Effects of Drip Fertigation Management on Nutrient Losses and Pear Production at Chongming Dongtan in Yangtze River Estuary, China

Drip fertigation was applied to evaluate the effects on nutrient losses and crop production in a pear orchard at Chongming Dongtan in Yangtze River Estuary in 2006 and 2007, compared to conventional irrigation and fertilization practices. Based on runoff paddocks and leaching pipes construction, the volumes of runoff and leaching water, and the corresponding concentrations of nitrogen and phosphorus were measured and estimated. The results indicated that, under the experimental conditions, N and P losses through runoff and leaching occurred mainly in the period of rain season from June to October, and leaching was the dominating pathways for N loss while runoff was the main pathways for P loss. Compared with the conventional irrigation and fertilization system, under the consistency of crop yields, the drip fertigation system could decrease the total amounts of nitrogen and phosphorus losses through runoff and leaching by 36.4% and 16.5%, and reduce the total amounts of nitrogen and phosphorus consumptions of chemical fertilizer application by 73.4% and 61.1%, respectively.