Browse on keywords: fertility WA soil quality
Search results on 07/17/18
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.
3524. Kardos, L.T.. 1948. Lysimeter studies with cultivated and virgin soils under subhumid rainfall conditions.. Soil Science, 65:367-381.
Pullman, WA study. Lateral flow beneath the soil was significant, enough to cause erosion, but none was noticed. Less silaceous and compact layers in virgin soil. Total N in leachate water tended to be higher from the cultivated plot - cultivated ranged from 1-15 ppm, virgin 2-3 ppm. 2-5 times more total solids in cultivated leachate. Nitrate N higher from cultivated. Nitrate N leaching subsurface from slopes and concentrated in basins. Does not occur on virgin area. Subsurface leaching 20-30 inches below surface. W-P rotation encouraged erosion loss and subsurface nutrient loss. T: leachate chemical analysis.
6258. Sievers, F.J. and H.F. Holtz. 1924. The fertility of Washington soils (eastern WA section).. WA Agr. Expt. Sta. Bull. #189.
Description of soils and agronomy of the Palouse. Discusses annual cropping vs. summer fallow, and fertilizations. T: Yield of wheat under summer fallow vs. annual cropping. Effects of sodium nitrate on summer fallow vs. annual cropping. Alfalfa yields on Palouse silt loam as influenced by treatments.
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.
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.
7796. Zobler, L.. 1942. The effects of various cropping and fertility practices on the structure of a Palouse silty clay loam.. M.S. Thesis, Dept. of Agronomy and Soils, WSU, Pullman, WA.
Soil structure from a series of cropping experiment plots was analyzed. Treatments had been ongoing since 1920 and included continuous wheat and fallow/wheat systems that received: wheat straw, sodium nitrate, alfalfa hay, ammonium nitrate, and manure in various combinations. Continuous wheat system was destructive to macroaggregates while wheat/fallow system was destructive to microaggregates. T: Aggregate analysis - continuous wheat. Aggregate analysis - alternate wheat. Cationic exchange status cations and OM. Macrostructure and exchange cations. Microstructure and exchange cations. Structure and organic matter: macrostability and microstability.
8735. Haimanot, K.. 1977. Long-term effects of crop and soil management practices on crop yield and soil chemical composition.. M.S. Thesis, Dept. of Agronomy and Soils, Washington, ST. Univ., Pullman, WA 99164-6420.
The study site was located near Dusty, WA in the intermediate rainfall zone. Cropping system treatments were run from 1952 to 1970. Thirteen different cropping systems with three N fertilizer levels were used, including continuous cropping, green manures, and fallow systems. Wheat yields in rotation using 30 lb N/ac were higher than yields in an alfalfa rotation. Wheat yields were higher after Austrian winter pea green manure than after alfalfa or sweetclover. Per acre per year crop yields were highest for fertilized, continuous cropping. Soil pH increased with sweetclover GM and decreased with N fertilizer added. Significant increases in soil organic matter occurred in rotations with alfalfa (+0.08%), on winter wheat - fallow (+0.30%), and with winter wheat - spring wheat - fallow with N (+0.26%).
10287. Bhatti, A.U., D.J. Mulla, and B.E. Frazier. 1991. Estimation of soil properties and wheat yields on complex eroded hills using geostatistics and thematic mapper images.. Remote Sensing Environ. 37:181-191.
Spatial variability of organic carbon, soil P, and wheat yields was measured in eastern Washington using classical statistics and geostatistics. Organic carbon content was estimated from Landsat Thematic Mapper images. Goestatistics revealed strong spatial correlations relative to classical statistics. The spatial patterns were associated with changes in surface organic matter content across the landscape resulting from extensive erosion.