浙江河网平原水稻土的肥力特点及其变化

Characteristics and Variations of Soil Fertility of Paddy Fields in River-network Plains of Zhejiang

利用耕地地力调查数据,分析了浙江省河网平原水稻土的肥力状况及其变化。结果表明:研究区水稻土酸碱度继承了以中性和微酸性为主的河网平原典型水稻土的特征,但因受长期施用化学肥料的影响土壤酸化显著,主要表现在pH<5.5的土壤比例增加。复种指数和施肥结构的改变对长期植稻水田土壤有机质和氮素的积累影响不明显,但不科学的土地平整及长期种植蔬菜等经济作物可导致土壤有机质和氮素的显著下降。30年来,河网平原水稻土有效磷和速效钾均有显著的提高,平均分别比第二次土壤普查时提高了168.02%和12.52%;但仍有较大比例的土壤存在缺磷和缺钾问题。受土壤质地的影响,宁绍平原和温台平原土壤有机质、全氮和速效钾含量一般高于杭嘉湖平原;土壤酸化也以宁绍平原和温台平原较为明显。研究认为,测土配方施肥工作仍将是维持这一地区土壤养分平衡的重要技术。

The characteristics and spatial-temporal variations of soil fertility in paddy fields in river-networkplains of Zhejiang were analyzed based on the recently acquired investigation data of farmland productivity.The results showed that the pH value of paddy soils in the study region inherited the characteristics of neutraland slightly acidic soils in the river network plains. However, soil acidification was significant due to long-term application of chemical fertilizers, and proportion of the soil with pH 5.5 increased. The effect of thechanges in multiple-crop index and fertilizer application on soil organic matter and nitrogen accumulation inthe paddy soil with long-term plantation of rice was not significant, but unscientific land leveling and long-term planting of vegetables and other economic crops could lead to a significant decline in soil organic matterand nitrogen. Status of phosphorus and potassium in paddy soil of the river-network plains were significantlyimproved in the past 30 years. On average, available P and K increased by 168.02% and 12.52%, respectively,as compared with the second national soil survey. However, there was still a large proportion of the soil with thedeficiency in phosphorus and potassium. Affected by soil texture, contents of organic matter, total N, andavailable K in the soil of the Ningbo-Shaoxing plain and Wenzhou-Taizhou plain were higher than that of theHangzhou-Jiaxing-Huzhou plain. The acidification was also more obvious in the Ningbo-Shaoxing plain andWenzhou-Taizhou plain. It was suggested that soil testing and formula fertilization should still be an important technology to maintain the balance of soil nutrients in this region.