Benefits of Conservation Agriculture on Soil and Water Conservation and Its Progress in China

Available online at www.sciencedirect.comAgriculural Sciences in ChinaScienceDirect2011, 10(6): 850-859June 2011Benefts of Conservation Agriculture on Soil and Water Conservation and ltsProgress in ChinaLI Ling-ling', HUANG Gao-baol, ZHANG Ren-zhi, Bill Belotti, Guangdi Li4 and Kwong Yin Chan'sIGansu Provincial Key Laboratory of Aridland Crop Sciene/Faculty of Agronomy, Gansu Agricultural University, Lanzhou 730070, P.R.China2Faculty of Resource and Environment, Gansu Agricultural University, Lanzhou 730070, P.R. China3 School of Nalural Sciences, University of Western Sydney, NSW 1797, Australia. EH Graham Centre for Agriculural Innovation (lliance Between Invesiment & Industry NSW and Charles Sturt Universily), WaggaWagga Agricultural Institute, NSW 2650, Australia3 Investment & Industry NSW, NSW 2753, AustraliaAbstractConservation agriculture has been practised for three decades and has been spread widely. There are many nomenclaturessurrounding conservation agriculture and differ to each other lightly. Conservation agriculture (CA) is a system approachto soil and water conservation, high crop productivity and profitability, in one word, it is a system approach to sustainableagriculture. Yet, because conservation agricuture is a knowledge-intensive and a complex system to learn and implement,and also because of traditions of intensive cultivation, adoption rates have been low, since to date, only about sevenpercent of the world's arable and permanent cropland area is farmed under conservation agriculture. The practice and widerextention of conservation agriculture thus requires a deeper understanding of its ecological underpinnings in order to manageits various elements for sustainable intensification, wbere the aim is to conserve soil and water and improve sustainability overthe long term. This paper described terms related to conservation agriculture, presented the effects of conservation agricultureon soil and water conservation, crop productity, progress and adoption of CA worldwide, emphasized obstacles and possibleways to increase CA adoption to accelerate sustainable development of China agriculture.Key words: China, conservation tllage, crop residue mulch, no-till, soil and water conservation, sustainabilityfood and energy, climate change, water scarcity, deg-INTRODUCTIONradation of ecosystem services and biodiversity, thefinancial crisis, and expected increase in population.Since the 1980s, there has been an increased aware-Ye, as reported in many papers (e.g., Nolan et al.2008),ness of the need to improve ecosystem health, maintainsome agagricultural systems are still being promoted withthe quality of the environment, and control the rate ofunacceptably high environmental, economic and socialresource consumption, thus the concept of sustainable:osts, and albeit with the promise of gains in output.development has been a driving force in research andAgricultural development, as curently practiced in manydevelopment (Mermut and Eswaran 2001). The chal-parts of the world is increasingly considered inadequatelenge of agricultural sustainability has become more to deliver sustainable production intensification to meetintense in recent years with the sharp rise in the cost of futur中国煤化工Received 7 July.2010 Accepted 31 December, 2010TYHCNMHGu Lingling. P D. Tel: +86 931-7631156 Fax: +86 931-7630810, E-mail: lil@gsmu oducn;CE-mai: huanggbe@gsau.cdu.n蚊10 1718121100070Benefits of Conservation Agriculture on Soil and Water Conservation and Its Progress in China851Conservation agriculture (CA) represents the most tainable agricutural production standard that all human-dramatic change in soil management in modern kind obviously wishes to achieve. At the operationalagriculture. It has been thoroughly studied in large ar-level there are field practices that have been promotedeas under many cropping systems worldwide (Fabrizzito achieve these aims and give life to the concepts andet al. 2005). In general, conservation agriculture is principles. Several are closely related but have subtlebeing increasingly promoted as constituting a set of variations.principles and practices that can make a contribution tosustainable production (Pretty 2008) bcause it ad-dresses missing components in the intensive tllage-basedConservation agriculureapproach to agriculture. As a result, conservation