Study On Nitrogen Management Of Cucumber And Tomato In Solar Greenhouse

Cucumber and tomato is the most important vegetable growing in solar greenhouse. Fertilizer increasing crop yield is out of question, but in recent years, crop yield was not increasing with amount of fertilizer application increased, at the same time, apparent N fertilizer recovery decreased. Over-use chemical fertilizer was very serious in protected vegetable cultivation. Over-use N fertilizer may not only cause economic losses, but produce many environmental problems. The experiment was carried out in Mujiazhai of Yangling and Nanzhuang of Yangling, respectively, to study the effects of different N rate on the soil NO₃^--N content,yield,dry matter,N use efficiency,N agronomy efficiency and income of cucumber and tomato in solar greenhouse; the survey was carried out in Xingping Xianyang and Yangling from 165 household, to analysis the fertilizing present situation and problems of cucumber and tomato in Guanzhong. The main results were showed as follow:1. Experiment of cucumber was done in two solar greenhouses and designed 5 N rate treatments. N rate as follow: CK was no inorganic; OPT was N 675 kg/hm² and 788 kg/hm²; 50%N was N 338 kg/hm² and 394 kg/hm²; 150%N was N 1 013 kg/hm² and 1 181 kg/hm²; FP was N 848 kg/hm² and 884 kg/hm². The result was that cucumber yield(135 t/hm² and 169 t/hm²),the amount of dry matter (5.7 t/hm² and 10.3 t/hm²),N use efficiency(8.8% and 16.8%) and N agronomy efficiency(76 kg/kg and 16 kg/kg) is most when the N rate reached 675 kg/hm² and 788 kg/hm², cucumber yield was 61.1% and 24.5% higher compared to CK. Cucumber yield was 14.9%,2.1% lower,N use efficiency was 76.1%,67.3% lower and N agronomy efficiency was 56.2%,52.5% lower compared to N rate reached 675 kg/hm² and 788 kg/hm² when the N rate reached 1 013 kg/hm²å’Œ1 182 kg/hm². It showed that profie was decreased as N rate increased.2. Experiment of tomato was also done in two solar greenhouses and designed 5 N rate treatments. N rate as follow: CK was no inorganic; OPT was N 775 kg/hm² and 760 kg/hm²; 50%N was N 387 kg/hm² and 380 kg/hm²; 150%N was N 1 162 kg/hm² and 1 140 kg/hm²; FP was N 1 616 kg/hm² and 918 kg/hm². The result was that tomato yield (119.8 t/hm² and 130.2 t/hm²) is most when the N rate reached 760 kg/hm² and 775 kg/hm², and tomato yield was 14.76% and 18.38% higher compared to CK. The amount of dry matter was 9.5% and 17.7% higher compared to CK when the N rate reached 760 kg/hm² and 775 kg/hm². Tomato yield was 0.23%,0.06% lower compared to N rate reached 760 kg/hm² and 775 kg/hm² when the N rate reached 1 140 kg/hm²å’Œ1 162.5 kg/hm². The N use efficiency of tomato was between 0.7% to 13.2%. Except 50%N treatment for solar greenhouse 2, the N use efficiency and N agronomy efficiency were decreased with N rate increasing. Over-use N no only wast fertilizer but also reduced the profit of farmer.3. The survey of fertilizing present situation and household income by cucumber and tomato in Guanzhong showed that the average fertilizer rate of tomato in Guanzhong was N 1697.5 kg/hm², P₂O₅ 938.5 kg/hm², K₂O 1504.1 kg/hm², and the ratio of N P₂O₅ K₂O was 1:0.553:0.886. The average fertilizer rate of cucumber was N 1892.7 kg/hm², P₂O₅ 992.7 kg/hm², K₂O 1930.3 kg/hm², and the ratio of N P₂O₅ K₂O was 1:0.524:1.020. The fertilizer ratio of N P₂O₅ K₂O was unreasonable. The recommended fertilizer rate of tomato is N 500-800 kg/hm², P₂O₅ 150-230 kg/hm², K₂O 400-630 kg/hm². The recommended fertilizer rate of cucumber is N 600-900 kg/hm², P₂O₅ 100-175 kg/hm², K₂O 500-800 kg/hm². Most of N and P₂O₅ used as basal fertilizer, and Most of K₂O used as topdressing fertilizer, paid more attention to use organic manure and topdress K₂O in tomato and cucumber product. N P₂O₅ K₂O fertiliaer rate of tomato and cucumber all over needed, and over 57.7% household that fertiliaer rate was slightly high.