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Search results on 06/22/18
5181. Peterson, P.P.. 1919. Soil and climatic factors in relation to crop production on the Palouse.. ID Agr. Expt. Sta. Bull. #118.
8 rotations with N, P, K trts; clear response to N - 3 bu/ac on wheat at 200 #/ac NaNo3; manure response = 6 bu/ac; wheat yielded same after potatoes and fallow than peas or corn; made the most money with wheat/oats/peas ($51/ac/yr); ave. oat yield 1916 = 70+ bu/ac, 1918 = 26 bu/ac. Wheat, oats more affected by drought than corn or potatoes; this is the first mention of statistical methods. T: fertilizer response, rotation X net return.
10070. Mahler, R.. undated. Catena management in northern Idaho.. unpublished handout for Extension agent training.
In northern Idaho, water is often not limiting to crop production. Also, nutrient use efficiency is lower than in drier areas. Where annual precipitation is <17", fall application of all N fertilizer is best. But as rainfall increases, nutrient use efficiency can be increased by applying a greater share of N in the spring. Fertility experiments have shown that growers are probably underfertilizing bottomland positions and overfertilizing slopes for maximum net return from fertilizer. Several questions need to be answered to help improve nutrient efficiency. Is the value 2.7 lb N/bu wheat linear? Research results indicate that only 2.4 lb N/bu is needed at 80-90% of maximum yield. Is residual N used as efficienctly by plants from surface layers versus subsurface layers? What is the best approach to estimating N mineralization rates in a soil? Rates in northern Idaho can vary as much as 100% depending on weather conditions.