| 1 Effects of tillage and soil moisture on water consumption characteristics and yield formation of wheatThe field fixed position experiment was conducted with high-yield medium-gluten winter wheat cultivar Jimai 22 in Shiwang village (35.41°N, 116.41°E), Yanzhou, Shandong, China. The five tillage practice treatments which were strip rotary tillage (SR), strip rotary tillage after subsoiling (SRS), rotary tillage (R), rotary tillage after subsoiling (RS) and plowing tillage (P) respectively, were designed and conducted on the same experimental plots during 2007~2010 growth seasons. However, SRS and RS were no longer subsoiling during 2008~2009 and 2009~2010 wheat growth seasons. This paper analyzes the results of two wheat growth seasons from 2008 to 2010, in order to verify the effects of the subsoiling during the first year on grain yield and water use efficiency. The soil moisture treatments were no irrigation (W0), in 2008~2009, 80% of relative soil moisture content in 0~140 cm soil layers at sowing, 80% at prewintering, 75% at jointing and 75% at anthesis (W1); 80% at sowing, 85% at prewintering, 75% at jointing and 75% at anthesis (W2); 85% at sowing, 80% at prewintering, 75% at jointing and 75% at anthesis (W3); 85% at sowing, 85% at prewintering, 75% at jointing and 75% at anthesis (W4);in 2009~2010, 85% at sowing, 85% at prewintering, 70% at jointing and 75% at anthesis (W'1); 85% at sowing, 90% at prewintering, 70% at jointing and 75% at anthesis (W'2); 85% at sowing, 85% at prewintering, 75% at jointing and 75% at anthesis (W'3); 85% at sowing, 90% at prewintering, 75% at jointing and 75% at anthesis (W'4). The object of this study was to discover the effects of tillage practice and soil moisture on water consumption characteristics, carbon and nitrogen metabolism and grain yield in wheat. The results were as follows:1.1 Effects of tillage and soil moisture on water consumption characteristics1.1.1 Effects of tillage on water consumption characteristics in different soil moisture The total amount of water consumption in SRS was lower than that in RS treatment, the irrigation amount was lower than that in RS and P treatments, but the ratio of the amount of soil water consumption to the amount of total water consumption was higher than that in P, SR and R treatments. SRS treatment had lower soil evaporation at every stage in wheat growth season, the amount of water consumption during sowing - prewintering was lower than that in P, RS and R treatment, and there was no significant difference between SRS and SR treatment. The amount and the percentage of water consumption during anthesis - maturity in SRS treatment were higher than those in P, SR and R treatments. The results suggested that the SRS treatment which was strip rotary in 2008~2010 after once subsoiling in 2007~2008 decreased the amount of irrigation but increased the amount of soil water consumption. The amount of water consumption during sowing - prewintering and soil evaporation were lower, the amount of water consumption during anthesis - maturity was greatest, which was benefit for wheat to decrease water consumption at early stage, and increase water absorption after anthesis.1.1.2 Effects of soil moisture on water consumption characteristics under different tillage practicesThe total amount of water consumption in W0 treatment was the lowest, the ratio of precipitation and the ratio of the amount of soil consumption to total amount of water consumption in W0 treatment were greatest. The soil evaporation and the amount of water consumption during jointing - maturity in W0 treatment were lower than those in the other treatments. The results indicate that W0 treatment decreased soil evaporation, and promoted the use of stored soil water by wheat.In W3 and W'3 treatments, the amount and percentage of water consumption during anthesis - maturity were greatest, the amount of irrigation and its ratio to total amount of water consumption and the total amount of water consumption were lower than those in W4 and W'4 treatments. However, the ratio of the amount of soil water consumption to the total amount of water consumption was higher than that in W4 and W'4 treatments, and there was no significant difference between W3 and W2, and W'3 and W'2 treatments. It suggested that W3 and W'3 treatments which the relative soil moisture content in 0~140 cm soil layers was 85% at sowing, no irrigation at prewintering, 75% at jointing and 75% at anthesis stage achieved lower total water consumption, consumption percentage and soil evaporation during prewintering - jointing, compared to those in the treatments which were irrigated at the prewintering stage. The amount of water consumption during anthesis - maturity in W3 and W'3 treatments was greatest. It was encouraged to higher water absorption by the wheat after anthesis.1.2 Effects of tillage and soil moisture on physiological characteristics and the accumulation and distribution of dry matter