摘要
试验选择具有3年棚龄的大棚和砂壤质地的旱耕人为土,进行不同施肥条件下,土壤养分与盐分变化的冬春两茬西红柿栽培小区试验,对施肥引起的土壤养分与水溶性盐分含量及盐基离子组成的变化进行了系统的定量分析。试验结果表明,在整个生育期采用地膜覆盖的条件下,施用尿素可以快速增加土壤速效N素的含量和水溶性铵盐的含量水平。羊圈厩肥的P、K、Ca和Mg等元素含量较高,其施用会很快增加土壤速效态P、K的含量和土壤水溶性K+、Ca2+、Mg2+等盐基离子的含量。回归分析显示,施用1kg尿素N或1t羊圈厩肥引起土壤电导率增加量分别为6.45×10-4mS/cm和5.45×10-3mS/cm。土壤盐基离子含量的增加,主要由于水溶性NH4+、K+、Ca2+、Mg2+含量的增加而引起。施用尿素不但增加土壤水溶性NH4+的含量,而且通过NH4+的交换作用增加了土壤K+、Ca2+和Mg2+的含量水平。
A three-year old plastic greenhouse with sandy loam soil was selected for an experiment on effects of fertilization on soil nutrients and salts in the soil under two consecutive croppings of tomato （spring and winter tomato） and the mechanism of soil salinization was elucidated quantitatively. In the autumn of 2000, nine treatments （N0M0, N0M1, NOM2, N1M0, N1M1, N1M2, N2M0, N2M1 and N2M2, where N stands for urea, and NO： N 0 kg/hm^2, N1： N 255 kg/hm^2 and N2： N 600 kg/hm^2; and M for sheep manure and M0：0 kg/hm^2, MI： 26250 kg/hm^2 and M2：52500 kg/hm^2） were arranged at random each having three replicates, and in the following winter six treatments N0M0, N0M1, N0M2, N1M0, N1M1 and N1M2 were laid out. During the experiment the field was covered with plastic sheet to keep warmth and water regime. The results showed that over-supply of urea or sheep manure led to fast accumulation of nutrients and salts. The increase in the content of water soluble NH4^＋, which resulted from transformation of the urea applied, led to increase in water soluble K^＋. Ca^2＋ and Mg^2＋ through exchange of ammonium cations. Sheep manure with high contents of water soluble K^＋. Ca^2＋ and Mg^2＋ supplied the soil with high quantity of K^＋. Ca^2＋ and Mg^2＋.
出处
《土壤》
CAS
CSCD
北大核心
2005年第6期620-625,共6页
Soils
