不同施氮措施对茶叶品质及茶园土壤环境的影响

Effects of different nitrogen fertilization treatments on soil condition of tea garden and tea quality

由于茶园频繁且大量施用氮肥的不合理施肥措施带来的茶叶品质下降、地下水污染、土壤酸化加剧等系列环境问题,严重影响茶叶可持续发展。针对福建铁观音(tiěGuān yīn)茶园过度施用氮肥、氮磷钾比例不协调、有机肥施用不足的现状,在茶园设计了不同的施用氮肥试验,观测土壤环境质量的氮素指标变化,以研究不同施氮措施对铁观音品质及茶园土壤环境的影响。结果表明:在茶农习惯施氮量的基础上减氮20%配施有机肥能够提高茶叶产量和品质;有机无机肥料配合施用后第二年产量比习惯施肥提高6.8%;茶多酚、氨基酸、水浸提物比习惯施肥分别提高14.1%、15.0%、4.7%;施肥处理对含氮高的茶园土壤氮养分的动态变化趋势没有明显影响;单施无机肥处理茶园土壤NH4+-N和NO3--N质量分数随着施肥量的增加而增加,从而导致NH4+-N和NO3--N的淋溶损失的几率增加。同样施肥量的有机肥处理茶园土壤NO3--N平均质量分数仅为单施无机肥处理的45.23%。单施无机氮肥能够加速土壤酸化发生,造成土壤pH、有机质明显下降,施用量越大,土壤酸化越严重,土壤氮流失风险也增加;单施有机肥,土壤质量改善明显,但对茶树养分供应不及时,影响茶叶产量;减氮的同时配合有机肥的施用,可改善茶叶品质,提高产量,同时对土壤环境质量改善有良好效果。因此铁观音茶园应增施有机肥,适当控制速效氮肥的施用量可减少茶园氮素流失而提高利用率,也相应的减少了环境的污染。

The sustainable development of tea has been seriously affected due to serious environmental problems such as bad tea quality, groundwater pollution and aggravated soil acidification caused by unreasonably frequent and excessive nitrogen fertilization. Aiming at current situation of excessive application of nitrogen fertilizer, inconsistent NPK ratio and lack of applying organic fertilizer in Fujian Tie Guanyin tea garden, different nitrogen fertilizer trials were designed through observing changes of nitrogen index in the soil environment in order to study the effects of applying different nitrogen fertilizer on Tie Guanyin tea quality and soil environment. The results showed that 20%nitrogen reduction on the basis of nitrogen fertilizer FFP （farmers＆#39; fertilization practice） coordinated with organic fertilizer improved the yield and quality of tea. The tea yield increased by 6.8%in the second year while applying inorganic fertilizer mixed with organic fertilizer. Compared to FFP, tea polyphenols, amino acids, and water extract improved by 14.1%, 15.0%and 4.7%, respectively. There’s no obvious dynamic trend change caused by different fertilizer in high nitrogen tea garden. Soil NH4＋-N and NO3--N content increased with the increase of fertilizer application as applying inorganic fertilizer only, which would result in a higher NH4＋-N and NO3--N leaching losses rate. On average, NO3--N content with applying the same amount of organic fertilizer only accounted for 45.23%of inorganic fertilizer treatment. Application of inorganic nitrogen fertilizer would accelerate soil acidification, and reduce soil pH and organic matter content. Furthermore, when it applied more, soil acidification became worse and the risk of soil nitrogen loss rate increased as well. Single application of organic fertilizer obviously improved soil quality, but it would affect the yield due to non nutrient supply in time. Nitrogen reduction simultaneously fertilized with organic fertilizer could apparently improve tea quality and yield, and at the same time it enhanced soil environmental quality. Therefore, we should boost organic fertilizer application and control the amount of available nitrogen appropriately, which can enhance N fertilizer efficiency and cut down nitrogen loss, and reduce environmental pollution correspondingly.