agri-A sct of principles and practics onwhich l0 base sustainable useculture has been adopted in North and South America,Australia, and, to lesser extent, in Europe (Kassam▲et al.2009). Yet, because conservation agriculture is aknowledge intensive and a complex system to leam and1 Three ojgciv o Imiproivaimplement, and also because of traditions of intensivepromoie soil and water conservaion:;aiincrease corp productivity:cultivation, adoption rates have been low among mostincrese poflibiliy-farming communities. The practice and wider exten-sion of conservation agriculture thus requires a deeperunderstanding by farmers and extention workers of itsTllge practice:ecological underpinnings in order to manage its variousminimum il;elements. The overall aim was to conserve soil andno-tiwater and improve sustainability over the long term.This paper () discussed terminology related to conser-vation agriculture, (i) presented the effects of conser-vation agriculture on soil and water conservation andMaintenance ofcrop productity, and (ii) asessed problems and pros-soil coverpects for adoption of CA worldwide, emphasized ob-stacles and possible ways to increase conservation ag-riculture adoption to accelerate sustainable developmentFig. Conservation agriculture sens lat is best thought of a nestedof China agriculture.hierarchy of concepts, principles, and field practices. At the upperlevel concepts they are dominant, at the lower level they are thefield practices that underpin long term sustainability.TERMINOLOGY AND NOMENCL ATURERELATED TO CONSERVATION AGRICULTUREStubble retention and crop residue mulchConservation agriculture sens lat is best thought of anested hierarchy of concepts, principles, and field prac- For the conservation purpose, the 30% of crop resi-tices (Fig). Some of the apparent confusion in the due is regarded as the threshold of stubble retentionterminology that surround CA sterms from the fact that (Allmaras and Dowdy 1985), but it is rather arbitraryCA has both conceptual and operational dimensions.and higher levels of soil cover imply even greater re-FAO defines CA by its objectives and expected out- ductions of soil erosion. Crop residue mulch (CRM)comes as“conservation agriculture aims to achieve can be defined as a technology that ensures that thesustainable and profitable agriculture and subsequently soil surface is covered by at least 30% organic resi-aims at improved livelihoods of farmers through the due from the previous crop at the time of new cropapplication of the three conservation agricultureemergence. The reliance on organic residues fromprinciples: minimal soil disturbance, permanent soilthepri中国煤化工irom other formscover and crop rotations". This encompasses the sus- of mu:TYHCNMHG852LI Ling-ling et al.Notil, direct drilig, zeortillage, minimumillage,EFFECTS OF CONSERVATION AGRICUL-and reduced tllageTURE ON SOIL _AND WATER CONSERVATIONNumerous types of tllage exist with some tllage termsConserving soil water(partially) overlapping and occasionally used inter-changeably (Benites et al.2003). No-ill, direet dilling,and zeo-illge have the same meaning of sowing with-Effects of conservation agriculture on soil water con-out tlge compared to conventional tilge. Minimumservation have been observed in almost all of the re-search on it because of the inherent relationship be-or reduced tllages typically implies that substantial quan-tween water and soil conservationes as well as croptities of residues remain as mulch (Sullivan 2003).productivity in the rainfed areas.In conservation agriculture, the presence of a cropConservation tlgeresidue at the soil-atmosphere interface alters the entiresoil ecology. Huang et al. (2008b) showed that no-tillBaker et al. (2007) gave conservation tllage a very de-with stubble retention increased surface soil water con-tailed definition as follows:“conservation tllage is thetent significantly. Retaining residues on the soil sur-collctive umbrella term commonly given to no-tillage,face can provide cover to reduce evaporation, providedirect dilling, minimum-illage, and/or ridg-tillage, tobarriers against runoff, and improve precipitation infil-denote that the specific practice has a conservation goaltration (Franzluebbers 2002b; Lampurlanes andof some nature. Usually, the retention of 30% surfaceCantero-Martinez 2006). In addition, the crop resi-cover by residues characterizes the lower limit of clas-dues can also reduce the rate of evaporation by isolat-sification for conservation tllage, but other conserva- ing the soil from sun heating and ambient airtion objectives for this practice include conservation oftemperature, and increasing resistance to water vapourtime, fuel, earthworms, soil water, soil structure andflux by reducing wind speed. Some crops do not pro-nutrients. Thus residue levels alone do not adequatelyduce sufficient residue to intercept the raindropsdescribe all conservation tllage practices".