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Saturday, March 24, 2018


Browse on keywords: legume crop rotation nitrogen

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Search results on 03/24/18

805. Bezdicek, D.. no date. (STEEP green manure plots). unpublished.
Examined 3 legume green manures (red clover, Austrian winter pea, hairy vetch) and harvested spring pea, with 3 incorporations (plow, disk, chemical kill) and 3 N rates (0, 67, 134 kg N/ha). Prior to tillage, red clover and hairy vetch depleted 3.4 cm/m more moisture than spring pea, and AWP depleted 1.8 cm/m more. Soil residual N was highest under spring pea and lowest under red clover. N fixation estimates ranged from 76 for spring pea to 114 for AWP. Winter wheat yield was highest following red clover that had been plowed or disked. Chemical kill appeared to inhibit wheat yield, and N fertilizer could not overcome this depression. Yields after AWP were lower than red clover but higher than spring peas. Recovery of pea and wheat residue N ranged from 7-10% by a following wheat crop. Overseeding of red clover in a spring cereal was successful. T: residual moisture, N; yield response to the various treatments; recovery of N.

826. Bezdicek, D. and R. Lockerman. no date. Crop rotation and the response of cereal crops to nitrogen in the PNW. unpublished.
Experiments conducted at Pullman, WA and Bozeman, MT. Year 1 - legumes (rainfall -Pullman 500 mm, Bozeman 480 mm). Year 2 -Pullman winter wheat + N (rainfall 350 mm); Bozeman barley + N (rainfall 200 mm). Compared fababean, pea, lentil, chickpea, fallow at both locations. Pullman legumes were used as green manure, Bozeman legumes were harvested for seed. N fertilizer equivalents ranged from 30-86 kg/ha N at Pullman (fallow = 125) and from 27-81 kg/ha N at Bozeman (fallow = 53). All cereals responded to added N, although less so at Pullman. More N was removed in seed than was fixed. Seed legumes appeared to fix 50-100 kg/ha N. The rotation effect was more significant at Pullman. T: cereal yields; fertilizer N equivalent; moisture depletion.

1015. Bowren, K.E. (ed.).. 1986. Soil improvement with legumes.. Saskatchewan Agriculture, Soils and Crops Branch.
This excellent publication summarizes research over the past 40 years pertaining to the use of legumes for soil improvement in Saskatchewan. The role of legumes in maintaining soil nitrogen was crucial prior to available fertilizer. But their value extends beyond their nitrogen contribution to the improvement of soil physical properties. One study found the tillage draft requirement to be up to one-third lower where legumes had been a regular part of the rotation. The positive effects of alfalfa were measured for over ten years in a series of wheat crops compared to plots with no alfalfa. Over 17 years, the average grain yield from a wheat-wheat/clover-clover green manure rotation with no fertilizer were 30% higher that a wheat-wheat-fallow rotation with fertilizer. Moisture depletion by legumes is the biggest hurdle to their use in very dry areas. Adequate fertility for the legumes is necessary to maximize their benefit. Use of selected Rhizobium strains can improve nitrogen fixation, especially on acid soils. Several varieties of sweetclover are mentioned with adaptation to forage or green manure use. The booklet has numerous color photos and many data tables and figures.

2507. Heichel, G.H.. 1987. Legumes as a source of nitrogen in conservation tillage systems.. IN: J.F. Power (ed.) The role of legumes in conservation tillage systems..
A review of legume N contributions in crop rotations across the U.S. Covers nitrogen nutrition of legumes, legume nitrogen and companion plants, management effects, nonlegume yield response. T: examples of regional rotations with legumes; seasonal N fixation for various crops in various locations; N transfer from legume to grass; N budgets; N recovery.

2965. Ingham, I.M.. 1924. Effect of legumes in rotation upon the nitrogen content of the soil.. M.S. Thesis, Washington State College, Pullman, WA.
Soils at WSC farm were sampled to show residual effect of legumes upon following crops of wheat, and upon the N content of soil. T: Effect of legumes upon the following crops as shown by yields of wheat. Changes in the N content of soils after 5 years of crop rotations. Influence of various rotations on the N/C ratio of the soil.

