摘要
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5 250 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。
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-, CI, 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 1 st-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 CI 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 CI contents in the root zone significantly decreased after many years of irrigation. Similar to the total salt content, the CI- 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＋, 8042 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.
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2014年第4期90-99,共10页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家自然科学基金项目(51369027
U1203682)
国家973计划前期研究专项(2009CB125901)
关键词
灌溉
盐分
土壤
干旱区
盐碱地
膜下滴灌
irrigation
salts
soil
arid zone
saline-alkali soil
drip irrigation under mulch
