Special Issue "Renewable Agriculture"

Guest Editor
Dr. Stephen S. Jones
Director, Northwestern Research and Extension Center, Washington State University, Mount Vernon, Washington 98273, USA
E-Mail:

Dear Colleagues,

For centuries the perceived need for an immediate and dramatic increase in agricultural production has been a theme throughout the developed world. But only very recently, and with less urgency, has society recognized the need for the true sustainability of agricultural production. For long-term sustainability, agriculture must have the capacity for renewal.

Even the most basic forms of agriculture require an input of energy, this in essence is what defines the system as agricultural. Starting with human and animal labor, energy inputs have developed into an industrial system using fertilizers, water, seed, pest control, and other products often brought in from off the farm. While these products may increase production, for the most part they are non-renewable, require vast amounts of fuel to produce and transport, are costly, and may harm the native organisms and environment. Additionally, most seed in industrial agriculture is non-renewable due to legal and genetic mechanisms that make it problematic for farmers to save and replant what they have grown on their farms.

Is a renewable agriculture with a high level of productivity possible? What research is underway to test the robustness of current systems when measured against a standard of true long-term sustainability?

Stephen S. Jones, Ph. D.
Guest Editor

Submission Information

All papers should be submitted to sustainability@mdpi.com. To be published continuously until the deadline and papers will be listed together at the special issue website.

Submitted papers should not have been published nor be under consideration for publication elsewhere. All papers are refereed through a peer-review process. A guide for authors is available on the Instructions for Authors page. Sustainability is a new international, peer-reviewed, quarterly open access journal published by MDPI.

Article Processing Charges (APC) for publication in this open access journal are waived for well-prepared manuscripts submitted by 30 June 2010. English correction or formatting fees of 250 CHF (Swiss Francs) will be charged in certain cases for those paper accepted for publication, that require extensive additional formatting and/or English corrections.

• renewable agriculture
• sustainable food systems
• sutainability
• input
• off-farm
• low-input
• seed
• animal-integrated

Type of Paper: Review
Title: Can Soil Ecology help prevent Human Malnutrition?
Authors: Miranda M. Hart ¹ and Pedro M. Antunes²
Affiliations: ¹ Corresponding author: Integrative Biology, University of Guelph, Guelph ON, N1G 2W1 Canada. Email: mhart@uoguelph.ca
²Freie Universität Berlin, Institut für Biologie, Plant Ecology, Altensteinstr. 6. D- 14195 Berlin, Germany.
Abstract: Plant-based micronutrient delivery through the food chain has the potential to alleviate human malnutrition. Sustainable agricultural practices that enhance or manipulate soil biota promise to improve the nutritional status of crops without the use of biotech, supplements or fortification, which may be cost prohibitive or socially inacceptable in many areas of the world.
There is considerable evidence that soil microbes are essential for plant health, in particular arbuscular mycorrhizal fungi, plant growth promoting rhizobacteria and endophytic symbionts. These microbes are essential for taking up micro- and macronutrients, defense against pathogens and for altering the production of many plant secondary metabolites, many of which are important human nutrients.
Modern cropping practices, however, discourage the growth and health of natural soil microbial populations, and the efficacy of inocula is untested. Managing for improved microbial communities may be a local, low input means of boosting production and the nutrient value in crops without relying on biotechnology.
Currently, there is limited evidence that soil microbial activity translates into improved food nutritional value. Can plants take up enough nutrients in their tissues to create a significant improvement in human health? And can the management of soil microbes accentuate nutrient uptake and synthesis?
This is a timely review as it describes the earliest stages of a new discipline: soil microbe mediated food quality and human nutrition. This subject will be of interested to anyone interested in human malnutrition, and sustainable agriculture at a global scale. In this review, we will examine the latest literature linking soil microbes and nutritional value of food. We will also highlight what research is lacking before we can successfully manage soils to promote improved nutrition.

