Optimization of Subsurface Drip Irrigation Schedule of Alfalfa in Northwest China

Abstract

Determination of an optimum irrigation amount and buried depth of subsurface drip irrigation laterals is significantly important in improving crop yield and irrigation water using efficiency in arid regions. In this study, the effects of three irrigation volumes (15.0, 22.5 and 30.0 mm) and three burial depths (10, 20 and 30 cm) of drip laterals on water consumption, yield and water productivity of alfalfa were investigated in a field trial. The water balance equation and FAO-56 crop coefficient methods were applied to determine the evapotranspiration of alfalfa. The results showed that the alfalfa evapotranspiration estimated by the dual crop coefficient method was closer to the actual measured values. The alfalfa water consumption, yield and water productivity increased significantly (p < 0.01) with the increase in irrigation amount, but the increasing trend turned to decrease (p < 0.05) with the increase of the buried depth of the drip irrigation laterals. During the whole growing period of alfalfa, the total water consumption ranged from 400 to 500 mm, the total yield ranged from 7500 to 12,000 kg/hm2 and the water productivity was 1.80 to 2.50 kg/m3. An optimized irrigation amount of 22.5 to 30.0 mm for an irrigation event with a frequency of 5 to 7 days using buried drip irrigation with an irrigation lateral depth of 20 cm was recommended for alfalfa in the study area.

Study on Modeling and Evaluating Alfalfa Yield and Optimal Water Use Efficiency in the Agro-Pastoral Ecotone of Northern China

“…Under the considerations of purple alfalfa’s growth requirements, efficient water resource use, and economic profitability, it was advisable to ensure initial soil moisture levels between 0.8 θ fc and 1.0 θ fc before regreening, with an optimal irrigation quota of 30 mm for subsequent growth phases. Zheng et al’s [ 11 ] research suggested an optimized irrigation amount of 22.5 to 30.0 mm per event, with events occurring every 5 to 7 days for alfalfa in their study area. Our study results were consistent with Zheng’s findings.…”

“…It markedly improved soil moisture profiles, boosted alfalfa yields, and enhanced the overall efficiency of water use in irrigation practices. Zheng et al [ 11 ] employed a water balance approach and FAO-56 guidelines to ascertain the evapotranspiration rates and the optimal amount and depth of subsurface drip irrigation, concluding values of 22.5–30.0 mm and 20 cm, respectively. In a similar quest, Wang Xing et al [ 12 ] utilized a two-factor split-plot design to determine the ideal irrigation and fertilization rates for alfalfa seed production in Ningxia’s drip-irrigated fields.…”

Effects of Shallow-buried drip irrigation on growth, yield, and water productivity of potato in the Yin-mountain region of China

“…The depth of burial of the drip tape has an important effect on yield and water savings with subsurface drip irrigation. A burial depth of 20 cm has been recommended for alfalfa in northwestern China (Zheng et al, 2023). For spring maize, 30 cm of drip irrigation laterals in silty clay soils is considered bene cial (Guo et al, 2021).…”

“…However, the lm residue causes white pollution, damages the soil structure, and destroys the normal growth and development of seedlings, which is not conducive to the sustainable development of potato production. Subsurface drip irrigation, in which drip tape is buried in the eld soil, has been shown to be a novel means of conserving water resources and improving water use e ciency for some crops (Yao et al, 2021;Zheng et al, 2023). Compared with the surface irrigation mode, the soil covered with drip tape reduced the ineffective evaporation from the surface and saved water, and showed a similar effect with mulch lm covering.…”

“…Compared with the surface irrigation mode, the soil covered with drip tape reduced the ineffective evaporation from the surface and saved water, and showed a similar effect with mulch lm covering. In addition, the mode had many other advantages, such as yield increase, quality improvement, improvement of soil microenvironment of root zone, convenience of eld management and operation, and prevention of capillary aging (Hu et al, 2000;Ma et al, 2020;Zheng et al, 2023). It was found that the evapotranspiration of maize in subsurface drip irrigation was reduced by 39% compared to surface drip irrigation, soil evaporation was reduced by about 40 mm throughout the growing season, and irrigation water productivity increased by 5% (Valentín et al, 2020).…”