(Baumhardt and Lascano 1996). .In summary, previous research shows that conser-vation agriculture with no-till and crop residues retainedConservation agricultureon the soil suface can reduce evaporation, and im-prove infiltration of precipitation. Soil and water ero-Hobbs (2007) argued that Baker's (2007) definition ofsion can be reduced by adopting conservationconservation tllge has led to confusion among theagriculture.agricultural scientist and the farming community andsuggested to use the FAO definition of conservationImproving soil qualityagriculture (see above).Therefore, methods described as no-till, minimumSoil quality is a subject that is receiving increasingtill, incomplete tllage, reduced tllage, or conservationattention. Soil quality is usually considered to have threetllage differ from each other slightly. Even in no-tillmain aspects: physical, chemical, and biological. It issystem, the soil may be opened by coulters, rowconsidered to be important for the assessment of ex-cleaners, disc openers, in-row chisels, or rotofillers priortent of land degradation or amelioration, and for identi-to planting the seed. All of these termns related to con-fying management practices for sustainable land use.servation tllage are operational aspects of conservationPhysical quality (soil structure) has big efects on chemi-agriculture (Fig.). These farming practices and sys-cal and biological process in the soil, therefore, it playstems they have created are revolutionary because overa central role in studies of soil quality (Dexter 2004). Itthe centuries crop agriculture has traditionally empha-is well中国煤化工xop residues orsized the opposite.increas!YHCNMHG-2rove soil prop-211.A.Ateresonod PutethedbybereuBenefts of Conservation Agriculure on Soil and Water Conservation and Its Progress in China853erties (Loveland and Webb 2003). Therefore, conser-larger number of macropores (e.g., McGarry et al.2000)vation agriculture practices should be able to improveas a result of increased fauna activity (Suwardji andsoil quality because of crop residues retained on theEberbach 1998), and accumulated organic matter form-soil surface. No-till and/or minimum till reduces soiling a ltter of residues (Arshad et al. 1999). Disruptioncompaction and prevent soil structure decline.of macropore continuity by tllage can reduce infiltra-Increase soil organic carbon and organic matter Soiltion and hydraulic conductivity (Logsdon et al.1990).organic matter sustains many key soil functions by pro-However, a few researchers, for example, Ferreras et al.viding the energy, substrates, and biological diversity(2000) found that infiltration and/or hydraulic conduc-to support biological activity, which affects soil aggre-tivity was lower under NT than inversion tllage as NTgation and water infiltration (Franzluebbers 2002b). Theincreased bulk density (small porosity) whereas tllagedegree of soil organic matter stratification with depthincreased porosity, particularly large pores (Tebriggehas been suggested as an indicator of soil quality, be-and Diring 1999).cause surface organic matter is essential to erosionThe use of crop residues in conservation agriculturecontrol, water infiltration, and conservation of ntri-protect the soil from raindrop impact reduce slaking ofents (Franzluebbers 2002a).surface aggregates and prevent pore sealing and crustConservation agriculture is promoted, in part, for itsformation, residues left over the soil also slow the flowbeneficial effects on carbon retention that occur withof surface runoff, thus increase the opportunity fortime (Zibilske et al. 2002). Organic carbon levels werewater to infiltrate. The combination of these beneficialsignificantly higher with direct drilling, compared toeffects of residues can increase water infiltration (Potterconventional cultivation (Chan et al. 2002). The con-et al.1995).tents of organic carbon in soil can also be improved byIn summary, hydraulic