Effect Of Fertilization On Crop Yield And Quality And Its Environmental Risk In Dianchi Lake Drainage Area

Dianchi lake is the biggest plateau lake in southwest of China. Thanks to its appropriate weather condition and area advantage, Dianchi lake drainage area has become famous producing base of vegetables and flowers in China. However, owing to intensive agricultural production and cropland intensive use, the environment in Dianchi Lake is faced with a challenge. Pollution of Dianchi Lake becomes severity increasingly. How to realize the area's crops yield stability, to improve crops quality and to reduce environmental risk of fertilization has become an urgent problem to be solved. Therefore, in this paper, study on effect of fertilization on crops yield, quality and environmental risk has been carried out in Yunnan.The yield of celery is increasing slowly with increase of fertilizer input. It is significant negative correlation between sweet pepper yield and fertilizer input. Lettuce yield is sensitive to N and P input. Effect of fertilizer P on celery yield is not significant, which is significant to reduction of sweet pepper yield. Effect of fertilizer K on sweet pepper yield is not significant, which is significant to increase of celery yield. Compared with conventional fertilization, the yield of the three vegetables is not reducted under reducing 50%-100% N and P in current season.Excessive amount of applying N and P brings about apparent quality of lettuce and celery worse. The correlation between NO3- in celery and sweet pepper and N input is significantly positive, which is the same between NO3- in sweet pepper and P input. Appropriate P input is able to reduce NO3- in celery, while excessive P input increases it. Increasing K input reduces NO3- in celery. Fertigation and reduction of N and P input improve carnation's quality.Uptake of K by the three vegetables is biggest, N takes second place and P is the third. N input is 4.8-10 times of N uptake by the three vegetables, P being 9.3-21.9 and K having a deficit up to -239kg.hm-2.The correlation between N input and NO3--N in soil is significantly positive. The velocity of NO3--N accumulation is fastest in surface soil. Appropriate P input is able to reduce NO3--N in soil, while excessive P input increases it. Fertigation significantly reduce NO3--N in soil and the amount of NO3--N downflow. Increasing K input can reduce NO3--N in soil.Supposing Olsen-P 70mg.kg-1 as the breakpoint of P runoff in soil, Olsen-P in soil is still over the breakpoint under no P input after harvest of celery and lettuce. The correlation between P input and Olsen-P in soil is significantly positive. Increasing N input increases Olsen-P in soil significantly. Fertigation significantly reduce Olsen-P in soil.During the whole crops growth period, available K in soil is reducing. Available K in soil is increasing with increase of K input. Available N is continuously accumulating in the whole growth period. The correlation between N input and available N in soil is significantly positive. Increasing P input increases available N in soil. Fertigation significantly reduce available N in soil.