| One year's field experimentation for spring wheat and maize under hole irrigation has been carried out in the semi-arid areas on Zhangye city of Gansu in the North-west of China where is 127.5mm average precipitation and its average evaporation is about 2047.9mm per year. The purpose of this paper was to deal with the impacts of plastic film mulch on soil temperature in the seedling period, soil moisture, effect on irrigating and the yield in the whole growth period of spring wheat and maize irrigated by border irrigation on plastic film-mulching. The main results were as follows: 1.The variation of soil water content was very slight and it could be increased under the plastic film mulch of hole irrigation: In the 40 days from sowing to the first irrigation, the soil water content were increased by 8.27% and 2.30% under 1.25m and 0.75m film-mulching respectively; at the same time, soil water content appeared obvious downtrend in bare field under conventional irrigation system. In spite of the plastic film mulch width of 1.25m or 0.75m, the change of soil moisture under plastic film-mulching maize was between percentage of 0.377 and 0.869; but it was percentage of 1.255 in CK. Thus, it showed that film mulching could maintain and increase soil moisture. 2.Plastic film mulching of hole irrigation could increase soil temperature in seedling period of spring wheat obviously, and the improvement of soil temperature by 1.25m film-mulching was better than that of 0.75m: with the soil depth of 5~25cm, average soil temperature under 1.25m film-mulching was higher 0.92℃than that of 0.75m. In the same soil depth, average soil temperature under film-mulching was increased by 1.8℃compared with bare field. Similarly soil temperature under 1.25m film-mulching was better than that of 0.75m to maize, and the extent of diurnal change was consistent. With soil depth of 5~25cm, the time of highest soil temperature was retrusive correspondingly, after 10:00 AM, the range of soil temperature rising was distinct. During the day-time, the variation range of soil temperature were 14℃, 13℃, 10℃, 6℃, 4℃with soil profiles of 5cm,10cm, 15cm, 20cm and 25cm, respectively. 3.In the seedling stage of film-mulching spring wheat, the soil storage difference was significant at 0.05 level with bare field. From elongating stage to booting stage, soil storage in hole irrigation was higher than that of bare field; during milk stage, soil storage with 40~80cm soil layers where root was mass was lower than that of bare field. It was because deep-seated soil storage represented active redeeming function. Before shooting stage of maize, the variation of soil storage presented minor variety; the soil storage in 0~40cm was lower than that of 40~80cm and 80~120cm, but it was always higher than that of bare field. During heading and booting period, soil storage in the treatments of film-mulching was less than that of bare field. Because the ripening time of film-mulching maize was about 10~15 days earlier than that of bare maize, the soil storage in film-mulching treatments was higher than that of bare field during this period obviously. 4.The irrigation quotas of film-mulching spring wheat was only 67% of conventional irrigation. The increasing of soil storage after irrigating in hole irrigation was 22% of irrigation quotas; while that in bare field was only 18% of its irrigation quotas. With the same irrigation quotas, the increasing of soil storage in 1.25m plastic film was 1.32 times of 0.75m plastic film. Thus, the results indicated that the irrigating impact under 1.25m film was better than that of 0.75m plastic film. The soil storage after irrigation under hole irrigation in 20~60cm soil layers was lower than that of 0~20cm, but it was higher than that of 60~120cm obviously because of avoiding deep-leakage by hole irrigation. In the reason of excessive irrigation quotas of bare field, the increasing of storage in topsoil was apparent while it was also high in deep-seated soil profiles. Consequently, the study showed that irrigating water seeps out of tilth in bare field with conventional irrigated system. As for the irrigating well-proportioned, hole irrigation was better than bare field. After irrigating, soil moisture was collected in topsoil mostly under hole irrigation. With same irrigation quotas, the irrigating well-proportioned of 1.25m plastic film on spring wheat was better than that of 0.75m film and there was no significant difference between them. For maize, soil water content after irrigation in 1.25m plastic film was 78%~85% of DUL (Drained Upper Limit); while that in 0.75m plastic film was only 74% of DUL (Drained Upper Limit). Thus, it was evident that the irrigating well-proportioned in 1.25m plastic film was better than that of 0.75m plastic film for film-mulching maize. The density of crops had obvious influence on the advance of irrigating current. Spring wheat belongs to dense-planting crop, and the irrigating well-proportion was optimal with 2.1L/m.s dischargeper unit width. While maize is sparse crop, the distribution of soil water content was well-proportioned with 1.3L/m.s discharge per unit width. So this model was compatible to popularize into the practice. In the whole growth period of sprig wheat, water consumption amount under 1.25m plastic film was higher by 2.30% than that of 0.75m plastic film; while the bare border irrigation consumes the most amount. This amount was significant to the treatments of hole irrigation. By statistical analysis, the number of ear, the 1000-wheat weight and the yield in the treatments of hole irrigation were significant at 0.05 level to the bare field's. The yield of film-mulching increased by 12.85%~19.44% and WUE increased by 26.32%~36.09% on the bare field. Thinking of the illumination, soil water requirements and the operation regulations in the practice of spring wheat itself, this study educed that hole irrigation with 1.25m plastic film-mulching was more suitable to the inland irrigation district of Hexi, and this model was compatible to popularize into the practice under the condition of local technique of produce and cultivation as well. The average water consumption amount under 0.75m plastic film-mulching with different discharge per unit width was 652.93mm; while it was 645.51mm under 1.25m plastic film-mulching. In the whole growth period of maize, the water consumption amount of hole irrigation was significant to the bare field's at 0.05 level. The yield components of hole irrigation was higher than that of bare border irrigation apparently. Through statistical analysis, the weight of seed per plant,the 100-maize weight , the yield and WUE were significant to the CK. The rate of yield and WUE increase of 1.25m plastic film mulch was 2.5 and 1.66 times of 0.75m plastic film mulch respectively. Thus the conclusion was that the effect of hole irrigation with 1.25m plastic film mulch was better than that with 0.75m plastic film mulch in terms of the increase of yield and earning or WUE generally. Under the condition of soil texture and the technique of produce and cultivation of crops, it was suitable to popularize this model into the practice.
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