| The effect of water saving of no-tillage with stubble mulch (NTS) for storage irrigation was studied at Zhangye, in Hexi irrigation district, Gansu province. The study examined the effects of NTS on soil moisture, soil temperature, soil bulk density, the growth of Spring Wheat, the change of yield and water use efficiency (WUE). The results were as follows:⑴NTS could effectively increase precipitation conservation and reduce soil moisture evaporation during summer and winter fallow. The anti-evaporation rate was reduced and the daily evaporation was increased with the increase of storage irrigation norm (P<0.05). As for the water consumption of Spring wheat during the whole growing period, NTS system didn't reduce the soil water consumption, but changed the distribution of soil water in space and time during the spring wheat growth season. The results showed that the storage irrigation norm can be lowered to 750m~3/hm~2 with NTS system compared with conventional storage irrigation. During summer fallow, the anti-evaporation rate of NTS was 12.87%, and 18.32% higher than those of CTS and CTB, respectively (P<0.01), the daily evaporation of NTS was 59.85% and 64.14% (P<0.01) lower than that of CTS and CTB, respectively. The daily evaporation of a storage irrigation norm of 750 m~3/hm~2 was 23.58%, 38.64% and 44.91%(P<0.05)lower than that of 1200, 1650 and 2100 m~3/hm~2, respectively. During winter fallow, the anti-evaporation rate of NTS was 1.04% and 9.66% (P<0.01) higher than those of CTS and CTB, respectively. The daily evaporation of NTS, CTS and CTB was 0.24, 0.28 and 0.40mm/d, respectively. The daily evaporation of NTS was 16.53% and 41.10% (P<0.01) lower than that of CTS and CTB, respectively. The daily evaporation of a storage irrigation norm of 750 m~3/hm~2 was 42.03%, 59.41% and 76.36%(P<0.01)lower than that of 1200, 1650 and 2100 m~3/hm~2, respectively. The soil water consumption of NTS was 0.16 and 0.13 mm/d more than that of CTB and CTS (P<0.05), respectively. During early and late-season of spring wheat growing stage, NTS reduced soil water consumption. During the mid growing season, the soil water consumption increased due to vigorous crop growth. In space NTS only changed the proportion of soil evapotranspiration. In addition, with the increase of storage irrigation norm, the daily evaporation during the growth stage was increased (P<0.01). These data further confirm that the storage irrigation norm can be reduced to 750m~3/hm~2 with NTS system.⑵During the growth stage of spring wheat, NTS had the obvious effect of low soil temperature. During growth phase, the daily average soil accumulated temperature of NTS was lower than that of than CTS and CTB. The changes in the daily average soil accumulated temperature of NTS, CTS and CTB mainly occurred within 0-10cm depth from the soil surface, especially within 5cm depth of the soil mainly because of changes in the structure of soil surface. The magnitude of daily change in the soil temperature was significantly lower in NTS than in CTS and CTB. With the increase in the soil depth, the time of the peak of daily change was delayed. For example, the time of the peak of daily change at a soil depth of 0, 5, 10, 15, 20 and 25cm was 14:00, 15:00, 16:00, 18:00, 19:00 and 20:00, respectively. The soil temperature was significantly reduced after irrigation, and the magnitude of daily change in the soil temperature was markedly reduced compared with that before irrigation, especially at the soil depth of 0 cm layer at 14:00.⑶NTS had the effects of decreasing soil bulk density and heat conductivity within the soil depth of 0~15 cm. This explained why the soil temperature of NTS was lower than that of CTS and CTB.
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