Browse on keywords: crop rotation soil quality WA
Search results on 07/21/18
978. Bolton, H., L.F. Elliott, R.I. Papendick and D.F. Bezdicek. 1985. Soil microbial biomass and selected soil enzyme activities: effect of fertilization and cropping practices.. Soil Biol. Biochem., 17:297-302.
The microbial properties of two adjacent fields were compared, one being under organic management, the other conventional management. Microbial indices tended to be more favorable on the organic field, with higher microbial biomass and enzyme activities.
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.
5771. Reganold, J.P., L.F. Elliott and Y.L. Unger. 1987. Long-term effects of organic and conventional farming on soil erosion.. Nature, 330(26 Nov.):370-372.
The long-term effects (since 1948) of organic and conventional farming on selected properties of the same soil are compared. The organically-farmed soil had significantly higher organic matter content, thicker topsoil depth, higher polysaccharide content, lower modulus of rupture and less soil erosion than the conventionally-farmed soil. This study indicates that, in the long term, the organic farming system was more effective than the conventional farming system in reducing soil erosion and, therefore, in maintaining soil productivity. T: Mean values of conventional and organic farm soil properties.
5780. Reganold, J.P.. 1989. Farming's organic future.. New Scientist, 10 Jun 1989.
Describes the results of the paired farm study of Lambert-Claussen in eastern WA. Lamabert's long-term use of green manure and alfalfa/grass in rotation has maintained his yields and soil fertility, and apparently limited soil erosion to about 6" less than the neighboring field over the past 50 yr.
5761. Reganold, J.P.. 1988. Comparison of soil properties as influenced by organic and conventional farming systems.. Am. J. Alt. Agric., 3(4):144-155.
This paper summarizes data from previous and current studies on two adjacent farms, one organically managed and the other conventionally managed, in the Palouse region of eastern Washington. The 320-hectare organic farm has been managed without the use of commercial fertilizers and only limited use of pesticides since the farm was first plowed in 1909. The 525-hectare conventional farm, first cultivated in 1908, began receiving recommended rates of commercial fertilizers and pesticides in 1948 and the early 1950's, respectively. The organically-farmed Naff silt loam soil had significantly higher organic matter, cation exchange capacity, total nitrogen, extractable potassium, water content, pH, polysaccharide content, enzyme levels, and microbial biomass than did the conventionally-farmed Naff soil. Also, the organically-farmed soil had significantly lower modulus of rupture, more granular structure, less hard and more friable consistence, and 16 centimeters more topsoil. This topsoil difference between farms was attributed to significantly greater erosion on the conventionally-farmed soil between 1948 and 1985. The difference in erosion rates between farms was most probably due to their different crop rotation systems; i.e., only the organic farm included a green manure crop in its rotation, and it had different tillage practices. These studies indicate that, in the long-term, the organic farming system was more effective than the conventional farming system in maintaining the tilth and productivity of the Naff soil and in reducing its loss to erosion.
6117. Schafer, E.G., L.C. Wheeting and S.C. Vandecaveye. 1937. Crop rotations.. WA Agr. Expt. Sta. Bull. #344.
Evaluations of crop rotations conducted on plots at Pullman college farm, 1916-34. Bulletin is in two parts, Part I: effect of crop rotation on succeeding crops; Part II: effect of crop rotations on productivity of the soil. The highest average yield was the wheat/summer fallow rotation. Much variation was found in the N/C content of soil in the different plots under the same system of management. This bulletin contains an extensive amount of data. T: yield of winter wheat/summer fallow. Yield of winter wheat/peas. Yield of winter wheat/corn. Yield of spring wheat/peas. Yield of winter wheat/spring wheat/summer fallow. Yield of winter wheat/spring wheat/corn. Yield of winter wheat/spring wheat/sunflowers. Yield of winter wheat/spring wheat/potatoes. Yield of winter wheat/oats/corn. Yield of winter wheat/ sweetclover/peas.
6174. Severance, G., B. Hunter and P. Eke. 1930. Farming systems for eastern Washington and northern Idaho.. ID Agr. Expt. Sta. Bull. #173.
same as WA AES Bull. 244
6684. Stephens, D.E.. 1944. Effect of tillage and cropping practices on runoff, erosion, and crop yields in the wheat growing areas of Washington, Idaho, and Oregon.. USDA-SCS. Conservation practices on wheat lands of the Pacific Northwest..
An excellent summary of the dryland experiment station research in WA, ID and OR. Describes research on stubble mulching, tillage implements, crop rotations, fallow, etc. The use of sweetclover or alfalfa-grass were encouraged. T: yield, runoff, soil loss by tillage, rotation, fertilizer.
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%).
10256. Mallawatantri, A.P.. 1990. Effects of long-term management, slope position, and depth on pesticide transport parameters.. manuscript, Dept. of Crops & Soils, Washington State University, Pullman..
Pesticide adsoprtion was compared on soils from adjacent farms, with one farm using a low-input system and the other a conventional system. Adsorption of pesticide by soil is signficantly controlled by the organic carbon content of the soil. Carbon content was higher on the low-input farm, and also varied with landscape position on both farms. The relative adsorption of the four pesticides studed was diuron > metribuzin, triallate > 2,4-D. Adsorption was higher on the low-input farm, at bottom slope positions with higher soil carbon, and in surface soils than in subsoils. Weakly adsorbed pesticides should be avoided on top slope and eroded areas due to increased risk of movement. The green manure rotation on the low-input farm reduced potential pesticide transport due to higher soil carbon levels.