Concerns about sustainability in agricultural systems centre on the need to develop technologies and practices that do not have adverse effects on environmental goods and services, are accessible to and effective for farmers, and lead to improvements in food productivity. Despite great progress in agricultural productivity in the past half-century, with crop and livestock productivity strongly driven by increased use of fertilizers, irrigation water, agricultural machinery, pesticides and land, it would be over-optimistic to assume that these relationships will remain linear in the future. New approaches are needed that will integrate biological and ecological processes into food production, minimize the use of those non-renewable inputs that cause harm to the environment or to the health of farmers and consumers, make productive use of the knowledge and skills of farmers, so substituting human capital for costly external inputs, and make productive use of people's collective capacities to work together to solve common agricultural and natural resource problems, such as for pest, watershed, irrigation, forest and credit management. These principles help to build important capital assets for agricultural systems: natural; social; human; physical; and financial capital. Improving natural capital is a central aim, and dividends can come from making the best use of the genotypes of crops and animals and the ecological conditions under which they are grown or raised. Agricultural sustainability suggests a focus on both genotype improvements through the full range of modern biological approaches and improved understanding of the benefits of ecological and agronomic management, manipulation and redesign. The ecological management of agroecosystems that addresses energy flows, nutrient cycling, population-regulating mechanisms and system resilience can lead to the redesign of agriculture at a landscape scale. Sustainable agriculture outcomes can be positive for food productivity, reduced pesticide use and carbon balances. Significant challenges, however, remain to develop national and international policies to support the wider emergence of more sustainable forms of agricultural production across both industrialized and developing countries.

/pdf/agricultural-sustainability-concepts-principles-and-evidence-1a7o9ckp26.pdf

Agricultural sustainability: concepts, principles and evidence

Erosion rates and annual soil loss tolerance (T) values in evaluations of soil management practices have served as focal points for soil quality (SQ) research and assessment programs for decades. Our objective is to enhance and extend current soil assessment efforts by presenting a framework for assessing the impact of soil management practices on soil function. The tool consists of three steps: indicator selection, indicator interpretation, and integration into an index. The tool's framework design allows researchers to continually update and refine the interpretations for many soils, climates, and land use practices. The tool was demonstrated using data from case studies in Georgia, Iowa, California, and the Pacific Northwest (WA, ID, OR). Using an expert system of decision rules as an indicator selection step successfully identified indicators for the minimum data set (MDS) in the case study data sets. In the indicator interpretation step, observed indicator data were transformed into unitless scores based on site-specific algorithmic relationships to soil function. The scored data resulted in scientifically defensible and statistically different treatment means in the four case studies. The efficacy of the indicator interpretation step was evaluated with stepwise regressions using scored and observed indicators as independent variables and endpoint data as iterative dependent variables. Scored indicators usually had coefficients of determination (R2) that were similar or greater than those of the observed indicator values. In some cases, the R2 values for indicators and endpoint regressions were higher when examined for individual treatments rather than the entire data set. This study demonstrates significant progress toward development of a SQ assessment framework for adaptive soil resource management or monitoring that is transferable to a variety of climates, soil types, and soil management systems.

https://pubag.nal.usda.gov/pubag/downloadPDF.xhtml?id=9094&content=PDF

The Soil Management Assessment Framework

/pdf/a-comparison-of-soil-quality-indexing-methods-for-vegetable-2zhgmj82t1.pdf

A comparison of soil quality indexing methods for vegetable production systems in Northern California

Does organic farming reduce environmental impacts?--a meta-analysis of European research.

Organic agriculture refers to a farming system that enhance soil fertility through maximizing the efficient use of local resources, while foregoing the use of agrochemicals, the use of Genetic Modified Organisms (GMO), as well as that of many synthetic compounds used as food additives. Organic agriculture relies on a number of farming practices based on ecological cycles, and aims at minimizing the environmental impact of the food industry, preserving the long term sustainability of soil and reducing to a minimum the use of non renewable resources. This paper carries out a comparative review of the environmental performances of organic agriculture versus conventional farming, and also discusses the difficulties inherent in this comparison process. The paper first provides an historical background on organic agriculture and briefly reports on some key socioeconomic issues concerning organic farming. It then focuses on how agricultural practices affect soil characteristics: under organic management soil los...

Environmental Impact of Different Agricultural Management Practices: Conventional vs. Organic Agriculture

Chemical and biological indicators of soil quality in organic and conventional farming systems in Central Italy

The high-value, large-scale crop production systems in the San Joaquin Valley (SJV) of California typically entail intensive tillage and large fertilizer and water inputs but few C additions to the soil Such practices often contribute to a decline in soil quality Our objective for this participatory study was to examine the effects of supplemental C management practices (SCMPs) on various soil quality indicators To increase farmer participation, we conducted the study on farms using a variety of SCMPs, including cover crops, compost and manure amendments, and several different crop rotations common to the region The SCMPs significantly changed a number of soil properties, including soil organic matter (SOM); total Kjeldahl N; microbial biomass C and N; exchangeable K; Olsen P; and extractable Fe, Mn, and Zn A comparison including previously established, adjacent organic, conventional, and transitional fields in addition to the treatment fields at one farm revealed significant differences in 16 of 18 soil quality indicators A soil quality index computed for this farm scored the established organic system significantly higher than the conventional system Our results suggest that significant changes in several soil quality indicators occur with a variety of SCMPs This is especially noteworthy considering the intensive tillage, irrigation, and hot, semiarid environment of the SJV, California, where increases in SOM and related soil properties are generally not expected in a 3-yr study

On-Farm Assessment of Soil Quality in California's Central Valley

Soil biochemical indicators as a tool to assess the short-term impact of agricultural management on changes in organic C in a Mediterranean environment

Roberto Mancinelli

Papers

Chemical and biological indicators of soil quality in organic and conventional farming systems in Central Italy

On-Farm Assessment of Soil Quality in California's Central Valley

Soil biochemical indicators as a tool to assess the short-term impact of agricultural management on changes in organic C in a Mediterranean environment

Effect of cover crops and mulches on weed control and nitrogen fertilization in tomato (Lycopersicon esculentum Mill.).

Soil carbon dioxide emission and carbon content as affected by conventional and organic cropping systems in Mediterranean environment