in wheat1.2.1 Effects of tillage on physiological characteristics and the accumulation and distribution of dry matter in different soil moisture The flag leaf water potential, photosynthetic rate and leaf water use efficiency in SRS andRS treatments were greatest during middle and late grain filling stage, which was followed by those in P treatment, but those in SR treatment were the lowest. The sucrose phosphate synthase activity and sucrose content of flag leaf in SRS treatment were higher than those in P treatment at early and middle grain filling stages. However sucrose content was lower than that in RS and P treatments at late grain filling stage, which in turn improved the accumulation of sucrose in grain and the translocation of sucrose from flag leaf to grain. The accumulation of dry matter after anthesis and its contribution ratio to grain, and dry matter distribution in grain at maturity in SRS and RS treatments were higher than those in the other treatments. Dry matter distribution in stem+sheath+leaf in P treatment at maturity was higher than that in SRS and RS treatments. The results suggested that the SRS treatment which was strip rotary in 2008~2010 after once subsoiling in 2007~2008 improved the accumulation of dry matter after anthesis and its distribution ratio to grain, which was the physiological basis of high-yield in the SRS treatment.1.2.2 Effects of soil moisture on physiological characteristics and dry matter accumulation and distribution under different tillage practicesThe photosynthetic rate, transpiration rate, Fv/Fm,ΦPSII, SPS activity and the amount of dry matter accumulation in the W0 treatment were lower than those in the irrigated treatments, while its dry matter distribution ratio in grain was greatest. In this way, the production of dry matter was decreased and the distribution of dry matter to grain at maturity was encouraged in drought conditions.The photosynthetic rate during the middle and late grain filling stages in the W3, W4 and W'3, W'4 treatments were greatest. The transpiration rate at the late grain filling stage in the W3 and W'3 treatments was lower than that in the W4 and W'4 treatments. The amount of dry matter accumulation after anthesis and its contribution ratio to the grain, and dry matter distribution to grain in the W3 and W'3 treatments were higher than those in the W4 and W'4 treatments. In 2008~2009 growth season, the flag leaf water potential, root activity, SPS activity and sucrose content during 7 d - 28 d after anthesis in the W3 and W4 treatments were higher than those in the W1 and W2 treatments. However, the sucrose content at 28 d after anthesis in the W3 treatment was lower than that in the W4 treatment, which were facilitated to the translocation of sucrose from flag leaf to grain. The results indicated that the W3 and W'3 treatments where the relative soil moisture content in 0~140 cm soil layers was 85% at sowing, no irrigation at prewintering, 75% at jointing and 75% at anthesis stage were beneficial for maintaining the ability to produce a high level of dry matter, delaying flag leaf senescence, and improving dry matter translocation to grain after anthesis. 1.3 Effects of tillage and soil moisture on nitrogen accumulation, translocation and distribution in wheat1.3.1 Effects of tillage on nitrogen accumulation, translocation and distribution in different soil moistureThe amount of nitrogen accumulation at anthesis and maturity, the amount of grain nitrogen accumulation and the distribution ratio of grain nitrogen in the SRS and the RS treatments were higher than those in the SR and the R treatments. However, the nitrogen translocation efficiency from vegetative organs to grain and its contribution proportion in the SRS and the RS treatments were lower than those in the SR and the R treatments. At maturity, the content of NO3––N in 0~80 cm soil layers in the SRS treatment was lower than that in the SR, R and P treatments, and was also lower than that in 120~140 cm soil layers in RS treatment. The results suggested that the SRS treatment which was strip rotary in 2008~2010 after once subsoiling in 2007~2008 encouraged higher nitrogen accumulation at anthesis and maturity, and increased nitrogen uptake efficiency and nitrogen production efficiency, decrease nitrogen translocation from vegetative organs to grain, while the nitrate nitrogen residual in deep soil layers was lower than that in the RS treatment.1.3.2 Effects of soil moisture on nitrogen accumulation, translocation and distribution under different tillage practicesThe amount of nitrogen accumulation in the plant after anthesis and that in spike axis+glume and sheath+stem+leaf at maturity in the W0 treatment were lower than those in the treatments with irrigation, the efficiency of nitrogen translocation from vegetative organs to grain and its contribution proportion were higher than those in the treatments with irrigation. At maturity, the content of NO3––N in 0~60 cm