ORGANIC FARMING :: Nutrient Management
Plant root system is always in close association with multitude of microorganisms and other nutrients. The microbes in root zone are maintained due to a variety of secretions from the roots and constitute what is often described as ‘rhizosphere’. These microbes in their turn supply nutrients to the soil system through their heterotrophic activity. Maintenance of these microbes in the rhizosphere, therefore, is also necessary for soil health. Crop productivity and nutrient cycles, however, are integral parts of the exploitation of soil health and have led to soil degradation through nutrient depletion and erosion, so that long term strategies are needed to avoid the use of chemical fertilizers without adversely affecting crop productivity. The use of organic manures, composts, Biofertilizers has received increased attention in our cropping systems. Following are the components in Nutrient management system
Maintaining or enhancing long-term soil productivity is a key provision of the National Organic Program (NOP) regulation § 205.203, which states that the producer must (a) select and implement practices “that maintain or improve the physical, chemical, and biological condition of soil and minimize soil erosion,” (b) “manage crop nutrients and soil fertility through rotations, cover crops, and the application of plant and animal materials,” and (c) “manage plant and animal material applications to maintain or improve soil organic matter,” but minimize “contamination of crops, soil, or water by nutrients, pathogenic organisms, heavy metals, or residues of prohibited substances.” Any soil-applied product, including composts or manures, must be produced in compliance with NOP regulations. The National Organic Standards Board (NOSB) periodically revises the NOP list of allowed or prohibited substances by considering the need for the product and the impact it may have on human health and the environment. The Organic Materials Review Institute (OMRI) review manufacturer claims for specific products annually to determine whether they meet NOP requirements. OMRI maintains an extensive, up-to-date list of approved substances available at www.omri.org. When a specific fertilizer or amendment is not OMRI-listed, farmers should consult their third-party certifying agency prior to application to ensure compliance. The use of organic materials, biofertilizers, cover crops, and crop rotations according to National Organic Program standards are addressed in this NebGuide.