Improving soil fertility is one of the key approaches for ecological restoration of the wind-sand area in northwest Liaoning Province. Taking wind-sand area in northwest Liaoning Province as test object, we conducted a fertilization experiment with treatments of inorganic fertilizer (nitrogen, phosphorus and potassium fertilizers), organic fertilizer, combined application of organic and inorganic fertilizers, and organic fertilizer combined with a biologically organic matrix (γ-polyglutamic acid), and no fertilizer as control. We measured soil organic matter content and extractable cations concentrations, vegetation coverage, and biomass under different fertilization treatments and determine the suitable fertilization mode. The results showed that compared to the control, inorganic fertilizer rapidly increased vegetation coverage and biomass, but high levels of inorganic fertilizer (150 kg N·hm-2) led to soil acidification and Ca2+ leaching. Organic fertilizer increased soil organic matter content, exchangeable K+, Ca2+, and Mg2+ contents, as well as coverage and biomass vegetation, especially combined with γ-polyglutamic acid. Overall, the combination of low levels of inorganic fertilizer (50 kg N·hm-2) and moderate levels of organic fertilizer (30000 kg·hm-2) was the best fertilization practice for the rapid and stable restoration of grassland in wind-sand area. Moreover, the extra addition of γ-polyglutamic acid (60 kg·hm-2)could effectively improve soil fertility.
培肥是辽宁省西北部风沙区生态恢复的关键措施之一。本研究以辽西北沙化草地为对象,设置施用无机肥(氮磷钾肥)、有机肥、有机肥+无机肥配施、有机肥+生物有机基质(γ-聚谷氨酸)配施处理,以不施肥为对照,分析不同培肥模式下土壤有机质及养分含量、地上植被盖度和生物量的变化特征,以筛选辽西北沙化草地适宜培肥模式。结果表明: 与对照相比,施用无机肥能够快速提升地上植被盖度和生物量,但施用高量无机肥(150 kg N·hm-2)会导致土壤pH降低及Ca2+的淋失;施用有机肥提高了土壤有机质含量,显著提高了土壤交换性K+、Ca2+、Mg2+含量及地上植被盖度和生物量,以有机肥配施γ-聚谷氨酸处理效果最好。在不加生物有机基质的培肥处理中,低量无机肥(50 kg N·hm-2)与中量有机肥(30000 kg·hm-2)配施对天然草地的快速、稳定性恢复效果最好,若配施有机基质(60 kg·hm-2γ-聚谷氨酸),则能够起到更好的土壤改良与养分调控作用。.
Keywords: desertified grassland; organic fertilizer; polyglutamic acid; soil improvement; vegetation restoration.