Browse on keywords: legume nitrogen equivalent
Search results on 05/20/13
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 unpublished.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 unpublished.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.
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.
7662. Wright, A.T. and E. Coxworth. 1987. Benefits from pulses in the cropping systems of northern Canada. p. 108. IN: J.F. Power (ed.). The role of legumes in conservation tillage systems..
Investigated yield and N response in barley and wheat, 1 and 2 years after pulse crops of fababean, pea, and lentil. Overall yields were higher on fababean and field pea residues than lentils. Soil tests could not attribute yield differences among crop residues to differences in soil N levels at time of seeding. Nitrogen fertilizer equivalents for barley were 105, 85, and 50 lb N/ac for fababean, peas, and lentils. Legume residues influenced barley grain quality. In the second year following pulses, the dry matter yield, grain yield, and N uptake of wheat was 15% higher than in the continuous cereal sequence. Analysis of 3 completed rotation cycles showed that cropping sequences that included pulses were considerably more productive than the continuous cereal sequence in terms of net energy production and economic gross margin to cash costs. Field peas were the most effective first-year crop in terms of net energy production.
8578. Pannkuk, Chris. n.d.. Estimating N credits for no-till wheat.. unpublished report, Land Management unit, USDA-ARS, Pullman, WA 99164.
N contributions from tinga pea (hayed or green manure) and black medic (green manure) of 70, 54, and 59 lb N/ac, respectively, were made on a subsequent spring wheat crop. All crops were planted no-till. Poor wheat stand establishment after the green manure tinga pea may have caused the low apparent contribution. Three nitrogen rates of 0, 50, and 100 lb N/ac were used. Wheat yields after legume at zero N were about twice as high as in continuous wheat, but the 100 N rate brought the latter yields up to par with the wheat after legume.
8763. Smith, Larry. n.d.. An evaluation of green manure plowdown systems in Nex Perce County, Idaho.. unpublished results from Cooperative Extension, 1239 Idaho St., Lewiston, ID 83501.
Three growers evaluated the nitrogen benefits and economics of their use of green manure legumes prior to winter wheat production. Two farmers used Austrain winter pea, and one used a sweetclover/red clover mix. Soil tests at various stages of production indicated an increase in available N (0-3') after green manure plowdown of 60-200 lb/ac. The cost of the green manure ranged from $15-27/ac. Clover appeared to produce the most N (191 lb/ac) while winter peas returned 62-116 lb/ac. Landlords did not charge rent for the green manure year, which helped the economic viability. Residual N values indicated that fertilizer N could have been greatly reduced or eliminated for the winter wheat after plowdown. Net returns for the two-year period ranged from $95-215/ac.
9674. Lory, J.A., M.P. Russelle and T.A. Peterson. 1989. Refining the legume nitrogen credit.. Agronomy Abstracts, p. 245. Amer. Soc. Agron., Madison, WI.
The fertilizer N replacement value of a legume (or N credit) has been mistakenly interpreted by some producers and researchers as a measure of the amount of legume N available to the non-legume, when it is actually an index of combined rotation effects and availability of legume-N. Much N-credit research has failed to consider the impact of cultural practices on the resulting calculation of legume N-credits. For example continuous corn fertilizer-N response curves used to develop N-credits are affected by management and evironmental factors. These factors influence the shape of fertilizer response curves, and thereby affect the N-credit determined from them. For example, improving fertilizer-N use efficiency by changing time, source, or method of application to continuous corn increases the resulting legume N-credit. Only careful attention to choice of cultural and fertilizer-N management will produce reliable estimates of N-credit.