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Thursday, March 22, 2018


Browse on keywords: legume nitrogen ID

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Search results on 03/22/18

816. Bezdicek, D.. no date. (Influence of residual soil N on N2 fixation; N2 fixation of chickpeas). unpublished.
High levels of residual soil N decreased N2 fixation. There was a negative correlation between the fraction of plant N derived from N2 fixation and total mineralizable N and KCl extractable N. N2 fixation was reduced by about 2.8 kg/ha for each kg/ha of available soil N. Seed yield response from inoculation ranged from 5-70% and was negatively correlated with available soil N. Residual soil moisture in July was greatestfor large seeded legumes > forage legumes > winter wheat. T: N fixation in chickpeas.

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.

4022. Mahler, R.L.. 1990. Nitrogen database project - final report.. unpublished report for Dryland Cereal/Legume LISA project.
This project had two components: 1) development of a comprehensive database on winter wheat response to nitrogen fertilizer rates; 2) evaluation of the potential of peas, alfalfa, and wheat straw as nitrogen sources for a following wheat crop in rotation. The database study examined winter wheat yield response to 41 nitrogen rates. When soil test N + mineralizable N + fertilizer N ranged from 101 to 175 kg/ha, a requirement of 2.75 lb N per bushel of wheat was calculated. This agrees with the figure calculated by Leggett in the 1950's, indicating that modern varieties have not changed in their basic nitrogen requirement, when nitrogen fertilizer efficiency is assumed to be 50%. At total available N rates greater than 175 kg/ha, the N requirement per bushel of wheat increased dramatically. Low rates did not show a large increase in efficiency on a per bushel basis. At Moscow, N fertilizer application rates less than 95 kg/ha resulted in greater than 50% N use efficiency. Efficiency declined rapidly at rates above this. The green manure study compared alfalfa, pea, and green wheat straw residues applied at 1, 2, and 3 mt/ha. In general, higher rates of pea and alfalfa resulted in higher wheat yields. The highest yields were with the high rate of pea residue. It was more effective than alfalfa residue, probably due to faster decomposition. Alfalfa provided more N per ton of residue (31 kg/mt) than the peas (29 kg/mt), while straw added 19 kg/mt.

6518. Smith, S.C., D.F. Bezdicek, R.F. Turco, and H.H. Cheng. 1987. Seasonal N2 fixation by cool-season pulses based on several 15N methods.. Plant Soil 97:3-13.
Used 15N to determine N2 fixation by fababean, lentil, Alaska pea, Austrian winter pea, blue lupin, and chickpea. Mean seasonal N2 fixation by fababean, lentil, and AWP was near 80 kg N/ha, pea and lupin near 60 kg N/ha, and chickpea less than 10 kg N/ha. The net effects on the soil N pool ranged from 70 kg N/ha input by lentil to a removal of 48 kg N/ha by chickpea. Pulse crops often remove more N in the seed than they fix, leaving a deficit for the next crop. T: legume DM, total plant N, seed yield, seed N; N fixation values by different methods.

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.

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.

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