The effects of three techniques that change the wetting patterns over subsurface drip-irrigated potatoes

Abstract

Wetting pattern enhancement is one of the goals of irrigation designers and researchers. In this study, we addressed three techniques (dual-lateral drip, intermittent flow and physical barrier methods) that change the wetting pattern of subsurface drip irrigation. To study their effect on the yield and water-use efficiency (WUE) of potatoes, field experiments were conducted for four seasons, during which the soil-water balance was continuously monitored using a set of capacitance probes. The results of the soil water patterns showed that both the dual-lateral and intermittent techniques increased lateral water movement and eliminated deep percolation, whereas the physical barrier had a limited effect on the top soil layer. The crop results indicated that the yield and WUE increased significantly in response to the application of the dual-lateral drip (up to 30%); the intermittent application also positively affected the yield (~10%) and the WUE (~14%), but these effects were not statistically significant according to the statistical model. The physical barrier showed a non-significant negative effect on the yield and WUE. These findings suggest the following recommended practices: the use of dual-lateral drip technique due to its beneficial results and its potential for increasing yields and reducing water consumption; the application of intermittent flow with more than three surges; and restricting the use of physical barriers to soils with high permeability.Additional key words: intermittent application; subsurface drip irrigation; dual-lateral drip; physical barrier; water movement in the soil; Solanum tuberosum L.Abbreviations used: CWT (consumed water per tuber); DM (dry matter); H (dual later technique); LSD (least significant difference); P (physical barrier technique); S (intermittent application technique); SC (starch content); SG (specific gravity); WC (water content); WUE (water-use efficiency).Citation: Elnesr, M. N.; Alazba, A. A. (2015). The effects of three techniques that change the wetting patterns over subsurface drip-irrigated potatoes.

Simulations of Soil Moisture Distribution Patterns Between Two Simultaneously-Working Surface Drippers Using Hydrus-2D/3D Model

“…Overall, an increase in watering frequency resulted in an increase in wetting size in both directions and produced a less pronounced moisture content gradient at the wetting front. The results confirm that a frequency of three days gives a more adequate wetting; this approach is consistent with the conclusions of El-Nesr & Alazba [2].…”

“…. The DI has a significant reduction of water loss by evaporation and runoff due to the direct injection of water and fertilizers into the root zone [2].…”

“…The soil properties: texture, structure, hydraulic conductivity, etc… The application scheme which includes: application rate, frequency, method of application, duration… Some researchers have proved that the wet area around the drippers can be controlled by adjusting the irrigation application scheme [2], [3], [4]. However, the precise distribution of moisture around the drippers must be known in order to ensure acceptable uniformity of water distribution.…”

Precision Irrigation Scheduling Using ECH2O Moisture Sensors for Lettuce Cultivated in a Soilless Substrate Culture

“…The root system is the important organ to obtain water for a plant; the root growth and its distribution determine the ability of a plant to absorb the water from the wetting pattern, which then affects the crop biomass growth and grain yield [19]. The wetting pattern depends on the substrate properties and the irrigation application scheme [20]. The amount of irrigation water calculated on the basis of evapotranspiration is difficult to be administered, because the high porosity, the low bulk-density, and the initial water content of the substrate facilitate the formation of a finger stream, resulting in a reduced size of the wetting pattern and in increased losses of water, which then affects the crop root distribution and grain yield.…”

Response of different colour plastic mulches on water dynamics under drip fertigated greenhouse capsicum (Capsicum annuum)

“…Water flow under drip irrigation is normally threedimensional and becomes two dimensional when dripper used as line source for water application. Thus, comprehensive knowledge of water distribution is essential for design and management of surface drip irrigation system (Subbaiah 2013, Elnesr et al 2015. This can be achieved by conducting field experiment or by modelling.…”