conductivity and infiltrationconservation agriculture by keeping crop residues con-can be improved and evaporation can be decreased bytaining carbon and nutrients at the soil surface layerno-tillage and crop residue cover in conservation agri-(Moreno et al. 2006). Another mechanism by which culture in general, this will, in turm, decrease runoffsoil organic carbon and organic matter is retained inand soil erosion.conservation-tillage systems may be due to reduced Improving soil stability and aggregation Soil stabil-oxygen avaiability below the surface of no-till systems,ity refers to the susceptbility of soil to change underwhich affects decomposition rates (Wershaw 1993) andnatural or anthropogenic perturbations (Lal 1993). Soilthe distribution of aerobic and anaerobic microbes andaggregate stability has been recognized as a relevantmicrobial processes. Slower subsurface decomposi- factor in the control of water erosion (Castro Filho et al.tion rates lower oxidative losses of organic C. Long-1991) because erodibility of soils is directly related toterm field experiments on conservation agricultureaggregate stability (Madari et al.2005). There is me-showed that OC was improved by direct drill stubbledium to high aggregate correlation between aggregateretained on the soil surface (Chan et al. 2002; Chenstability in water, aggregate size, and total organic car-et al. 2009; Sombrero and de Benito 2010).bon content (Castro Filho et al. 2002).Improving hydraulic conductivity and infiltra-The favourable effect of conservation agriculturetion Infiltration and evaporation are the most signifi-systems on soil aggregation has been reported in dif-cant processes determining soil water storage. Infil-ferent soil types and climates (Oyedele et al, 199). Intration is also an important soil feature that controlscontrast, conventional tllae promotes loss of soil or-leaching, runoff, and crop water availabilityganic matter, which leads to disruption of soil aggre-(Franzluebbers 2002b). The impact of different tllagegates contributing to erosion (Roldan et al.2003). Con-systems on infiltration has been well investigated usingservation agriculture systerms that leave more crop resi-rainfall simulators and ponded or tension infiltrometersdues on the soil surface generally allow improvements(Luo et al. 2005).in soil aggregation and aggregate stability (e.g.. MadariIn general, infitration is greater under ni-illage (NT)etal. 2中国煤化工。also results inthan in tlleld soils (e.g., McGarry et al. 2000) due to the erosioface aggregatesTYHCNMHG854L Ling-ling e1 al.against the effects of raindrops (Chan et al. 2002).runoff intensity was reduced with no-till with stubbleResearch on conservation agriculture showed that no- retention, soil loss from erosion was reduced bytill with subble retained treatment had more water stable 62.4% (Zhao et al.2007).aggregation (Li et al.2007; Zhang et al. 2009).In summary, conservation agriculture could decreaseIn summary, conservation agriculture characterizedsoil detachment and increase water infilration that im-by no-tillage and crop residues retention is helpful for plies a decrease of water runoff, consequently, soil ero-soil aggregating and the aggregate stabilit, thus, in turm, sion would be reduced. Effects of conservation agri-will help to control or reduce soil erosion.culture on reducing erosion were mainly caused by cropresidues retained on the soil surface. Table sets out aReducing soil and water erosioncomparison of CA and conventional agriculture andsummarizes the principles and practices that underlieRunoff and soil loss are problems common to mosteach.cropland in the world, especially those with unstableaggregates in the suface horizon both from the stand-CROP PRODUCTIVITY UNDER CONSERVA-point of sustainability and offsite environmental dam-TION AGRICULTUREage (Rhoton et al.2002), so it has been, and continuesto be, a very important research area.Effects of conservation agriculture on crop productiv-Conservation agriculture, with crop residue mulchity have been extensively studied under different condi-can provide soil cover to reduce rain impact and pro- tions of soil and climate. Effects of tllage and cropvide barriers against runoff (Franzluebbers 2002b), thisresidue on changing the soil ecology caused higher cropwill help to increase moisture infiltration (Shaver et al.productivity under conservation agriculture. The mar-2002) and decrease soil