Project Number: 5354-21660-002-03
Project Type: Specific Cooperative Agreement

Start Date: Mar 06, 2008
End Date: Mar 05, 2013

Objective:
(i) Estimate biomass production and nutrient reserve in leguminous cover crops, i.e. sunn hemp, and velvetbean, under an arid temperate vs. humid tropical climatic condition in vegetable production systems. (ii) Estimate mineralization rates of the above cover crops and carbon sequestration rates under the above agroclimatic vegetable production systems. (iii) Trace gas emissions and ammonia volatilization with different nutrient and residue management practices in a vegetable rotation system. (iv) Estimate nutrient transformation, trace gas emissions, and carbon sequestration during decomposition and residue turnover from biofuel coproducts and other agricultural wastes. (v) Investigate real-time changes in soil water contents and temperature that influence the cover crops residue decomposition, N mineralization and transport, and carbon sequestration. (vi) Estimation of soil water mass balance to predict leaching of water and nutrients below the rootzone. (vii) Collection of field data for validation of potato growth simulation model in commercial growing conditions to incorporate nutrient and water dynamics component to enhance nutrient and water uptake efficiencies.

Approach:
Field studies will be conducted in Columbia Basin irrigated production region in WA (arid, temperate) and near Homestead, FL (humid, subtropical). Sunn hemp and velvetbean cover crops will be grown following the standard production practices for each of the above production regions. Total biomass production and nutrient reserves in each of the cover crops will be estimated. Following the incorporation of the cover crops, the decomposition of the residue, rate of mineralization, and carbon sequestration rate will be estimated. Trace gas emissions and ammonia volatilization will be evaluated under different fertilizers and residue management for potatoes, including fertigation, controlled release fertilizer, and during decomposition and mineralization of organic amendments including biofuel coproducts and animal manures. Formerly 5354-21660-001-06S (10/08). Soil water, temperature and conductivity sensors will be installed in irrigated potato field for real-time measurement and estimation of soil water mass balance. Biomass samples will be taken for evaluation of crop growth, nutrient distribution and validation of growth simulation model predictions.