Browse on keywords: crop rotation green manure soil quality
Search results on 06/24/18
2406. Hanley, Paul (ed.). 1980. Earthcare: Ecological agriculture in Saskatchewan.. Earthcare Information Centre.
A well-written text covering all aspects of biological farming in the prairie region of Saskatchewan. Practices apply to small and large farms. Includes reports from selected farms. References at the end of chapters.
5705. Rasmussen, P.E., H.P. Collins, and R.W. Smiley. 1989. Long-term management effects on soil productivity and crop yield in semi-arid regions of eastern Oregon.. OR Agr. Expt. Sta. Bulletin 675.
Summary of over 50 years of plot research at Pendleton, OR, with some results from Weston and Moro. Focuses on results from a continuous set of plots at the Pendleton station. Manure maintained highest yields, highest soil organic matter, highest pH compared to other treatments. Nitrogen fertilizer had a more marked effect on water infiltration than various tillage treatments. Green manure systems are generally not economic in the drier areas, due to competition for moisture with wheat, which is the most profitable crop. Legumes can contribute between 40 and 80 lb/ac N to the following crop. Varietal improvement over the past 50 years has been the most significant factor in increasing wheat yields. Burning straw accelerated organic matter losses from the soil and eventually reduced yields. Marginal returns have generally been lower from alternative crops than from wheat.
6684. Stephens, D.E.. 1944. Effect of tillage and cropping practices on runoff, erosion, and crop yields in the wheat growing areas of Washington, Idaho, and Oregon.. USDA-SCS. Conservation practices on wheat lands of the Pacific Northwest..
An excellent summary of the dryland experiment station research in WA, ID and OR. Describes research on stubble mulching, tillage implements, crop rotations, fallow, etc. The use of sweetclover or alfalfa-grass were encouraged. T: yield, runoff, soil loss by tillage, rotation, fertilizer.
8735. Haimanot, K.. 1977. Long-term effects of crop and soil management practices on crop yield and soil chemical composition.. M.S. Thesis, Dept. of Agronomy and Soils, Washington, ST. Univ., Pullman, WA 99164-6420.
The study site was located near Dusty, WA in the intermediate rainfall zone. Cropping system treatments were run from 1952 to 1970. Thirteen different cropping systems with three N fertilizer levels were used, including continuous cropping, green manures, and fallow systems. Wheat yields in rotation using 30 lb N/ac were higher than yields in an alfalfa rotation. Wheat yields were higher after Austrian winter pea green manure than after alfalfa or sweetclover. Per acre per year crop yields were highest for fertilized, continuous cropping. Soil pH increased with sweetclover GM and decreased with N fertilizer added. Significant increases in soil organic matter occurred in rotations with alfalfa (+0.08%), on winter wheat - fallow (+0.30%), and with winter wheat - spring wheat - fallow with N (+0.26%).
10576. Janzen, H.H. and G.D. Radder. 1989. Nitrogen mineralization in a green manure amended soil as influenced by cropping history and subsequent crop.. Plant Soil 120:125-131.
In a greenhouse study, surface soil from long-term experimental spring wheat rotations was amended with 15N labelled legume green manure and subsequently cropped (canola and spring wheat) or incubated. N mineralization from both the indigenous soil N and from green manure was suppressed in cropped soil. Net N mineralization in the uncropped and cropped treatments averaged 73 and 43 mg/kg, respectively. This difference was attributed in part to enhanced biological immobilization in the rhizosphere. These data suggest that short-term N mineralization is favored by fallowing soil after green manure application whereas N retention in organic matter is favored by immediate cropping.