中文摘要：

以土壤大面积碱化的新疆奇台绿洲为研究区，探讨了盐（碱）生植被盖度与土壤碱化指标pH、碱化度（ESP）、钠吸附比（SAR）、残余碳酸钠（RSC）、总碱度（TA）的关系。研究表明：研究区土壤存在大量的可代换性钠，碱化强烈。植被盖度与各土壤碱化指标均呈极显著的负相关关系，其与pH的相关系数最高，达0．810，其次为ESP，植被盖度主要受土壤碱化程度的影响。以盐（碱）生植被盖度为主要依据并结合多种土壤碱化指标对研究区碱化土壤进行分级：植被盖度50％左右，pH〈8．0，ESP〈3％，SAR〈3，为非碱化土；植被盖度10％-40％，pH8．0—9．5，ESP3％～35％，SAR3—40，为碱化土；植被盖度〈10％，pH〉9．5，ESP〉35％，SAR〉40，为碱土。以植被盖度对碱化土壤的响应为依据建立的土壤碱化分级标准既拓宽了碱化土壤分级的研究视角，也符合研究区的实际情况。

英文摘要：

Qitai Oasis in Xinjiang has a large tract of sodic alkali soil and was hence selected as a study zone to explore relationships of halophyte coverage with soil alkalization indices （pH, exchangeable sodium percentage （ESP） , sodium adsorption ratio （SAR） , residual sodium carbonate （RSC） , total alkalinity （TA） ）. It was found that in the soil of the study zone, existed large volumes of exchangeable sodium, strongly alkalizing the soil. Halophyte coverage was negatively related to all the soil alkalization indices to an extremely significant extent, especially to soil pH, being the highest （0. 810） , which was followed by ESP. Soil alkalization was the major factor affecting halophyte coverage, which could, therefore, be used as a good indicator of the former. Based on halophyte coverage as the major index in combination with some soil alkalizaiton indices, such as pH and ESP, alkalized soil in the study zone was classified. Soils 50% or so in halophyte coverage, 〈8.0 in pH, 〈3% in ESP and 〈 3 in SAR were classified as non-alkaline soil, those 10% ~ 40% in halophyte coverage, 8.0 -9.5 in pH, 3%-35% in ESP and 3 -40 in SAR as alkaline soil, and those 〈 10% in halo- phyte coverage, 〉 9.5 in pH, 〉 35% in ESP and 〉 40 in SAR as Solonetz. Such classification not only broadens the look angle of the study on grading of alkalized soils, but also tallies with the local practical situation.