海南砖红壤上优化施肥对线椒产量及氮肥利用的影响

Effects of Optimized Fertilization on Yield of Line Pepper and Utilization of Nitrogen in Latosols in Hainan

蔬菜生产中片面追求高产,过量施用氮肥非常普遍,引起水体或大气污染。本文通过田间小区试验,以农户习惯施肥为对照,研究了减氮对线椒产量和植株地上部氮素积累量的影响,同时结合^(15)N标记肥料的微区试验,研究了肥料氮的去向。结果表明:以农民习惯施氮肥450 kg/hm^2为对照,减氮30%后线椒产量略增加,但差异不显著。^(15)N标记肥料的微区试验结果表明不同氮肥用量处理的线椒整个生育期果实、茎和叶的氮素总累积量几乎相等,农民习惯施氮肥较多,主要增加了土壤中的0～40cm残留量和表观损失量,大量残留的氮可能在线椒收获后被雨水淋失,环境风险大。氮肥利用率无论通过差值法还是^(15)N示踪法计算,都是减氮30%处理显著高于习惯施氮。因此目前海南线椒生产中,相比农民习惯施氮肥450 kg/hm^2减少30%氮肥施用非常必要,既不会影响产量,还可减轻环境污染。

Excessive application of nitrogen(N) fertilizer is very common to get high yield in vegetable production which causes water or air pollution. Compared with traditional N fertilizer application, the effects of reduced N fertilizer on the yield and accumulation of nitrogen in line pepper were studied by field experiments and the fate of N fertilizer was observed by the 15N micro-plot. The results showed that the line pepper yield by reduced 30% N was slightly improved but the difference was not significant compared with conventional N fertilizer input of 450 kg/hm^2. The results of the 15 N micro-plot experiment indicated that the accumulation of nitrogen in fruits, stems and leaves was almost equal during the whole growth period of line pepper even though more N fertilizer was applied in conventional N fertilizer treatment which resulted in the increment of the residual N in 0–40 cm soil and the loss of N. The residual N may be leached after the harvest of line pepper and contributed to environment pollution. The nitrogen use efficiency of reduced 30% nitrogen was significantly higher than that of conventional N fertilizer obtained by the percentage of fertilizer N uptake by crop to N fertilizer rate or 15N tracer technique. Therefore, compared with conventional N fertilizer input of 450 kg/hm2, it was necessary to reduce 30% nitrogen fertilizer in the line pepper production in Hainan, which would not affect the yield, and reduce environmental pollution.