Browse on keywords: crop rotation green manure fertility
Search results on 03/18/18
754. Bennett, W., D. Pittman, D. Tingey, D. McAllister, H. Peterson, and I. Sampson. 1954. Fifty years of dry land research (at the Nephi Field Station).. Utah Agr. Expt. Sta. Bulletin 371.
Summarizes the results of 50 yr of research at the Nephi Field Station in cental Utah. Discusses climate - spring rainfall crucial, fall emergence of wheat correlated to high yields. Ave. annual precipitation is 12.65 in. Tillage experiments - fall verus spring plowing did not affect yields, while late spring plowing lowered yields. Plowing to 8" depth increased yields by 8% compared to plowing at 5". Yields were higher with plowing and no further cultivation on fallow (weeds controlled) than with normal fallow tillage. Yields were poor with stubble mulch. Fertility: A pea green manure increased wheat yields both in the short and long term. Wheat yields were sometimes depressed by green manure, due to moisture shortage or N immobilization. Manure application increased wheat yields in all treatments, and was more beneficial in wet years. N fertilizer increased wheat yields and protein. Burning straw increased yields for 30 yr, then they began to decline. No response to P. Wheat-fallow gave the greatest yields and net returns, and wheat was the only crop distinctly benefitted by summerfallow. Alfalfa depressed the following wheat yields but improved soil fertility. Continuous wheat yielded less than 40% of wheat-fallow. Wheatgrasses showed potential for forage and seed. Spring wheats yielded 60% of winter wheat. Only 32% of rainfall was stored as soil moisture in summerfallow. Overall, yields were low (15-25 bu/ac) and treatment differences were small (1-3 bu). These results predate the semidwarf wheat varieties.
3875. Leggett, G.E. and W.L. Nelson. 1960. Wheat production as influenced by cropping sequence and nitrogen fertilization.. WA Agr. Expt. Sta. Bull. #608.
The average wheat yields resulting from annual cropping with optimum nitrogen fertilization were 13 bu/ac at Ritzville, 23 and Harrington and 29 at Dusty. The yields at Ritzville were too low for this practice to compete economically with the summer-fallow system. The average yields were high enough at Harrington and Dusty for this cropping system to be seriously considered. At Dusty annual cropping resulted in a yearly average yield of 6 bu/ac more than was obtained on fallowed ground. The yield of wheat following Austrian winter peas as a green manure crop at Dusty was greater than that obtained after alfalfa or sweetclover. Soil analysis revealed that nitrogen fertilization resulted in a carryover of nitrate-nitrogen for subsequent crops. This was especially notable under annual cropping and with high rates of application on summer-fallow. The protein content of the wheat was increased markedly by nitrogen fertilization. T: Nitrate-nitrogen in the soil before fertilization and the available soil moisture used by wheat as influenced by nitrogen fertilization cropping practice, Dusty. Yields of barley and wheat as influenced by alfalfa, sweetclover, and Austrian winter peas as green manure crops.
7761. Zentner, R.P., E.D. Spratt, H. Reisdorf and C.A. Campbell. 1987. Effect of crop rotation and N and P fertilizer on yields of spring wheat grown on a black chernozemic clay.. Can. J. Plant Sci., 67:965-982.
Including grass-legume forage, or legume green manure crops in the rotation increased yields of wheat grown on the unfertilized partial fallow by 15-24% and on unfertilized stubble by 33-71%; the yields were similar and sometimes higher than those obtained on fallow in the well-fertilized monoculture wheat rotations. Yields of fallow- and stubble-wheat were generally maintained over time with the application of recommended rates of N and P fertilizers, or by inclusion of legume-forage crops in the rotation, but yields of unfertilized stubble-wheat declined with time possibly reflecting declining soil fertility.
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%).