Browse on keywords: crop rotation NE
Search results on 12/05/13
2221. Goldstein, Walter A.. 1986. Alternative crops, rotations, and management systems for dryland farming.. Ph.D. dissertation, Agronomy and Soils, WSU.
This work covers a number of research areas, including the use of edible white lupine as an alternative crop, the use of black medic in rotation with spring peas and winter wheat (the PALS concept), performance of winter wheat as influenced by rotations, fertilization, and fumigation; rotational effects of medics; wheat interference with weeds; costs and returns of alternative systems; comparison of agronomic effects of conventional, organic, and biodynamic management. The PALS (perpetuating alternative legume system) concept was field-tested using a pea + medic - medic GM - winter wheat rotation with limited inputs of agrichemicals and tillage. This system was more economic using market prices of commodities at both a low and high yield level. With government support prices, the PALS system was competitive in the low yield situation, but not the high. Rotational effects appeared to suppress weeds in wheat with the medic compared to a continuous cereal system.
7524. White, J.G.H.. undated. Grain legumes in sustainable cropping systems; a review.. unpublished manuscript, Plant Science Dept..
This paper briefly reviews the role that grain legumes can play in sustaining cropping systems. It presents various estimates of N fixation of grain legumes, with lupin and fababean showing the highest rates, followed by peas and lentils, chickpeas, and soybeans. Phaseolus beans are generally poor N fixers. Fababeans are more tolerant of soil mineral N than other species and will still fix large quantities of N when mineral N is present. Under drought stressed conditions, peas and lentils were more efficient in N fixation than fababeans. Only in lupins and fababeans was N fixation normally greater than the N removed in the seed. The roots and nodules of grain legumes are likely to be the greatest source of N for following crops. This N is often quickly mineralized within several weeks after harvest, and strategies are needed to prevent its loss. Grain legumes are also beneficial break crops, particularly for soil-borne diseases, and can help to control certain grassy weeds. Preceding grain legumes with a brassica crop has reduced the incidence of Aphanomyces root rot in peas, due to sulfur containing compounds. Most grain legumes suffer reduced yields if soils are compacted and poorly aerated. The paper contains numerous references and tables on nitrogen relations.
7662. Wright, A.T. and E. Coxworth. 1987. Benefits from pulses in the cropping systems of northern Canada. p. 108. IN: J.F. Power (ed.). The role of legumes in conservation tillage systems..
Investigated yield and N response in barley and wheat, 1 and 2 years after pulse crops of fababean, pea, and lentil. Overall yields were higher on fababean and field pea residues than lentils. Soil tests could not attribute yield differences among crop residues to differences in soil N levels at time of seeding. Nitrogen fertilizer equivalents for barley were 105, 85, and 50 lb N/ac for fababean, peas, and lentils. Legume residues influenced barley grain quality. In the second year following pulses, the dry matter yield, grain yield, and N uptake of wheat was 15% higher than in the continuous cereal sequence. Analysis of 3 completed rotation cycles showed that cropping sequences that included pulses were considerably more productive than the continuous cereal sequence in terms of net energy production and economic gross margin to cash costs. Field peas were the most effective first-year crop in terms of net energy production.
7770. Zentner, R.P., M.A. Stumborg, and C.A. Campbell. 1989. Effect of crop rotations and fertilization on energy balance in typical production systems on the Canadian prairies.. Agric., Ecosys., Environ. 25:217-232.
Non-renewable energy inputs, metabolizable energy output, and the energy efficiency of 10 spring wheat rotations were examined over 18 yr. Conventional tillage was used. Results showed total energy input per unit of land was lowest for the traditional wheat-fallow rotation (3482 MJ/ha), intermediate for N and P fertilized fallow-wheat-wheat (4470 MJ/ha), and highest for fertilized continuous wheat (7100 MJ/ha). Fuel accounted for 30-50% of the energy inputs, and fertilizer accounted for 15-49%. Pesticides were only 4-11%. Energy output to input ratios and the quantity of wheat per unit of energy decreased with cropping intensity. The average energy O/I was: F-W 3.6, F-W-W 3.3, cont. W 2.6. Rotations that included flax or cereal forage crops had the lowest energy efficiency.