soil layers was higher, but in 140~200 cm soil layers it was lower than in the treatments with irrigation.With the amount of irrigation increased, the amount of nitrogen accumulation in the wheat plant at anthesis and maturity increased, but the efficiency of nitrogen translocation from vegetative organs to grain and its contribution proportion decreased. Under the conditions of the SR treatment, the ratio of nitrogen distribution in grain in the W3 and the W2 treatments were lower than that in the W1 treatment, but higher than that in the W4 treatment. The ratio of nitrogen distribution in grain in the W3 and the W1 treatments were higher than that in the W2 and the W4 treatments under the conditions of the SRS, R and P treatments. That in the W3 treatment was higher than that in the W4, W2 and W1 treatments under the conditions of the RS treatment. The NO3––N content in the W3 treatment was lower than that in the W1 and the W2 treatments. The nitrate nitrogen residual in 100~140 cm soil layers in the W4 treatment was greatest. The results indicated that the W3 treatment which the relative soil moisture content of 0~140 cm soil layers was 85% at sowing, no irrigation at prewintering, 75% at jointing and 75% at anthesis was beneficial to increase the amount of nitrogen accumulation in the plant at anthesis and maturity and the efficiency of nitrogen translocation from vegetative organs to grain. The W3 treatment improved the utilization of soil nitrogen in the 40~120 cm soil layers, the efficiency of nitrogen uptake and the efficiency of nitrogen production, decreased the content of NO3––N in the 140~180 cm soil layers, compared to that in the W4 treatment.1.4 Effects of tillage and soil moisture on grain yield, quality and water use efficiency in wheat1.4.1 Effects of tillage on grain yield, quality and water use efficiency in different soil moistureThe water use efficiency and irrigation benefit were greatest in the SRS treatment. There was no significant difference on grain yield between the SRS and the RS treatments. However, the grain yield of the SRS and the RS treatments was higher than that of the other treatments. There was no significant difference on grain yield between the P treatment and the R treatment when there was no irrigation, but the grain yield of the P treatment was higher than that of the R treatment under irrigation condition. The grain yield of the SR treatment was the lowest of all the treatments. The protein content, wet gluten content, dough development time and the dough stability time of the SRS and the RS treatments were higher than those of the P treatment. The results suggested that the SRS treatment which was strip rotary in 2008~2010 after once subsoiling in 2007~2008 was favorable to increase the grain yield and water use efficiency at the same time. The grain quality of the SRS treatment was also superior to that of the P treatment.1.4.2 Effects of soil moisture on grain yield, quality and water use efficiency under different tillage practicesThe grain yield of the W0 treatment was lower than that of the treatments with irrigation. However, the protein content, wet gluten content, dough development time and dough stability time of the W0 treatment were higher than that of the treatments with irrigation. Compared with the W3 and the W'3 treatments, water use efficiency of the W0 treatment was higher in the SR system, but was lower in the SRS, RS and P systems, and there was no significant difference in the R system.The irrigation benefit of W3 and W'3 treatments was highest. There was no significant difference on grain yield between the W3 and W4, and W'3 and W'4 treatments, but higher than the other treatments. The water use efficiency of the W3 treatment was higher than that of the W2 and the W4 treatments, as well, the water use efficiency of the W'3 treatment was higher than that of the W'2 and the W'4 treatments. The W4 treatment with the most irrigation achieved the lowest protein content, wet gluten content, dough development time and dough stability time. The results indicated that the W3 treatment which the relative soil moisture content of 0~140 cm soil layers was 85% at sowing, no irrigation at prewintering, 75% at jointing and 75% at anthesis stage achieved the greatest irrigation benefit and grain yield, and higher water use efficiency. The protein content, wet gluten content, dough development time and dough stability time of the W3 treatment were higher than those of the W4 treatment.Therefore, we recommend that the most appropriate treatment for high-yielding and water-saving production of wheat was the SRS– W3 and SRS– W'3 treatments with strip rotary for two years after once subsoiling, and 85% of relative soil moisture content in the 0~140 cm soil layers at sowing, no irrigation at prewintering, 75% of relative soil moisture content in the 0~140 cm soil layers at jointing and 75% of relative soil moisture content in the 0~140 cm soil layers at