Impact of Genetically Engineered Crops on Farm Sustainability in the United States. Committee on the Impact of Biotechnology on Farm-Level Economics and Sustainability; National Research Council. ISBN: 0-309-14709-3, 240 p. Link.
Food Security: The Challenge of Feeding 9 Billion People. Charles H., J. Godfray, J.R. Beddington, I.R. Crute, L. Haddad, D. Lawrence, J.F. Muir, J. Pretty, S. Robinson, S.M. Thomas, and C. Toulmin. 2010. Science, V. 327, 12 February.
Carbon Dioxide Enrichment Inhibits Nitrate Assimilation in Wheat and Arabidopsis. Bloom, A.J., M. Burger, J.S.R. Asensio, and A.B. Cousins. 2010. Science, V. 328, 14 May.
The Rational Optimist: How Prosperity Evolves. Ridley, M. Harper. 448 p. See book review on The Economist and at Amazon.
Doses e Formas de Aplica
The main objective of this study was to evaluate the efficiency of potassium fertilizer application, as related to rate, placement (in-row, broadcast, and split topdress) and time (before sowing, at sowing, and topdressing), in a soybean, pearl millet, and cotton no-till rotation system, in a typic dystrophic Red Latosol (Hapludox), in Turvel
Potassium Substitution by Sodium in Sugar Beet (Beta vulgaris) Nutrition on K-Fixing Soils.
Alluvial soils with illite and vermiculite clay minerals are highly potassium (K)-fixing. Such soils have been reported to require a huge amount of K fertilization for optimum plant growth. For halophytic plants such as sugar beet, sodium (Na) can be an alternative to K under such conditions. This study was conducted to investigate the possible substitution of K by Na fertilization with reference to K-fixing soils. Three soils, i.e., Kleinlinden (subsoil), Giessen (alluvial), and Trebur (alluvial), differing in K-fixing capacities, were selected, and sugar beet plants were grown in Ahr pots with 15 kg soil pot-1. Three treatments (no K and Na, K equal to K-fixing capacity of soil, and Na equivalent to regular K fertilization) were applied. In a second experiment, containers (90 cm
Performance of Annual and Perennial Biofuel Crops: Nutrient Removal during the First Two Years.
Nutrient removal is an important factor that must be consideredin lignocellulosic fuel production. This study was conductedto determine the macronutrient (N, P, and K) composition ofgrain and stover, as well as the nutrient removal in grain,stover, and total biomass of annual and perennial C4 crops innortheast Kansas in 2007 and 2008. Crops studied were corn (Zeamays L.) grown continuously or rotated with soybean [Glycinemax (L.) Merr.]; five sorghum [Sorghum bicolor (L.) Moench]cultivars, brown midrib (bmr), photoperiod sensitive, sweet,and two dual-purpose forage cultivars; and three perennial warm-seasongrasses, switchgrass (Panicum virgatum L.), big bluestem (Andropogongerardii Vitman), and Miscanthus (Miscanthus x giganteus). Perennialgrass yields were from the first two harvests after establishment.Yields and total nutrient removal rates were greater for annualcrops than for perennial grasses. Perennial grass nutrient concentrationswere greatest in the establishment year (2007). Perennial grassyields increased from 2007 to 2008, but nutrient removal wasnot affected by the yield increase. Grain nutrient removal rateswere greatest for corn even though nutrient concentrations wereless than or equal to those for sorghum grain. Total nutrientremoval rates were most affected by biomass yield and soil testP levels. Total K removal was greatest for the photoperiod-sensitive,sweet, and dual-purpose forage sorghum cultivars. These resultsindicate that higher annual crop yields will remove more nutrientsthan perennial grasses during the grass establishment period.