detachment. Moreover, re-ginal yield effect depends on the extent these changestaining crop residues on the soil surface lead to an in- influence the constraint(s) for crop growth. This makescrease of soil organic carbon, which gives rise to im-the yield effect of conservation agriculture crop- andproved soil aggregate stability (Limon-Ortega et al. site-specific, and somewhat difficult to disentangle in2002) and the returm of biological diversity to the soil, view of the numerous intractions (Govaerts et al.2005).particularly earthworms (Chan 2001). It results in aManagement of crop residues in conservation agri-increase in moisture infiltration too. Research on theculture is the most important factor afecting crop yield.Westerm Loess Plateau of China showed that under aThe water conserving effect of crop residue on thewheat-pea rotation system, runoff was alleviated and surface of soil can induce a substantial yield increaseObjeetiveConseration agriculureConventional agriculurePromote soil and waler conservation Soil surface covered during fallow.Soil urfrce bare during fllowStubble retention:Stubble removed, gathered, burnt or turned under(i) reduces soil water evaporationTillage is at core of seed bed preparation(问) increascs soil water holding capacity(间) increases soil organic carbon(iv) reduces rain drop impact(v) reduces wind speed at soil surfaceSowing without tlling:们weed control with herbieides or suppressed by cover crop(问) prolection of soil structure against compactionIncrease crop poductivitytAdd more ertilizorMess nutrient loss in nunoffMore frequent illngHigher soil water storagebocreased profiabilityBetter nutrient cyclingch s fuel and frilizrInerease area under culivationPreveat soil compaction and soil struclure declinedImprove loog term sustainabilityDevelop self susaining system中国煤化工om um dpxnaemnRemove unecesary chemical pollutants from thecrop enviromentMHCNMHG02011.CMS.ANuys rod PbdbyBereet855Benefts ofConsevation Agriculure on Soil and Water Conservation and lts Proges inChinswhen drought stress is an ise (Huang et al. 2008b).benefits accumulate over time as mulching arrests soilThe organic matter contributed by crop residue mulchdegradation processes and gradually improves the soilcan have different short-term yield implications, typi-in biological, chemical, and physical terms.cally hinging on the quality of that organic matter asreflected by the C:N ratio. Crop residue mulch alsoPROGRESS OF CONSERVATION AGRIC-affects the incidence of crop weeds, pests, and diseases.ULTURE RESEARCHAND ITSADOPTION INHowever, the yield effet is uncertain as many weeds,pests, and diseases respond uniquely to the crop resi-CHINAdue mulch-induced alterations in the crop-soilecosystem. Crop productivity can also be modified byAdoption of conservation agriculture wordwideconservation agriculture through its effect on soiltemperature. In most instances, it has been shown thatConservation agriculture is a system approaches to sus-the higher levels of residue cover associated with no-tainable agriculture indeed according to the points listedtllage can lead to lower soil temperature early in seasonabove. Yet, most of the conservation agriculture is pres-that may reduce plant growth rate and yield under cer-ently done in USA, Brazil, Argentina, Canada, Australia,tain soil and climatic conditions. But, Al-Darby et al.and other developed countries. As it has been well de-(1987) in USA found that the greater amounts of waterscribed by Kassam et al. (2009), briefly, it is estimatedstored with the conservation agriculture systems elimi-that, worldwide, there are now some 106 million ha ofnated the potential for reduction in dry matter and grainarable crops grown each year in conservation agricul-yield with these systems due to lower soil temperatureture systems. Currently, South America has the largestearly in the growing season. Moreover, there are re-area under conservation agriculture with 49 586900 haports of increased soil temperature by stubble retention(46.6% of total global area under conservationtoo (Franzluebbers et al.1995), that in tum helps cropsagriculture) fllowed by North America (39981 000ha,to survive through cold winter, or reduce time to emer- 37 5%). Australia and New Zealand have 12 162000 hagence and improve crop productivity.