2种土地利用方式下红壤优先流特征及其对氮运移的影响

Characteristics of Preferential Flow of Red Soils under Two Land Use Patterns and Their Effects on Nitrogen Transport

以江西省水土保持生态科技园的耕地和枇杷林地为研究对象,通过野外染色试验和室内淋溶试验研究2种土地利用方式下的红壤优先流特征及其对氮运移的影响。结果得出:2种土地利用方式下优先流的分布特征有明显的区别。耕地优先流到达的最大深度为40 cm,枇杷地优先流到达的最大深度为60 cm。耕地的优先流宽度随着深度的增加而逐渐较小,枇杷地的优先流宽度随着深度的增加呈现先增加后减小的趋势。耕地和枇杷地淋出液总氮的浓度都随着试验时间增加而逐渐增加,在试验前120 h内,枇杷地淋出液总氮浓度比耕地淋出液总氮大,在120 h之后,两地淋出液总氮浓度大致相等,但是,枇杷地所有淋出液总氮的平均浓度是耕地的1.21倍。硝酸根离子在耕地的穿透速率比在枇杷林地快。耕地淋出液检测到总氮是在试验开始后4 h,枇杷地淋出液检测到总氮是在试验开始后8 h。

In this paper,the cultivated land and loquat land of Jiangxi Province Soil and Water Conservation Ecological Science and Technology Park were taken as research objects.The field characteristics of red soil under two land use modes and their effects on nitrogen transport were studied by field dyeing experiment and indoor leaching experiment.The experimental results showed that there were obvious differences in the distribution characteristics of preferential flows under the two land use modes.The maximum depth of the preferential flow of cultivated land was 40 cm,and the maximum depth of the preferential flow of loquat land was 60 cm.The preferential flow area of cultivated land gradually decreased with the increase of depth,and the preferential flow area of loquat land increased first and then decreased with the increase of depth.The concentration of total nitrogen in cultivated land and loquat land leaching solution increased with the increase of experimental time.With in 120 hours before the experiment,the total nitrogen concentration in the leaching solution of laquat land was larger than that in the leaching solution of cultivated land.After 120 hours,the total nitrogen concentrations in the leaching solution of the two places were approximately equal,but the average concentration of total nitrogen in all the leachate in loquat land was 1.21 times that of the cultivated land.The penetration rate of nitrate ions in cultivated land was faster than that in loquat land.The total nitrogen detected in the leaching solution was 4 hours after the experiment,and the total nitrogen detected in the leaching solution was 8 hours after the experiment.