Browse on keywords: organic matter UT
Search results on 05/22/13
1033. Bracken, A.. no date. Dry farming.. USU (Logan) Course notes for Agronomy 116.
Describes climatic factors that cause dry lands, the dryland regions of the world, soils of dry areas, organic matter and N relations. Dry farms in northern UT have lost 16% of soil N and 22% of SOM from first foot of soil, after 44 years of cropping.
2974. International Atomic Energy Agency and UN Food and Agriculture Organization. 1968. Isotopes and radiation in soil organic matter studies.. Proceedings series, IAEA, Vienna, 584pp..
See especially: Effects of microorganisms on the absorption of inorganic nutrients by plants. p.365. Availability of nitrogen on changes in the humus quality in biochemical threshold range of soils. p.515. T; many.
3013. Stroo, H.F., K.L. Bristow, L.F. Elliott, R.I. Papendick, and G.S.Campbell. 1989. Predicting rates of wheat straw decomposition.. Soil Sci. Soc. Am. J. 53:91-99.
Predicting the rate and extent of decomposition of residues at the soil surface is necessary to evaluate the impacts of minimum tillage practices on erosion control and thus ensure the most effective use of residues. A mechanistic model simulating the decomposition of surface-managed winter wheat residues was developed and model predictions were compared to results from field studies of decomposition rates.
3670. Knapp, E.B., L.F. Elliott, and G.S. Campbell. 1983. Carbon, nitrogen, and microbial biomass interrelationships during the decompostion of wheat straw: a mechanistic simulation model.. Soil Biol. Biochem. 15:455-461.
The effect of N on the disappearance of C from a wheat straw system, and the response of the biomass to N additions, was simulated using microbial growth and maintenance terms from the literature. Straw decomposition rate was shown to be strongly dependent on available C and N during initial decomposition. When N is limiting, excess available C apparently is immobilized as polysaccharides.
6154. Seligman, N.G., S. Feigenbaum, D. Feinerman and R.W. Benjamin. 1986. Uptake of nitrogen from high C to N ratio, 15N labeled organic residues by spring wheat grown under semiarid conditions.. Soil. Biol. Boichem., 18(3):303-307.
Most of the N in organic residues with high C-to-N ratios is rapidly incorporated into the stable organic N fraction and after a modest initial flush in the first and second years, it is released at a rate equivalent to that of the mineralization of soil organic N.
6592. Sommerfeldt, T.G., C. Chang, and T. Entz. 1988. Long-term annual manure applications increase soil organic matter and nitrogen, and decrease carbon to nitrogen ratio.. Soil Sci. Soc. Am. J. 52:1668-1672.
Studied the effects of long-term annual additions of cattle feedlot manure on the accumulation, decomposition, and movement of organic matter and total N. Significant increases in SOM and total N in the first 8 and 6 yr, repsectively, were limited to the surface 30 cm of soil of both the nonirrigated and irrigated land, and were similar on both fields. Tillage did not affect the amount of accumulation. The rates of accumulation decrease with years of application such that after two or three decades, increases will be small. A model was developed to predict changes and develop guidelines for land disposal of feedlot manure.
7189. Vaughan, D., B.G. Ord and R.E. Malcolm. 1978. Effect of soil organic matter on some root surface enzymes of and uptake into winter wheat.. J. Exp. Bot., 29(113):1337-1344.
Soil organic matter (SOM) fractions inhibit the activity of root invertase and phosphate, but the extent of the inhibition depends on the SOM fraction. All SOM fractions inhibit the uptake of glucose into roots but in general stimulate the uptake of inorganic phosphate.
7712. Young, A., R.J. Cheatle, and P. Muraya. 1987. The potential of agroforestry for soil conservation. Part 3. Soil changes under agroforestry (SCUAF): a predictive model.. ICRAF working paper no. 44..
Predicts soil carbon changes in different climatic zones under various agroforestry management schemes. Can be used for prediction of changes under other land use as well.