Fertilizer Application on Crop Yield


Book Description

Fertilizer application can increase crop yields and improve global food security, and thus has the potential to eliminate hunger and poverty. However, excessive amounts of fertilizer application can contribute to groundwater pollution, greenhouse gas emissions, eutrophication, deposition and disruptions to natural ecosystems, and soil acidification over time. Small farmers in many countries think inorganic fertilizers are expensive and degrade soils, and thus policymakers want to promote organic instead of inorganic fertilizers. To develop practical fertilizer recommendations for farmers, yield responses to applied fertilizers from inorganic and organic sources, indigenous nutrient supply from soil, and nutrient use efficiency require consideration. There is a lack of sufficient scientific understanding regarding the need and benefit of integrated nutrient management (i.e., judicious use of inorganic and organic sources of nutrients) to meet the nutrient demand of high-yielding crops, increase yields and profits, and reduce soil and environmental degradation. Inadequate knowledge has constrained efforts to develop precision nutrient management recommendations that aim to rationalize input costs, increase yields and profits, and reduce environmental externalities. This Special Issue of the journal provided some evidence of the usefulness of integrated nutrient management to sustain soil resources and supply nutrients to crops grown with major cereal and legume crops in some developing countries.




An Appraisal of Research on the Economics of Fertilizer Use


Book Description

During fiscal year 1954, a program was undertaken by TVA to develop a clearer perspective of the problems arising from economic interpretation of fertilizer-response research.




Carbon Sequestration in Urban Ecosystems


Book Description

Urbanization drastically alters the ecosystems structure and functions, disrupts cycling of C and other elements along with water. It alters the energy balance and influences climate at local, regional and global scales. In 2008, urban population exceeded the rural population. In 2050, 70% of the world population will live in urban centers. The number of megacities (10 million inhabitants) increased from three in 1975 to 19 in 2007, and is projected to be 27 in 2025. Rapid urbanization is altering the ecosystem C budget. Yet, urban ecosystems have a large C sink capacity in soils and biota. Judicious planning and effective management can enhance C pool in urban ecosystems, and off-set some of the anthropogenic emissions. Principal components with regards to C sequestration include home lawns and turfs, urban forests, green roofs, park and recreational/sports facilities and urban agriculture.




Residual Effects of Fall- and Spring-applied Nitrogen Fertilizers on Crop Yields in the Southeastern United States


Book Description

Nitrogen fertilizer broadcast in November or December on widely different soils at seven locations in Alabama, Georgia, and Mississippi during 1955-59 was only 49 percent as effective as nitrogen fertilizer applied the following spring when measured by corn yields. In terms of nitrogen recovered, the relative effectiveness was 62 percent. There were no consistent differences among the five nitrogen sources applied in the fall as measured by corn yields, but nitrogen recovery tended to be lower from urea than from the other sources. Considerable residual effects of spring-applied nitrogen were found over a period of 16 months based on both yield and nitrogen uptake by the crops. Average uptakes of 25 and 34 pounds per acre of additional nitrogen were made by the second and third crops, respectively, from the 200-pound original application. This residual nitrogen produced average yield increases of 1,600 pounds of dry forage and 19 bushels of corn per acre. These results emphasize the economic importance of residual nitrogen and the need for soil test procedures for its estimation.