Water balance and migration for maize in an oasis farmland of northwest China

Abstract

Water balance and migration characteristics are vital to the establishment of an efficient irrigation management system. Based on the observed data including microclimate and growing parameters of maize from 2009 to 2012, actual evapotranspiration during the growth period was estimated by a combination of the FAO-56 crop coefficient approach and the Penman-Monteith model; the changes in soil water storage were estimated through the monitored water content at different depths from 0 to 3 m; the water content monitoring zone was divided into three sub-zones according to the water-balance characteristics of different soil layers and water monitoring data. On these bases, in combination of water-balance model, three aspects were analyzed: water-balance characteristics at different growth stages; water-balance characteristics in the three different sub-zones; and water-migration characteristics of ten sunny days following irrigation. These analyses revealed severe deep leakage under present irrigation management, which could be remedied by limiting onetime irrigation practices and increasing irrigation frequency. Additionally, some practical suggestions are provided for different growing stages.

Estimating Deep Drainage Using Deep Soil Moisture Data under Young Irrigated Cropland in a Desert‐Oasis Ecotone, Northwest China

“…The actual deep drainage rate can be estimated using methods such as soil water balance, chloride mass balance, and numerical modeling. However, each of the methods has limitations (Healy, 2010; Lin et al, 2013; Wang et al, 2016; Zhao and Zhao, 2014). In this study, we have shown that the HYDRUS‐1D model driven by soil moisture data measured below the root zone could accurately simulate deep drainage under young irrigated croplands in the desert‐oasis ecotone.…”

“…Moreover, the soil is generally coarse textured, with low organic matter and weak structure (Zhang et al, 2017, 2018). The deep drainage coefficient (i.e., the ratio of deep drainage to water input) under the irrigated croplands in this region is more than 20% in the growing season (Ji et al, 2007; Zhao and Zhao, 2014). This deep drainage compounds the problem of agricultural water shortage in this and similar arid areas.…”

“…The numerical model determined the effect of the root to be too complex to evaluate deep drainage in many areas (Ji et al, 2007; Min et al, 2017; Wang et al, 2016; Zhou et al, 2012). In the desert‐oasis region, the deep drainage rate was estimated using soil water balance (Zhao and Zhao, 2014) and numerical modeling (Ji et al, 2007; Zhou et al, 2012). The deep drainage rate under cropland ranged from 20 to ∼42% in the growing season (Ji et al, 2007; Zhao and Zhao, 2014).…”

“…In the desert‐oasis region, the deep drainage rate was estimated using soil water balance (Zhao and Zhao, 2014) and numerical modeling (Ji et al, 2007; Zhou et al, 2012). The deep drainage rate under cropland ranged from 20 to ∼42% in the growing season (Ji et al, 2007; Zhao and Zhao, 2014). However, the prior deep drainage estimates were restricted to the growing season.…”

“…However, the prior deep drainage estimates were restricted to the growing season. Moreover, the deep drainage rate under different croplands varied greatly due to crop type, irrigation amount, fertility level, and field management (Ji et al, 2007; Li et al, 2015a; Zhao and Zhao, 2014). The deep drainage rates under young cropland remains poorly understood, especially for winter irrigation, a common practice in Northwest China.…”