Frontiers in alley cropping: Transformative solutions for temperate agriculture

Annual row crops dominate agriculture around the world and have considerable negative environmental impacts, including significant greenhouse gas emissions. Transformative land-use solutions are necessary to mitigate climate change and restore critical ecosystem services. Alley cropping (AC)-the integration of trees with crops-is an agroforestry practice that has been studied as a transformative, multifunctional land-use solution. In the temperate zone, AC has strong potential for climate change mitigation through direct emissions reductions and increases in land-use efficiency via overyielding compared to trees and crops grown separately. In addition, AC provides climate change adaptation potential and ecological benefits by buffering alley crops to weather extremes, diversifying income to hedge financial risk, increasing biodiversity, reducing soil erosion, and improving nutrient- and water-use efficiency. The scope of temperate AC research and application has been largely limited to simple systems that combine one timber tree species with an annual grain. We propose two frontiers in temperate AC that expand this scope and could transform its climate-related benefits: (i) diversification via woody polyculture and (ii) expanded use of tree crops for food and fodder. While AC is ready now for implementation on marginal lands, we discuss key considerations that could enhance the scalability of the two proposed frontiers and catalyze widespread adoption.

[1]  J. Fuhrer,et al.  Agroforestry solutions for buffering climate variability and adapting to change. , 2014 .

[2]  S. Lovell,et al.  Agroforestry—The Next Step in Sustainable and Resilient Agriculture , 2016 .

[3]  J. Klironomos,et al.  Arbuscular mycorrhizal fungi in tree-based intercropping systems: A review of their abundance and diversity , 2011 .

[4]  C. Messier,et al.  A general framework for the quantification and valuation of ecosystem services of tree-based intercropping systems , 2014, Agroforestry Systems.

[5]  P. Burgess,et al.  Do European agroforestry systems enhance biodiversity and ecosystem services? A meta-analysis , 2016 .

[6]  J. R. Smith,et al.  Tree Crops: A Permanent Agriculture , 1978 .

[7]  M. Ha-Duong,et al.  Climate change 2014 - Mitigation of climate change , 2015 .

[8]  B. Babcock,et al.  Subfield profitability analysis reveals an economic case for cropland diversification , 2016 .

[9]  G. Michon.  Research, part of a Special Feature on Public policies and management of rural forests: lasting alliance or fool's dialogue? Revisiting the Resilience of Chestnut Forests in Corsica: from Social- Ecological Systems Theory to Political Ecology , 2011 .

[10]  K. F. Wiersum,et al.  Diversity, composition and density of trees and shrubs in agroforestry homegardens in Southern Ethiopia , 2013, Agroforestry Systems.

[11]  S. Jose,et al.  Interspecific interactions in temperate agroforestry , 2004, Agroforestry Systems.

[12]  Pradeep Kumar Nair,et al.  Safety-net role of tree roots: evidence from a pecan (Carya illinoensis K. Koch)-cotton (Gossypium hirsutum L.) alley cropping system in the southern United States , 2004 .

[13]  M. Loreau,et al.  Tropical tree diversity enhances light capture through crown plasticity and spatial and temporal niche differences , 2014 .

[14]  P. Reich,et al.  Diversity and Productivity in a Long-Term Grassland Experiment , 2001, Science.

[15]  J. Whalen,et al.  Carbon Sequestration and Carbon Markets for Tree-Based Intercropping Systems in Southern Quebec, Canada , 2016 .

[16]  F. Cubbage,et al.  A real options model to assess the role of flexibility in forestry and agroforestry adoption and disadoption in the Lower Mississippi Alluvial Valley , 2013 .

[17]  C. Collet,et al.  Response of tree growth and species coexistence to density and species evenness in a young forest plantation with two competing species. , 2014, Annals of botany.

[18]  Agroforestry promotes soybean yield stability and N2-fixation under water stress , 2015, Agronomy for Sustainable Development.

[19]  S. Lovell,et al.  Temperate agroforestry research: considering multifunctional woody polycultures and the design of long-term field trials , 2017, Agroforestry Systems.

[20]  T. Molnar,et al.  Advances in hazelnut research in North America , 2012 .

[21]  M. K. Jones.  Structure and diversity of cestode epithelia. , 1998, International journal for parasitology.

[22]  R. Farrell,et al.  Soil-atmosphere exchange of carbon dioxide, methane and nitrous oxide in shelterbelts compared with adjacent cropped fields. , 2016 .

[23]  Richard N. Williams,et al.  Belowground ecological interactions in mixed-species forest plantations , 2006 .

[24]  Growth and development of ‘Illini Hardy’ blackberry (Rubus subgenus Eubatus Focke) under shaded systems , 2015, Agroforestry Systems.

