Fertilization response

Franzluebbers, A.J., and Francis, C.A. 1991. Farmer participation in research and extension N fertilizer response in crop rotation. Journal of Sustainable Agriculture 2(2) 9-30. 

Franzluebbers, A.J., Francis, C.A. and Walters, D.T. 1994. Nitrogen fertilizer response potential of corn and sorghum in continuous and rotated crop sequences. Journal of Production Agriculture 7 193-194. 

In this section we use a simple model to examine the possible magnitude of phosphorus constraints on the CO, fertilization response of tropical rain forests. The model presented is based on that originally developed by Lloyd and Farquhar (1996) and modified by Lloyd (1999a). In brief, the model consists of a simulation of ecosystem plant growth in response to changing CO concen-... 

Model runs were set up to simulate nitrogen and phosphorus fertilization for all of the LSAG sites (Fig. 15.7) and compared with observed data for the sites where fertilizer response data was collected (3000,... 

Figure 2.9. Expected Changes in Fertilizer Response to P or K as Fertilizers Are Used.

Various mathematical models or algebraic equations can be used to estimate fertilizer response curves such as those shown in Figures 2.10 and 2.11, Mathematical models selected for this purpose are equations that properly represent agricultural production-fertilizer relationships that can be estimated using statistical methods. A quadratic function model is commonly used to estimate fertilizer response functions that properly represent agricultural output increasing at a decreasing rate as a result of increased fertilizer application rates. A quadratic response function model may be written as ... 

Soil Nutrient. Molybdenum has been widely used to increase crop productivity in many soils woddwide (see Fertilizers). It is the heaviest element needed for plant productivity and stimulates both nitrogen fixation and nitrate reduction (51,52). The effects are particularly significant in leguminous crops, where symbiotic bacteria responsible for nitrogen fixation provide the principal nitrogen input to the plant. Molybdenum deficiency is usually more prominent in acidic soils, where Mo(VI) is less soluble and more easily reduced to insoluble, and hence unavailable, forms. Above pH 7, the soluble anionic, and hence available, molybdate ion is the principal species. 

Research on an hCG vaccine has been conducted over the past 15 years. WHO has conducted a phase I clinical study in AustraUa, using a vaccine based on a synthetic C-terminal peptide (109—141) of P-hCG conjugated to Diptheria Toxoid (CTP-DT), that showed potentially effective contraceptive levels of antibodies were produced in vaccinated women without any adverse side effects. Phase II clinical studies are under consideration to determine if the immune response, raised to its prototype anti-hCG vaccine, is capable of preventing pregnancy in fertile women volunteers (115). While research on the C-terminal peptide from the P-subunit of hCG has been carried out under the auspices of WHO, research supported by the Population Council and the National Institutes of Health has involved two alternative vaccine candidates (109,116,118). 

Fig. 7. Response of Kentucky bluegrass to polymer/sulfur-coated fertilizers (PSCF) and sulfur-coated urea (SCF). Apphcation of 2 lbs N/1000 fF (9.76...

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