节约与增长：木薯-可持续生产集约化指南.pdf

SAVE AND GROW:CASSAVAFAOTis guide is the frst on the practical application of FAOs“Save and Grow”model of agriculture to specifc smallholder crops and farming systems.It comes as cassava production intensifes worldwide,and growers shift from traditional cultivation practices to monocropping,higher-yielding genotypes,and greater use of agrochemicals.Intensifcation carries great risks,including soil nutrient depletion and upsurges in pests and diseases.Te guide shows how ecosystem-based“Save and Grow”approaches and practices can help tropical developing countries to avoid the risks of unsustainable intensifcation,while realizing cassavas potential for producing higher yields,alleviating hunger and rural poverty,and contributing to national economic development.SAVE AND GROWA GUIDE TO SUSTAINABLE PRODUCTION INTENSIFICATIONCMYCMMYCYCMYKcopertina cassava save and grow.pdf 1 25aprile2013 12.00Save and Grow:CassavaA guide to sustainable production intensificationFOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONSRome,2013The designations employed and the presentation of material in this information product do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations(FAO)concerning the legal or development status of any country,territory,city or area or of its authorities,or concerning the delimitation of its frontiers or boundaries.The mention of specific companies or products of manufacturers,whether or not these have been patented,does not imply that these have been endorsed or recommended by FAO in preference to others of a similar nature that are not mentioned.ISBN 978-92-5-107641-5(print)E-ISBN 978-92-5-107642-2(PDF)FAO 2013FAO encourages the use,reproduction and dissemination of material in this information product.Except where otherwise indicated,material may be copied,downloaded and printed for private study,research and teaching purposes,or for use in non-commercial products or services,provided that appropriate acknowledgement of FAO as the source and copyright holder is given and that FAOs endorsement of users views,products or services is not implied in any way.All requests for translation and adaptation rights,and for resale and other commercial use rights should be made via www.fao.org/contact-us/licencerequest or addressed to copyrightfao.org.FAO information products are available on the FAO website(www.fao.org/publications)and can be purchased through publications-salesfao.orgForeword Cassava is a tropical root crop,originally from Amazonia,that provides the staple food of an estimated 800 million people world-wide.Grown almost exclusively by low-income,smallholder farmers,it is one of the few staple crops that can be produced efficiently on a small scale,without the need for mechanization or purchased inputs,and in marginal areas with poor soils and unpredictable rainfall.Since 2000,the worlds annual cassava production has increased by an estimated 100 million tonnes,driven in Asia by demand for dried cassava and starch for use in livestock feed and industrial applications,and in Africa by expanding urban markets for cassava food products.There is great potential for further production increases under optimal conditions,cassava yields can reach 80 tonnes per hectare,compared to the current world average yield of just 12.8 tonnes.Booming demand offers millions of cassava growers in tropical countries the opportunity to intensify production,earn higher incomes and boost the food supply where it is most needed.But how smallholder cassava growers choose to improve productivity should be of major concern to policymakers.The Green Revolution in cereal production,based on genetically uniform varieties and intensive use of irrigation and agrochemicals,has taken a heavy toll on agricultures natural resource base,jeopardizing future productivity.In moving from traditional,low-input to more intensive cultivation,small-scale cassava growers should not make the same mistakes.Sustainable intensification of cassava production is the subject of this guide,the first in a series to the practical application of FAOs“Save and Grow”model of agriculture to specific smallholder crops and farming systems.Endorsed by FAO in 2010,“Save and Grow”is an ecosystem approach to agriculture that aims at improving productivity while conserving natural resources.It promotes practices that can help the worlds half a billion smallholder farm families to produce more from the same area of land while enhancing natural capital and ecosystem services.Drawing on two decades of research findings and on-farm experi-ences in Africa,Asia,Latin America and the Caribbean,the guide presents an eco-friendly approach to managing cassava more inten-sively.Many recommended practices combine traditional knowledge with modern technologies that are adapted to the needs of small-scale iv Save and Grow:Cassavaproducers.They include:minimizing tillage to protect soil health,optimizing timing and methods of