Rapid human population growth and urbanization have led to the loss of many ecosystem services. However, by 2050 food production must have doubled to support human needs. How to manage agro-ecosystems efficiently and make them provide enough food, fiber, fuel and other services for humanity is a great challenge. To harmonize the agricultural production and environmental services, we take Haihe watershed as a case study to evaluate the agro-ecosystem services and the environmental cost of agricultural production. The Haihe watershed, which locates in North China, covers 3.2×105 km2. Now Haihe watershed is undergoing rapid economic development and urbanization. The overall area of farmland of the Haihe watershed has, and will continue to decrease, with agro-ecosystem services correspondingly impeded or reduced.
In this paper, the agro-ecosystem services (including direct and indirect services), as well as environment costs were evaluated by the mixing approach including market valuation method, shadow engineering method and opportunity cost method etc.
Results/Conclusions
The results showed that: the total value of agro-ecosystem services was 1579.8 billion RMB. The direct and indirect values accounted for 1057.9 and 521.9 billion RMB, respectively. The values of different agro-ecosystem services ranked as follows: provisioning (1057.9 billion RMB), water conservation (406.1 billion RMB), nutrient cycling (55.5 billion RMB), carbon sequestration and oxygen release (25.5 billion RMB), soil conservation (12.3 billion RMB), waste purification (9.9 billion RMB), pollution purification (8.4 billion RMB), fuel (3.2 billion RMB), and straw return (1.0 billion RMB). The environmental costs of agro-ecosystem from the aspects of pesticide/fertilizer input and greenhouse gas emission is 51.5 billion RMB. The linear relationship between value per unit area and factors were modeled (adjusted R2=0.747). Six significant factors had been chosen to reflect their impact upon the value per unit area and were named as indicators, ie.: population, rain, income, sown area of vegetables and oil plants, and available irrigation area. Sowing areas of vegetables and population changes were identified as the main factors affecting the value per unit area of the agro-ecosystem. It could be intuitively understood that high population districts where the sown area of vegetables are big, sowing area of oil plants and irrigation areas are small would result in a high value per unit area of agro-ecosystem services. The technique and academic framework of our research could be applied to other places to various degrees.