Abstract: Strategies for managing livestock manures and slurries in a sustainable manner have become an import issue with the rapid development in livestock and poultry industry in China. The manure production and utilization, usually involves the farming population, livestock and poultry breeding and crop cultivation, can achieve planting-breeding balance and reduce emissions of nutrients and pollutants to the environment. Understanding the process of manure nutrients in this comprehensive system can be helpful to strategies for the efficient recycling of manures. We develop a STELLA (Structural Thinking, Experiential Learning Laboratory with Animation) model for predicting the manure productions in agricultural and rural livelihoods and the changes in arable land bearing capacity for manure resources, and estimating the balance between local manure nutrients supply and fertilizer demand under different scenarios of crop straw returning to field and manure processing methods. The study aimed to provide scientific information for optimize planting and breeding structure, achieve the sustainable recycling of manures, and promote the formulation of relevant policies. The model was applied to Dongguan in Pearl River Delta, an ideal candidate for investigating regional dynamics of manure nutrients with the adjustment of stock breeding industry and continuing reduced livestock and poultry breeding in recent years. The dynamics of manure nutrients included in the model were: 1) The loading capacity of agricultural land soil for nitrogen and phosphorus nutrients according to limitations on nitrogen and phosphorus application issued by the European Union; 2) The estimated amount of crop straw and its nutrient content. The crop straw nitrogen (N), phosphorus (P2O5) and potassium (K2O) nutrients returned to field were also quantified separately under three returning proportions; 3) The amount of livestock manure estimated by the excretive coefficient method. Manures produced from different livestock species were converted into pig equivalent. Manure nutrients were calculated under three manure processing methods; 4) Nutrients derived from rural domestic manures; 5) The average values of arable land loading of nitrogen and phosphorus nutrients. The model was calibrated using the statistical data during 1979－2017 and then used for the future prediction. The results showed that nutrients demand of crops and fruit trees in 2025 was 4.613 6×103 t, while nutrients supplied by crop residue retention, livestock farming and rural domestic wastes were 430.64 and 4.5143×103 t, respectively. Under scenarios of three typical manure management methods (stockpiling, biogas production and composting), the actual available nutrient elements were estimated to 3.913 9×103, 4.803 7×103 and 3.055 0×103 t , respectively. According to the rule of organic fertilizer N substituting 50% of chemical fertilizer N, the amount of N, P, K contained in organic wastes has exceeded the requirements of crop and fruit trees and should be transported out to reduce the risk of environmental pollution. Under the scenario of all straw returned to field, up to 87% of livestock manures should be exported out. Moreover, the additional K needed to be supplied with chemical fertilizers to meet the needs of crops and fruit trees under the compost processing scenario. The prediction posed a caution that the livestock farms and farmers in Dongguan should ensure the amount of manure nutrients supplied by crop residue retention, livestock farming and rural domestic not to exceed the demand of crops and fruit trees.