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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.
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.