Effective use of irrigation water is a key issue in agricultural development in arid area since irrigation is a precondition for crop production. Xinjiang Uygur autonomous region of China locates in a typical arid zone, where water is the most important limiting factor for agriculture development. Increasing water use efficiency has been an urgent issue in this region as ecological water demand has been increasingly concerned.
Partial rootzone irrigation (PRI) is an irrigation practice with which only part of rootzone is wetted through proper irrigation design and management while the rest of root system is left in drying soil. When roots are distributed in wet and dry parts of soil, the roots in drying part will produce chemical signals to narrow stomata opening and thus reducing transpiration.
The group of Professor Tang Lisong, Xinjiang Institute of Ecology and Geography, Chinese of Academy of Sciences, researched the effects of PRI on stomata behavior, plant growth, biomass allocation, yield formation and water use efficiency of cotton in arid area. They found that moderate water stress reduced shoot biomass accumulation and increased root biomass. While the vegetative and reproductive parts of shoot were reduced in the same proportion under the PRI, the final yield was much less reduced in PRI indicating an increased reproductive efficiency of cotton. Furthermore, PRI advanced the development of reproductive organs and led to earlier flowering. They also found that PRI increased the proportion of applied water that is transpired, and therefore led to higher water use efficiency than regular irrigation.
The results have been published on Agricultural Water Management (doi:10.1016/j.agwat.2010.05.006) and Plant and Soil (doi: 10.1007/s11104-010-0537-5).