| Optimum winter irrigation amount of subsurface drip irrigation in alfalfa grassland |
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| DOI：10.7606/j.issn.1000-7601.2020.01.22 |
| Key Words: alfalfa subsurface drip irrigation winter irrigation amount soil water storage soil water consumption freezing\|thawing alternation |
| Author Name | Affiliation | | DU Jianmin | Institute of Desertification Control, Ningxia Academy of Agricultural and Forestry Sciences, Yinchuan, Ningxia 750002, China | | WANG Zhanjun | Institute of Desertification Control, Ningxia Academy of Agricultural and Forestry Sciences, Yinchuan, Ningxia 750002, China | | YU Hongqian | Institute of Desertification Control, Ningxia Academy of Agricultural and Forestry Sciences, Yinchuan, Ningxia 750002, China | | JI Bo | Institute of Desertification Control, Ningxia Academy of Agricultural and Forestry Sciences, Yinchuan, Ningxia 750002, China |
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| Abstract: |
| In order to study the effects of different winter irrigation amounts on soil water content and temperature of over\|winter and spring green\|upstage,growth and hay yield of first stubble alfalfa (medicago sativa) were analyzed. Different winter irrigation single factor tests were carried out by a randomized block design including four water treatments (600 m3·hm-2as T1,900 m3·hm-2as T2,1 200 m3·hm-2 as T3, 1 500 m3·hm-2 as T4） of winter irrigation amounts were set up. The results showed that the effects of different winter irrigation amounts on soil water content and temperature were obvious and the duration of freezing\|thawing ranked as CK=T3＜T2＜T1,respectively, up to 6 d,6 d,12 d, and 18 d; freezing period was as CK＜T3＜T2＜T1, respectively, up to 51 d,61 d,63 d, and 67 d. With the increase in winter irrigation amount, the duration of freezing\|thawing and freezing period became shorter and delayed, the melting period was prolonged and gradually advanced 1 to 4 days; the duration of each treatment was as CK＞T3=T2＞T1, and the end of March 5 was the earliest. During the overwinter period, the soil water storage gradually decreased with the increase of winter irrigation amount in 0~100 cm layer, and the soil water consumption of T1, T2, T3 and CK were 53.70，102.95，301.5, and 469.16 m3·hm-2, respectively. The 40~60 cm layer was the highest, the change of soil water storage was different in 60~100 cm layer, T1 and T2 water storage increased and it was inversely proportional to winter irrigation, T3 and CK water storage decreased with the increase of winter irrigation. During the period of green\|up stage, the soil water storage was consumed in 0~100 cm layer, and the highest value 212.87 m3·hm-2 storage was with 900 m3·hm-2 of T2. Overwinter rate and first stubble hay yield of alfalfa were positively correlated with winter irrigation, butthere was no significant difference in the number of primary branches among treatments. Taking the overwintering rate, the number of primary branches, the yield of the first stubble, the water consumption during the overwintering, and greening stages of medicago sativa as the indexes,the subordinate function method was used to comprehensively evaluate each treatment. It indicated that the average value of subordinate function of each treatment was in the order of T2＞T3＞T1＞CK. It was concluded that the optimal winter irrigation amount was 900 m3·hm-2 of T2 for subsurface drip irrigation for alfalfa field in Ningxia area, which was conducive to the water use efficiency of winter irrigation and the overwintering and green\|up stage of alfalfa. |
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