Browse on keywords: yields landscape management
Search results on 12/09/13
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 unpublished handout for Extension agent training.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.
10287. Bhatti, A.U., D.J. Mulla, and B.E. Frazier. 1991. Estimation of soil properties and wheat yields on complex eroded hills using geostatistics and thematic mapper images.. Remote Sensing Environ. 37:181-191.
Spatial variability of organic carbon, soil P, and wheat yields was measured in eastern Washington using classical statistics and geostatistics. Organic carbon content was estimated from Landsat Thematic Mapper images. Goestatistics revealed strong spatial correlations relative to classical statistics. The spatial patterns were associated with changes in surface organic matter content across the landscape resulting from extensive erosion.