Browse on keywords: moisture NE
Search results on 06/20/13
3298. Burt, O.R. and M.S. Stauber. 1989. Dryland cropping decision theory with application to saline seep control.. J. Production Agr. 2:47-57.
A model for decision making in a flex-crop system is presented, based on plant available soil water at seeding, previous land use, and economic return. The strategy can be used for winter or spring wheat.
3652. Kmoch, H.G., R.E. Ramig, R.L. Fox, and F.E. Koehler. 1957. Root development of winter wheat as influenced by soil moisture and nitrogen fertilization.. Agronomy J. 49:20-25.
Although there was little top growth in November, root development was extensive for all moisture treatments. Roots which developed under less favorable moisture conditions were finer and had more and longer branches. April samples revealed that the primary root system was in the process of decay. Living roots were generally confined to regions of moist soil. Total weight of roots was highest where nitrogen had been applied. June samples revealed roots to a depth of 13 feet where moisture conditions were favorable. There was evidence of moisture depletion to a depth of 8'. N fertilizer increased root weights and moisture utilization at all moisture levels.
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.
7893. Sims, J.R.. 1978. Predicting nitrate accumulation in fallowed soils.. Agronomy Abstracts p. 162, Amer. Soc. Agron., Madison, WI.
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.
8822. Brandle, J.R. and D.L. Hintz. 1987. An ill wind meets a windbreak.. Nebraska State Forester, Univ. Nebraska, Lincoln, NE 68583-0814.
Windbreaks are valuable for reducing soil erosion and lowering evaporative stress on crops, leading to higher yields. Crop yields begin to decline at a distance from the windbreak of about 5 times its height.
10128. Greb, B.W., D.E. Smika and A.L. Black. 1967. Effect of straw mulch rates on soil water storage during summer fallow in the Great Plains.. Soil Sci. Soc. Amer. Proc. 31:556-559..
A soil water storage experiment was conducted in the Great Plains by tilling in known amounts of wheat straw. Net gains in soil water storage during fallow varied from 1.0 to 4.3 cm at Sydney, MT, from 2.1 to 4.1 cm at Akron, CO, and from 3.1 to 3.3 cm at North Platte, NE. Average amounts of straw at each site were 2,600, 3,800, and 6,000 kg/ha, respectively. The soil water gains were primarily during the spring months of the 14-month fallow season. The water gained by straw mulches tended to improve the soil water content throughout the soil profile.