摘要
采用耕层红油土进行盆栽试验,在每千克土施0.40gN和0.30gP2O5的基础上,种植小白菜(黑油菜)和菠菜(宁夏圆叶)。采样前10d设置150,200和250g/kg3个土壤水分等级,研究土壤水分对蔬菜生长和硝态氮累积的影响。结果表明,在土壤水分为200和250g/kg时,菠菜的生长量比水分为250g/kg时提高108.7%和174.8%,小白菜提高108.9%和109.9%;而菠菜的硝态氮含量却分别降低29.7%和19.4%,小白菜降低22.5%和25.0%;2种蔬菜的硝酸还原酶活性亦明显降低。对蔬菜生长、硝态氮吸收及还原的分析表明,土壤水分增加不仅促进蔬菜生长,还促进硝态氮的吸收及向地上部分转移。但生长量和硝态氮吸收的增加并不同速,由于生长超前引起的植物体内养分释稀效应,是增加土壤水分蔬菜硝态氮含量降低的主要原因。
Pot experiments were carried out with a redoil soil by using Chinese cabbage and spinach as indicating crops,in order to study the influences of soil water on nitrate accumulation in vegetables at a fertilization rate of 0.40 g N and 0.30 g P2O5 per kg soil.The results obtained showed that the yields of the two vegetables increased more significantly at the soil water contents of 200 g/kg and 250 g/kg than at that of 150 g/kg ,an increase of 108.7% and 174.8% for cabbage,and 108.9% and 109.9% for Chinese cabbage.In contrast,the nitrateN contents of the two vegetables decreased obviously,being 29.7% and 19.4% for spinach,and 22.5% and 25.0% for Chinese cabbage.Also decreased the nitrate red uctase activities of the vegetables.Comparing the vegetable growth and the nitrateN absorption and reduction,it is found that high soil water supply increased not only the vegetable growth but also the nitrate absorption and its translocation from roots up to the aboveground parts.However,both the biomass and the nitrate increases were not in the same proportion.The dilution effects caused by more increase of biomass than nitrate absorption were the major cause for the decrease of nitrateN contents at high soil water supply.
出处
《西北农业大学学报》
CSCD
北大核心
1997年第6期15-20,共6页
Journal of Northwest Sci-Tech University of Agriculture and Forestry(Natural Science Edition)
基金
陕西省农业发展办公室资助
杨凌基金
关键词
土壤水分
蔬菜
硝态氮累积
soil water,vegetable,nitrate accumulation