林草生态模式改良盐碱土的效果研究

Effects of soil amelioration of saline-alkali soils on forest-grass ecological patterns

对辽河三角洲区域内典型的泥质海岸盐碱地段进行工程整地修筑台田,利用耐盐碱牧草苜蓿、田菁构建银中杨+苜蓿、银中杨+田菁两种林草生态模式,以银中杨纯林为对照进行改土效果研究,结果表明,3种模式林分郁闭度达到90%以上,保存率在89%以上,银中杨+苜蓿模式能显著促进树高、胸径生长,树高和胸径分别比银中杨+田菁模式和CK增加15.8%、16.7%和15.8%、16.6%。脱盐改土作用是银中杨+苜蓿模式好于银中杨+田菁模式好于CK;银中杨+苜蓿模式可显著降低土壤全盐量、pH、容重,增加土壤孔隙度,改善土壤水分状况,同时还能提高土壤有机质、全氮、全磷总量,增加土壤氮、磷有效性;其中,对0～10 cm土层的改良效果要好于10～30 cm土层和30～50 cm土层。

The studies on soil amelioration effects of two forest-grass ecological patterns ofMedicago sativa-Populus alba ＇Berolinensis＇ and Sesbania cannabina-R alba ＂Berolinensis＂ （M sativa and S. cannabina were both saline-alkali tolerant grasses）, and pure P. alba ＂Berolinensis＂ plantations which planted in the raised fields established by soil preparation engineering measures were conducted in the typical saline-alkali soils along muddy seacoast in Liaohe River Delta. The results indicate that canopy densities of the three patterns were more than 90%, and the survival rates of those were more than 89%. M. sativa-P, alba ＇Berolinensis＇ pattern significantly improved the growth of tree height and DBH, and the pattern＇s tree height increased by 15.8%, 16.7% compared with S. cannabina-P. alba ＇Berolinensis＇and pure P. alba ＇Berolinensis ＇patterns respectively, and DBH increased by 15.8% and 16.6% respectively. The desalination effects of M. sativa-P, alba ＇Berolinensis＂ pattern was the best in the three patterns as well. The soil total salt content, pH, bulk density of M. sativa -P. alba ＂Berolinensis＂ pattern were significantly reduced,the soil porosity was increased, the soil moisture condition was improved, and the soil organicmatter, total N, total P, available N and P increased. The soil amelioration effects in the 0-10 cm soil depth were better than that in 10-30 cm and 30-50 cm.