Published 2009-12-01
Abstract
The use of improved irrigation scheduling techniques has been shown to greatly increase irrigation water use efficiency. Consequently, fertilizer is retained longer in the effective root-zone, resulting in substantial water savings and reduction of N-leaching losses. The present paper focuses on vegetable irrigation with soil moisture sensing methods used in North-Central Florida. Field experiments were conducted to test different thresholds of soil moisture sensor-based irrigation control systems on tomato (Lycopersicon esculentum Mill.) and pepper (Capsicum annuum L.) for sandy soils. The use of subsurface-drip irrigation and soil moisture sensor-based systems consistently increased tomato yields while greatly improving irrigation water use efficiency and thereby reduced both irrigation water use and potential N leaching. For peppers, high irrigation rates as applied for fixed-time irrigation did not increased yield, conversely, irrigation scheduling using soil moisture sensors allowed application of less water, which resulted in higher irrigation water use efficiency values. While fixed-time irrigation treatment had a single irrigation event (high volume, low frequency), which promotes excessive water percolation and N leaching. In addition, appropriate use of soil moisture sensor monitoring and/or sensor-based irrigation systems can allow growers to sustain profitable yield while reducing irrigation application and reducing NO3-N leaching in sandy soils.