(11.4%), Asia 2630000 ha (2.3%), Europe 1 536 100 haLong term research on the Westerm Loess Plateau of (1.4%), and Africa 470 100 ha (0.4%). USA ranked theChina showed that grain yield under no tll with stubblefirst (26 500000 ha) among different countries.retention (NTS) was always greater than under con-Except in a few countries (USA, Canada, Australia,ventional tllage over a 6-yrτ in wheat-pea rotation, andBrazil, Argentina, Paraguay, Uruguay, etc.), these即the advantage of NTS was the greatest in drier yearsproaches to sustainable agriculture have not been(2003 and 2007). On average, grain yield under NTS'mainstreamed' in agricultural developmentwas 18 and 20% higher than T for wheat (2.0 versusprogrammes or backed by suitable policies and institu-1.7 t ha") and pea (1.4 versus 1.1 t ha'), respectivelytional suppor. Consequently, the total area under con-(Huang et al. 2008a). A 3-yr experiment conductedservation agriculture is still small (about 79%) relative tounder dry land conditions in northwesterm Iran showsareas farmed using tllage. Nonetheless, the rate ofthat average grain yields with conservation agricultureincrease globally since 1990 has been at the rate ofwere significantly greater (25-.42%) than grain yieldssome 5.3 million ha per anum, mainly in North andusing conventional treatment, probably owing to greaterSouth America and in Australia and New Zealand.water availability (Hemmat and Eskandari 2006).Reasons for slow adoption are many, traditions ofTherefore, various conservation agriculture practicesintensive cultivation is the first one. Nevertheless, con-affect crop production differently in the differentservation agriculture is knowledge-intensive and a com-environments. Experiences so far have highlightedplex system to learn and implement. It cannot be re-positive, neutral, and negative short-tem yield responsesduced to a simple standard technology and thus pio-to crop residue mulch. Over time, the yield effectsneers and earlv adopters face manv hurdles before thetend to be neutral to positive. Indeed, some productivefull be中国煤化工e can be reapedYHCNMH G2011.CAAS Aragphn roro.tahdbyeorwrer856LI Ling-ling et al.(Derpsch 2008). Also, it is appeared that in mostLoess Plateau of Gansu Province, China, to study thecountries, conservation agriculture is as yet a relativelylong-term effects of conservation agriculture on soilunknown concept (Kassam 2009). Indeed, conserva-chemical, physical, and biological processes as well astion agriculture is not an easily transferable single com-crop productivity and profitability to explore the bestponent technology, the appropriateness of conserva-conservation agricultural practices for the rainfed farm-tion agriculure depends on both biophysical and socio- ing systems on the Westerm Loess Plateau (Huang et al.economic factors and their interactions (Lal 1991). The2008b). In 2006 2010, the National Key Technologiesconservation agriculture knowledge base developed inR&D Program of China during the 11th Five-Year Planthe USA, Canada, and Australia is not directly transfer-period, (2006BAD15B00) focused on conservation tll-able to developing countries, thus, there is a great needage research and demonstration in whole China. It hasfor research into conservation agriculture in develop-been increasingly realized that conservation agricultureing countries.would be of great importance in China to combat se-vere soil erosion on the Loess Plateau (Gao and LiProgress of conservation agriculture research2003; Gan et al.2008; Huang et al. 2008b), however,and its adoption in Chinain 2008-2009, only about 1.3 million ha of agricultureland practiced conservation agriculture in China. TheIn China, soil erosion on the Loess Plateau is amongstpossible obstacles for its adoption are: First, traditionalthe highest erosion in the world. The severe erosionattitude prevents the adoption of conservationhas been a serious problem, endangering food securityagriculture. Despite clearly benefits from conservationand resuting in poverty in the area. Reasons for severeagriculture, there is still a strong belief among farmers,erosion on the Loess Plateau are many, among whichextension agents, and even some researchers that culti-traditional agriculture has being one of the most impor-vation is necessary for successful crop production.tant man made factors. Traditional crop productionThus, ongoing demonstration and extension will be re-practice involves intensive cultivation; normally soil isquired for many years to overcome traditional beliefsploughed three times and harrowed twice between