Sod-Based Farming Systems for Advance Conservation Effectiveness and Ecosystem Services.

Carbon sequestration and water purification are ecosystem services depending on the management of agricultural land. Water filtration is improved by sustainable percolation systems resulting from conservation tillage and crop rotations without or with sod and cover crops. Maintaining a stable stock of decaying plant/crop residues is thought to be beneficial for earthworms, microbiological activities, and soil moisture as well. However, during the decay processes, nitrogen is released to the environment, which is also a public concern. Both insufficient and excess nitrogen can negatively affect crop productivity and water quality. Insufficient nitrogen often reduces leaf are, photosynthetic rate, and overall biomass production, while excess nitrogen may potentially increase production cost and/or cause water pollution.

Under the scope of a sod-based project agronomic measures are developed at the University of Florida, IFAS-NFREC in Quincy to advance conservation efforts. Integrating sod and cover crops in a conservation-tilled cropping system seeks to close nutrients cycling within the system and thus promote water purification services by improving soil physical properties and increasing soil organic matter. In addition to conservation tillage a grass sod within the system has positive effect on nitrogen cycling and cover crops are further decreasing surface runoff and nitrogen leaching. If livestock is available to graze, the nutrients are kept in the upper soil layer, which keeps nitrates out of the groundwater. Grazing bahiagrass for 2 consecutive years and the following winter cover crop had no adverse effect on soil moisture content. No considerable differences for soil bulk density are detected after bahiagrass grazing, row crops growing and following cover crops grazing, while percentage of soil organic matter is increased by grazing livestock in both rain-fed and irrigated fields. These improvements require further research to define techniques for measuring the conservation effectiveness of sod-based rotation and valuing ecosystem services from agricultural land.