[25]  S. Carpenter,et al.  Solutions for a cultivated planet , 2011, Nature.

[26]  G. Campbell,et al.  Design and development of agroforestry systems for Illinois, USA: silvicultural and economic considerations , 1991, Agroforestry Systems.

[27]  Xianzeng Niu,et al.  Carbon sequestration potential by afforestation of marginal agricultural land in the Midwestern U.S. , 2006 .

[28]  D. Tilman,et al.  Global environmental impacts of agricultural expansion: the need for sustainable and efficient practices. , 1999, Proceedings of the National Academy of Sciences of the United States of America.

[29]  Edward Jones,et al.  A survey of image processing techniques for plant extraction and segmentation in the field , 2016, Comput. Electron. Agric..

[30]  E. Schulze,et al.  More efficient aboveground nitrogen use in more diverse Central European forest canopies , 2014 .

[31]  S. Jose,et al.  Agroforestry strategies to sequester carbon in temperate North America , 2012, Agroforestry Systems.

[32]  R. Leakey.  The role of trees in agroecology and sustainable agriculture in the tropics. , 2014, Annual review of phytopathology.

[33]  E. Schulze,et al.  Forest Diversity and Function , 2005 .

[34]  Ivette Perfecto,et al.  Conservation of biodiversity in coffee agroecosystems: a tri-taxa comparison in southern Mexico , 2003, Biodiversity & Conservation.

[35]  J. Hanspach,et al.  Reframing the Food-Biodiversity Challenge. , 2017, Trends in ecology & evolution.

[36]  Scott M. Swinton,et al.  Reconciling agricultural productivity and environmental integrity: A grand challenge for agriculture , 2005 .

[37]  K. Cassman,et al.  Limited potential of no-till agriculture for climate change mitigation , 2014 .

[38]  Brenda B. Lin,et al.  Agroforestry management as an adaptive strategy against potential microclimate extremes in coffee agriculture , 2007 .

[39]  M. Kopjar,et al.  Influence of buckwheat and chestnut flour addition on properties of corn extrudates , 2012 .

[40]  S. Gardiner,et al.  Breeding better cultivars, faster: applications of new technologies for the rapid deployment of superior horticultural tree crops , 2014, Horticulture Research.

[41]  Wes Jackson,et al.  Natural systems agriculture: a truly radical alternative , 2002 .

[42]  F. Herzog.  Streuobst: a traditional agroforestry system as a model for agroforestry development in temperate Europe , 1998, Agroforestry Systems.

[43]  A. Sorooshian,et al.  Frequency and Character of Extreme Aerosol Events in the Southwestern United States: A Case Study Analysis in Arizona , 2015, Atmosphere.

[44]  D. W. Reeves,et al.  USING WINTER COVER CROPS TO IMPROVE SOIL AND WATER QUALITY , 2001 .

[45]  W. B. Morris,et al.  Integrating agroecology and landscape multifunctionality in Vermont: An evolving framework to evaluate the design of agroecosystems , 2010 .

[46]  J. Six,et al.  Productivity limits and potentials of the principles of conservation agriculture , 2014, Nature.

[47]  C. Böhm,et al.  Ecological benefits provided by alley cropping systems for production of woody biomass in the temperate region: a review , 2012, Agroforestry Systems.

[48]  R. Standish,et al.  Benefits of tree mixes in carbon plantings , 2013 .

[49]  M. Delonge,et al.  Investing in the transition to sustainable agriculture , 2016 .

[50]  C. Black,et al.  Trees improve water storage and reduce soil evaporation in agroforestry systems on bench terraces in SW Uganda , 2012, Agroforestry Systems.

[51]  J. Baudry,et al.  Hedgerows: An international perspective on their origin, function and management , 2000 .

[52]  F. Cubbage,et al.  Early tree growth, crop yields and estimated returns for an agroforestry trial in Goldsboro, North Carolina , 2012, Agroforestry Systems.

[53]  Richard K. Johnson,et al.  Revealing the Organization of Complex Adaptive Systems through Multivariate Time Series Modeling , 2011 .

[54]  C. Böhm,et al.  Wind speed reductions as influenced by woody hedgerows grown for biomass in short rotation alley cropping systems in Germany , 2014, Agroforestry Systems.

[55]  Shibu Jose,et al.  Agroforestry for ecosystem services and environmental benefits: an overview , 2009, Agroforestry Systems.

[56]  Dubravko Justic,et al.  Reducing hypoxia in the Gulf of Mexico: Advice from three models , 2004 .

[57]  M. Hanna,et al.  Nutritional and anti-nutritional compositions of defatted Nebraska hybrid hazelnut meal , 2011 .

[58]  Edward C. Lefroy.  Agroforestry and the functional mimicry of natural ecosystems , 2009 .

