Sub-surface drip irrigation fertigation for site-specific, precision management of cotton

摘要

A subsurface drip irrigation study was installed at the Tennessee Valley Research and Extension Center in 2006 to evaluate the effect of four precision fertigation management scenarios and a non-fertigated control on cotton yield, nutrient uptake andlint quality. Approximately 7,500feet of SDI tape and four positive displacement liquid fertilizer injectors were used to evaluate five nutrient timing treatments with four replications in a randomized complete block design. Each of the twenty treatmentplots was made up of eight, 345-foot rows of cotton on 40-inch row spacing, with drip tape between every other row of cotton. In 2006, fertigated cotton yields were significantly higher than the surface-applied control. In 2007 and 2008, however, yield in surface-applied control was significantly higher than the fertigated treatments. The better non-fertigated control yield in 2007 and 2008 was possibly due to beneficial downward movement of surface-appliedfertilizer as a result of early season rainfallin 2007 and possibly the leaching offertigated nutrients beyond roots zone as a result of heavy seasonal rainfall in 2008. Fertigated cotton yields averaged 3.0, 2.9 and 3.5 and the control yields averaged 2.7, 3.1 and 3.9 bales/acre in 2006, 2007 and 2008, respectively. Generally, surface sidedressing enhanced nutrients uptake better than fertigation but none of them had a direct effect on cotton fiber qualities. These results show that surface sidedressing andfertigation are not mutually exclusive under rainfed cotton production and the observed responses to SDI fertigation were directly related to the amount and distribution of rainfall during the seasons.