郑州市夏玉米生长季土壤水分变化特征分析

利用线性趋势估计、Mann—Kendall检验等方法对1981—2010年郑州市夏玉米生育期内土壤湿度的年际及垂直变化特征进行了分析，结果表明：近30a来郑州地区夏玉米生长季土壤水分呈显著的下降趋势，0—40cm、40—100am下降速率分别为-3．34％／10a和-5．94％／10a；0—40em在1986年形成一个突变点，40一100CIYI在1998年形成一个突变点，突变点后土壤湿度下降明显；夏玉米生育期内，土壤湿度随生育进程的推进不断增加，到乳熟期后维持在较高水平，同一生育阶段由浅及深各层土壤湿度变异系数逐步减小；各层次土壤湿度的垂直分布基本呈现上干下湿的状态，各生育阶段各层土壤湿度多表现为乳熟期的〉抽雄期的〉拔节期的〉出苗期的。

Variation Characteristics Analysis of Soil Moisture in Summer Maize Growth Season in Zhengzhou

Based on statistics methods of linear tendency estimate and Mann-Kendall test, the annu- al and vertical variation of soil moisture in summer maize growth season in Zhengzhou region in recent 30 years were analyzed. The result showed that： the soil moisture had a significant decreasing trend in whole growth season of summer maize in recent 30 years,the decreasing rate in 0--40 em and 40--100 cm soil layer were - 3.34%/10a and - 5.94%/10a respectively. The catastrophe points of 0--40 em and 40-- 100 em were in 1986 and 1998 respectively. In summer maize growth season the soil moisture increased with growth process,it was maintained at a high level after milky stage. The variation coefficient of soil moisture from shallow to deep layers decreases in same growth phase. The characteristics of vertical chan- ges in soil moisture layer basically showed surface dry and deep wet condition, and comparison of the soil moisture in different growth phase were Milky stage 〉 Tasseling stage 〉 Jointing stage 〉 Seedling stage.