Browse on keywords: fertility WA organic matter
Search results on 01/17/18
1657. Doughty, J.L., F.D. Cook, and F.G. Warder. 1954. Effect of cultivation on the organic matter and nitrogen of brown soils.. Canadian J. Agr. Sci. 34:406-411.
Over 14 yr of cropping, soils lost 26% of OM and 33% of total N. Only part of the N loss is accounted for by crop removal. Some N is lost by leaching, also some gaseous loss of N other than as ammonia.
2137. Fulmer, E.. 1896. Some notes concerning the nitrogen content of soils and humus.. WA Agr. Expt. Sta. Bull. #23.
In Whitman Co., the organic matter in cultivated soils ranged from 3-8%. The first part of this bulletin is an excellent discussion on soil N components. "The author became concerned that humus was not receiving the attention that its importance as a factor in soil fertility demanded. Only a small proportion of soil analysis has included a determination of humus..." T: Shows fractions of soil N for soils from various counties - including Whitman Co. includes: Humus; Total N in soil; Organic N; N in humus; Organic matter.
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.
6268. Sievers, F.J. and H.F. Holtz. 1926. The significance of N in soil organic matter relationships.. WA Agr. Expt. Sta. Bull. #206.
"...there is such a close relationship between soil productivity and soil organic matter that this relationship has long been used as a basis for determining soil fertility. ...should agricultural practices strive arbitrarily to increase or maintain OM so that larger yields may be obtained, or should they be so conducted that larger yields are the primary consideration, thus taking for granted that the necessary maintenance of OM will follow? The answer to this is governed quite as largely by economic as scientific relationships." This bulletin coins the adage "you maintain the N and you maintain it all." It provides detailed descriptions of: moisture/OM relationships; N/C ratios; OM decomposition; maintainance of OM; crop residues.
6479. Smith, H.W. and S.C. Vandecaveye. 1946. Productivity and organic matter levels of Palouse silt loam as affected by organic residues and nitrogen fertilizers.. Soil Science 62:283-291.
Considers changes to soil over 23 yrs, 1921-1944, and summarizes yield data. T: Soil treatment and crop yields. N content and effect of treatment. C content and effect of treatment.
6555. Smith, V.T.. 1941. The effect of organic residues and fertilizers on the yield and quality of wheat and on the organic matter status of a semi-arid soil.. MS Thesis, Washington State College, Pullman, WA.
OM was increased most by addition of manure and least by 40 lb/ac application of straw. Suggestions for OM maintenance are: a) addition of straw and manure increases C-N of soil without depressing yield; b) addition of ammonium sulfate both with and without straw increases C, N in the spring, N in grain and straw, and yield of straw, without depressing yield; c) addition of either straw and manure or straw and N are equally efficient in increasing C and N in soil. T: many. eg.: grain yields from the Organic Matter Maintenance Series of plots, 1923-1940. Acre inches of available moisture in the soil at the Organic Matter Maintenance Series. Pounds of nitrates per acre at the Organic Matter Maint. Series plots.
7326. Washington Agr. Expt. Sta.. 1923. Soil fertility problems in eastern Washington.. 33rd Annual Report, Bull. #180, p.49-52..
"Forty years of wheat cropping in the Palouse have depleted soils of 22% N and 35% OM, and nitrate accumulation is proportional to OM levels. It is evident that future crop production must be based upon OM or legumes in crop rotation." Some deductions: 1) OM maintenance depends on N content of the (crop) residue; 2) It becomes more difficult to maintain OM and N as the soil becomes more depleted; 3) the biological activity of the soils in eastern Washington decreases directly with loss of OM and N. T: CO2 evolution and nitrate-N accumulation from soils. CO2 evolution from soils of varying N treated with straw and alfalfa.
11116. Wegner, G.. 1992. The benefits of biosolids.. Wheat Life (April 1992), p. 11-13.
Dryland cereal farmers are beginning to test the value of biosolids (treated sewage sludge) on their fields. Gary Wegner has found that his crop yields are increasing where biosolids are applied, perhaps due to addition of trace elements such as zinc. Also, biosolids add organic matter which improves soil structure and reduces erosion potential. Biosolids are a free source of nutrients for farmers, but not enough are available to cover very many acres each year.