Browse on keywords: crop rotation wheat tillage
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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.
1773. Durst, L., G. Kahnt and E. Kubler. 1988. Effects of preceeding "break crops" on winter wheat and influence of cultural practices.. J. Agron. Crop. Sci., 160:239-249.
After the break crops wheat yield decreased within a range of 4 dt/ha as follows: alfalfa-beans-rape/clover-grass/maize. Raising N-fertilization hardly allowed to improve the value of break crops. The manner of primary tillage exerted stronger influence on the yield than the level of N-fertilization. Using the rotary tiller, at beginning of growth there may be calculated on 15% higher NO3-values and/or higher N-mineralization or N-transformation. Eyespot disease could not be prevented sufficiently and purposefully by another break crop, N-fertilization or primary tillage. Recurrent rotavating suppressed weeds less than ploughing.
4798. Nelson, A.L.. 1930. Methods of spring wheat tillage.. WY Agr. Expt. Sta. Bulletin 173.
No spring wheat yield benefit was realized from having winter rye or peas as green manure in the rotation over 17 years. Some years it was observed that the green manure had not begun to decay a year after plowdown. For the first five years of the study, the pea green manure in rotation was superior to fallow preceding spring wheat. A 3-year rotation study found spring wheat to yield 23% more following dry beans compared to corn.
4807. Nelson, A.L.. 1950. Methods of tillage for winter wheat.. WY Agr. Expt. Sta. Bulletin 300.
Fallow/winter wheat production decreased soil N by 33% in the top 6" over 35 years. Continuous cropping lost 24% of the soil N. Crop rotations using green manure every 4th year did not decrease the loss of soil N. Average winter wheat yields (bu/ac) over 34 years for 3 rotations were: oats/rye(GM)/winter wheat/corn - 12.9; oats/peas(GM)/winter wheat/corn - 12.7; fallow/winter wheat - 13.7; oats/corn/winter wheat/rye - 13.2; oats/corn/winter wheat/peas - 14.1; oats/corn/winter wheat/fallow - 13.2. It was observed that green manure took years to break down. Tillage with an eccentric one-way increased winter wheat yields 2 bu/ac over 10 years compared to plowing. The eccentric one-way conserved moisture. Continuous cropping resulted in winter wheat yields 55% of biennial yields following fallow. Soil moisture was 3-4% lower in October after continuous cropping versus fallow.
5981. Rovira, A.D.. 1986. Influence of crop rotation and tillage on Rhizoctonia bare patch of wheat.. Phytopathology, 76(7):669-673.
Rhizoctonia bare patch was more severe in direct drilled wheat than in wheat sown into cultivated soil. The area of affected crop was consistently larger when wheat followed a mixed annual pasture of grasses and Medicago spp. than when wheat followed wheat, peas, or grass-free pasture of Medicago spp. All isolates of R. solani were pathogenic on wheat, barley, peas, Medicago spp., annual ryegrass, and barley grass.
6359. Smiley, R., D. Wilkins, W. Uddin, S. Ott, K. Rhinhart, and S. Case. 1989. Rhizoctonia root rot of wheat and barley.. OR Agr. Expt. Sta. Special Report 840, p. 68-79..
Rhizoctonia root rot is now considered the most severe root disease of barley in the PNW. It is more important than take-all and Pythium on wheat produced in drier areas (<16" precip.). Based on long-term plots at Pendleton, different management systems are unlikely to greatly influence the biological resistance of soils to Rhizoctonia. Rotational crops susceptible to Rhizoctonia include wheat, barley, peas, chickpeas, lentils, and rapeseed. The disease is less apparent on small grains after legumes than after cereals. Rhizoctonia damage is always highest on no-till systems, but yields may not suffer due to improved water relations under conservation tillage. Australian research indicates that applications of N and P fertilizers can reduce the disease. There appear to be detrimental herbicide interactions with Rhizoctonia, particularly Glean on high pH soils. Also, the use of glyphosate increased disease incidence, perhaps by signalling the pathogens to move from the dying plants to newly seeded ones. A delay of at least 2 weeks is suggested between chem kill and planting of a new crop.
7753. Young, Frank. 1989. Integrated pest management project update.. Paper presented at WA state weed conference, Nov. 13,1989.
This paper briefly describes the IPM weed study underway near Pullman, WA. This experiment uses field size plots for several rotation, tillage, and weed control treatments. Four years of research have been completed. Generally, the yield of spring cereals has not been affected by either weed management levels or tillage systems. Yields of spring peas were 17% greater with maximum weed management compared to the minimum level. Only three of the minimum tillage systems left sufficient residue cover to meet the 30% SCS requirement. However, all reduced tillage systems left more than 30% residue during the critical winter months. Yields of peas under conservation tillage were 13% greater than with conventional tillage, indicating the ability to reduce erosion potential with this crop and not suffer a yield penalty. No-till seeding has been successful either after spring wheat or spring peas, but not after the high residue of winter wheat.