CAJ | 학술논문

盐碱地长期膜下滴灌作物根区土壤盐分是否累积及适宜耕作问题引起很多学者关注和思考，并成为制约干旱区农业生产、影响绿洲生态稳定和膜下滴灌可持续应用的重要因素。该文通过对新疆典型灌区5块不同膜下滴灌应用年限农田进行连续4a的定点监测，尝试揭示长期膜下滴灌农田根区土壤盐分演变趋势。结果表明，在现行灌溉制度条件下，新疆干旱区绿洲膜下滴灌棉田0～60 cm膜内根区盐分随滴灌年限呈降低趋势，在滴灌1～4年根区总盐变化幅度及降低幅度均较大，滴灌5～7a盐分继续小幅降低，根区平均含盐量均低于5 g/kg，棉花根系生境合适，基本满足耕种条件，棉苗存活率在60%以上，产量在5250 kg/hm2以上；滴灌8～15 a盐分趋于稳定，根区平均含盐量均低于3 g/kg，且Cl-含量低于0.12 g/kg时，棉花成活率及产量较高且稳定，棉苗存活率在90%以上，产量在6000 kg/hm2以上，根区土壤盐分中Na+与Cl-随滴灌年限降低趋势明显。当地的灌溉制度是造成根区盐分降低的主要原因，坚持现行的灌水制度有利于膜下滴灌长期可持续应用，但应适当减少花铃后期及吐絮期的灌水定额以节约水资源。
염감지장기막하적관작물근구토양염분시부루적급괄의경작문제인기흔다학자관주화사고，병성위제약간한구농업생산、영향록주생태은정화막하적관가지속응용적중요인소。해문통과대신강전형관구5괴불동막하적관응용년한농전진행련속4a적정점감측，상시게시장기막하적관농전근구토양염분연변추세。결과표명，재현행관개제도조건하，신강간한구록주막하적관면전0～60 cm막내근구염분수적관년한정강저추세，재적관1～4년근구총염변화폭도급강저폭도균교대，적관5～7a염분계속소폭강저，근구평균함염량균저우5 g/kg，면화근계생경합괄，기본만족경충조건，면묘존활솔재60%이상，산량재5250 kg/hm2이상；적관8～15 a염분추우은정，근구평균함염량균저우3 g/kg，차Cl-함량저우0.12 g/kg시，면화성활솔급산량교고차은정，면묘존활솔재90%이상，산량재6000 kg/hm2이상，근구토양염분중Na+여Cl-수적관년한강저추세명현。당지적관개제도시조성근구염분강저적주요원인，견지현행적관수제도유리우막하적관장기가지속응용，단응괄당감소화령후기급토서기적관수정액이절약수자원。
In the arid area after long-term drip irrigation, the accumulation of soil salinity in the crop root zone and its farming availability have attracted a lot of attentions and concerns from researchers, which was also an important factor to limit the agricultural production and affect the oasis ecological stability and the sustainable application of drip irrigation. In this paper, we try to reveal the trend of soil salinity evolution in the root zone with the long-term drip irrigation based on a four-year (2009-2012) sentinel surveillance in five typical farmlands of Xinjiang drip irrigation district (Paotai County, Shihezi City, Xinjiang) where the drip irrigation under mulch was applied. The drip irrigation under plastic film in these five cotton fields has been respectively started from 2008, 2006, 2004, 2002, and 1998. And the conditions of these five cotton fields including the soil texture, structure, irrigation and fertilizer regime, cotton variety and planting pattern were basically the same, except their drip irrigation history (2-5, 4-7, 6-9, 8-11 and 12-15 years). Since 2009, the drip irrigation has been carried out and continually run until 2012. Na+, Ca2+, K+, SO42-, Cl-, HCO3-and Mg2+were the major ions in these fields, and changes of their contents in the root zone inside the film with years of drip irrigation were analyzed. The results indicated that the salt content of the root zone soil (0-60 cm) under the plastic film in the drip irrigation cotton fields decreased along with the increasing year of drip irrigation in Xinjiang arid oasis region under the current irrigation regime. The decrease of total salt content was notable for the 1st-4th years irrigation, while it became slowly during the 5th-7th years with an average salt content less than 5 g/kg in the root zone. The salt content became stable during the 8th-15th years of irrigation and the average salt and Cl-content were respectively less than 3 g/kg and 0.12 g/kg in the root zone. Relative to the uncultivated lands, the desalinization rate of total salts was more than 94%, and Na+ and Cl- contents in the root zone significantly decreased after many years of irrigation. Similar to the total salt content, the Cl-content tended to decrease exponentially as a whole. Na+and Cl-were the major decreasing ions after long-term drip irrigation as well as Ca2+, SO42-and Mg2+, while other ions (e.g. HCO3-) showed no obvious change with different irrigation histories. The duration of drip irrigation under plastic film had a significant effect on the survival rate and yield of cotton in arid regions, which were 7.1%and 1 279.2 kg/hm2 for 2-years drip irrigation, 60% and 5 250 kg/hm2 for 5-years irrigation, and >90% and 6 500 kg/hm2 for > -years irrigation, respectively. The survival rate could reach more than 80% after 6-years irrigation. Finally, it is found the local irrigation regime is the main reason inducing the decrease of salt content in the root zone, so it is favorable to maintain the existing irrigation regime for the long-term sustainable application of drip irrigation under plastic film. However, the irrigation should be properly reduced to save water during the late flowering, boll setting and boll opening stages.