Effects of Different Soil Water Potential at Tillering Stage on Rice Yield and Physiological Traits in Saline-alkali Soil

To explore the effects of different soil water potential of tillering stage on rice yield and physiological traits in saline-alkali soil, using four treatment levels of soil water potential of 0 kPa (H1: soil moisture), soil water potential of -15 kPa (H2), soil water potential of -30kPa (H3), and CK (continuously flooded), a comparative study of different soil water potential of tillering stage on grain yield, dry matter production, leaf physiological treats and growth dynamic was conducted. The results showed that the period of water stress, the leaf relative water content of the soda saline soil of rice had declined rapidly, and the falling range with the same level of water stress. The H1 had recovering the level of CK after 15days of rewatering. The tiller number from high to low showed a trend of CK > H1 > H2 > H3 with the drop of water potential in saline-alkali soil, the date of top tillering was the same from CK to H1, but H2 and H3 had 5-10 days later than CK. Water stress could restricted the expansion of the rice leaf area and with the exacerbation of the water stress degree, the rice leaf area index decreased. The date ofH1,H2 and H3 come to maximum LAI were delayed 5days compared with CK. There had a significantly different among all treatments as to the dry matter accumulation, showed a trend of H1 > CK > H2 > H3, and the difference between H1, CK and H2, H3 had reached significant level(P < 0.05). The rice yield from high to low showed a trend of CK > H1 > H2 > H3, compared with the CK, the H1\H2 and H3 decreased 11.45 %, 24.92% and60.24% respectively in the soda saline-alkali soil under moist irrigation at the tillering stage. So in soda saline-alkali soil continuously flooded irrigation is necessary.