Aims
Water deficiency together with soil salinization have been seriously restricting the sustainable agricultural in southern Xinjiang, China for a long time. Optimal soil moisture regulation contributes to the amelioration of soil water and salinity for crops, which is favorable for plants production.
Methods
The field experiment with five soil water lower limit levels (85% FC (T1), 75% FC (T2), 65% FC (T3), 55% FC (T4) and 45% FC (T5), where FC is the field capacity) was conducted in southern Xinjiang to investigate the responses of soil water-salt dynamics and the cotton performance to soil moisture regulation strategies.
Results
The results indicated that the humid perimeter of soil water and leaching range of soil salt increased with the decrease of soil moisture lower limit. Though more soil salt was leached out for T5 treatment at flowering stage, soil salinity increased again at boll setting stage owing to the long irrigation interval. Soil salt accumulated in 0-100 cm after cotton harvest, and the accumulation amount followed T3 > T5 > T1 > T2 > T4. Moreover, with the decline of soil moisture lower limit, both the plant height and nitrogen uptake decreased significantly, while the shoot root ratio increased. Compared with the yield (7233.2 kg·hm-2) and water use efficiency (WUE, 1.27 kg·hm-2) of T1 treatment, the yield for T2 treatment only decreased by 1.21%, while the WUE increased by 10.24%.
Conclusion
The soil moisture lower limit of 75% FC was recommended for cotton cultivation in southern Xinjiang, China.