Luoping Zhang

Validation of an agricultural non-point source (AGNPS) pollution model for a catchment in the Jiulong River watershed, China.

This study tested and evaluated the agricultural non-point source (AGNPS) model for the Wuchuan catchment, a typical agricultural area in the Jiulong River watershed, Fujian Province, China. The AGNPS model was calibrated and validated for the study area with observed data on ten storms. The data on eight storms in 2002 were used for calibration while data on two storms were used for validation of the model. Considering the lack of water quality data over a long-term series, a novel method, comparing an internal nested catchment with its surrounding catchment, was used to supplement the less long-term series data. Dual calibration and validation of the AGNPS model was obtained by this comparison. The results indicate that the correlation coefficients were 0.99 and 0.98 for runoff, 0.94 and 0.95 for the peak runoff rate of the large catchment and the small catchment, respectively, and 0.76 for the sediment of the small catchment only. Each pair of correlation coefficients is homogeneous for the same event for the two catchments. With the exception of the sediment yield and particulate phosphorus, the peak runoff rate and other nutrients were well predicted. Sensitivity analysis showed that the Soil Conservation Service curve number and rainfall quantity were the most sensitive parameters, which resulted in high output variations. Erosivity and other parameters had little influence on the hydrological and quality outputs.

Risk assessment of nitrogen discharge from a coastal watershed

Abstract Probabilistic risk assessment (PRA) uses probability theory to quantify the probability of occurrence of an event. In this study, PRA was conducted for the discharge of excess nitrogen (N) from an agricultural (Jiulong River) watershed in Southeast China. Using fault tree analysis, a type of PRA, the probability of occurrence of excess N discharge into the river during a runoff event was evaluated both qualitatively and quantitatively. Land use maps, soil maps, fertilizer use records, and expert opinions were used to determine probabilities of individual events within the fault tree and to calculate the overall probability of excess N discharge during a runoff event. Qualitative analysis showed that the risk of excess N discharge was mainly related to crop and livestock practices in the watershed. Proper management of tillage, fertilizer, and manure was necessary to control N releases. Quantitative assessment results indicated that alternative practices including reduction of fertilization, installation of vegetative strip buffer around the pig farms, and installation of more riparian buffers along the Jiulong River could reduce the likelihood of N discharge through runoff.

Developing public environmental education: Improving community-based environmental management

This paper presents the experience of institutional capacity building in environmental education, and the achievement of the participatory approach in environmental management for the Canadian International Development Agency funded project ‘Community-Based Conservation Management: China and Vietnam’ in Xiamen. The project has enhanced teaching capacity and applied research skills of the local training institutions with integrated social and physical science lessons in multiple levels of a post-secondary environmental education programme. The focus of the project was to integrate the local secondary and post-secondary schools environmental education plans. Approaches to promote public awareness on environmental conservation are also illustrated. The study highlights the conservation activities of the Community Based Conservation Management project in Xiamen to encourage the involvement of a variety of community groups, including university students, youth and women. In addition, it explores the social responsibility of the faculty as an essential link between the public and decision-makers for effective public involvement in environmental management. We argue that the success of public environmental education relies on institutional capacity building, interdisciplinary studies and community participation.

Evaluation of nitrogen balance on pig/crop farm systems in Jiulong River watershed, China

Field surplus nitrogen and farm disposal nitrogen (N) are major sources of environmental pollution in farm systems. The purpose of this study was to use nitrogen balances at the field and farm level approaches to estimate the effects of pig production in the Jiulong River watershed, Fujian province, China, on nitrogen losses to the environment on 67 pig farms. The field surplus nitrogen ranged from 6.19 to 18.19 t nitrogen ha−1, which was caused by high pig density and excessive application of manure. Manure application rates of more than 450 to 510 kg nitrogen ha −1 would increase the potential nitrate concentration to more than 10 to 20 mg l −1. Therefore, 44 to 48 heads of pig ha −1 was suggested to as the environmental capacity for sustaining optimal nitrogen cycling in pig farms in the Jiulong River watershed. The majority of farms have potential environmental risks because of high farm nitrogen imbalances. With more than a 2:1 ratio of N inputs to outputs, N inputs were 50 percent higher than outputs. Feed was the main input source, while pig production and manure exported were the major managed outputs. Based on the farm nitrogen balance calculation, the management options that would contribute to a more favorable nitrogen balance were also identified.

An improved ion-exchange/diffusion method for 15N isotope tracing analysis of nitrate in surface waters from watersheds.

An improved method, suitable for collecting nitrate from surface waters in the watershed for 15N isotope tracing analysis, was developed on the basis of the anion exchange coupled with diffusion through systematic simulation and comparison experiments. The results showed that the nitrate could be separated and enriched from the waters efficiently by using the improved method. Being simple and practical in operation principle and procedures, cost-economic, and highly efficient in nitrate separation/enrichment, the method met the requirements of delta(15)N mass spectrum analysis and would lay a foundation for the application of 15N isotope tracing approach to the research on non-point source pollution in watershed.

Mixed integer programming for a swine manure handling system in the Jiulong River watershed

Swine finishing produces a large contribution of manure to nearby surface water and ground water in Jiulong upstream watershed, south Fujian Province, China. It is urgent to find a comprehensive, cost-effective way, not only to solve the manure pollution problem, but also to utilize the nutrients of manure for local farming. Gekou, a small hoggery village in the dense swine-farming core area of the upstream watershed, was selected as the study area. Mixed integer programming models based on uncertain interval numbers were employed to generate optimal whole farm plans for specialized hoggery. Emphasis was placed on discerning the most profitable ways to formulate hog feed rations, manure collection, manure storage, and manure application to achieve the maximum profit and the minimum pollution emission. Analyses were concentrated on ammonia emissions, excess total nitrogen and excess total phosphorus from manure operations, not only as nutrients applied to croplands, but also as pollutants to be minimized in compliance with environmental criteria. Three different hog feed rations, two alternative ways of collecting hog manure, and two alternative storage methods were combined with five alternatives for field application of manure to provide different combinations of hog feeding and manure-handling to be evaluated in the mixed integer programming models. Results indicated tradeoffs between economic goals and environmental goals, the latter being achieved only at some expense to farm net returns. The kaleyard and fishpond are recommended alternatives for field application of manure compared to three other alternatives.