Evaluation of irrigation water salinity and leaching fraction on the water productivity for crops

Abstract

In arid and semi-arid irrigated croplands, the excessive accumulation of soluble salts in the root zone is an extensive problem that seriously limits crop yield and water productivity (WP). To avoid affects the yield potential of crops, the application of extra irrigation for leaching of excessive salts from the root zone was required. Quantitative knowledge of effects of the irrigation water salinity and leaching fraction (LF) on the relative yield (RY) and the unit water productivity of crop evapotranspiration (UWP ET) and the unit water productivity of irrigation water (UWP I) were becoming gradually important. This article provided theoretical models for estimating the UWPs (UWP ET and UWP I) and optimizing leaching fraction according to irrigation water salinity. In the present study, eight levels of irrigation water salinity (ECw = 0.25, 0.50, 0.75, 1, 2, 3, 4, and 5 dS/m) and 39 levels of LF values ranging from 0.04 to 0.80 were set and tested to assessing their effects on the RY and UWPs for four typical crops (barley, bean, wheat, and maize) with different salt tolerance levels. Almost every curve determined between the UWPs and LFs for the four crops had an inflection point. It was indicated that the UWP ET and UWP I could be maximized by optimizing the LF under different irrigation water salinities. Furthermore, the linear regression relationships were established to estimate the maximum values of UWPs and their corresponding optimal LFs for four crops by using the irrigation water salinity. Moreover, the theoretical models for estimating the UWPs were validated by data of wheat from previous literature, and the models could be suitable with acceptable relative errors when LFs ranging from 0.07 to 0.17.

Future of Sustainable Agriculture in Saline Environments

“…For instance, Corwin et al ( 2007) described the use of steady-state and transient models to characterize leaching requirements for soil salinity control. Ning et al (2020) evaluated the irrigation water salinity and leaching fraction on the water productivity of barley, bean, wheat and maize crops in China. The required leaching fraction depended on the salt tolerance of the crop and the salinity of the irrigation water.…”

“…Despite the advantages of leaching, its application has not always been successful or accepted by decision-makers. Ning et al (2020) noted that the risk of environmental contamination might be increased due to the leaching of pesticides, nutrients and trace elements. Furthermore, it is worth noting that drought and water crises exist in many regions because there is limited access to freshwater.…”

Effects of organic amendments on soil properties and growth characteristics of Melon (Cucumis melo L.) under saline irrigation

“…Saline irrigation reduces the yield and quality of crops, since it might lead to secondary soil salinization [27] . However, moderately saline water can be utilized for irrigation when proper strategies are applied [28,29] . In this study, saline irrigation had no significant effect on soil pH at yearly scale.…”

Modeling salinity risk response to irrigation practices for cotton production under film mulched drip irrigation in Xinjiang

“…Similar results were obtained in scenarios 1-15. LF is defined as the ratio of D relative to IA, and it is usually used to quantify the leaching rate (Ning et al 2020(Ning et al , 2021. In the lower and higher AS scenarios, the LF values ranged from 9.97 to 30.90% (mean ¼ 17.67%) and 31.13% to 52.15% (mean ¼ 41.38%), respectively, thereby indicating that LF was higher under salt stress than that without salt stress in the cotton field under FMDI.…”