[Objectives] Drip irrigation could effectively inhibit nutrient leakage as water and nutrients can be accurately sent to close the crop root zone .In this paper , the soil mineral N contents and environmental qualities were detected under different N rates and drip irrigation , to provide a base for efficient N management in vegetable production .[Methods] A three-years feild experiment was conducted with winter-spring cucumber and autumn-winter tomato double cropping system in a greenhouse .Four N rates were applied as 0, 300, 600, 900 kg/hm2 for cucumber and 0, 225, 450, 675 kg/hm2 for tomato under drip irrigation ( correspondingly recorded as N 0 , N1 ,N2 , N3 ) .The mineral nitrogen contents , salinity ( EC5:1 ) and acidity ( pH ) of 0-100 cm soil depth were investigated , and the economic and environmental efficiencies of N were calculated .[Results] As the elongation of the cropping year, the NO3--N contents under N2 and N3 treatments in 0-100 cm soil profile were significantly increased from 14.4-31.1 and 14.9-41.0 mg/kg in cucumber season in 2008 , respectively , to 76.4-119.8 and 129.0 -184.5 mg/kg in tomato season in 2010 , respectively , increased by 0.3 -1.8 and 0.5 -2.0 times respectively.The electrical conductivity ( EC5:1 ) of 0-100 cm soil profile under N2 and N3 was significantly increased from 379.6-514.3 and 407.0-476.7 μS/cm, respectively , to 663.0-1212.4 and 710.0-1359.6μS/cm of tomato season in 2010, respectively, increased by 0.3-1.8 and 0.5-2.0 times.The N rates in N1 was 33.3%-50%of N2 and N3 .Compared with N2 and N3 , the NO3--N content and EC 5:1 of N1 decreased by 35.5%-67.4%and 6.0%-25.2%after three years cultivation , and the pH and NUE increased by 0.06-0.18 unit and 9.0-13.8 percentage points .[Conclusions] Under this condition , the proper N rate for winter-spring cucumber and autumn-winter tomato was recommend as N 300 and 225 kg/hm2 .In most crop seasons ( 5 seasons ) , the NO3--N contents in 0-60 cm depth were in the proper range for cucumber and tomato growth , and no significant accumulation of NO 3--N was observed below 60 cm in the soil under this recommended N rate .%[目的]滴灌施肥较传统施肥更为精准的将肥水输送至作物的根区,减少肥料的用量,降低土壤水分和养分深层渗漏带来的环境风险. 本试验研究滴灌管理下不同氮肥( N)用量对设施菜地供氮能力及环境质量的影响,以期获得滴灌水肥一体化管理条件下最佳施氮用量. [方法]采用日光温室冬春茬黄瓜-秋冬茬番茄轮作,共设计4个化肥氮用量梯度( N0、N1、N2、N3 ,对应冬春茬黄瓜季施氮0、300、600、900 kg/hm2;秋冬茬番茄季施氮0、225、450、675 kg/hm2 ) ,3年定位研究比较不同氮用量下0—100 cm土体硝态氮、电导率( EC5:1 )、pH动态变化,计算了各施氮水平下设施蔬菜生产的氮素表观平衡、氮肥利用率和经济效益. [结果]随着种植年限的延长,N2 和N3 处理0—100 cm土体硝态氮和盐分积累显著,土壤硝态氮含量分别由2008年黄瓜季季平均14.4 31.1和14.9 41.0 mg/kg增至2010年番茄季季均76.4 119.8和129.0 184.5 mg/kg,分别增加了1.9 5.1和3.5 7.7倍;两处理EC5:1分别由2008年黄瓜季季平均379.6 514.3和407.0 476.7 μS/cm增至2010年番茄季季平均663.0 1212.4和710.0 1359.6 μS/cm,分别增加了0.3 1.8和0.5 2.0倍. 与N2 和N3 处理相比,N1 处理节氮50% 66.7%,经过三年的种植0—100 cm土层季均硝态氮含量和EC5:1分别下降了35.5% 67.4%和6.0% 25.2%,pH增加0.06 0.18 ,氮肥利用率显著增加9.0 13.8个百分点,而种植蔬菜的经济效益未有显著下降. [结论]温室滴灌冬春茬黄瓜-秋冬茬番茄经济施氮量分别为N 300和225 kg /hm2 ,既能保证3年5季蔬菜根层(0—60 cm)土层硝态氮处于相对适宜水平,具有较好的经济和环境效益.
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