Browse on keywords: fertility OR IA
Search results on 01/22/18
1077. Broadbent, F.E. and F.J. Stevenson. 1966. Organic matter interactions.. Agricultural anhydrous ammonia: technology and use. p. 169-197..
1257. Cerrato, M.E. and A.M. Blackmer. 1990. Comparison of models for describing corn yield response to nitrogen fertilizer.. Agron. J. 82:138-143.
The study compares and evaluates several models (linear-plus-plateau, quadratic-plus-plateau, quadratic, exponential, and square root) commonly used for describing corn response to N fertilizer. All models indicated similar maximum yields, but there were marked discrepancies among models when predicting economic optimum rates of fertilization. Statistical analysis indicated that the most commonly used model, the quadratic model, did not give a valid description of the yield responses and tended to indicate optimal rates of fertilization that were too high. The quadratic-plus-plateau model best described the yield responses.
3356. Jain, J.M., G. Narayanasamy, M.C. Sarkar and M.N. Datta. 1980. An evaluation of nitrification retardation property of Citrullus colosynthis.. J. Indian Soc. Soil Sci., 28(4):480-484.
An evaluation of nitrification retardation property of Citrullus colosynthis cake and its influence on yield and N uptake by wheat. Citrullus colosynthis oilcake was tested as nitrification retarder under laboratory and greenhouse conditions. The same showed NH4-N conservation when applied at the rate of 5 and 10% by weight of urea. Higher rate (20%) of the cake resulted in NO2-N accumulation leading to lower N recovery by wheat.
4077. Mason, J.L. and J.E. Miltimore. 1959. Increase in yield and protein content of native bluebunch wheatgrass from nitrogen fertilization.. Canadian J. Plant Sci. 39:501-504.
Native bluebunch wheatgrass in Okanagan Valley (11" precip.) showed marked response to nitrogen fertilization. Dry matter production doubled with 60N added as ammonium nitrate, protein increased from 3.9 to 6.2 %. Fertilizer also increased ground cover by the desirable grasses.
4518. Molla, M.A.Z., A.A. Chowdhury, A. Islam and S. Hoque. 1984. Microbial mineralization of organic phosphate in soil.. Plant and Soil, 78:393-399.
Phosphate-dissolving microorganisms were isolated from non-rhizosphere and rhizosphere of plants. These isolates included bacteria, fungi and actinomycetes. The mixed cultures were most effective in mineralizing organic phosphate and individually Bacillus sp. could be ranked next to mixed cultures.
6001. Russell, J.S. and C.H. Williams. 1982. Biogeochemical interactions of carbon, nitrogen, sulfur, and phosphorus in Australian agroecosystems.. IN: J.R. Freney and I.E. Galbally (eds.). Cycling of C,N,S, and P in terrestrial/aquatic ecosystems..
An excellent review article looking at nutrient cycling and gains and losses over time under different agricultural management. Estimates that over 3 million tons C are tied up in soil organic matter additions each year in Australian farmland. SOM levels are higher now than the native condition under systems that have used a legume pasture in the rotation. There was a generally downward trend in the soil C:N over the first 25 yr of OM accumulation. A WWPP rotation slightly increased SOM, while WWWP decreased it slightly, and fallow systems decreased it significantly. Increases in SOM increased the water-stable aggregates in the soil and improved infiltration. Leguminous pastures had an acidifying effect on the underlying soil.
6359. Smiley, R., D. Wilkins, W. Uddin, S. Ott, K. Rhinhart, and S. Case. 1989. Rhizoctonia root rot of wheat and barley.. OR Agr. Expt. Sta. Special Report 840, p. 68-79..
Rhizoctonia root rot is now considered the most severe root disease of barley in the PNW. It is more important than take-all and Pythium on wheat produced in drier areas (<16" precip.). Based on long-term plots at Pendleton, different management systems are unlikely to greatly influence the biological resistance of soils to Rhizoctonia. Rotational crops susceptible to Rhizoctonia include wheat, barley, peas, chickpeas, lentils, and rapeseed. The disease is less apparent on small grains after legumes than after cereals. Rhizoctonia damage is always highest on no-till systems, but yields may not suffer due to improved water relations under conservation tillage. Australian research indicates that applications of N and P fertilizers can reduce the disease. There appear to be detrimental herbicide interactions with Rhizoctonia, particularly Glean on high pH soils. Also, the use of glyphosate increased disease incidence, perhaps by signalling the pathogens to move from the dying plants to newly seeded ones. A delay of at least 2 weeks is suggested between chem kill and planting of a new crop.