摘要
滨海盐碱地是滨海地区重要的土地资源,随着滨海地区城镇化进程及生态文明建设的发展,迫切需要低成本、快速、可持续的滨海盐碱地原土植被构建技术。针对滨海盐碱地原土建植与咸水/微咸水资源的利用,该研究以月季(Rosa chinensis)为例,采用微咸水滴灌技术进行滨海盐碱地水盐调控植被构建。试验在渤海湾曹妃甸区吹沙造田形成的典型沙质滨海盐渍土上进行,设计了灌溉水电导率(ECiw)为0.8、3.1、4.7、6.3、7.8 dS/m的5个处理,研究滴灌水盐调控对土壤盐分淋洗及月季根系生长和分布特征的影响。结果表明:在渤海湾滨海地区气候条件下,先进行淡水滴灌盐分强化淋洗和缓苗灌溉,随后采用<7.8 dS/m的微咸水滴灌,0~100 cm土层土壤盐分得到了有效的淋洗,尤其是根层0~40 cm土壤盐分经过一个月左右,由初始28.33 dS/m降低到均小于4 dS/m,一个低盐适生的土壤环境得到快速营造;随着ECiw的增加,0~40 cm土层土壤最终趋于稳定的盐分呈增加趋势,土壤脱盐过程可以被logistic方程描述,脱盐过程可划分为快速脱盐、缓慢脱盐和盐分趋于稳定3个阶段;94%以上的月季根系主要分布在0~20cm的表层土壤中,随着ECiw的增加,根系生物量显著降低,根系受盐分胁迫生理干旱影响向土壤深处生长以扩大水分空间。研究认为,采用短期淡水滴灌盐分强化淋洗和缓苗淡水滴灌、随后进行微咸水滴灌的方法,可以实现土壤盐分的快速淋洗并维持在较低水平,但受盐分对根系生长的影响会作用于植物地上部分生长及植物存活,因此需要结合植物耐盐性及生产目标(产量、景观)确定适宜灌溉水矿化度阈值。
Coastal saline land is an important resource in coastal area,with the development of urbanization process and ecological civilization construction,there is an urgent need to improve the landscape to meet the demand of living environments for cities and districts.Presently the main method of vegetation rehabilitation is to replace saline soil with non-saline soil for depths of 0-100 cm.However,this method is expensive and unsustainable due to the shallow and saline groundwater,thus a technology of low cost,rapid and sustainable for re-vegetation on coastal saline land is needed.A common practice for reclaiming salt-affected soils is leaching of soils to move excess soluble salts from upper to lower soil depths or out of the root zone,while large scale of salt leaching will consume large quantities of water,and supplies of fresh water are already low in coastal regions,thus likely saline water rich in coastal regions are alternatives to freshwater resources.For the landscape construction in coastal saline land and saline/brackish water utilization,a field experiment was conducted on the sandy saline soil formed by sea reclamation at Caofeidian District near the Bohai Gulf in 2012-2014.Five treatments of salinity levels of 0.8,3.1,4.7,6.3 and 7.8 dS/m of irrigation water was imposed.A gravel-sand layer was created at 100 cm depth.Tensiometers were buried at a depth of 20 cm to control the soil matric potential(SMP),keeping the SMP over– 5 kPa at first year,and over–10 kPa at second year,and over–15 kPa at third year.Chinese rose(Rosa chinensis)was chosen as the representative plant.Salt leaching characters and root growth and distribution were studied.The results showed that:under the climatic condition in the coastal area of Bohai Gulf,when fresh water was applied using drip irrigation for salt enhanced leaching and seedling establishment first in a short period,and then followed drip irrigation with water salinity<7.8 dS/m,soil salinity decreased significantly in 0-100 cm soil profile,especially in 0-40 cm soil profile,soil salinity decreased from 28.33 dS/m to<4 dS/m taking one month.Irrigation water depth for soil salinity decreased from 28.33 dS/m to 4 dS/m in 0-40 cm soil profile for<7.8 dS/m irrigation water salinity were 160-220 mm,and 8-20 mm of water depth is needed for soil salinity of1 dS/m decreasing.The soil desalting process can be described by the logistic equation,and it can be divided into three stages including rapid desalting,slow desalting and salinity stabilization.More than 94%of the roots are mainly distributed in the topsoil of 0-20 cm.The root biomass decreased significantly with irrigation water salinity increasing,and the root is affected by the physiological drought of salinity stress to expand the water space in the deep soil.More winter irrigation water depth needed when there is less rainfall after October to prevent salt accumulation in topsoil in the spring of next year.The method of drip irrigation with fresh water for salt enhanced and seedling establishment in a short-term and subsequent drip irrigation with saline/brackish water can be used to realize the rapid salt leaching and maintain lower soil salinity,but the appropriate irrigation water salinity threshold should be determined in combination with salt tolerance of plant and the production target as root growth suffered salt stress and thus affect the growth of plant and its survival.
作者
李晓彬
康跃虎
Li Xiaobin;Kang Yuehu(Key Laboratory of Water Cycle and Related Land Surface Processes,Institute of Geographic Sciences and Natural Resources Research,CAS,Beijing 100101,China;College of Resources and Environment,University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2019年第11期112-121,共10页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家自然科学基金项目(51709251)
中国科学院前沿科学重点研究项目(QYZDJ-SSW-DQC028)
国家重点研发计划项目(2016YFC0400104,2016YFC0501305)
关键词
灌溉
盐分
滨海盐渍土
微咸水
盐分淋洗
土壤基质势
根系
irrigation
salt
coastal saline soil
brackish water
salt leaching
soil matric potential
root
