The addition of organic residues to the soil may modify the amounts of plant available phosphorus (P) found in this ssytem. These studies were undertaken to evaluate the suitability of the sorption isotherm technique for estimating the amounts of inorganic P required for optimum plant growth, the correlation of P availability with the amount of P extracted by three chemical methods, and with the activity of two phosphatase enzymes, when soils were amended with organic materials. Acid phosphatase and phosphodiesterase activities were also compared with the P availability to plants. Soil phosphodiesterase activity correlated better with corn yield and plant uptake than acid phosphatase activity. The correlation of phosphodiesterase activity with microbial activity might be used to indicate the contribution of the soil organic P pool in the P supply to the plant.
Methodology. Relationships between total organic P and other soil propeties. Effects of climate and soil drainage. Effects of land class and vegetation type. Seasonal variation. Variation with soil type. Variation with soil parent material. Distribution in soil profiles. prediction of content in surface soils. Effects of land-management practices. Mobility in soils. Weathering and pedogenesis. Total quantity in the soil profile. Chemical nature. Association with organic matter. Importance in plant nutrition. Mineralization in soils. The release of inorganic P from organic detritis.
Growing for 100 - the complete year-round guide for the small-scale market grower. Across North America, an agricultural renaissance is unfolding. A growing number of market gardeners are emerging to feed our appetite for organic, regional produce. But most of the available resources on food production are aimed at the backyard or hobby gardener who wants to supplement their family's diet with a few homegrown fruits and vegetables. Targeted at serious growers in every climate zone, Sustainable Market Farming is a comprehensive manual for small-scale farmers raising organic crops sustainably on a few acres. Informed by the author's extensive experience growing a wide variety of fresh, organic vegetables and fruit to feed the approximately one hundred members of Twin Oaks Community in central Virginia, this practical guide provides: Detailed profiles of a full range of crops, addressing sowing, cultivation, rotation, succession, common pests and diseases, and harvest and storage Information about new, efficient techniques, season extension, and disease resistant varieties Farm-specific business skills to help ensure a successful, profitable enterprise Whether you are a beginning market grower or an established enterprise seeking to improve your skills, Sustainable Market Farming is an invaluable resource and a timely book for the maturing local agriculture movement.
"'Published by the Sustainable Agriculture Research and Education (SARE) program, with funding from the National Institute of Food and Agriculture, U.S. Department of Agriculture."
Edited by One of the Best Specialists in Soil Science Recent studies reveal that Phosphorus (P) in the form of phosphate, a macronutrient essential for plant growth, and crop yields can influence the bioavailability, retention, and mobility of trace elements, metal(loid)s, and radio nuclides in soils. When this occurs, phosphates can affect the dynamics of heavy metals and influence soil characteristics, impacting soil mobility and toxicity. Phosphate in Soils: Interaction with Micronutrients, Radionuclides and Heavy Metals utilizes the latest research to emphasize the role that phosphate plays in enhancing or reducing the mobility of heavy metals in soil, and the soil-water-plant environment. It provides an in-depth understanding of each heavy metal species, and expands on phosphate interactions in geological material. Composed of 12 chapters, this text: Provides an overview of the reactions of metal(loid)s and common P compounds that are used as fertilizer in soils Emphasizes the effect of phosphorus on copper and zinc adsorption in acid soils Discusses findings on the influence of phosphate compounds on speciation, mobility, and bioavailability of heavy metals in soils as well as the role of phosphates on in situ and phytoremediation of heavy metals for contaminated soils Places emphasis on the influence of phosphate on various heavy metals species in soils, and their solubility/mobility and availability Provides extensive information on testing various high phosphate materials for remediation of heavy metal, micronutrients, and radionuclides contaminated sites Explores the reactivity of heavy metals, micronutrients and radionuclides elements in several soils Presents a case study illustrating various remediation efforts of acidic soils and remediation of Cu, Zn, and lead (Pb) contaminated soils around nonferrous industrial plants Emphasizes the significance of common ions (cations and anions) on phosphate mobility and sorption in soils, and more The author includes analytical and numerical solutions along with hands-on applications, and addresses other topics that include the transport and sorption modeling of heavy metals in the presence of phosphate at different scales in the vadose zone.
Phosphorus (P) stands second to nitrogen in terms of its essentiality as a plant macronutrient, as well as due to its involvement in almost all plant developmental stages, primary and secondary plant metabolisms, maintenance of membrane structures, and in the structural skeleton of major biomolecules. An optimum P-supply also helps plants combat abiotic stress impacts. Most P in soil remains unavailable for uptake by plants. P-containing fertilizers are being added to agricultural lands to sustain high yields. Only the least amount of the applied P (20%–30%) is used by most cultivated plants, and the rest remains as legacy P (P surpluses), which eventually causes eutrophication. This book, Phosphorus in Soils and Plants, reviews P in soils and plants, P dynamics in the soil–water–sediment environment, the major roles of P in the photosynthetic dark phase-biochemical pathways, major approaches for the sustainable management of P in agriculture, main mechanisms underlying the role of P in the regulation of plant–microbe interactions in the rhizosphere, literature on the role of microbial phosphate solubilization in management of soil and plant nutrients, and insights into P recovery through waste transformation. This volume is an important resource for plant biologists involved in teaching or research who wish to advance their knowledge of P in soils and plants.