[59]  P. Miller,et al.  Nitrous oxide emissions from a Northern Great Plains soil as influenced by nitrogen management and cropping systems. , 2008, Journal of environmental quality.

[60]  Lynne M. Westphal,et al.  How to build multifunctional agricultural landscapes in the U.S. Corn Belt: Add perennials and partnerships , 2010 .

[61]  H. E. Garrett,et al.  Agroforestry practices, runoff, and nutrient loss: a paired watershed comparison. , 2002, Journal of environmental quality.

[62]  Philip M. Dixon,et al.  Diverse perennial crop mixtures sustain higher productivity over time based on ecological complementarity , 2011, Renewable Agriculture and Food Systems.

[63]  S. Anderson,et al.  Variations in soil aggregate stability and enzyme activities in a temperate agroforestry practice , 2008 .

[64]  P. Reich,et al.  Forest productivity increases with evenness, species richness and trait variation: a global meta‐analysis , 2012 .

[65]  W. T. Stamps,et al.  The ecology and economics of insect pest management in nut tree alley cropping systems in the Midwestern United States , 2009 .

[66]  Owen L. Petchey,et al.  Biodiversity and Resilience of Ecosystem Functions. , 2015, Trends in ecology & evolution.

[67]  Gary Bentrup,et al.  Branching out: Agroforestry as a climate change mitigation and adaptation tool for agriculture , 2012, Journal of Soil and Water Conservation.

[68]  G. Robertson,et al.  Greenhouse gases in intensive agriculture: contributions of individual gases to the radiative forcing of the atmosphere , 2000, Science.

[69]  K. Ma,et al.  Mixed afforestation of young subtropical trees promotes nitrogen acquisition and retention , 2014 .

[70]  Marc Hanewinkel,et al.  Assessing natural hazards in forestry for risk management: a review , 2011, European Journal of Forest Research.

[71]  P. Tittonell.  Ecological intensification of agriculture — sustainable by nature , 2014 .

[72]  A. Gordon,et al.  Ecology of tree intercropping systems in the North temperate region: Experiences from southern Ontario, Canada , 2004, Agroforestry Systems.

[73]  A. Prasad,et al.  Estimating potential habitat for 134 eastern US tree species under six climate scenarios , 2008 .

[74]  R. Naiman,et al.  Freshwater biodiversity: importance, threats, status and conservation challenges , 2006, Biological reviews of the Cambridge Philosophical Society.

[75]  F. Herzog,et al.  Target regions for silvoarable agroforestry in Europe , 2007 .

[76]  D. J. Pilbeam,et al.  Silvoarable Systems in Europe – Past, Present and Future Prospects , 2006, Agroforestry Systems.

[77]  H. Margolis,et al.  Ectomycorrhizal mediation of competition between coniferous tree species. , 1989, The New phytologist.

[78]  Daniel Piotto,et al.  A meta-analysis comparing tree growth in monocultures and mixed plantations , 2008 .

[79]  R. Claassen,et al.  Conservation-Practice Adoption Rates Vary Widely by Crop and Region , 2015 .

[80]  A. Gordon,et al.  Avian diversity in a temperate tree-based intercropping system from inception to now , 2016, Agroforestry Systems.

[81]  M. Kirschbaum,et al.  Carbon sequestration and net emissions of CH4 and N2O under agroforestry: Synthesizing available data and suggestions for future studies , 2016 .

[82]  J. Colletti,et al.  Riparian forest buffers in agroecosystems – lessons learned from the Bear Creek Watershed, central Iowa, USA , 2004, Agroforestry Systems.

[83]  Sarah Taylor Lovell,et al.  Identifying barriers and motivators for adoption of multifunctional perennial cropping systems by landowners in the Upper Sangamon River Watershed, Illinois , 2016, Agroforestry Systems.

[84]  É. Malézieux,et al.  Mixing plant species in cropping systems: concepts, tools and models. A review , 2011, Agronomy for Sustainable Development.

[85]  Paul J. Burgess,et al.  Development and application of bio-economic modelling to compare silvoarable, arable and forestry systems in three European countries , 2007 .

[86]  L. Verchot,et al.  Climate change: linking adaptation and mitigation through agroforestry , 2007 .

[87]  Martin S. Wolfe,et al.  Reconciling productivity with protection of the environment: Is temperate agroforestry the answer? , 2012, Renewable Agriculture and Food Systems.

[88]  H. Pretzsch,et al.  Resistance of European tree species to drought stress in mixed versus pure forests: evidence of stress release by inter-specific facilitation. , 2013, Plant biology.

[89]  R. Aparicio,et al.  A comprehensive study of hazelnut oil composition with comparisons to other vegetable oils, particularly olive oil. , 2003 .

[90]  D. Freese,et al.  Carbon Sequestration in European Agroforestry Systems , 2011 .

