Location: Northwest Irrigation and Soils Research
Project Number: 2054-12000-011-15-T
Project Type: Trust Fund Cooperative Agreement
Start Date: Nov 1, 2017
End Date: Jun 30, 2019
Develop recommendations for optimal manure application rates and timing (annual or biennial, for a few years or several years of manure application), on the basis of yield potential, grain quality, soil quality, disease pressure, and nutrient uptake.
This eight-year study is entering its fifth year. The selected crop rotation for field #1 is wheat-potatoes-barley-sugar beets, and will be planted to wheat in 2017. The selected crop rotation for field #2 is barley-sugar beets-wheat-potatoes, and will be planted to wheat in 2019. Treatments (trt) are manure application timing (manure will be applied prior to grain establishment every year or every other year) and rate (9, 18, and 27 ton/acre, dry weight basis). Additional fertilizer treatment (chemical sources applied at agronomic rates based on University of Idaho (UI) fertilizer guides) and a control treatment (no nutrient source applied) is also included, for a total of 8 treatments per field (2 application timings at 3 rates + 1 standard chemical fertilizer trt + 1 control trt). Treatments are replicated four times in a randomized complete block, for a total of 32 treatments per field. Manure samples are analyzed for moisture, soluble salts (EC), pH, organic matter, carbon, nitrogen, ammonium, and other agronomic macro- and micronutrients. Manure is applied in October and is incorporated the same day as application to avoid ammonia volatilization losses. Hard red spring wheat (Jefferson) will be planted into field #1 in 2017 in early April at standard irrigated rate of 1 million seeds per acre. Response variables will include soil tests, tissue tests, disease reactions, grain quality, falling number, and baking quality. Soil tests will include a spring comprehensive soil test prior to fertilization and planting at 0-12 and 12-24 inch depths. Plant uptake of nitrogen (N), phosphorus (P), potassium (K), and other macro/micronutrients will be analyzed through destructive sampling of above soil-line plant biomass near harvest. Approximately one week prior to harvest, whole plant samples will be collected from a 3 ft. X 5 ft. section in non-yield rows in each plot. Plants will be clipped at the soil surface and weighed. A subsample will be collected, dried, and weighed again. Dried tissue subsamples will be analyzed for total N, P, and K content. These values will be used to estimate nutrient removal potential, and how it is affected by the manure application treatments. Disease pressure will be monitored throughout the growing season, with samples collected in the seedling stage prior to tillering and at harvest to measure soil-borne disease pressure. Foliar diseases will be controlled with an appropriate fungicide in order to protect economic yield, to reflect standard best management practices (BMP). Plots will be harvested in mid-August using the UI Wintersteiger harvester, harvesting 5-foot wide by 30-foot length. Test weight and moisture will be measured using the Juniper System Grain Gauge on the combine. Protein analysis of grain will be conducted at the UI Aberdeen Wheat Quality Lab. Yield will be determined using designated row areas in each plot, and will not be sampled or disturbed as not to compromise yield potential or quality traits.