Type of Paper: Review
Title: Soil Microbes and Sustainable Agriculture
Authors: Ademir Sérgio Ferreira de Araújo*, Romero Francisco Vieira Carneiro, Elzane Freitas Leite Silva
Affiliation:Soil Quality Lab, University Federal of Piauí – Agriculture Science Center, 64000-000, Teresina, PI, Brazil.
* Author to whom correspondence should be addressed: E-mail: asfaruaj@yahoo.com.br
Abstract: Agricultural systems have to combine sustainability and increase in food, fiber and energy production. In this context, soil is an essential resource for sustain the plant and animal production and maintain the global balance of the ecosystem. Soil microbes are the key to sustainability because they are responsible for a variety of functions in the ecosystem as nutrient cycling and the degradation of pollutants. For example, nutrients mineralization and immobilization are mediated by soil microbes and linked closely to soil organic matter (SOM) content. Thus, the knowledge of soil microbes and soil microbial ecology is essential to enhance the best agriculture management for the optimum sustainability. This review describes the state of art about the role of soil microbes in sustainable agriculture.
Keywords: Soil microbial ecology, Agriculture systems, soil quality.

Type of Paper: Article
Title: Concentration of dissolved phosphate in water in relation to acid acetate extractable soil P and pH
Author: Into Saarela
Affiliation: MTT Agrifood Research, FI-31600 Jokioinen, Finland
Abstract: The chemical tests developed for estimating the supply of nutrients from the soil to plant roots are also used to predict the dissolution of phosphorus (P) from agricultural soils to runoff and drainage waters. Acid acetates are mild extraction agents of acid soils and primarily indicate the intensity factor of soil P status. The soil test P values (STP) obtained by the Finnish acid ammonium acetate method (P_Ac) could thus be reliable indicators of the equilibrium concentration of phosphate in soil solution (EPC) and consequently the dissolved reactive phosphate (DRP) in runoff water. For evaluating and calibrating the routine soil testing method as an indicator of potential P leaching, soil samples were obtained from all regions and soil types of Finland at 154 heavily enriched sites and their P_Ac values were compared to the EPC values measured in 0.005 M CaCl₂. A close curvilinear pH-dependent correlation was established between EPC and P_Ac in acid (pH_w < 6.7) mineral soils (n = 79, R² = 0.80-0.86). EPC increased with P_Ac the steeper the lower the pH was and was thus much lower in heavily limed soils than in acid soils at the same STP. In Histosols EPC was many times higher than in mineral soils but less closely dependent on P_Ac and pH. The EPC/P_Ac equations were well obeyed with the DRP/P_Ac ratio in the runoff water from some weakly acid leaching fields in southern Finland. If calibrated with soil pH, the P_Ac values appear to be reliable indicators of EPC in acid and even in neutral mineral soils. Additional studies and possibly a more sensitive method would be needed for reliable prediction of P leaching from Histosols.

Type of Paper: Article
Title: U.S. Demand for Organic and Conventional Fresh Fruits
Authors: Biing-Hwan Lin 1,*, Steven T. Yen 2 and Chung L. Huang 3
Affiliations: 1 Economic Research Service, U.S. Department of Agriculture, 1800 M Street NW, Rm N2110, Washington, DC, 20036-5831, USA
2 Dept. of Agricultural Economics, The University of Tennessee, 2621 Morgan Circle, Knoxville, TN 37996-4518, USA
3 Dept. of Agricultural & Applied Economics, 313-E Conner Hall, The University of Georgia, Athens, GA 30602-7509, USA
* Author to whom correspondence should be sent. E-mail: BLIN@ers.usda.gov
Abstract: Concerns over human health and environmental degradation may have motivated U.S. consumers to purchase organically grown foods. However, there exists a dearth of empirical analyses on the demand for organic foods and few studies have reported demand elasticities for organic foods. The objective of this study is to investigate the interrelationship between consumption of organic and conventional fruits using national retail purchase data. The study fills an important research void by estimating the much needed price elasticities for organic fruits as well as the cross-price elasticities between organic and conventional fruits. Aside from prices, income and several socio-demographic characteristics, such as region of residence, marital status and educational attainment, are found to be significant determinants of organic fruit consumption. Results show that consumers are quite responsive to price changes in organic fruits with own-price elasticities ranging from -1.06 for apples to -3.19 for bananas and -3.54 for grapes. In contrast, demand for conventional fruits is price inelastic with own-price elasticities varying from -0.49 for grapes to -0.83 for apples. Asymmetric cross-price effects are found between organic and conventional fruits, suggesting that a change in relative prices will more likely induce “cross-over” by consumers from conventional fruits to organic fruits, while the reverse is less likely, that is, organic fruit consumers will not likely revert to conventional fruits.
Keywords: National Organic Standards, Nielsen Homescan, organic fruit demand, price elasticities

