生态垫及保水剂对废弃砂石坑立地造林的影响

Effects of eco-mat and super absorbent polymers on forest in waste sand and gravel pit sites

北京市平原造林中废弃砂石坑地类的石砾含量比例高达30%~40%,土壤保水保肥能力差。为增强土壤蓄水保墒能力、减少土壤养分流失、促进苗木健康生长,笔者对生态垫及保水剂进行组合设计（处理1为生态垫,处理2为保水剂,处理3为生态垫＋保水剂,对照为无任何处理）,综合应用于砂石坑造林工程,并对各处理土壤水分状况、养分状况、植物生理及形态指标等进行了测定。结果表明：综合各土层指标分析,处理3较对照及其他处理表现出最佳的保水保肥及促进植物生长效果,其中,土壤瞬时含水量提高10%以上,田间持水量、涵养水源量及最大蓄水量分别提高了4？？45%、41.34%、8.26%以上;土壤有机质、全氮、有效磷、速效钾含量提高了64？？49%、19？？28%、132%、40%以上;丙二醛、可溶性糖、脯氨酸含量低于对照34%以上,叶片相对含水量、叶绿素、叶水势、有机质、全氮、有效磷、速效钾含量、根系活力提高了9？？61%、70？？96%、17？？99%、12？？58%、22？？81%、44？？62%、74？？94%、141？？53%;冠幅增量较对照提高1？？9 m;综合因子分析表明处理3与其他处理及对照差异显著。因此,建议在类似困难立地造林过程中推广综合应用生态垫及保水剂。

The soil which contains 30% to 40% of chad in waste sand and gravel pits planting sites in Beijing plain areakeeping moisture and nutrient is poor. To enhance the soil moisture preservation ability, and reduce the loss of the nutri-ents in soil and ensure healthy growth, the author combined eco-mat and super absorbent polymers with 4 different treat-ments（Treatment 1 applied only eco-mat. Treatment 2 applied only super absorbent polymers. Treatment 3 applied both.And treatment 4 applied nothing as a control test） and applied into the project of gravel pits afforestation. Then the inde-xes of the soil moisture level, nutrients properties, plant physiological indexes and morphological index were measured.The results showed that treatment 3 was the best for improving the moisture and nutrient status of soil and promoting plantgrowth. Among them, instantaneous moisture content was improved more than 10%, water-holding capacity, water con-servation quantity and maximum storage capacity increased more than 4.45%,41.34% and 8.26%. The organic matter,total nitrogen, available phosphorus and available potassium significantly increased by more than 64？？ 49%,19？？ 28%,132%,40% separately. The Pro, SP and MDA significantly reduced more than 34%. Water content, chlorophyll, leafwater potential organic matter and N,P,K content of leaf, root activity significantly increased 9.61%,70？？ 96%,17？？ 99%,12？？ 58%,22？？ 81%,44？？ 62%,74？？ 94%,141？？ 53% separately. The crown stretch increment was 1.9 m higher than control.The factor analysis showed that treatment 3 was significantly different with other treatments and control. Therefore, wesuggest to popularize the comprehensive application of eco-mat and super absorbent polymers in the process of similardifficult afforestation site.