Agroecological impact of farming systems

农业通过对水资源的影响、生境的丧失、气候变化和污染，是环境退化的主要原因。作为回应，主要农业产业和国际组织（粮农组织、环境署）正在促进农业系统的生态重新设计。例如，在加拿大，维持本地传粉者群落和授粉是关键农业部门持续成功的一个日益令人关切的问题。由于我们面临着迫在眉睫的全球磷（P）短缺，减少养分使用和提高养分利用效率也至关重要。总体研究目标是提高我们对农业生态影响的理解，对比耕作制度，或不同的管理强度的系统，并与生产力的权衡。我们最近的研究表明，豆类，有机种植系统的重要组成部分，似乎促进土壤真菌（真菌），提高植物磷的利用效率，但所涉及的机制知之甚少。此外，大型土壤生物（甲虫、蚯蚓）的丰度和多样性似乎对有机耕作系统植物多样性的增强特别敏感。减少对绿色肥料的耕作可能会进一步增强这些益处，包括对菌根的益处，但尚未得到研究。最后，作物的营养复杂性，边缘和景观，字段大小，和农场管理系统对本地传粉者的丰度和多样性的影响在北美很大程度上是未经审查的。具体研究目标包括：（i）作物生产力和土壤养分耕作制度对氮磷动态的影响（有机和常规）、轮作、更多地使用豆类和新技术，如减少绿色肥料的耕作管理（ii）土壤微生物的丰度、多样性和活性（细菌和真菌）的影响，耕作制度，豆类和减少耕作管理的绿色肥料（iii）任何变化的土壤微生物种群的关系，养分动态和效率的作物利用磷，及（iv）在加拿大东部和西部的有机和传统谷物农场，农业系统，植物（花卉资源）的复杂性，字段大小和农场栖息地，加上周围的景观复杂性，对本地传粉者（野蜂）的丰富性和多样性的影响。 拟议的是一个多规模（小地块，成对的商业农场）研究计划，该计划将应用新技术，并以跨学科合作为特色。该研究将阐述低投入和有机种植系统的养分动态和N、P效率，与耕作制度相对于耕作实践和管理强度相关的地上和地下农业生态影响，以及可能与提高所需生态属性相关的生产力的内在权衡。

Agriculture is a chief cause of environmental degradation through its impact on water resources, loss of habitat, climate change, and pollution. In response major agricultural industries and international organizations (FAO, UNEP), are promoting ecological redesigns for agricultural systems. In Canada, for example, maintaining native pollinator communities and pollination is a growing concern for the continued success of key agricultural sectors. As we face looming global shortages of phosphorus (P), reducing nutrient use and improving nutrient use efficiency is also critical. The overall research objectives are to improve our understanding of the agro-ecological impacts of contrasting farming systems, or systems varying in management intensity, and tradeoffs with productivity. Our recent research showed legumes, an essential component of organic cropping systems, appear to promote soil fungi (mycorrhizae) that enhance plant P use efficiency but the mechanisms involved are poorly understood. Also, the abundance and diversity of larger soil organisms (beetles, earthworms) appear especially sensitive to the enhanced vegetative diversity of organic farming systems. Reduced tillage for green manures may further enhance these benefits including for mycorrhizae but remains unexamined. Finally, the impact of vegetative complexity of crop, margins and landscape, field size, and farm management system on native pollinator abundance and diversity is largely unexamined in North America. Specific research objectives include examination of: (i) crop productivity and soil nutrient (nitrogen and phosphorus) dynamics as effected by farming system (organic and conventional), crop rotation, greater use of legumes, and novel techniques such as reduced tillage management of green manures (ii) the abundance, diversity and activity of soil microbes (bacteria and fungi) as effected by farming system, legumes and reduced tillage management of green manures (iii) the relationship of any shifts in soil microbe populations to nutrient dynamics and the efficiency of crop use of phosphorus, and (iv) on organic and conventional grain farms in eastern and western Canada, the impact of farming system, vegetative (floral resources) complexity, field size and on-farm habitat, plus surrounding landscape complexity, on native pollinator (wild bee) abundance and diversity.  Proposed is a multi-scale (small plot, paired commercial farms) research program, which will apply novel techniques and feature interdisciplinary collaborations. The research will elaborate nutrient dynamics and N and P efficiency of low input and organic cropping systems, the above and belowground agro-ecological impacts associated with farming system versus farm practice and intensity of management, and the inherent tradeoffs with productivity that may be associated with enhancing desired ecological attributes.