摘要
研究了石灰性土壤日光温室不同栽培年限及番茄不同程度缺镁的土壤水溶盐分中离子组成、比例及Mg2+、Ca2+、K+离子活度等的变化及关系。结果表明:随着栽培年限的增加,温室土壤水溶盐分中Ca2+、K+、NO3-含量显著增加;水溶性盐分中阳离子以Ca2+为主,栽培5 a后NO3-成为阴离子主要成分;土壤中NO3-含量的增加是导致土壤盐分累积的主要因素。随番茄缺镁程度的加剧,土壤水溶性盐中Ca2+、K+、NO3-、全盐量及Ca2+/Mg2+、K+/Mg2+摩尔比均呈增加趋势,番茄出现缺镁的土壤含盐量达到盐渍化水平。随着土壤盐分含量增加,Ca2+、Mg2+活度均呈指数下降趋势,番茄缺镁的土壤溶液中Mg2+和Ca2+活度显著低于不缺镁土壤,(K+)/(Mg2+)、(Ca2+)/(Mg2+)活度比显著高于不缺镁土壤,(K+)/(Mg2+)活度比随缺镁程度加剧达显著差异,番茄缺镁的土壤溶液(K+)/(Mg2+)活度比大于1。盐分累积使Mg2+活度大幅降低以及K+富集对植物吸收Mg2+的拮抗作用是石灰性土壤上番茄缺镁的主要诱因。
Ion composition and proportion of soluble soil salts and activities of Mg2＋ , Ca2 ＋ and K＋ ions were deter- mined in soils different in greenhouse cultivation history and in degree of magnesium deficiency reflected in tomato growing therein, and their relationships with Mg deficiency of tomato were analyzed. Results show that among the soluble soil salts Ca2＋ , K ＋ and NO3- in the soil increased in concentration linearly with the history of greenhouse cultivation going on. Ca2＋ ion was the dominate cation in the soluble salt and NO3- ion became the dominate anion after 5 years of greenhouse euhiva-tion. significant relationships were found of Ca2＋ and NO3- ions with total salts and NO3- ions in the soil, indicating that NO3- ion was the major factor contributing to soil salinization. Mg deficiency symptom became more obvious, when con- tents of Ca2 ＋ , K ~ and NO~ ions, total salts, and mole ratios of Ca2 ＋/Mg2 ＋ and K＋/Mg2＋ rose in the soil. In soils where tomato displayed Mg deficiency, salt content reached the level of soil salinization. With the content of soil salt rising, Ca2 ＊ and Mg2 ＋ activities decreased exponentially. Activities of Ca2 ＋ and Mg2 ＋ were significantly lower in soils where toma- to displayed Mg deficiency than in soils where tomato grew normally, while activity ratios of （K＋）/（ Mg2＋ ） and （Ca2＋ ）/ （Mg2＋ ） were the other way round, and the activity ratio of （K ＋ ）/（ Mg2＋ ） increased significantly with the extent of Mg deficiency, reaehing higher than 1. The decrease in Mg2＋ activity due to salt accumulation in soil and the antagonistic effect of K＋ enrichment on plant Mg2＋ absorption were the two major causes inducing appearance of the symptom of magne- sium deficiency on tomato growing in calcareous soil.
出处
《土壤学报》
CAS
CSCD
北大核心
2013年第2期388-395,共8页
Acta Pedologica Sinica
基金
陕西现代农业产业技术体系(蔬菜)项目
西北农林科技大学拔尖人才支持计划资助
关键词
日光温室
番茄缺镁
土壤盐分
离子比例
离子活度
Sunlight greenhouse
Tomato Mg deficiency
Soil salt
Ion ratio
Ion activity
