摘要
【目的】北方石灰性土壤钙、镁含量丰富,镁素供应充足,缺镁主要发生在南方高度风化的酸性土壤,但近年来北方日光温室栽培番茄等作物缺镁现象频发。因此,解析导致石灰性土壤日光温室栽培番茄缺镁的主要因素,可为日光温室番茄镁素缺乏的矫正和合理施肥提供科学依据。【方法】在陕西省杨凌示范区大寨镇日光温室栽培基地,于秋冬茬栽培番茄普遍发生缺镁的盛果期(11月份),选择番茄定植时间和品种一致,叶片形态呈现不同程度缺镁症(不缺镁:外观未观察到番茄缺镁失绿症状;中度缺镁:上部1/2叶片未表现缺镁失绿症状;严重缺镁:上、下叶片均表现缺镁失绿症状)的日光温室,分别采集温室0—20 cm耕层土样和番茄第2穗与第3穗果间的叶片(下部叶片)以及上部完全展开的新生叶片(上部叶片)样品;测定土壤p H、电导率、有机质、NO_3^--N、NH_4^+-N、有效磷、速效钾以及交换性钾、钙、镁离子含量,番茄叶片钾、钙、镁含量,计算土壤交换性钾、钙、镁离子饱和度和K/Mg、Ca/Mg、Ca/K离子比例,并调查番茄产量;分析番茄缺镁程度不同的日光温室土壤基本性质差异,交换性钾、钙、镁离子含量及平衡状况与番茄叶片养分含量和产量的关系。【结果】番茄缺镁程度不同的温室土壤性质存在差异,番茄缺镁严重的土壤电导率、NO_3^--N、速效钾显著增加。番茄缺镁和不缺镁的土壤交换性镁含量均高于缺镁临界值(0.5 cmol·kg^(-1));随番茄缺镁程度加剧,钾离子饱和度增加,钙、镁离子饱和度降低,Ca/Mg和K/Mg离子比例升高,Ca/K离子比例下降;与不缺镁相比,番茄中度缺镁的土壤交换性钾离子饱和度、K/Mg离子比例均增加了22%,严重缺镁的则分别显著增加了56%和88%;番茄严重缺镁的土壤Ca/Mg比例较未缺镁的升高了17%;番茄中度缺镁和严重缺镁的土壤Ca/K比未缺镁的分别降低了19%和37%。番茄
[ Objective] It is generally considered that the contents of calcium and magnesium （Mg） in calcareous soil are rich. Therefore, Mg deficiency usually occurs in acidic soil in south China, where the weathering is very strong. However, Mg deficiency of tomato under solar greenhouses in calcareous soil in north China becomes common. It is urgent to understand the reason of Mg deficiency of tomato under solar greenhouses in the region, which will provide scientific knowledge to solve the Mg deficient problem in the solar greenhouse. [ Method ] The different degrees of Mg deficiency of tomatoes with the same transplanting times and varieties in the greenhouses in Dazhai, Yangling, Shaanxi were chosen. The degrees of tomato Mg deficiency were divided into three types based on the severity of the symptoms. The three types of Mg deficiency included the leaves without Mg deficiency, the leaves with moderate （half of the upper leaves showed deficiency） and severe （all leaves showed deficiency） Mg deficiency. The soil samples （0-20 cm）, lower leaves samples （the leaves between the second and third fruit sets） and upper leaves samples （the fully developed leaves on the top plant） were taken from different greenhouses. The basic soil properties were determined, including soil pH, electric conductivity （EC）, organic matter, available nitrogen, phosphorus, and potassium, and soil exchangeable K^＋, Ca^2＋, and Mg^2＋, and their contents in tomato leaves. The ratios of exchangeable K^＋, Ca^2＋, and Mg^2＋ ions, and their saturation percentages in soil colloid were calculated. The fruit yields of different greenhouses were also surveyed. The relationships between Mg deficiency of tomato and the parameters determined were analyzed. [ Result ] There were significant differences in soil properties between the greenhouses with different degrees of Mg deficiency. The soil EC, contents of nitrate, readily available K in soil of tomato with severe Mg deficiency were significantly increased. The content
出处
《中国农业科学》
CAS
CSCD
北大核心
2016年第18期3588-3596,共9页
Scientia Agricultura Sinica
基金
国家"十二五"科技支撑计划(2012BAD15B04)
陕西省农业攻关项目(2014K01-14-03)
中英农业生产中养分资源可持续利用合作项目
关键词
日光温室
番茄缺镁
土壤性质
阳离子平衡
养分含量
solar greenhouse
magnesium deficiency of tomato
soil properties
balances of cations
nutrient contents