anthesis.2 Effects of irrigation methods on water consumption characteristics and yield formation of wheatThe field experiment was conducted with high-yield and medium-gluten winter wheat cultivar Jimai 22 in Shiwang village (35.41°N, 116.41°E), Yanzhou, Shandong, China in 2009~2010 growing season. The control treatment expressed as I0 irrigated no water, and two irrigation methods were designed,i. e., border flooding irrigation (I1 and I3);sprinkler irrigation (I2 and I4). Two relative soil moisture contents in each irrigation regime were designed to investigate the effects of irrigation methods and soil moisture on water consumption characteristics and grain yield in wheat.2.1 Effects of irrigation methods on water consumption characteristicsThe percentage of water consumption during jointing - maturity of the I0 treatment was significantly lower than that of the irrigated treatments, while the ratio of the amount of soil water to the amount of the total water consumption in the I0 treatment was higher than that in the irrigated treatments. The amount of total water consumption, the amount and the percentage of the water consumption during jointing - anthesis and the ratio of the amount of irrigation to the total amount of water consumption increased with the relative moisture content at jointing and anthesis stage increased. The ratio of the amount of soil water consumption to the total amount of water consumption, the percentage of the water consumption during anthesis - maturity and the amount of soil water consumption from the 60~140 cm soil layers in the sprinkler irrigation treatments were higher than those in the border flooding irrigation treatments. However the soil evaporation at anthesis and grain filling stage in the sprinkler irrigation treatments were lower than those in the border flooding irrigation treatments. The results indicated that the sprinkler irrigation reduced the amount of irrigation, increased the amount of the soil water consumption from the 60~140 cm soil layers and the amount of soil water consumption during anthesis - maturity, which was favorable to increase the water absorption by wheat after anthesis, and decrease soil evaporation.2.2 Effects of irrigation methods on photosynthetic rate and the accumulation and distribution of dry matterThe photosynthetic rate after anthesis in the I0 treatment was significantly lower than that in the irrigated treatments. The amount of dry matter accumulation after anthesis and the contribution of dry matter assimilated after anthesis to grain were the lowest. The amount of dry matter accumulation after anthesis and its contribution to grain increased with the relative moisture content at jointing and anthesis stage increased. The photosynthetic rate at late grain filling stage, the amount of dry matter accumulation after anthesis and its contribution to grain in sprinkler irrigation treatments were higher than those in border flooding irrigation treatments. The results suggested that sprinkler irrigation encouraged an increase in the amount of dry matter accumulation and its translocation to grain after anthesis.2.3 Effects of irrigation methods on nitrogen accumulation and distributionThe amount of nitrogen accumulation in plant at anthesis and maturity, the amount and the efficiency of nitrogen translocation from vegetative organs to grain in the I0 treatment were significantly lower than those in the irrigated treatments. However the ratio of nitrogen distributed to grain in the I0 treatment was greatest. The amount of nitrogen accumulation at anthesis and maturity increased, but the ratio of nitrogen translocated to grain and the contribution proportion of translocated nitrogen decreased when the relative moisture content at jointing and anthesis was increased. The amount of nitrogen accumulation at maturity, the amount and the efficiency of nitrogen translocation from vegetative organs to grain in sprinkler irrigation treatments were higher than those in the border flooding irrigation treatments. 2.4 Effects of irrigation methods on grain yield, water and nitrogen use efficiencyThe amount of water consumption, grain yield and nitrogen uptake efficiency were the lowest but nitrogen use efficiency was greatest in I0 treatment. There was no significant difference in water use efficiency between the I0 treatment and the I1 treatment. However, the water use efficiency of the I0 and the I1 treatments was lower than that of the other treatments. The grain yield, water use efficiency and nitrogen uptake efficiency increased while the nitrogen harvest index decreased with the relative moisture content increased. Considering the balance of grain yield, water and nitrogen use efficiency, the appropriate treatment under these research conditions was the I4 treatment with sprinkler irrigation, and 75% of the relative soil moisture content in the 0~140 cm soil layers at jointing and anthesis.
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