planting,and using biological control agents to counter pests and diseases.The guide shows how well-balanced applications of mineral fertilizer,in combination with intercropping,crop rotation,mulching,manure and compost,can make a cassava-based farming system not only more productive and profitable,but also more sustainable.The adoption of“Save and Grow”agriculture will require significant improvements in the provision of extension,inputs and production credit to small-scale producers.Moreover,FAO recognizes that improved productivity may not bring about sustainable,long-term development outcomes:a major effort is needed to integrate smallhold-ers into higher levels of value addition.Transforming cassava into a multipurpose subsector that generates income,diversifies economies and ensures food for all will require political commitment,investment,institutional support and a demand-driven approach to technology development.This guide will be a valuable resource for policymakers in assessing how a dynamic cassava sector can help them to achieve their goals of poverty alleviation,economic development and food security,and of practical use to agricultural researchers,technicians and other profes-sionals in preparing programmes for sustainable cassava production intensification.Clayton CampanholaDirector,FAO Plant Production and Protection DivisionContentsForeword iiiAcknowledgements viOverview viiChapter 1:Cassava,a 21st century crop 1Chapter 2:Farming systems 19Chapter 3:Varieties and planting material 35Chapter 4:Water management 49Chapter 5:Crop nutrition 59Chapter 6:Pests and diseases 73Chapter 7:Harvest,post-harvest and value addition 87Chapter 8:The way forward 97Annex tables 109References 121Abbreviations 129vi Save and Grow:CassavaAuthorsThis guide was prepared by Reinhardt HowelerCIAT emeritus scientist NeBambi Lutaladio and Graeme Thomasof the FAO Plant Production and Protection DivisionAcknowledgementsThe contributions of the following are gratefully acknowledged:Kolawole Adebayo(Abeokuta University of Agriculture,Nigeria)Jean Pierre Anota(FAO consultant)Tin Maung Aye(CIAT)Jan Breithaupt(FAO)Hernn Ceballos(CIAT)Swarup K.Chakrabarti(CTCRI,India)Mark Davis(FAO)Dominique Dufour(CIAT)Emerson Fey(State University of West Paran,Brazil)Marjon Fredrix(FAO)Theodor Friedrich(FAO)Gualbert Gbehounou(FAO)Winfred Hammond(FAO)Lawan Jeerapong(Department of Agricultural Extension,Thailand)Jippe Hoogeveen(FAO)Josef Kienzle(FAO)Lava Kumar(IITA)Chikelu Mba(FAO)Danilo Meja(FAO)Linn Borgen Nilsen(FAO)Christian Nolte(FAO)Bernardo Ospina Patio(CLAYUCA)Dai Peters(Great Lakes Cassava Initiative)Adam Prakash(FAO)Chareinsak Rojanaridpiched(Kasetsart University,Thailand)Teresa Snchez(CIAT)Brian Sims(FAO consultant)Mario Takahashi(Agricultural Institute of Paran,Brazil)Namthip Thongnak(Thai Tapioca Development Institute)Bernard Vanlauwe(IITA)Andrew Westby(University of Greenwich,UK)James Whyte(FAO consultant)Amporn Winotai(Department of Agriculture,Thailand)Book design Thomas+SansonettiCover and illustrationsCecilia SanchezEditorial assistanceDiana GutirrezOverview1.Cassava,a 21st century cropThe“food of the poor”has become a multipurpose crop that responds to the priorities of developing countries,to trends in the global economy and to the challenge of climate change.Long regarded as unsuitable for intensification,cassava has grown dramatically in importance in world agriculture.The 2012 harvest reached record levels,thanks to expansion of global trade in cassava products and strong growth of output in Africa.Production is intensifying worldwide.In the years ahead,cassava will see a shift to monocropping,higher-yielding genotypes,and greater use of irrigation and agrochemicals.But intensification carries great risks,including upsurges in pests and diseases,and depletion of soil nutrients.This guide shows how FAOs“Save and Grow”farming approach can help developing countries to avoid the risks of unsustainable intensification,while realizing cassavas potential for producing higher yields,alleviating rural poverty and contributing to national economic development.2.Farming systemsMany smallholder cassava growers already practise three key“Save and Grow”recommendations:reduced or zero tillage,soil surface cover and crop diversification.Planting cassava without prior tillage in degraded soils may produce lower yields in the initial years;once soil health is restored,however,untilled land can produce high yields at a lower cost to the farmer and the farms natural resources.Mulch and cover crops help to reduce weed infestations and create soil conditions that improve productivity.Growing cassava in associations,sequences and rotations increases net income per unit area of land,and reduces the risk of crop failure.Intercropping with grain legumes can produce higher incomes than monocropping,and supplies food for the household.Protective hedgerows reduce soil erosion,while rotating cassava with legumes and cereals helps to restore