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利用养分渗滤池研究了北京潮土地区春小麦—夏玉米连作期间NO_3—N在土壤剖面中移动的时空动态。结果表明,NO_3—N的移动同降雨、灌水以及整个土壤系统中的水分状况密切相关。在春小麦期间只有个别处理在0—20cm和20-40cm中有显著移动,而夏玉米期间在0—130cm的土体中NO_3—N发生了“波浪式”的移动。淋失量同当时的降雨量线性相关。130cm深处NO_3—N含量在淋失高峰期可达10mgN.L~(-1)以上。此外,NO_3—N的移动同尿素施用量的多少有着密切关系,而尿素、硝铵和硫铵等肥料品种之间差异则不明显。~(15)N示踪结果表明,在春小麦前期尿素中的酰胺态氮或NH_4—N在0-20cm土层中直接移动,而来自肥料的NO_3—N在40—60cm处移动;夏玉米生长期间,在60cm以下深处有大量来自尿素和硝铵等残留标记氮的NO_3—N移动。
The temporal and spatial dynamics of NO_3-N movement in the soil profile during spring wheat-summer maize continuous cropping in Beijing alluvial soil were studied using a nutrient infiltration filter. The results show that the movement of NO 3 -N is closely related to rainfall, irrigation and water status in the soil system. During spring wheat only individual treatments showed a significant shift in 0-20 cm and 20-40 cm, while NO 3 -N in the 0-130 cm soil during summer corn shifted “wavy”. The leaching loss is linearly related to the current rainfall. The content of NO_3-N in the depth of 130cm can reach more than 10mgN.L -1 at the leaching peak. In addition, the movement of NO_3-N is closely related to the amount of urea applied, while the differences between fertilizer varieties such as urea, ammonium nitrate and ammonium sulfate are not obvious. ~ (15) N tracer results show that amido nitrogen or NH_4-N in the urea of the early spring wheat moves directly in the 0-20cm soil layer while NO_3-N from the fertilizer moves at 40-60cm; summer maize growth In the depths below 60 cm, there was a large amount of NO 3 -N moving from residual labeled nitrogen such as urea and ammonium nitrate.