水稻梯田土壤速效氮、磷、钾的迁移与分布特征研究

研究水稻梯田氮、磷、钾速效成分迁移与分布规律,为实现精准配方施肥提供依据。选择白石村10个有水稻梯田分布的村民小组,每个村民小组为一个采样区,按照水流路径,每个采样区梯田分成6层,每层采用“S”形布点法采集5个土样,分别测定土壤的碱解氮、速效磷和速效钾含量,并建立与梯田层次间的函数关系式,研究其横向迁移分布情况与规律。结果表明：白石村土壤主要养分平均含量：碱解氮103.3±13.67 mg/kg、速效磷42.84±5.42 mg/kg、速效钾95.25±13.91 mg/kg,营养等级为中上;碱解氮、速效钾从上层梯田向下层梯田迁移,并有显著的指数回归趋势,平均相关系数分别为0.9719和0.9885,低洼地氮素含量偏高;速效磷纵向迁移不明显,但其含量与碱解氮含量呈负相关,拟合度为72.72%。白石村水稻梯田碱解氮、速效钾含量随着水流由上层向下层迁移,并具有明显的指数回归趋势;速效磷随水流迁移不明显,分布相对稳定,有富集倾向。

Migration and Distribution Characteristics of Available Nitrogen,Phosphorus and Potassium in Rice Terrace Soil

To provide a basis for the realization of precision formula fertilization, the migration and distribution of available components of nitrogen, phosphorus and potassium in rice terraces were studied. Ten villagers’ groups with rice terraces in Baishi Village were selected. Each villagers’ group was a sampling area. According to the water flow path, the terraces in each sampling area were divided into six layers. Five soil samples were collected in each layer by serpentine distribution method. The contents of alkali-hydrolyzable nitrogen, available phosphorus and available potassium were measured respectively, and the functional relationship with the terraces was established to study the horizontal migration and distribution. The results showed that the average content of main nutrients in Baishi Village soil were alkali-hydrolyzable nitrogen 103.3±13.67 mg/kg, available phosphorus 42.84±5.42 mg/kg, available potassium 95.25±13.91 mg/kg, and the nutritional grade was above average. Alkali- hydrolyzable nitrogen and available potassium migrated from upper terrace to lower terrace, and there was a significantly exponential regression trend. The average correlation coefficient was 0.9719 and 0.9885 respectively. The nitrogen content in low-lying land was high. The vertical migration of available phosphorus was not obvious, but its content was negatively correlated with the content of alkali-hydrolyzable nitrogen, and the fitting degree was 72.72%. The contents of alkali-hydrolyzable nitrogen and available potassium in rice terraces in Baishi Village migrated from the upper layer to the lower layer with the water flow, and had an obvious exponential regression trend. The migration of available phosphorus was not obvious with the flow, but the distribution was relatively stable and tended to be enriched.