关中旱地小麦生育期土壤速效养分时空变异特征研究

The spatio-temporal variability of soil available nutrients in the Guanzhong plain

为了揭示旱塬地区土壤主要养分的动态变化规律,探明其时空有效性,在较为精确的时空尺度条件下研究了关中地区小麦生育期间土壤剖面0~100 cm范围内硝态氮、碱解氮、速效磷和速效钾动态变化特征。结果表明：土壤硝态氮在0~100 cm范围内空间分布特征较为明显,在30~40 cm处为硝态氮累积峰值,第90~150天范围为剖面上硝态氮素快速消耗期;土壤碱解氮在0~100 cm范围内存在着二元变异结构,0~40 cm空间变异特征较明显,而40 cm以下则时间变异特征更为突出;土壤速效磷空间梯度变异明显,表现为从上至下速效磷含量递减,小麦生育期间土壤剖面速效磷几乎是同步递减;土壤速效钾则是时间变异特征比空间变异特征更显著,小麦生育期间剖面上各层土壤速效钾含量降低幅度均在50 mg/kg左右。

To investigate the dynamic variety disciplinarian of the main soil nutrients in the Guanzhong plain, and to prove up its spatio-temporat validity, in the condition of the accurate spatio-temporal scale, a field experiment was conducted to study the spatio-temporal variability of soil nitrate nitrogen, alkali-hydrolyzable nitrogen, available phosphorus and available potassium of the wheat fields （0-- 100 cm soil layers） m the whole growth stage in the Guanzhong plain. The results showed that the gradient of spatial distribution of the soil nitrate nitrogen in 0-100 cm soil layers was more significant than that of temporal distribution. And the soil nitrate nitrogen in 30--40 cm soil layers reached cumulative peak and it deleted fast from 90th to 150th during the growth stage. It was found that the content of the soil alkali-hydrolyzable nitrogen was in binary variability structure in 0- 100 cm soil layers, and the gradient of its spatial distribution in 0- 40 cm soil layers was more significant than that of temporal distribution, but it was opposite below 40 cm. The gradient of spatial distribution of the soil available P was more significant than that of temporal distribution. And the depletion layer went deeper as the wheat grew. It was also found that the gradient of temporal distribution of soil available K was more significant than that of spatial distribution, and its content decreased by about 50 mg/kg every layer during the growth stage.