两茬收割饲用甜高粱灌溉定额试验研究

Experimental study on irrigation quota of two crops harvesting feeding sweet sorghum

为探索饲用甜高粱最佳灌溉定额和节水效果,设置了不同灌溉定额(2 400,3 000,3 600,4 200,4 800 m^3/hm^2)对两茬收割甜高粱生长和生物产量的影响的田间试验.结果表明,甜高粱茎粗和株高的峰值分别出现在播后62 d和158 d.随灌溉定额增加在形态上表现为株高增加、茎粗减小的趋势.在头茬收割(播后76 d)时,株高日增长率最大,为4. 00～4. 89 cm/d.两茬收割甜高粱鲜、干生物学产量分别为63. 9～115. 5 t/hm^2,12. 7～21. 4 t/hm^2,全生育期耗水量为326. 95～504. 24 mm,鲜生物学产量WUE为15. 53～24. 63 kg/m^3,干生物学产量WUE为3. 89～4. 51 kg/m^3.灌溉定额为4 200 m^3/hm^2时,甜高粱总鲜、干生物量最大,灌溉定额为4 800 m^3/hm^2时,甜高粱总鲜、干生物量增幅不大.从节水和增加生物量角度而言,畦灌方式下的两茬收割饲用甜高粱全生育期灌水4次,灌水定额为1 050 m^3/hm^2,灌溉定额为4 200 m^3/hm^2的灌溉效果最佳.

In order to explore the optimal irrigation quota and water-saving effect suitable for feeding sweet sorghum,a field experiments was conducted to study the effect of the irrigation quota(2 400,3 000,3 600,4 200,4 800 m^ 3/hm^2 respectively)on growth and biomass of two crops of feeding sweet sorghum.Results show that the peak of stems diameter and plant height of sweet sorghum appear respectively at 62 th day and 158 th day after sowing.Plant height increases with increasing irrigation quota,while stems diameter has a reducing with increasing irrigation quota.Daily growth rate of sweet sorghum appears at 76 th day after sowing is the biggest,which are between 4.00-4.89 cm/d.With different irrigation quota,fresh or dry biomass of sweet sorghum is 63.9-115.5 t/hm^2 and 12.7-21.4 t/hm^2 respectively,water consumption of that in the whole growth stage is 326.95-504.24 mm,WUE of fresh and dry biomass is 15.53-24.63 kg/m^3 and 3.89-4.51 kg/m^3 respectively.When irrigation quota was 4 200 m^3/hm^2,Fresh or dry biomass of two crops of sweet sorghum are all the biggest,and no significant increase is achieved by adding irrigation quota.In conclusion,for water-saving and increasing the biomass,irrigation schedule with irrigation quota of 4 200 m^3/hm^2(irrigation frequency was 4 times)is thereby recommended as an optimized irrigation to increase the biomass of two crops of feeding sweet sorghum.