农业系统中生物多样性利用的研究现状与未来思考

"现代农业"生产力高,但生物多样性简单化、生物之间的相互作用及其生态学效应常常被忽略,其生产力的稳定性主要依赖于化学肥料、农药、灌溉和高产品种等的投入。传统农业则是利用当地生物多样性(物种多样性和遗传多样性)和生物之间的相互作用来产出食物和维持系统的稳定。因而现代农业能否借鉴传统农业对生物多样性利用的经验,将工业化模式的现代农业转换为生物多样性利用与现代技术相结合的农业受到关注。本文分析了农业系统中生物多样性的特点及农业方式对农业生物多样性的影响;综述了农业系统中生物多样性利用模式与效应方面的研究进展;讨论了在现代农业系统中,利用生物多样性需要开展的研究,即区域上如何布局农业景观多样性,农田内如何根据生物之间的互惠关系配置物种多样性的种养体系,如何建设与生物多样性利用相应的田间设施和发展新型的农业机械、并建立以信息化为基础的管理体系。

Utilization of biodiversity in agriculture: today and tomorrow

Currently, world agriculture was faced with drastic challenges to produce sufficient food while minimizing negative environmental effects of crop cultivation. Unlike traditional agriculture, which used local biodiversity and species interactions to sustain food production, modern agriculture used fewer high-yield crop varieties and largely ignored species interactions. Modern agriculture relied on chemically-driven modern varieties and irrigation to ensure high production. At the same time, modern high production induced negative environmental effects, pest resistance to pesticides and high agro-production costs. Whether and how biodiversity integrated into modern agriculture was a recent trend of research. Here, we reviewed the researches on the utilization of biodiversity in agriculture in the last decades. We then proposed future researches on intensified development of sustainable global agriculture with integrated biotechnology, precision agro-technology and biodiversity utilization. Unlike natural ecosystems, agro-ecosystem species consisted of productive biota (e.g., crops, forest trees and animals), resource biota (e.g., pollinating insects and crop-related wild species) and destructive biota (e.g., weeds and insect pests). Productive biota cultured by farmers dominated agro-systems and contributed to food production. Thus designing productive biota diversity was critical for biodiversity utilization of agro-systems. Utilization of productive biota diversity in agriculture included applications of genetic, species and landscape diversity. Studies indicated that uses of multi-gene varieties and mixtures of varieties were the key approaches to genetic diversity. This effectively controlled diseases in coffee, barley, wheat and rice crops. Genetic diversity mechanisms controlled diseases via resistant plant pathogen dilution or physical isolation. For species diversity utilization, intercropping and co-culture of crops and animals were the two common approaches. Legume-cereal intercropping and rice-fish co-cultures were the two successful examples of species diversity use in agro-systems. Species intercrops or co-cultures reduced the applications of chemical fertilizers and pesticides and promoted super-harvests. Positive species interactions and complementary resource uses explained why intercrops and co-cultures promoted super-harvests. For example, super-harvests often occurred in legume-cereal intercrops mainly as a result of facilitative root interactions, including nitrogen transfers and nutrient mobilizations. In rice-fish systems, fish reduced rice pests whereas rice moderated fish water environment which in turn enhanced pest removal. This positive relationship between rice and fish resulted in reduced pesticide use. Experiments also indicated that complementary use of nitrogen (N) in rice-fish systems resulted in low N fertilizer use and low N release into the environment. Within agricultural areas, diverse croplands in mosaic patterns maintained natural habitats (e.g., small grassland) and field margins helped develop diverse agro-landscapes. Studies showed agro-landscape diversity potentially provided shelter and alternative foods for resource biota in agro-systems. Although biodiversity utilization in agriculture was successful in many traditional agro-systems, studies on successful integration of biodiversity into modern agriculture were rare. For example, studies were needed in landscape diversity designs for large-scale agriculture. Positive species interactions and complementary resource uses also needed consideration in the development of modern agriculture such as intercrop or species co-culture systems. Field facility for diverse species co-existence needed sufficient construction. New machinery suitable for intercrop or species co-culture systems needed development as well. Information-based precision agro-technology suitable for intercrop or species co-culture systems likewise needed development.