennial grasses is an important economic activity in the southern Great Plains. Substantial increases in the price of nitrogen fertilizer is negatively affecting forage producers’ profitability. Two alternative nitrogen management systems that use annual and perennial legumes have been developed for bermudagrass pastures. The goal of the study is to determine if the legumes systems are more profitable than the conventional practice of applying synthetic sources of nitrogen. Enterprise budgeting techniques were employed to compare the economics of the legume systems relative to the common practice. Results of the two-year grazing study show that the …

Composting Or Stockpiling Of Feedlot Manure In Nebraska: Nutrient Concentration And Mass Balance, Matt K. Luebbe, G. E. Erickson, T. J. Klopfenstein, Matthew A. Greenquist, J. R. Benton

Department of Animal Science: Faculty Publications

When feedlot pens are scraped in the spring and summer, manure is often stored before land application can occur in the fall. Manure stockpiled or composted was evaluated for nutrient losses in 2 experiments for 104 (Exp. 1) and 111 d (Exp. 2). Stockpiles (n = 2 in Exp. 1 and n = 3 in Exp. 2) and compost windrows (n = 6 in Exp. 1 and n = 4 in Exp. 2) were constructed with feedlot manure scraped from pens and sampled upon construction and throughout the storage period. In Exp. 1, N loss was 3 times greater (P < 0.01) for compost compared with stockpile on d 104 (43.6 and 14.3%, respectively). Loss of C was 34.7% greater (P < 0.01) for compost compared with stockpile on d 104 (54.4 and 40.4%, respectively). Total mass loss (water + DM) was not different (P = 0.30) among storage methods on d 104 (20.0 and 15.8% for compost and stockpile, respectively). In Exp. 2, N loss from compost was 42.1% greater (P < 0.01) compared with stockpiling on d 111. Carbon losses in Exp. 2 were not different (P = 0.77) among storage methods on d 111 (38.4 and 37.5% for compost and stockpile, respectively). Total mass loss in Exp. 2 was less compared with Exp. 1 and was not different (P = 0.23) among storage methods (5.7 and 3.6% for compost and stockpile, respectively). When evaluated on a nutrient basis, stockpiled manure had greater N and C concentrations compared with composted manure.