Type of Paper: Article
Title: Alley Farming for Poverty Alleviation and Environmental Preservation in Thailand
Authors: Dr. Elizabeth Adebola Ogunlana¹, Prof. Athapol Noomhorm, Dr. Teerapol Silakul, ¹Address correspondence to: Dr. Elizabeth Adebola. Ogunlana, E-mail: elizabethadebola@yahoo.com
Abstract: Poverty alleviation and environmental preservation are very important issues to many governments. It has been observed that chemical fertilizers are destructive to the environment (UNEP, 1997). Many researchers focus on agricultural technologies that can increase agricultural production as well as preserve the environment. Alley farming conserves soil and sustains yields over time. It reduces soil erosion, which is a major problem in Thailand. Alley farming was conducted on the farmer’s field at Khaokwan thong village in Uthaithani province in Northern Thailand. We did a 2 by 2 factorial with and without alley farming and with and without fertilizer.
Keywords: Alley farming, poverty alleviation, environmental preservation, permanent field cultivation, sustainable agricultural technologies

Type of Paper: Article
Title: Conservative Land Management to Reduce Erosion and Improve Soil and Water Quality in the Mediterranean Agricultural Systems
Authors: Solange Ramazzotti, Michele Pisante and Fabio Stagnari *
Affiliation: Department of Food Science, University of Teramo, Via Carlo Lerici 1, 64023 Teramo, Italy
*Author to whom correspondence should be addressed; E-mail: fstagnari@unite.it
Abstract: Sustainable agriculture has become a crucial part of conceptual thinking in modern environmental science. Part of this area of scientific discussion surrounds the minimization of topsoil loss from agricultural land. Land under perennial crops grown in the Mediterranean region suffers a great soil losses. The objective of this work was to investigate the suitability of some agronomic practices for the conservation of soil and water quality and the minimization of soil erosion within Mediterranean orchards. The study area is well representative of the Mediterranean basin, where the climate is continental Mediterranean with an average annual precipitation around 700 mm concentrated in autumn and early spring. The main land use is dryland crops, mainly vineyard and olive orchards for perennial crops and cereal, sunflower and legumes for annual crops. The study was conducted in a vineyard at 170 a.s.l. on a typical slope of a hilly Adriatic belt with an average slope of 20 percent. The vineyard plots had an area of 155 m² (50 m by 3.1m). Two soil management methods were compared: conservation management and conventional tillage. A suitable trapping system was installed at the end of four vine rows. After each rainfall events the water and soil sediment, soil size and distribution of eroded particles, organic matter and mineral content were measured. Data collected in three-year study period demonstrated that with conservative land management there is considerable potential to lower rates of soil erosion and consequently to increase the potential for soil- water infiltration and to improve soil chemical and physical characteristics.

Type of Paper: Article
Title: Integrated Study of Energy Crops Management and Their Residues for Biofuels and Energy Production (Hi-Bred Fuels Greek Project)
Authors: A. Zabaniotou ^1,*, O. Ioannidou ¹, Z. Samaras ², G. Fontaras ², G. Zanakis ³, N. Mariolis ³, Th. Chadziavgoustis ⁴
Affiliations: ¹ Department of Chemical Engineering, Aristotle University of Thessaloniki, Un. Box. 455, 54124, University Campus, Thessaloniki, Greece
² Department of Mechanical Engineering, Aristotle University of Thessaloniki Un. Box. 458, P.C.541 24, University Campus, Thessaloniki
³ Pioneer Hi-Bred Hellas S.A., P.C.57001, Thermi, Thessaloniki, Greece
⁴Technological Educational Institution (TEI) of Western Macedonia, Greece
*Author to whom correspondence should be addressed; E-mail: sonia@cheng.auth.gr; Tel. +30 2310 996274; Fax: +30 2310 996209
Abstract: The present paper present results from a Greek project (Hi-Bred fuels) aimed at the integrated management of energy crops cultivated in Greece for biofuel production and their residue's energetic valorization. Oleiferous energy crops, some new for Greek agriculture and other indigenous (rapeseed, soya, sunflower and cotton) were cultivated under real farming conditions and assessed with regard to their liquid and solid biofuels production. Main target of the research activity was to assess energy crop's viability, economical feasibility and sustainability in order to meet the policy makers' requirements for increase of energy crops in the country's agricultural activities, promotion of biofuels production, enhancement of energy crops productivity, and sustainability. In addition, the use of the produced vegetable oils as fuel for internal combustion engines was also tasted and their emissions were estimated. First results concerning energy crops adaptability in Greek climate conditions and their products yields were quite promising with the exception of their water demands, which especially for rapeseed was not sustainable. Taking into consideration that there is already a fast developing, solid and liquid biofuels market the perspective of vegetable oil production from indigenous energy crops, as well as exploitation of their solid residues for energy, seems very attractive.
Keywords: Energy crops; biofuels; agricultural residues; bioenergy; sustainability

