Water is the single-most limiting resource for crop growth. Irrigation improves crop yield stability and profitability over time, but it is a costly input and may be limited or under restrictions in the future, making the development of new water conservation methods increasingly important.
The majority of peanut acreage (62 percent), cotton (61 percent), and corn (86 percent) in the United States is without irrigation, making a large portion of these commodities susceptible to drought conditions and high fluctuations in yield. Poor crop growth in non-irrigated crops is not usually due to poor seasonal rainfall, but rather the timing and amount of rainfall events.
Compared to other regions of the United States, the Southeast receives a fair amount of rainfall during the growing season. Precipitation usually comes down quickly in thunderstorms, making water susceptible to run-off rather than effectively infiltrating the crop root zone.
Furrow diking is commonly used by farmers in the arid regions of the Western United States to improve water-to-soil contact for better absorption and reduced evaporation of irrigation water. By enhancing water capture and percolation, furrow dikes may prolong the time that rainwater supplies moisture to the crop.
Furrow diking creates a series of basins and dams in the furrow between crop rows to help catch and absorb water from precipitation or overhead irrigation. It also breaks up and loosens soil surface crust that would otherwise impede infiltration and promote runoff and ponding, which lead to evaporation.
The equipment necessary for installing furrow dikes is not expensive and can be attached to common cultivation equipment.
The USDA-ARS National Peanut Research Laboratory at Dawson, Ga., is currently in the second year of research using furrow dikes in both irrigated and non-irrigated peanut, cotton and corn.
By improving how irrigation and rainwater are caught and stored compared to conventional tillage, this technology will lead to more efficient use of water. Initial testing showed consistently rapid soil moisture increases in furrow-diked plots compared to conventionally-tilled plots after rainfall or irrigation.
Expert system software (Irrigator Pro) for managing irrigation scheduling in peanuts, cotton, and corn has been developed and validated at the NPRL in collaboration with the University of Georgia. In 2005, recommendations from Irrigator Pro for corn called for reduced irrigation applications where furrow dikes were used, compared to corn without furrow dikes.
Because furrow dikes allow more water to become available for crop use, they can extend the time that a rain or irrigation is effective. Delaying irrigation can reduce total irrigation requirements for a crop season, especially when rain is only a few days away and takes the place of irrigation.
Peanut and cotton studies revealed no difference in yield or irrigation requirements because of high seasonal precipitation. Although 2005 was a wet growing season, the use of furrow dikes resulted in more rapid water infiltration and better maintenance of soil moisture.
There was concern that catching and holding more water in a wet year could cause problems, but no problems were observed in 2005, including disease incidence or digging losses in peanut.
This technology has broad potential to stabilize crop yield and quality, and provide economic and environmental benefits by saving irrigation costs and contributing to more efficient water use. Many parties may benefit from the use of furrow dikes, including agricultural producers and those interested in water and energy conservation.