Effect of Irrigation and Rainfall on Water Consumption Characteristics and Yield of High Yield Highland Barley in Tibet River Valley

This paper was to study the effect of irrigation and rainfall on water consumption characteristics and yield of high yield highland barley in Tibet river valley.In pots, highland barley-25 of Tibet was used as the test material to provide eight water stress treatments： normal water, slight water stress, middle water stress, and severe water stress in two environmental conditions（the whole growth period water stress and the rainwater irrigation after filling stage）. Test results indicated that water consumption increased with soil water rise. The maximum consumption of water was at the joining stage and filling stage. And then, the results showed that under rainwater irrigation treatment, the more the soil moisture was, the more the water consumption was. The water stress in whole highland barely growth period reduced biomass and yield. Compared with that of normal water treatment, biomass of slight water stress, middle water stress and severe water stress treatment was decreased by 29.9%, 41.7% and 47.6%, respectively, and yield of the three treatments was decreased by 15.8%, 43.7% and 57.2%, respectively. But rainfall after filling stage was beneficial to biomass and yield of highland barely. Compared with water stress on whole growth period, the biomass and yield of rainfall treatments after the filling stage were increased by 13%, 75.8%, 128.1%, 157.8% and 42.8%, 84%, 201.6%,and 269.5%. The results indicated that biomass and yield of rainwater irrigation after the filling stage had compensatory effect for highland barley growth under water stress, and could improve the water use efficiency. Therefore, properly rainwater usage is beneficial to the increase of yield and water use efficiency of Tibet highland barley-25 under water stress.

Effects of Tillage Practices on Water Consumption, Water Use Efficiency and Grain Yield in Wheat Field

Water shortage is a serious issue threatening the sustainable development of agriculture in the North China Plain, with the winter wheat （Triticum aestivum L.） as its largest water-consuming crop. The effects of tillage practices on the water consumption and water use efifciency （WUE） of wheat under high-yield conditions using supplemental irrigation based on testing soil moisture dynamic change were examined in this study. This experiment was conducted from 2007 to 2010, with ifve tillage practice treatments, namely, strip rotary tillage （SR）, strip rotary tillage after subsoiling （SRS）, rotary tillage （R）, rotary tillage after subsoiling （RS）, and plowing tillage （P）. The results showed that in the SRS and RS treatments the total water and soil water consumptions were 11.81, 25.18%and 12.16, 14.75%higher than those in SR and R treatments, respectively. The lowest ratio of irrigation consumption to total water consumption in the SRS treatment was 18.53 and 21.88%for the 2008-2009 and 2009-2010 growing seasons, respectively. However, the highest percentage of water consumption was found in the SRS treatment from anthesis to maturity. No signiifcant difference was found between the WUE of the lfag leaf at the later iflling stage in the SRS and RS treatments, but the lfag leaf WUE at these stages were higher than those of other treatments. The SRS and RS treatments exhibited the highest grain yield （9 573.76 and 9 507.49 kg ha-1 for 3-yr average） with no signiifcant difference between the two treatments, followed by P, R and SR treatments. But the SRS treatment had the highest WUE. Thus, the 1-yr subsoiling tillage, plus 2 yr of strip rotary planting operation may be an efifcient measure to increase wheat yield and WUE.