[91]  M. Ittersum,et al.  The crop yield gap between organic and conventional agriculture , 2012 .

[92]  John Vandermeer,et al.  The Ecology of Intercropping by John H. Vandermeer , 1989 .

[93]  Yael Edan,et al.  Harvesting Robots for High‐value Crops: State‐of‐the‐art Review and Challenges Ahead , 2014, J. Field Robotics.

[94]  T. Molnar,et al.  Tree Crops, a Permanent Agriculture: Concepts from the Past for a Sustainable Future , 2013 .

[95]  N. Malignier,et al.  Extent and Success of Current Policy Measures to Promote Agroforestry across Europe , 2016 .

[96]  M. Gold,et al.  Agroforestry systems for the temperate zone , 1987, Agroforestry Systems.

[97]  Katherine N. Suding,et al.  Plant–soil feedbacks: the past, the present and future challenges , 2013 .

[98]  M. Katoh,et al.  Structure and diversity of homegarden agroforestry in Thakurgaon District, Bangladesh. , 2010 .

[99]  S. Carpenter,et al.  Global Consequences of Land Use , 2005, Science.

[100]  D. Mulla.  Twenty five years of remote sensing in precision agriculture: Key advances and remaining knowledge gaps , 2013 .

[101]  P. Woodbury,et al.  Reporting on Marginal Lands for Bioenergy Feedstock Production: a Modest Proposal , 2014, BioEnergy Research.

[102]  Evan H. DeLucia,et al.  Alley cropping: Global patterns of species composition and function , 2018 .

[103]  H. E. Garrett,et al.  Arthropod diversity in alley cropped black walnut (Juglans nigra L.) stands in eastern Missouri, USA , 2002, Agroforestry Systems.

[104]  E. Somarriba,et al.  Interdisciplinary analysis of homegardens in Nicaragua: micro- zonation, plant use and socioeconomic importance , 2004, Agroforestry Systems.

[105]  Christian Wirth,et al.  Is forest diversity driving ecosystem function and service , 2010 .

[106]  B. Djordjevic,et al.  Biological and nutritional properties of blackcurrant berries (Ribes nigrum L.) under conditions of shading nets. , 2015, Journal of the science of food and agriculture.

[107]  D. Nandwani,et al.  Global Trends in Organic Agriculture , 2016 .

[108]  A. Häger.  The effects of management and plant diversity on carbon storage in coffee agroforestry systems in Costa Rica , 2012, Agroforestry Systems.

[109]  M. Williams,et al.  Changes in field workability and drought risk from projected climate change drive spatially variable risks in Illinois cropping systems , 2017, PloS one.

[110]  É. Malézieux.  Designing cropping systems from nature , 2011, Agronomy for Sustainable Development.

[111]  Mizanur Rahman,et al.  Effect of Tree Diversity on Soil Organic Carbon Content in the Homegarden Agroforestry System of North-Eastern Bangladesh , 2015, Small-scale Forestry.

[112]  James C. Fortson,et al.  Optimum plantation planting density and rotation age based on financial risk and return , 1991 .

[113]  M. R. Mosquera-Losada,et al.  Past, Present and Future of Agroforestry Systems in Europe , 2012 .

[114]  S. Jose,et al.  Interspecific competition in a pecan–cotton alleycropping system in the southern United States: Production physiology , 2006 .

[115]  A. Roache,et al.  Effects of windbreak structure on shelter characteristics , 2007 .

[116]  J. Vanclay.  Experiment designs to evaluate inter- and intra-specific interactions in mixed plantings of forest trees , 2006 .

[117]  Q. Zhang,et al.  Sensors and systems for fruit detection and localization: A review , 2015, Comput. Electron. Agric..

[118]  T. Searchinger,et al.  Cover crops in the upper midwestern United States: Potential adoption and reduction of nitrate leaching in the Mississippi River Basin , 2014, Journal of Soil and Water Conservation.

[119]  Yann Clough,et al.  Multifunctional shade‐tree management in tropical agroforestry landscapes – a review , 2011 .

[120]  Rattan Lal,et al.  Evolution of the plow over 10,000 years and the rationale for no-till farming , 2007 .

[121]  S. Mehlenbacher.  PROGRESS AND PROSPECTS IN NUT BREEDING , 2003 .

[122]  K. Thorp,et al.  Cover crops in the upper midwestern United States: Simulated effect on nitrate leaching with artificial drainage , 2014, Journal of Soil and Water Conservation.

[123]  Keith Douglass Warner,et al.  Enhancing the Multifunctionality of US Agriculture , 2010 .

[124]  H. E. Garrett,et al.  Soil water content and infiltration in agroforestry buffer strips , 2008, Agroforestry Systems.