栽培年限对新建日光温室番茄生长及土壤供氮能力的影响

Effect of cultivation year on tomato growth and soil nitrogen supply ability of newly built solar greenhouses

  • 摘要: 为评价栽培年限对新建日光温室土壤供氮能力的影响, 采用盆栽生物耗竭试验和间歇淋洗好气培养法相结合的方法研究了陕西杨凌不同年限新建日光温室(温室建造前的大田及温室建造后第2年和第3年取样)耕层(0~20 cm)土壤供氮能力的变化。结果表明: 随着温室栽培年限的增加, 番茄生物量和吸氮量与温室栽培前相比均显著增加, 其中栽培年限为第2年和第3年的番茄株高、茎粗、地上及根系生物量、叶片SPAD值均显著高于温室建造前, 而第2年和第3年间各指标无显著差异; 第2年和第3年温室的番茄吸氮量分别是建造前大田的2.53倍和3.01倍; 与种植前土壤相比, 第3年温室土壤有机质、全氮和速效养分含量均显著增加, 第2年及第3年温室土壤可矿化氮量分别是建造前大田的2.84倍和2.96倍, 说明随栽培年限的增加, 温室土壤供氮能力显著增强。相关分析表明, 土壤有机质、全氮、初始矿质氮及累积矿化氮量与番茄吸氮量间呈极显著正相关关系, 其中以土壤累积矿化氮量与番茄吸氮量间的相关系数最大, 说明这些指标均可用于评价土壤供氮能力。随栽培年限的增加, 日光温室土壤供氮能力显著提高, 生产中应随温室栽培年限增加适当降低氮肥用量。

     

    Abstract: Solar greenhouse, developed by China’s farmers and scientists in the early 1980s, makes it possible to produce vegetables during winter without additional heating and lighting in large parts of North China. Vegetable cultivation in greenhouses has high profitability. This has led to a rapid increase in the land area used for solar greenhouse production over the last three decades. Within the greenhouse system, it is common to overuse inorganic fertilizers and manure in vegetable production. It increases the organic matter in soil and the accumulation of nutrients and salts in the soil. The accumulation of nutrients in solar greenhouse soils, especially nitrate, has high environmental risks. Optimum application of nitrogen (N) fertilizer is critical for resolving this problem. Mineralized N in soils during crop growth supports a high rate of N uptake by crop. Therefore understanding nitrogen (N) mineralization in solar greenhouse soils with different cultivation histories is important for rational N fertilization. However, most of the studies on soil N mineralization studies have focused on arable soils and little remains known about N mineralization in solar greenhouse soils with different cultivation histories. In this study, the pot depletion method and Stanford and Smith aerobic incubation method were used to evaluate the effects of cultivation years on N supply ability in the 020 cm layer of soil under newly-built solar greenhouse with different cultivation years 0 year (before greenhouse construction), 2 and 3 years of operation in Yangling, Shaanxi. Response of tomato to cultivation years was also investigated. The results showed that tomato height, stem diameter, aboveground and root biomass, leaf SPAD in 2 and 3 years greenhouse were significantly higher than those in field of 0 year greenhouse, while these indexes were not significantly different between 2 years and 3 years greenhouses. Total N uptake of tomato increased with increasing age of solar greenhouse. Total N uptakes in greenhouse soils with 2 and 3 years of cultivation were 2.53 and 3.01 times that of soils before greenhouse construction. Soil organic matter, total nitrogen and available nutrients contents of 3 years solar greenhouse were significantly increased compared with those of field before greenhouse construction. Mineralized N in solar greenhouse soils with 2 and 3 years of cultivation was 2.84 and 2.96 times that of soils before greenhouse construction. It then indicated that as the age of solar greenhouse increased, soil N supply ability increased significantly. The contents of soil organic matter, total N, initial mineral N, and mineralized N were significantly positively related to tomato N uptake. The coefficient between mineralized N and tomato N uptake was highest. It indicated that these indexes could be used to evaluate soil N supply ability, mineralized N was the best one. In order to reduce N loss and increase N use efficiency in the study area, it was concluded that as the age of greenhouses increased, the addition of inorganic N fertilizer should be reduced in solar greenhouse production.

     

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