| Hainan is a well-known"tropical agriculture base"in China.Since the province was established in 1988,the scale,structure and production methods of agricultural production in Hainan Island have changed a lot in order to meet the increased food demand for population growth and improved dietary structure.Affects the degree of agricultural green development.Agricultural production invests a lot of agricultural resources,which brings a series of environmental problems such as nutrient loss and chemical pollution.For this,it has paid a huge price for land degradation and loss of ecological functions.In order to solve the above problems and achieve the goal of agricultural green development,it is necessary to first clarify the characteristics of agricultural development and its influencing factors,find out the bottleneck problems that restrict agricultural green development,and propose countermeasures accordingly.This study takes Hainan Island as an example,with the help of China's agricultural green development indicator system,using the NUFER model?NUtrient Flows in food chain,Environment and Resources?to quantitatively calculate and analyze Hainan's agricultural green development economy,social development,resource input,productivity and ecology The characteristics of spatio-temporal changes of five types of environmental indicators;constructing and perfecting an indicator system that conforms to the laws of Hainan's agricultural development;using the constructed indicator system to analyze the agricultural green development of different types of counties?cities?and discuss the realization of agricultural green development on large tropical islands.The main findings are as follows:?1?This study makes use of China's agricultural green development?AGD?indicator system,in which 20 indicators were selected and by using NUFER model?NUtrient Flows in food chain,Environment and Resources?the spatial and temporal changes of Hainan Island AGD indicators from 1988 to 2017 were quantitatively calculated.Moreover,the factors that restrict the AGD were discussed.The results show that the overall level of Hainan Island's AGD has shown a declining trend over the past 30 years.The numbers of indicators at lower levels?III and IV?have increased from 12 to 15,and those at higher levels?I and II?have decreased from 8 to 5.With the increase in the proportion of economic crops such as vegetables and fruits,the scale of livestock and poultry farming and the degree of intensification have increased.Hainan's agricultural output value and social development level have continued to increase.The agricultural output value per unit cultivated land area and agricultural mechanization level have been from 13,400 yuan hm-2and 3 kw hm-2increased to 339,000 yuan hm-2and 13 kw hm-2.In the past 30 years,the input of agricultural resources?nitrogen,phosphorus,pesticides and agricultural film?were excessive,in which the use intensity of pesticides and agricultural films increased the most,increasing from 8.0 kg hm-2and 0 kg hm-2to 47.1 kg?hm-2and 39.0 kg hm-2respectively;Due to the productivity level is low,the environmental emissions of nutrients?farm nitrogen surplus,farmland nitrogen runoff,agricultural source ammonia volatilization,etc.?have increased significantly,agricultural source ammonia volatilization and nitrogen surplus per unit sown area increased the most,increasing from 61.0 kg hm-2and 152.1 kg hm-2to 297.9 kg hm-2and 131.4 kg hm-2,respectively.Environmental pollution caused by an excessive input of agricultural resources and the separation of agriculture and animal husbandry is the main reason for restricting the AGD in Hainan Island.In terms of space,because the central part is a mountain forest area,it is a national key ecological function protection area,and the development effort was small.Therefore,the resource input of the coastal plains has grown faster and it lost more in the environment,and the economic,social,and productivity indicators have also improved more than those of mountain forest area.In the future,Hainan Island should rationally optimize the planting structure in coastal areas,improve the level of production management,strengthen the combination of agriculture and animal husbandry to reduce resource losses,and achieve the AGD goals in Hainan Island.?2?Build Hainan Island agricultural green development indicator system,analyze different types?according to Hainan Island agricultural development planting structure and breeding planning division?county?city?agricultural green development situation.According to the actual situation of Hainan Island,according to the two principles of systemic and completeness and representativeness and emphasis,the six indicators of social and productivity will be expanded and supplemented to build an indicator system for green development of Hainan agriculture.Introduce the comprehensive index score method,set the index to positive and negative categories,define"agricultural green development comprehensive score",evaluate the agricultural green development of different types of counties?cities?,and analyze the agricultural green development scores show that different areas of Hainan Island Affected by different factors such as climatic conditions,geographical location and development intensity,the level of agricultural green development is different:the productivity level of the northeast plain area is the best in the whole island;the degradation of crops in the western plain area restricts the cultivation of crops,and the agricultural economy and productivity level are improved.Less,the resource input and the environmental loss are relatively less;the southern hilly basin has the highest social development level,the highest total output of cash crops,and the agricultural output value is higher than other regions,but due to the low productivity level and the large amount of resource input,the environmental loss is also the most;Due to limited resource development,the forestry land in the central mountain area has less resource input and environmental emissions,and the agricultural economic output value is also lower.?3?By analyzing the correlation between indicators,the main factors affecting the green development of Hainan's agriculture are identified.Correlation analysis of all indicators shows that the increase in the proportion of fruits,vegetables and special economic crops and the increase in the carrying capacity of livestock and poultry are obviously related to the increase in economic growth,agricultural resource input and environmental losses.In the past 30 years,the proportion of tropical fruits,vegetables and special economic crops grown in Hainan Island and the carrying capacity of livestock and poultry have increased by 1.2 times respectively,which has a significant impact on the increase in agricultural output value per unit of arable land in Hainan,leading to an increase in the input of nitrogen fertilizers and pesticides.The increase in carrying capacity is more significantly related to the increase in nitrogen surplus per farmland and the increase in ammonia volatilization in agricultural systems.In summary,from 1988 to 2017,Hainan Island increased the proportion of cash crops planted through policy support and expanded the scale of livestock and poultry breeding.However,due to the limited optimization of management measures,the rapid development of agriculture has brought about problems such as the separation of agriculture and animal husbandry,loss of resources and serious environmental pollution.In the future,Hainan Island should adjust the planting structure in the southeast region and increase the development of the hills and mountains in the west and north-central regions.Optimize management measures,improve production management level,reduce agricultural chemicals input to reduce environmental risks,strengthen the combination of agriculture and animal husbandry to improve nutrient recycling efficiency and reduce resource and environmental losses;strengthen agricultural infrastructure construction in western arid regions to ensure water supply;strengthen policy Implement and supervise the efforts to ensure the green development of agriculture,and now the green development of agriculture in Hainan Island. |
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