3589. Kirby, E.M.. 1987. Soil moisture depletion and wheat yield response from annual legumes in the Pacific Northwest. M.S. Thesis, Dept. of Agronomy and Soils, WSU, Pullman, WA.
Legumes included chickpea, spring pea, lentil, fababean, sweetclover, rose clover, black medic, barrel medic. Sweetclover depleted more soil moisture than other legumes. Wheat yield increased following legumes relative to that after barley. Highest yield followed legume green manure with additional fertilizer N. Grain yields were similar for fallow, lentil, pea, chickpea, and fababean. T: soil moisture depletion; yield, N content of soil and grain.

3955. Mahler, R.L. and D.L. Auld. 1989. Evaluation of the green manure potential of Austrian winter peas in northern Idaho.. Agron. J. 81:258-264.
Austrian winter peas were evaluated as a green manure (GM) or seed pea (SP) crop, along with soil N levels, and subsequent yields of winter wheat (WW) and spring barley (SB). Four rotations were tested: GM-WW-SB; SP-WW-SB; SB-WW-SP; SF-WW-SB. Average N fertilizer equivalent values of 94, 75, and 68 kg/ha were provided by GM, SP, and SF (fallow) respectively, to the following wheat crop. Yield differences due to crop rotation or N fertilization rate were not observed in the third year of the cropping sequence. Austrian winter peas used as either a GM or SP provided more inorganic N than SF or SB. Although cereal crop yields were comparable, the SP-WW-SB was more profitable than GM-WW-SB or SF-WW-SB, due to the extra harvested crop.

6620. Speilman, R.S.. 1984. Nitrogen economy and agronomic evaluation of annual legume-cereal grain rotations.. M.S. Thesis, Plant and Soil Science, Montana State Univ., Bozeman, MT.
Legume biomass and seed yield were best for fababean, fieldpea, and chickpea. Potential for use of legumes for hay or silage. Barley yield after legumes was comparable to barley after fallow, and better than barley after barley or wheat. N contributions to the cropping system, except for field bean, were greater for legumes than for fallow. High N fertility levels from legume N plus fertilizer N resulted in premature soil moisture depletion. Optimum rotation performance will depend on balancing nitrogen fertility with expected available moisture.

7242. Veseth, R.. 1989. Reduced tillage for green manure legumes. STEEP Conservation Farming Update, Summer 1989, p. 3-5.
Three tillages were compared for incorporating Austrian winter pea or red clover green manure: moldboard plow plus shallow disk; shallow disk twice; no-till. At each N fertilizer rate, winter wheat yields were slightly higher with reduced tillage than with conventional tillage. A 60 lb/ac N rate substantially increased wheat yields after green manure, while the 120 N rate gave little or no yield increase. With no N fertilizer, the yield of winter wheat after both green manure crops compared favorably with yield of no-till winter wheat after a seed crop of spring peas. Legume N uptake by a following wheat crop was not affected by residue treatment, but recovery of legume N from the soil was about 10% lower with surface application than with soil incorporation. Also, wheat yields after chemically-killed green manures were consistently lower, and could not be fully recovered with fertilizer N. The mechanism of this suppression is not known.

7524. White, J.G.H.. undated. Grain legumes in sustainable cropping systems; a review.. unpublished manuscript, Plant Science Dept..
This paper briefly reviews the role that grain legumes can play in sustaining cropping systems. It presents various estimates of N fixation of grain legumes, with lupin and fababean showing the highest rates, followed by peas and lentils, chickpeas, and soybeans. Phaseolus beans are generally poor N fixers. Fababeans are more tolerant of soil mineral N than other species and will still fix large quantities of N when mineral N is present. Under drought stressed conditions, peas and lentils were more efficient in N fixation than fababeans. Only in lupins and fababeans was N fixation normally greater than the N removed in the seed. The roots and nodules of grain legumes are likely to be the greatest source of N for following crops. This N is often quickly mineralized within several weeks after harvest, and strategies are needed to prevent its loss. Grain legumes are also beneficial break crops, particularly for soil-borne diseases, and can help to control certain grassy weeds. Preceding grain legumes with a brassica crop has reduced the incidence of Aphanomyces root rot in peas, due to sulfur containing compounds. Most grain legumes suffer reduced yields if soils are compacted and poorly aerated. The paper contains numerous references and tables on nitrogen relations.

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