Farmland buffer strip planning, construction and protective effect on related natural enemy

At present, the application of buffer strips is becoming increasingly important in the development of modern eco-agriculture both at national and international scales. With proper design and construction, farmland buffer strips (e.g., field margins, wild flower strips, hedgerows and shelterbelts) can provide various ecosystem and landscape services, including erosion prevention, non-point pollution control, natural pollination, pest control and landscape pattern optimization. This paper used the construction project of Modern Urban Agricultural Demonstration Farm in Shunyi District in Beijing to discuss the concept, classification, functions and planning methods of farmland buffer strips. Backed by literature review, the study demonstrated integrated spatial planning and construction of farmland buffer strips and assessed natural enemy protection service of 4 typical buffer strips by sampling and measuring the density of spiders and natural enemies/aphids ratio. The study showed that:1) Farmland buffer strips can be defined as "a strip vegetation mosaic separating different landscape features and patches in an agricultural landscape". This classification measure of farmland buffer strips was based on 3 attributes-location and neighboring land use, vegetation composition and structure, and ecosystem services types. Ecosystem and landscape services were the main factors considered during planning of buffer strips. The planning process of farmland buffer strips was summarized into 5 steps-target identification, on-site investigation, spatial arrangement planning, construction pattern design, and supervision and management. 2) According to the landscape pattern and ecosystem services demand in the study area, the study proposed a spatial arrangement of farmland buffer strips that consisted of 3 types with a total of 7 construction patterns designed in combination with the construction of field ditches, roads and shelterbelts. The results of the assessment of natural enemy protection service showed that the area 10 m within wheat fields near shelterbelt buffer strips had the highest density of spiders. Also the ratio of natural enemies to aphids in wheat fields near artificial field margins (including field ditches and road buffer strips) was largest. To some degree, the evaluation showed the efficacy of farmland buffer strips in providing natural enemy protection service, although the results could have been affected by the short monitoring time at the early stage of the development of buffer strip vegetation and disturbance to wildlife during construction. 4) The study further showed that future development of eco-agriculture should take into consideration integration of farmland buffer strips and other ecological conservational practices along with the related spatial planning and implementation at larger scales. The application of such approach needed adjustment to specific local conditions as the paper only discussed the implementation of farmland buffer strips under dryland farming in plain areas. The overall effectiveness of such approach needed a more thorough assessment with long-term monitoring of a variety of indicators that account for the status of soil, watershed, biodiversity and other landscape characteristics.