日光温室辣椒基质栽培氮素矿化特性及残留氮迁移规律研究

This work focuses on the problems of nitrogen management of vegetable cultivation under cultivation substrates in solar-greenhouse. The aim of this study is to quantify the response rules of different water conditions, nitrogen fertilizing amounts,temperatures on nitrogen mineralization. To follow the fractions of organic nitrogen, including soluble organic N, amino acid N, non-hydrolysable N,hydrolysable unidentified N and amino sugar N, are measured. And organic nitrogen contribution to available N is evaluated. Organic residue substrates of pepper cultivation are used in the study, which has been applied on large area. Techniques of 15N isotopic tracing, et al. are employed. In addition, continuous pepper cultivation experiments of different cropping patterns are conducted in greenhouse for defining the dynamic variation rules of nitrogen supplyment and relevant enzyme activity of nitrogen mineralization, analysising the process of utilization and movement of residual nitrate in the substrates. And the growth, yield, fruit quality, physiological and biochemical indexes, uptake and distribution of nitrogen of pepper are monitored in the whole process of cultivation. Finally, the key influencing factors and enzymatic mechanism for nitrogen mineralization, rules of uptake and distribution of residual nitrate under substrates cultivation will be found. This would help to predict the effects of nitrogen on crops and optimization of nitrogen management for crop production in greenhouses.

针对日光温室蔬菜基质栽培中氮肥管理存在的问题，以生产上应用广泛的辣椒栽培基质为对象，借助15N同位素示踪等技术手段，研究氮素矿化过程及其对不同水分、施氮水平和温度的响应规律，分析基质可溶性有机氮、氨基酸氮、氨基糖态氮、非酸解氮等对矿化氮的贡献；研究辣椒不同茬口模式多茬栽培下基质氮素供应及与矿化相关酶活性的动态变化规律，分析基质残留氮的迁移、利用过程，并结合辣椒植株生长状况、果实品质、理化指标和氮素吸收、分配的全程监测，探明基质氮素矿化的关键影响因素、酶学机理及残留氮的迁移、利用规律，遴选出基质氮素矿化强度与有效性表征的指标。项目成果可为日光温室蔬菜基质栽培氮肥的精确调控提供理论依据。

以辣椒（陇椒10号）栽培基质为试验材料，研究了不同水氮供应处理对辣椒栽培基质氮转化微生物数量和相关酶活性，以及辣椒植株生长、光合特性、产量、品质、养分吸收和分配的影响，确定了适宜西北地区日光温室辣椒生产的适宜水氮施用配方（基质最大持水量的60% 、追施氮肥量64.73 kg N•666.7 m-2），提出了一套能提高基质氮素转化微生物数量及相关酶活性，辣椒产量较大，基质生产环境最优，生产潜力最大的水氮管理技术措施。同时，采用同位素示踪法将K15NO3分别标记于基质剖面不同层次，明确了不同灌水条件下辣椒植株各器官养分吸收分配特性及基质氮素运移累积规律，确定适宜灌水下限（基质最大持水量的60%）促进深层基质氮素向上运移，减少氮素损失率，有利于辣椒植株更好的吸收与利用。发表研究论文5篇，培养硕士研究生3名。本项目的研究成果为当地日光温室辣椒的高产优质栽培提供了技术支撑。