Understanding management effects on soil organic matter and ecological function in forage-based agroecosystems.

世界土壤在应对气候变化、养分污染和提供其他关键生态系统服务方面的潜在贡献正日益得到承认。众所周知，包括饲料和服务作物（牧草、干草、覆盖作物）在内的种植系统可以增加碳固存，并为土壤健康和养分循环提供许多好处。特别是，放牧的农业草地显示出通过增加地下生物量来固碳的巨大潜力；例如，一些研究表明，当采用轮牧（牲畜在围场中频繁轮换，并允许充分休息）时，以草饲为主的牛肉经营可能产生负温室气体净排放。为了更好地促进减缓气候变化，需要更好地了解放牧管理和牧场施肥如何影响土壤固碳。本提案的目标是确定饲料和服务作物提供的农业生态效益，并确定增加这些效益的管理做法。我将特别关注牛肉生产系统中的放牧管理，以及轮牧策略和氮肥力管理如何影响碳固存。我的研究将检查土壤有机质的质量，以便更好地了解它的生态功能（它有多稳定，等等）。我还将量化在轮作系统中纳入多年生牧草所提供的土壤健康效益，即降低后续作物的肥力建议的能力。这些研究问题将通过农场、受控环境和研究站研究的结合来完成。我的研究项目将提供数据，进一步科学地理解放牧生态系统中加强碳固存的机制，并为改善放牧土壤的土壤碳管理提出建议。这项研究预计将通过确定同时提高其生产力和生态影响（碳封存）的放牧管理策略来改善牛肉产业的环境结果。这一点很重要，因为牛肉行业经常被认为是温室气体的主要贡献者，但在放牧过程中对土壤碳封存的贡献通常没有被考虑在内。最后，由于使用以饲料为基础的种植系统，促进了土壤有机质和土壤健康，预计土壤质量的改善将对需要作为肥料施用的养分量产生影响。需要采取可能减少农业所需营养物，特别是磷含量的做法；这是当前跨部门的优先事项，对伊利湖流域的健康至关重要。

The world's soils, are increasingly being acknowledged for their potential contribution to the fight against climate change, nutrient pollution, and to provide other critical ecosystem services. Cropping systems that include forage and service crops (pasture, hay, cover crops) are known to increase carbon sequestration and provide numerous benefits to soil health and nutrient cycling. In particular, grazed agricultural grasslands show much potential for sequestering carbon by increasing belowground biomass; for example, some studies have indicated that net negative greenhouse gas emissions are possible for a predominantly grass-fed beef operation, when rotational grazing (where livestock are rotated frequently through paddocks, and allowing adequate rest periods) is employed. An improved understanding of how grazing management and pasture fertilization impact soil carbon sequestration is required in order to better contribute to climate change mitigation.   The objectives of this proposal are to determine the agro-ecological benefits provided by forage and service crops and to identify management practices that increase these benefits. In particular, I will focus on grazing management in beef production systems and how rotational grazing strategies and nitrogen fertility management can impact carbon sequestration. My research will examine the quality of the soil organic matter in order to better understand its ecological function (how stable it is, etc.). I will also quantify the soil health benefits provided by including perennial forage in a cropping system rotation in terms of the ability to lower fertility recommendations for a subsequent crop. These research questions will be accomplished through a combination of on-farm, controlled environment, and research station studies. My research program will provide data that will further scientific understanding on the mechanisms enhancing carbon sequestration in grazed ecosystems and make recommendations to enable improved soil carbon management in grazed soils. This research is expected to improve the environmental outcomes of the beef industry by identifying grazing management strategies that improve their productivity and ecological impacts (carbon sequestration) at the same time. This is important because the beef industry is frequently under scrutiny for being a major greenhouse gas contributor, but contributions to soil carbon sequestration during grazing are typically not considered. Finally, improvements in soil quality due to the use of forage-based cropping systems that promote soil organic matter and soil health are expected to have implications for the amount of nutrients that are needed to be applied as fertilizers. Practices that may reduce the amount of nutrients, particularly P, required in agriculture are needed; this is a current cross-sector priority, and critical for the health of the Lake Erie watershed.