7816. Ford, G.L. and J.L. Krall. 1979. The history of summer fallow in Montana.. Montana Agr. Expt. Sta. Bull. 704.
This excellent publication describes the historical development of summer fallow use in dry farming in Montana and some of its consequences. Data from 1974 indicate that aboaut one-third of the cropland in the state was in summer fallow (5 million acres). In Montana, the fallow period is 14 and 21 months for winter and spring grain respectively. Results from the early 1900's indicated more profitable returns from alternate crop-fallow compared to continuous cropping. This was due to both more moisture and available nitrogen built up under fallow. Summer fallow was not widely adopted until the 1920's, when a series of very unfavorable weather years occurred and showed the risk reduction value of fallow. Serious wind erosion became a problem at that time and led to the introduction and widespread adoption of narrow alternate crop-fallow strips perpendicular to the wind direction. Fallow led to a greater decrease in soil organic matter and total nitrogen (40 and 35 % decrease) than with continuous cropping (35 and 27 % decrease). Further research found that continuous cropping made more efficient use of moisture than fallow. As nitrogen fertilizer and herbicides became available, fallow was no longer as important for these aspects. Summer fallow has also caused the development of saline seep conditions on hundreds of thousands of acres. This condition occurs where summer fallow stores more moisture than a crop uses, and the water then moves deeper in the soil profile until it hits a confining layer, causing it to move laterally with dissolved salts, and to break out as a seep further downslope. In one watershed, the percentage of total land area affected by saline seep increase from 0.1% to 19% over 30 years. Continuous cropping and use of deep-rooted plants such as alfalfa can help solve this problem. The authors propose a new approach to cropping intensity, one called "flex-cropping" in which the decision to plant a crop is based on the presence of at least 3 inches of stored soil water at seeding time. This system would reduce some of the negative effects of summer fallow while also reducing exposure to drought risk. Federal acreage restrictions under the commodity programs pose a major barrier to this approach.
7979. Sims, J.R.. 1971. The resource inventory method of determining cropping practices for dryland farming.. Proc. of Saline Seep Workshop, Highwood Alkali Control Assoc., Great Falls, MT, Feb. 22-23.
9962. Chilcott, E.C.. 1910. A study of cultivation methods and crop rotations for the Great Plains area.. USDA Bureau of Plant Industry, Bulletin 187. 78 pp..
This paper reports the results of a four-year experiment in crop rotation and cultivation methods conducted at eleven stations in the Great Plains area. Some of the questions asked of this experiment were how can the largest average yields of corn, spring wheat, oats and barley be obtained, do moisture conservation methods pay where continuous cropping to the same crop is practiced, and can green manuring be profitably substituted for summer tillage? The results found that a 3-year rotation of corn, wheat and oats gave the most profitable returns. Continous cropping with moisture conservation methods of fall plowing and fall, winter and spring tillage did not give results to warrant its recommendation. The most highly recommended practice was that of green manuring. For greatest benefits to the soil, it was recommended to plow in a green manure crop in early season, with little summer tillage, until wheat planting time.
10098. Reeves, T.G., A. Ellington and H.D. Brooke. 1984. Effects of lupin-wheat rotations on soil fertility, crop disease and crop yields.. Austral. J. Expt. Animal Husb. 24:595-600..
Three experiments were conducted between 1974 and 1979 in northeastern Victoria to investigate the effects of rotating wheat and sweet lupins on crop yields, soil fertility and crop diseases. The grain yield of continuous wheat was 2.58 t/ha and of continuous lupins 0.66 t/ha. Wheat, grown after a lupin crop, yielded 750 kg/ha more than wheat after wheat, and a second wheat crop, after lupins, yielded 420 kg/ha more than a third successive wheat crop. Lupins, grown after wheat, yielded 50-165% more than lupins after lupins. Grain N of wheat was significantly increased after lupins. Differences in soil mineral N were apparent ten weeks after sowing, with mean N levels of 37 and 55 kg/ha under wheat and lupins, respectively. Soil mineral N was consistently greater after lupins than after wheat. Overall, mean accretion of mineral N under lupins was 41 kg/ha/year. Lupins after lupins suffered severly from brown leaf spot, up to 63% of plants being infected compared with only 18% after wheat. Disease incidence in wheat (mainly G. graminis) increased from less than 1% in the first year of cropping, to 36% infection in year 3 of continuous wheat. When wheat was grown after lupins, disease incidence was negligible.
10475. Campbell, C.A., G.P. LaFond, A.J. Leyshon, R.P. Zentner, and H.H. Janzen. 1991. Effect of cropping practices on the initial potential rate of N mineralization in a thin Black Chernozem.. Can. J. Soil Sci 71:43-53.
Potentially mineralizable N (No) was examined as a possible indicator of soil organic matter change due to management, using soil from 30 yr rotation plots near Indianhead, Saskatchewan. A parameter called the initial potential rate of N mineralization (No x rate constant k at time =0) was effective in distinguishing both the absolute and qualitative changes in soil organic N due to various management practices. The results showed that fertilizers can be as effective as legumes, used either for green manure or hay, in increasing the quantity and improving the quality of soil organic matter. Organic matter changes were similar between a 6 yr soil-building rotation and fertilized continuous wheat, but higher than unfertilized continuous wheat.
10576. Janzen, H.H. and G.D. Radder. 1989. Nitrogen mineralization in a green manure amended soil as influenced by cropping history and subsequent crop.. Plant Soil 120:125-131.
In a greenhouse study, surface soil from long-term experimental spring wheat rotations was amended with 15N labelled legume green manure and subsequently cropped (canola and spring wheat) or incubated. N mineralization from both the indigenous soil N and from green manure was suppressed in cropped soil. Net N mineralization in the uncropped and cropped treatments averaged 73 and 43 mg/kg, respectively. This difference was attributed in part to enhanced biological immobilization in the rhizosphere. These data suggest that short-term N mineralization is favored by fallowing soil after green manure application whereas N retention in organic matter is favored by immediate cropping.