har-and adapt conservation agricuture to local conditions.vest and spring sowing. Soil surface is bare during theSecond, lack of systematic research. Although, China7-8 mon-long fallow, which includes part of the rainyhas a long history of practices of conservation agricul-season. All stubble and residues are removed out ofture (Huang 2003), systematic research on modern con-fields at crop harvest for use as forage, fuel, etc. Allservation agriculture research is still sparse. Since thethese practices exacerbate degradation of soils, pro-conservation agriculture is not a simple transferablemote erosion and reduce production potential.technique, and it takes years to reap the full benefits ofConsequently, local farmers are trapped in a cycle ofit. There is a great need for systematic research into itsoil degradation and poverty.in various environment in China to accelerate itsChina has a long history of practices of conserva-adoption. Third, lack of appropriate no till seeders. Intion agriculture (Huang 2003). Gravel and stubbleChina, the large proportion of farm land is unsuitablemulches have been used to preserve soil moisture infor tractors because of difficult terrain limiting accessmany cash crops and vegetables probably for manyor small terraces, especially on the Loess Plateau. Bighundreds of years. But, moderm conservation agricul-machines developed in USA, Canada, etc, can not be. ture research in China has been started from the earlytransferred to use on small farms of China directly.1980s and more systematic research on conservationFourth, high opportunity cost of straw. On the West-agriculture has been commenced in the 1990s. Gaoerm Loess Plateau of China, crop stubbles and stalksand Li (2003) started conservation agriculture researchare always used as fuel for cooking and heating, and/orin Shanxi Province, China, focusing on development ofas feed for animals.no-till machinery for small scale operation for the rainfedTherefore, to accelerate adoption of conservationagriculture in China. In 2001, two conservation agri-agricu中国煤化工nable develop-culture experiments were established on the Westemment:RYHCNMHGded. Possible857ways are:Soil Science Society ofAmerica Jourmal, 60, 1908-1913.Farmer attitudes need to be changed by stronger andBenites J R, Despsch R, McGarry D.2003. Current status andwider demonstration.future growth potential of conservation agriculture in theTo assure enough stubble be retained in the field,world context. In: International Soil Tillage Researchnew fuel for cooking and feed for animals are needed.Organization 16th Triennial Conference. Brisbane, Australia.More effective and environmental friendly herbicidespp. 120-129.Castro Filho C, Henklain J C, Vieira M J, Casio Jr R.1991.are needed to control weeds.Tillage methods and soil and water conservation in southermBecause of treatment and fertilizer application rates,Brazil. Soil and Tllage Research, 20, 271-283.there is a gap between performance of crops in theCastro Filho C, Lourenco A, Guimardes M de F, Fonseca IC B.main experiment and local farms. More researches are202. Aggregate sabiliy under dferent management systemsneeded to confrm the real difference between differentin a red Latosol in the State of Parana, Brasil. Soil and Tllagetllage practices under the condition of farmer.Research, 65, 45-51.Therefore, to accelerate adoption of conservationChan K Y. 2001. An overview of some tllage impacts onagriculture as a basis for sustainable development ofearthworm population abundance and diversity - implicationsChina and globally, the points listed above need to befor functioning in sois. Soil and Tllage Research, 57, 179-considered carefully.191.Chan K Y, Heenan D P, Oates A.2002. Soil carbon fractions andrelationship to soil quality under dfferent tlage and stubbleAcknowledgementsmanagement. Soil and Tllage Research, 63, 133-139.This study was financially supported by the NationalChenHQ,HouRX,GongYs,LiHW,FanMs,KuzyakovY.Natural Science Foundation of China (40771132), the2009. Efects of1l years of conservation tlage on soil organicKey Technologies R&D Program of China during thematter fractions in wheat monoculture in Loess Plateau of1lth Five-Year Plan period (2006BAD15B06), the Aus-China. Soil and Tllage Research, 106, 85-94.tralian Center for Intermational Agricultural ResearchDerpsch R. 2008. Critical steps in no-till adoption. 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