不同施氮措施对柴达木枸杞园土壤无机氮的影响

通过施用不同量氮肥和硝化抑制剂，研究其对柴达木枸杞园土壤无机氮转化和枸杞产量的影响，并筛选出最佳的施氮措施。田间试验设置10个处理：除 CK 处理不施用任何肥料外，其余处理均施用1 667 kg/hm的商品有机肥和725 kg/hm的重过磷酸钙。N₆₆₇~N₀ 处理依次施氮667、534、400、267、133、0 kg/hm，Ni₄₀₀~Ni₁₃₃处理是在N₄₀₀~N₁₃₃处理的基础上，配施 Nitrapyrin 2、1.33、0.63 kg/hm 。结果表明：不同施氮处理土壤NO^-₃-N含量在 0~200 cm土层中均出现双峰，且 0~200 cm土层土壤NO^-₃-N平均含量较N₀处理增加34.65%~75.64%。施用氮肥增加0~40 cm土层中NH⁺₄-N含量，但对深层土壤无明显影响。Ni₄₀₀~Ni₁₃₃ 处理80~ 200 cm土层土壤NO^-₃-N含量较N₄₀₀~N₁₃₃ 处理降低12.13%~15.27%，但表层土壤 (0~20 cm) NH⁺₄-N含量增加338.5%~600%。Ni₂₆₇处理0~200 cm土壤硝态氮累积量较N₆₆₇处理降低 29.9%，但其枸杞产量较N₆₆₇处理增加 6.94%。适宜的氮肥用量以及增施 Nitrapyrin 可有效降低枸杞园土壤NO^-₃-N含量及累积量，同时使土壤中NH⁺₄-N含量保持在较高水平。综合经济效益和生态效益，施氮量为267~400 kg/hm且配施纯氮量0.5% 的Nitrapyrin为柴达木地区高肥力枸杞园的适宜施氮方案。

Effects of Nitrogen Applications on Soil Inorganic Nitrogen in Wolfberry Field of Qaidam

Nitrogen fertilizer rates combined with nitrification inhibitor were set to study the effects on soil inorganic N conversion and yield of wolfberry in Qaidam,and to obtain the optimum combination. Field study was conducted with 10 treatments: except for the control,other treatments had the fertilization with 1 667 kg/hm organic fertilizer and 725 kg/hm triple superphosphate. The N application rates were 667 (N₆₆₇),534 (N₅₃₄),400 (N₄₀₀),267 (N₂₆₇),133 (N₁₃₃) and 0 kg/hm (N₀). And 2, 1.33 and 0.63 kg/hm Nitrapyrin were added in Ni₄₀₀-Ni₁₃₃ treatments. The results showed that the soil NO^-₃-N of different treatments appeared double peaks in the soil layer of 0-200 cm,and the average NO^-₃-N increased by 34.65%-75.64%,compared with N₀. Moreover,N fertilizer application increased the NH⁺₄-N in 0-40 cm soil layer,but had no effect on the deeper soil. Compared with N₄₀₀-N₁₃₃,the NO^-₃-N of Ni₄₀₀-Ni₁₃₃ treatments in 80-200 cm soil layer decreased by 12.13%- 15.27%,and the NH⁺₄-N of surface soil (0-20 cm) increased by 338.5%-600%. The NO^-₃-N accumulation in 0-200 cm soil of Ni₂₆₇ was less 29.9% than that of N₆₆₇,but wolfberry yield was 6.94% higher than that of Ni₆₆₇. The N application and Nitrapyrin effectively decreased soil NO^-₃-N and accumulation,and maintained relatively a high NH⁺₄-N in wolfberry orchard. Synthesizing economic profit and ecological benefit,267-400 kg/hm N fertilizer with 0.5% Nitrapyrin were the suitable combinations for the high fertility wolfberry orchard in Qaidam.