Browse on keywords: fertility green manure
Search results on 01/23/19
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.
2480. Harris, G. and O.B. Hesterman. 1990. Quantifying the nitrogen contribution from alfalfa to soil and two succeeding crops using N-15.. Agron. J. 82:129-134.
This study quantified the N contribution from different alfalfa plant parts to a subsequent corn crop, various soil fractions, and a 2nd year spring barley crop. Corn recovered 17 and 25% of the alfalfa applied N-15 on a loam and sandy loam soil respectively. Alfalfa N-15 remaining in soil averaged 46% of the initial input. Most (96%) of the alfalfa N-15 remaining in soil was recovered in the organic fraction, with microbial biomass accounting for 18% of this recovery. More N-15 was reocvered by corn and in soil from alfalfa shoots than roots/crowns. More was recovered from a spring incorporation than a fall incorporation on the loam soil. Only 1% of the alfalfa N-15 from the original application was recovered by a 2nd year spring barley crop.
3163. Kouril, R.. 1988. Green manures as dynamic accumulators.. J. of Sustainable Agriculture (CA) 1:23-24.
The author describes various plants that appear to preferentially accumulate certain nutrient elements. By choosing these plants as green manures, fertility levels can potentially be increased. Typically, these plants thrive in areas with high amounts of the nutrient, but they can sometime make them more available. Buckwheat and mustards are considered phosphate accumulators, while oak leaves are calcium accumulators. A comprehensive listing of plants and their nutrient content is provided in the author's book "Designing and Maintaining Your Edible Landscape Naturally."
3875. Leggett, G.E. and W.L. Nelson. 1960. Wheat production as influenced by cropping sequence and nitrogen fertilization.. WA Agr. Expt. Sta. Bull. #608.
The average wheat yields resulting from annual cropping with optimum nitrogen fertilization were 13 bu/ac at Ritzville, 23 and Harrington and 29 at Dusty. The yields at Ritzville were too low for this practice to compete economically with the summer-fallow system. The average yields were high enough at Harrington and Dusty for this cropping system to be seriously considered. At Dusty annual cropping resulted in a yearly average yield of 6 bu/ac more than was obtained on fallowed ground. The yield of wheat following Austrian winter peas as a green manure crop at Dusty was greater than that obtained after alfalfa or sweetclover. Soil analysis revealed that nitrogen fertilization resulted in a carryover of nitrate-nitrogen for subsequent crops. This was especially notable under annual cropping and with high rates of application on summer-fallow. The protein content of the wheat was increased markedly by nitrogen fertilization. T: Nitrate-nitrogen in the soil before fertilization and the available soil moisture used by wheat as influenced by nitrogen fertilization cropping practice, Dusty. Yields of barley and wheat as influenced by alfalfa, sweetclover, and Austrian winter peas as green manure crops.
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.
5065. Patten, A.G.. 1982. Comparison of nitrogen and phosphorous flows on an organic and conventional farm.. M.S. Thesis, Dept. of Agronomy and Soils, WSU, Pullman, WA.
Two adjacent farms, one organically managed and the other conventionally managed, located in the Palouse region of eastern WA, were studied for 2 years. Soil organic matter, total N, extractable P, and extractable K tended to be higher in the top 30 cm of soil from the organic farm. Mineral nitrogen in the top 30 cm of soil from the conventional farm was higher than or equal to that of the organic farm. Average long-term changes calculated in soil N and P pools resulted in substantial deficits of 44 and 14 kg/ha/yr, respectively, for the organic farm and 23 and 5 kg/ha/yr for the conventional farm. However, nutrients deficits were not reflected in lower soil N and P levels in the plot area tested on the organic farm as compared to the plot area on the conventional farm.
6545. Smith, V.T.. 1948. Green manure crops for Idaho farms.. U. of Idaho Ext. Circ. #105.
Estimates legume N contribution and dollar value: alfalfa - 260 lb N, $40/ac; sweetclover - 160 lb N, $24/ac; clover - 140 lb N, $21/ac; peas/beans - 50lb N, $7/ac; green manure provides nitrogen, improved soil condition, organic matter; results from 10 yr experiment; grow legume seed for cash crop.
6738. Stickler, F.C. and L.R. Frederick. 1959. Residue paritcle size as a factor in nitrate release from legume tops and roots.. Agonomy J. 51:271-274.
Tested different particle sizes of tops and roots of alfalfa, sweetclover, red clover, and white clover. Coarse particles immobilized less N with alfalfa and white clover, but not red clover. Most treatments immobilized some N for the first 40-50 days, after which net nitrate release curves tended to become parallel. There was greater release of nitrate and recovery from tops than from roots. After 100 days incubation, recovery ranged from 43% for alfalfa, 34% for sweetclover, 25% for red clover, to 19% for white clover.
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.
8036. Welty, L.E. and L.S. Prestbye. 1988. Standing vs. disc-down green manure systems.. Agronomy Abstr. p. 142. Amer. Soc. Agron., Madison, WI.