Long-Term Monitoring of Rainfed Wheat Yield and Soil Water at the Loess Plateau Reveals Low Water Use Efficiency

Abstract

Increasing crop yield and water use efficiency (WUE) in dryland farming requires a quantitative understanding of relationships between crop yield and the water balance over many years. Here, we report on a long-term dryland monitoring site at the Loess Plateau, Shanxi, China, where winter wheat was grown for 30 consecutive years and soil water content (0–200 cm) was measured every 10 days. The monitoring data were used to calibrate the AquaCrop model and then to analyse the components of the water balance. There was a strong positive relationship between total available water and mean cereal yield. However, only one-third of the available water was actually used by the winter wheat for crop transpiration. The remaining two-thirds were lost by soil evaporation, of which 40 and 60% was lost during the growing and fallow seasons, respectively. Wheat yields ranged from 0.6 to 3.9 ton/ha and WUE from 0.3 to 0.9 kg/m3. Results of model experiments suggest that minimizing soil evaporation via straw mulch or plastic film covers could potentially double wheat yields and WUE. We conclude that the relatively low wheat yields and low WUE were mainly related to (i) limited rainfall, (ii) low soil water storage during fallow season due to large soil evaporation, and (iii) poor synchronisation of the wheat growing season to the rain season. The model experiments suggest significant potential for increased yields and WUE.

Wheat straw mulching with fertilizer nitrogen: An approach for improving soil water storage and maize crop productivity

“…The shortage of water in arid and semi-arid regions is a major problem causing limited crop production (Tavakkoli and Oweis 2004). The straw mulching provides a covering layer on the soil surface and saves rain water by reducing the runoff of rain water thus conserving more water and increasing the soil water storage (Yang and Guo 1994, et al , Qin et al 2013). The present study indicated that surface FS + N regime conserves higher soil moisture across the growing season principally during early growth stages compared with CK.…”

Mulching as water-saving technique in dryland agriculture: review article

“…Thus, agriculture water management is a major concern to save water in cultivated land. Also, rain-fed cultivation in dryland farming is being pressured which required more effective utilization by using water-saving technologies (Qin et al 2013). Therefore, conservative and efficient water-use has been practiced for many years in arid and semi-arid regions of the world with great success.…”

Evaluation of Organic and Inorganic Mulching as an Integrated Weed Management Strategy in Maize Under Rainfed Conditions

“…Also, plastic mulches are expected to reduce field management costs, e.g., costs of weed control (Xu et al, 2015). Plastic mulches not only reduced evaporation, field management costs and soil erosion but also reduced weed infestation and increased yields of crops such as okra (Qin et al, 2013;Kareem et al, 2015;Xu et al, 2015). Furthermore, rice straw significantly decreased weed density, relative weed density and fresh and dry biomass of weeds in maize.…”