Type of Paper: Review
Title: Food Production History: The Way Back to Sustainable Numbers
Author: Peter Salonius; E-Mail: Peter.Salonius@NRCan-RNCan.gc.ca
Abstract: This article briefly outlines the history of food production before the advent of agriculture, and the movement away from sustainable hunter gathering. The non renewable exploitation of arable soil mass, by erosion, and soil nutrient capital by leaching are seen as the starting point of natural resource mining (culminating with fossil and nuclear energy use) that has driven the expansion of the global economy and the exponential increase of human numbers. A move toward the much lower population that may be sustained by the renewal processes of our supporting ecosystems is recommended. Methods and policies are proposed to achieve the necessary decrease in human numbers which may allow humanity to soften the harshest aspects of the natural resource scarcities associated with the insatiable demands of a species that has far overshot the carrying capacity of its environment.

Type of Paper: Article
Title: Overcoming the Barriers to Organic Adoption in the United States: A Look at Conventional Farmers in Texas
Authors: Douglas H. Constance and Jin Young Choi
Affiliation: Department of Sociology, Sam Houston State University, Huntsville, Texas, USA; E-mails: soc_dhc@shsu.edu; jyc002@shsu.edu
Abstract: Organics is the fastest growing segment of food sales. Though the amount of certified organic land is increasing rapidly, supply of organic foods still lags behind demand in the United States. The reasons for this gap involve a mixture of lack of government support for organics compared to other countries and the peculiarities of organics as the adoption of an innovation. In an attempt to close this gap, and thereby increase the environmental sustainability of U.S. agriculture, this paper has two objectives. The first is to document the structural and institutional constraints to organic adoption in the U.S. This is accomplished through a review of organic programs and policies in the U.S., in particular the National Organic Program. The second is to document conventional farmers perceived production and marketing barriers to the adoption of organic farming methods. This is accomplished through a review of the literature on barriers to organic adoption, and empirical research carried out in Texas. Focusing on conventional farmers in Texas who indicate an interest in organic production, the paper documents predictors of such interest and investigates the perceived barriers to the adoption of organic production methods. The paper concludes with some policy prescriptions to facilitate organic adoption.

Type of Paper: Article
Title: U.S. Demand for Organic and Conventional Fresh Fruits
Authors: Biing-Hwan Lin ¹, Steven T. Yen ², Chung L. Huang ³, and Travis A. Smith ^1,*
Affiliations: ¹ Economic Research Service, US Department of Agriculture, 1800 M Street NW Washington, DC 20036-5831, USA
² Department of Agricultural Economics, The University of Tennessee, 2621 Morgan Circle, Knoxville, TN 37996-4518, USA
³ Department of Agricultural and Applied Economics, 313-E Conner Hall, University of Georgia, Athens, GA 30602-7509, USA
* Author to whom correspondence should be addressed: E-Mail: tsmith@ers.usda.gov; Tel. +1 202-694-5104; Fax: +1 202-694-5688
Abstract: This study investigates the demand for organic and conventional fresh fruits using retail purchase data. The study fills an important research void by estimating the much needed income and price elasticities for organic and conventional fruits. Household income is found to affect organic fruit consumption. Consumers are more responsive to price of organic fruits than to price of conventional fruits. Cross-price effects suggest that a change in relative prices will more likely induce consumers to "cross-over" from buying conventional fruits to buying organic fruits, while it is less likely that organic consumers will revert to buying conventional fruits.
Keywords: National Organic Standards; Nielsen Homescan; organic fruit demand; price elasticities; censored demand system

