Management Strategies and Practices for Preventing Nutrient Deficiencies in Organic Crop Production

Summary

Field experiments are underway in Canada to determine the influence of management practices (crop diversity, green manure, legumes) and amendments (Penicillium bilaiae, rock phosphate, elemental S, gypsum, manure, wood ash, alfalfa pellets) on crop yield. In the alternative cropping systems study established in 1995, crop yields for organic system without any chemical input were 30-40% lower than the conventional system with high inputs. But, lower input costs plus price premiums for organic produce normally more than offset lower yields, resulting in favourable economic performance and energy efficiency. Legume, green manure and compost manure helped to replace nutrients lacking in the soil and improved crop yields. In the organic system, amount of P removed in crop exceeded that of P replaced and this can be a major yield limiting factor. In amendments experiments, there was small effect of granular rock phosphate fertilizer and/or Penicillium bilaiae in increasing soil P level and crop yield in the application year. Other findings suggested the use of elemental S fertilizer, gypsum, manure, wood ash or alfalfa pellets to improve nutrient availability, and yield and quality of produce. In conclusion, integrated use of management practices and amendments has the potential to increase sustainability of crop production as well as improve soil quality plus minimize environmental damage.