北方滨海盐碱地冬季咸水结冰灌溉对菊芋生长及离子分布的影响

Effect of Freezing Saline Water Irrigation in Winter on Growth and Ion Distribution of Helianthus tuberosus L.in North Coastal Saline Soil

为探讨冬季咸水结冰灌溉对河北省滨海平原区盐碱土的土壤盐分变化以及对菊芋生长的影响,在冬季利用地下苦咸水对河北海兴盐碱地进行咸水结冰灌溉试验,设冬灌覆膜处理,其中包括膜上挖孔直接播种处理(T1)和揭膜播种再覆膜处理(T2),以无冬灌+覆膜处理作为第一对照(CK1),不冰灌和不覆膜的小区作为第二对照(CK2)。结果表明,冬季灌溉咸水结冰、春季咸水冰融化入渗后土壤各层次脱盐效果明显,播种期T1和T2处理的0～5cm、5～20cm表层土壤含盐量较CK1和CK2分别降低了41.9%、65.0%、46.5%、67.7%、29.9%、47.1%,40.8%和55.3%,在菊芋播种期耕层土壤含盐量降低到0.6%左右,T1和T2单位产量分别较CK1和CK2高54%、115%、97%和175%,T1和T2处理下Na+和Cl-含量较CK1和CK2显著降低,而K+含量和K+/Na+较CK1和CK2显著增高。通过冬季咸水结冰灌溉和覆膜措施可以确保土壤盐分下降,从而降低了盐分对菊芋生长的毒害作用,使菊芋产量得到显著提高。

Soil salinization and fresh water shortages are major limiting factors for crop productions and environmental rehabilitation in coastal plains around the Bohai Sea.Improving saline soils in such areas can greatly benefit agricultural productions and environmental protection in the context of fast economic development across the coastal zones of the Bohai Sea.Based on the mechanism of water desalinization by freezing and thawing processes,a field experiment was designed and conducted to investigate the water and salt dynamic of coastal saline soil with freezing saline water irrigation in winter over coastal saline soils in Haixing County,Hebei Province.A total of 160 mm saline water was applied to experimental plots in January in year 2010,which was frozen well after irrigation under the condition of a lower temperature of-9.5℃.The soil surface was mulched with plastic film after the infiltration of melted saline ice water in order to prevent salt accumulation induced by high evaporation in spring.The plots were designed as follows：irrigation and plant directly with digging into plastic film mulching plots as T1,irrigation and plastic film mulching plots as T2,no irrigation and mulching plots as CK1,no irrigation and no mulching plots as CK2.In this experiment the H.Tuberosus was planted.Results showed that with infiltration of melted saline ice water,the surface soil was significantly desalinized.Compared to CK1 and CK2,the salt content in the surface soil（0～5 cm and 5～20 cm） of T1 and T2 was decreased 41.9%,65.0%,46.5%,67.7%,29.9%,47.1%,40.8% and 55.3%,respectively.The surface soil（0～5cm and 5～20cm） salt content was about 0.6% in the seedtime.The yields of H.Tuberosus of the T1 and T2 treatments were higher 54%,115%,97% and 175% than the treatments of CK1 and CK2.Under the T1 and T2 treatments,the Na＋ and Cl-contents in root,stem and leaf were decreased and the K＋ content and the ratio of K＋/Na＋ increased significantly.The results obtained in the study indicated that the approach of freezing saline water irrigation in winter may benefit the use of local saline groundwater and improve coastal saline soil to some degree,then increase the yield of H.Tuberosus.The ultimate effect depends on many natural and human factors,such as soil chemical and physical properties,water quality and irrigation time and quantity.Further field experiments are required to formulate reasonable irrigation scheduling and related management methods.