Type of Paper: Article
Title: A Probabilistic Analysis of the Switchgrass Ethanol Cycle
Author: Tad W. Patzek
Affiliation: Department of Petroleum and Geosystems Engineering, The University of Texas at Austin, TX 78712, USA; E-mail: patzek@mail.utexas.edu; Tel. +512 232 8368
Abstract: The switchgrass process for producing ethanol has received much popular attention. However, a realistic analysis of this process indicates three serious limitations: (a) If switchgrass planted on 130 million hectares (the entire area of active US cropland) were used as feedstock and energy source for ethanol production, the net ethanol yield would replace on average about 18 % of today's gasoline consumption in the U.S; (b) Because nonrenewable resources are required to produce ethanol from switchgrass, the incremental gas emissions would be on average 55 million tons of equivalent carbon dioxide per year to replace 10 % of US automotive gasoline; (c) In terms of delivering electrical or mechanical power, ethanol from 1 hectare (10,000 m² of switchgrass is equivalent, on average, to 30 m² of low-efficiency photovoltaic cells. This analysis suggests that investing toward more efficient and durable solar cells, and batteries, may be more promising than investing in a process to convert switchgrass to ethanol.

Type of Paper: Article
Title: Short and Long-Term Sustainability of Meat Sheep Production in Relation to Mortality Rates of Ewes and Lambs
Authors: J. Cabaret ¹, Benoit M. ², Laignel G. ²
Affiliations: ¹ INRA, IASP 213, 37380 Nouzilly
² INRA, LEE, Theix 63122 Saint Genššs Champanelle
Abstract: Meat sheep production in most countries relies on grazing and profitability (gross margin per ewe) is low. Profitability is essentially founded on combining two basic criteria: concentrate food ingestion and the level of numeric productivity (no of lambs weaned per ewe and per year). Numeric productivity depends on fecundity and survival rates of ewes and lambs. These survival rates are extremely variable from one farm to another and from one year to another. These variations are detrimental to sustainability of the farms. We will study the mortality rates of ewes and lambs, taken as an indicator of diseases in meat sheep farms on several years (up to 15 years) and in different locations (up to 30 farms) in relation to gross margin taken as an indicator of economical sustainability.

Type of Paper: Review
Title: Mitigation or Adaptation: The Focus of Change for the Dairy Industry in a Changing Climate
Author: Julian Hill
Affiliation: Department of Agriculture and Food Systems, Land & Environment, University of Melbourne, Australia
Abstract: Various factors need to be considered in developing policies for low emission ruminant production systems based on mitigation (the reduction of C and N losses from a system by direct intervention) or adaptation (structural change within the industry) strategies. These policies have to be sensitive to changes in consumer and market forces insofar that change within an industry can have unintended consequences. This review will focus on two key issues - the management and control of C and N supply and demand within a system and the potential for intensive dairy systems to be a major method of sequestration in a changing environment.

Type of Paper: Review
Title: The Use of Reference Values in Indicator-Based Sustainability Assessments of Agricultural Systems
Authors: Ivonne Acosta-Alba ^1,2 and Hayo M.G. van der Werf ^1,2
Affiliations: ¹ INRA, UMR1069, Soil Agro and hydroSystem, 35000 Rennes, France
² Agrocampus Ouest, UMR1069, Soil Agro and hydroSystem, 35000 Rennes, France
Abstract: To assess the sustainability of an agricultural production system, its impacts on the environment must be quantified. Over the last decade many methods for the environmental evaluation of farming systems have been developed. Several reviews have shown that these methods have become increasingly complex, integrating a variety of impacts and the latest scientific knowledge. Indicators are essential features in all such methods; they are a favoured tool to understand complex systems, and their impacts on the environment. However, it is not the absolute values of the indicators that reveal whether the impacts of a system are acceptable, but rather the distance between these values and some kind of reference values. Thus, reference values help to interpret the indicator value and may guide the evolution of a system towards sustainability. This paper reviews a variety of recognised and widely used frameworks for the environmental assessment of agricultural systems that define explicit reference values for their indicators. We discuss the procedures used to establish reference values and explore how to improve these procedures to increase their use and relevance.