Does the addition of organic matter to the soil lead to an overall increase in nutrient use efficiency by reducing losses of nutrients from the cropping system?
A number of projects are underway to address this question. In the Sacramento Valley, rice farmers incorporate large amounts of residue in the soil, since the possibilities for burning rice straw are strongly reduced by environmental legislation.
We address the impact of incorporating large quantities of organic matter on nutrient cycling, nutrient use efficiency and retention.
Along similar lines, we characterize differences between nutrient cycling in conventional cropping systems and organic systems. The impact of adding different amounts of C to the soil through various N and water management practices on nutrient use is investigated.