Study On The Factor Of Accumulation Of The Nitrite In Chinese Cabbage

This paper studied on the effect of the form of nitrogen fertilizer(N- fertilizer), the dose rate of N-fertilizer, the temperature and time of storing, light intensity, the content of Nitreattitude -nitrogen in soil, etc. on the nitrite content in Chinese cabbage. It aimed at discussing the law of accumulation of the nitrite content in Chinese cabbage, so that we can provide the theoretical foundations for. improving the quality of vegetable and producing environmental-friendly vegetable. Results showed that:1 the extent which N fertilizer effects on the nitrite content in Chinese cabbahge is different.the nitrite content in Chinese cabbage is the highest by using potassium nitrate, is higher by using the urea, is minimum by using the carbonic acid ammonium.2 There is direct ratio between the dose rate of N- fertilizer and the nitrite content in Chinese cabbahge. when manuring these three N-fertilizer, they showed the same result: 30g/m~2 >20g/m~2 > 10g/m~23 There is direct ratio between the storing temperature and the nitrite content in Chinese cabbahge. the higher the storing temperature is , the higher the nitrite content in Chinese cabbahge is ; the nitrite content in Chinese cabbahge increased progressively with the storing days.the Chinese cabbahge was stored one day under 25 ℃, is amount to 4.9817mg/kg, which exceed the national standard ,when it was stored one day under 25 ℃. the nitrite content in Chinese cabbahge exceed the national standard in fifth day when it was stored under10℃.then the nitrite content in Chinese cabbahge did not exceeded the national standard when it was stored under 0℃. the storing temperature is under 10℃ is better..4 The content of nitrite in Chinese cabbage represented as a trend of increasing at daytime and decreasing at nighttime periodical. The content of nitrite in Chinese cabbage decreased 1.4321 in 2:00am,increased 5.3217 in 12:00am.when manuring potassium nitrate dose wae 30g/m~2.5 The content of nitrite in Chinese cabbage increased gradually after manuring fertilizer in first day. It reached the hightest in fifth day, then droped down, the Chinese cabbage should be harvested after senen days manuring fertilizer.6 The content of nitrite in Chinese cabbage was higher under the condtion of 45 percent shading light than CK.7 The dose rate of N- fertilizer and the content nitrite in Chinese cabbage were direct ratio. Their relevant coefficient (r) is 0.982279,0.924752,0.997606. The content of Nitreattitude-nitrogen in soil and the content nitrite in Chinese cabbage were direct ratio. Their relevant coefficient (r) is 0.997607, 0.675092, 0.997882...