Some Current Research at Michael Fields Institute

摘要

Summary of organic matter budgeting work: The importance of organic nutrient matter management for farming is highlighted by the fact that organic matter provides most of the nitrogen that is utilized by corn, even when mineral nitrogen fertilizers are applied. Farmers who use sustainable farming practices and reduce and/or eliminate the use of mineral fertilizers must enhance the management of their soil organic matter if they are to be successful. An organic matter and nutrient budgeter was developed to help farmers to evaluate and plan more sustainable systems for their farms. The system was tested with farmers on individual fields and for whole farms. Strip plot trials were carried out to validate the budgeter's predictions with respect to nitrogen budgets. Root health was evaluated because it was believed to be associated with nitrogen uptake. The results of this research suggest that the health of corn roots is improved in management systems that use perennial forages and animal manures. Greater health is linked with less nitrogen uptake per bushel of corn produced. These systems are also predicted to have the greatest impact in building or maintaining soil organic matter. Conventional corn and soybean systems are associated with more disease, less root growth, more nitrogen uptake per bushel of corn produced, and lower soil organic matter levels. Strip trials with and without fertilizer and manure revealed that corn was capable of extracting large quantities of nitrogen from soil organic matter without any fertilization. It appeared to be able to do this irrespective of total soil nitrogen content or quantities of biologically active soil organic matter. Root health and corn biology appeared to be a key factor relating to the success of organic farming or the problems associated with conventional farming. Clarifying the linkages between corn root growth and nitrogen and carbon decomposition from soil organic matter would improve our ability to assess the impacts of corn cropping on long-term soil dynamics and would improve the budgeter.