日光温室番茄灌水量与根层硝态氮淋溶特征及渗漏关系研究

针对蔬菜灌溉水肥渗漏问题,采用田间试验和室内分析相结合,研究了番茄膜下沟灌灌水量与土壤硝态氮的根层外渗漏关系,分析了灌水量与不同根层土壤硝态氮的淋溶和保蓄特征,结果表明:灌溉不施肥条件下灌水量与土壤硝态氮淋溶量和淋溶率、灌溉施肥条件下灌水量与土壤施入硝态氮的保蓄率和渗漏率均呈直线关系;灌溉均会引起浅根层(0—20 cm)硝态氮淋溶,灌溉施肥条件下7.5～15 mm灌水量范围硝态氮积累有一个峰值,而22.5～45 mm范围则有两个峰值;灌水量在7.5～15mm之间,灌溉不施肥条件下根层土壤硝态氮淋溶率为0,灌溉施肥条件下土壤硝态氮渗漏率为0～5.19%;灌水量在22.5～45 mm之间,灌溉不施肥土壤硝态氮淋溶率为5.38%～19.08%,灌溉施肥条件下根层土壤硝态氮渗漏率为21.91%～61.96%。日光温室番茄膜下沟灌能减少肥料淋溶与渗漏的节水灌水量为15 mm。

Study on the relationship between irrigation amount and NO-3-N leaching of tomato field in greenhouse

Aiming at the problems of water and NO₃^--N leakage that induced by irrigation practices in vegetable field, the relationship between furrow irrigation amount under the mulching and soil nitrate nitrogen amount that leaked out from the soil root layer was studied by combination of the field experiments and labor analysis in tomato field under greenhouse. The results show that the irrigation amounts are linearly related to NO₃^--N leakage amounts under both the NO₃^--N fertilization and no NO₃^--N application, and the irrigation practice could cause the NO₃^--N leaching definitely in 0-20cm root layer whether there is the fertilization. There is one peak value of soil nitrate nitrogen leakage amount in the range of 7.5mm-15mm water supply, while there are two peak values under the 22.5-45mm water supply. The NO₃^--N leakage rate is 0 under the no fertilizer application and 0-519% under the fertilizer application at the root layers the irrigation amount is from 75mm to15mm. Under the 22.5-45mm water supply, there is only 5.38%－19.08％ NO₃^--N leaked out of the root layers in the no fertilizer application, while the value is 21.91%-61.96% under the fertilizer application. The reasonable irrigation amount is 15mm for the greenhouse tomato in this research.