soil health and yields.viii Save and Grow:Cassava3.Varieties and planting materialThe full potential of cassava will not be realized until production constraints are mitigated in higher-yielding varieties,and cassava growers have access to disease-free planting material.The time is right for the genome-wide characterization of cassava genetic diversity,to fill gaps in landrace collections,and to create natural reserves to safeguard wild relatives.The harmonization of passport and evaluation data on genebank accessions should be a priority.Breeding should focus on developing varieties that are well-adapted to specific agro-ecologies,cropping systems and end-uses,and produce good yields with minimal need for agrochemicals and irrigation.The routine multiplication and distribution of disease-free planting material of improved varieties are essential for sustainable intensification.While few countries have formal seed systems for cassava,a 3-tier community-based system pioneered in Africa,involving NGOs and farmer associations,has helped ensure that improved varieties and healthy planting material are adopted by cassava growers.4.Water managementOnce established,cassava can grow in areas that receive just 400 mm of average annual rainfall.But much higher yields can be obtained with higher levels of water supply.Optimizing rainfed cassava production requires careful attention to planting dates,planting methods and planting positions,and soil management practices that help to conserve water.Although it can grow in areas with 400 mm of rainfall a year,maximum root yields in Thailand were correlated with rainfall totalling about 1 700 mm.Cassava responds well to irrigation full surface irrigation has doubled the root yield obtained without irrigation;drip irrigation can produce about the same yield as surface irrigation using 50 percent less water.In Nigeria,root yields increased sixfold when the quantity of water supplied by supplementary drip irrigation was equal to that of the seasons rainfall.Supplemental irrigation that increased the total water supply by 20 percent almost doubled root yields.Overview ix5.Crop nutritionCombining ecosystem processes and judicious use of mineral fertilizer forms the basis of a sustainable crop nutrition system that produces more while using fewer external inputs.Although cassava produces reasonable yields on poor soils,many varieties perform better with fertilization.Yields in Africa,especially,could be markedly improved if farmers had access to mineral fertilizer at a reasonable price.Farmers can improve soil fertility with other“Save and Grow”measures.Intercropping grain legumes,and mulching the residues of legumes and native weeds,boosts root yields.When combined with fertilizer,both alley cropping with deep-rooting leguminous trees and the use of organic compost or farmyard manure produce higher crop yields and net incomes.Options to reduce the loss of soil nutrients to erosion include zero tillage,which maintains soil aggregate stability and internal drainage,contour hedgerows of vetiver grass,and the application of mineral fertilizer,which leads to faster soil coverage by the plant canopy.6.Pests and diseasesProtecting cassava with pesticide is usually ineffective and hardly ever economic.A range of non-chemical measures can help farmers reduce losses while protecting the agro-ecosystem.Growers should use planting material of varieties with tolerance or resistance to major pests and diseases,as well as ecosystem-based practices,such as mulching,maintaining soil organic matter,and planting intercrops to provide a habitat for pest predators.Biopesticides,sticky traps and soapy water can help control many insect pests.Plant health strategies should encourage natural biological agents the mass release of a tiny wasp defeated serious outbreaks of cassava mealybug in Africa and Asia.To prevent weeds overwhelming young plants,farmers should use optimum planting densities and fertilization,and varieties with vigorous early growth.Regular hand weeding can be as effective as weed control with herbicides.Farmers need to exercise care in the choice of the herbicides and should follow the advice of local plant protection specialists.x Save and Grow:Cassava7.Harvest,post-harvest and value additionFood for the household,feed for livestock,and raw material for a wide array of value-added products,from coarse flour to high-tech starch gels cassava is a truly multipurpose crop.Harvested cassava roots are consumed directly by many farm households or fed to their livestock.Roots can be processed into granulated flour,or into high quality cassava flour which can be used as a substitute for some of the wheat flour in bread and confectionary.In Thailand and China,root starch goes into food products,plywood,paper and textiles,and is used as feedstock for production of sweeteners,fructose,alcohol and fuel ethanol.Two recent cassava mutations have starch properties that are highly v