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研究农田土壤速效钾的时空演变规律对改善土壤管理和提高土壤质量具有重要的指导作用.以长江三角洲地区的江苏省如皋市为例,对不同时期农田土壤速效钾的时空分异进行了研究.结果表明,自1982-1997-2002的20多年来,虽然速效钾在空间分布模式上变化不大,但近年来,空间分布趋于复杂化.土壤速效钾具有明显的时间分异特征,总体上经历了先下降后又有所回升的动态演变过程,在90年代中期土壤速效钾普遍亏缺,但近年来有显著回升.不同土壤类型速效钾的时空分异特征有明显差别.由江淮冲积物或长江现代冲积物发育而成的,质地较粗的雏形土(磨头系、郭园系和张黄港系)20年来持续下降,但下降幅度较小.由浅湖相冲积物发育而成的,质地较细的水耕人为土(白蒲系)和长江现代冲积物发育而成的,质地较细的潮湿雏形土(长青沙系)早期下降幅度较大,但近年来回升幅度也较大.其余土系则遵循先下降后上升的总体规律.影响土壤速效钾变化的驱动力分析表明,造成这些时空演变规律的主要因素包括:秸秆还田、施肥管理、种植结构和土地利用方式的改变等.且随着时间的推移,这些因素的影响趋于多元,导致农田土壤速效钾的空间变异性逐渐增强.
Studying on the temporal and spatial evolution of soil available K in farmland plays an important guiding role in improving soil management and soil quality.The spatial and temporal variability of available K in farmland at different periods is studied by taking Rugao City, Jiangsu Province as an example. The results showed that although the available potassium had little change in the spatial distribution pattern over the 20 years from 1982 to 1997-2002, the spatial distribution became more and more complicated in recent years. The available potassium in soil showed obvious time-differentiated characteristics, After the first decline and then the recovery of the dynamic evolution process, in the mid-90s the soil available potassium generally deficit, but in recent years there was a significant rebound in different soil types of available potassium spatial-temporal differences are significantly different characteristics of the Jianghuai alluvial Or from the development of modern alluvial deposits in the Yangtze River, coarse-grained loamy terrains (Mudou, Guoyuan and Zhanghuangang) continued to decline over the past 20 years, but with a smaller decrease. , Fine texture of hydroponic man-made soil (white Pu system), and the development of modern alluvial deposits of the Yangtze River, the fine texture of wet embryonic soil (Changqing sand system) decreased greatly in the early stage, but in recent years, And the other soil systems followed the first general trend of descending and then rising.The driving forces influencing the change of available K in soil showed that the main factors causing these spatial and temporal changes include straw returning, fertilization management, planting structure and land use The change of the way, etc. And with the passage of time, the influence of these factors tends to be diverse, resulting in the spatial variability of soil available K gradually increasing.