سبز نیوز
مطالب کاربردی گیاهان زینتی.گیاهان دارویی.کشت قارچ.کشت گلخانه ای.تراریوم و بونسای
سبز نیوز
مطالب کاربردی گیاهان زینتی.گیاهان دارویی.کشت قارچ.کشت گلخانه ای.تراریوم و بونسایخاکورزی نواری Strip Til
خاکورزی نواری چیست؟
در این روش تمام قسمتهای خاک تخریب نمی‌شود بلکه بخشهایی از خاک بصورت نواری و موازی با هم خاکورزی می‌شوند. در این روش عملاً یک چهارم یا کمتر از خاک، مورد خاکورزی قرار می‌گیرد و بقیة قسمتها دست نخورده باقی می‌مانند.
هدف اصلی از خاکورزی نواری این است که ضمن ایجاد بستر مناسب برای بذر، با حفظ بقایا در اطراف شیارها مانع از فرسایش خاک می‌شود.
اسامی متعددی برای خاکورزی نواری نامگذاری شده اند که برخی از آنها عبارتند از:
خاکورزی ناحیه‌ای(Zone-tillage)، و خاکورزی ردیفی (Row Clearing) و منطقه عمیق (Deep zoning) .
با توجه به ادوات قابل استفاده و نوع خاکورزی می‌توانیم سه نوع خاکورزی نواری را معرفی کنیم:
1- ردیف‌ها یا بقایای پاک شده(Row or residue clearing) که در آن:
- بقایا در بخشی از ردیف‌ها کنار زده می‌شوند.
* پیش‌بر انگشتی(Finger coulter)، دیسک‌ها، و بیلچة پااردکی (Sweeps) و یااختلاط پیش‌بر انگشتی با کاردگاوآهن برشی(Finger coulter+cutting coulter).
2-خاکورزی نواری(سطحی)- (Strip-tillage (shallow):
-برش و کنار زدن بقایا، آماده‌سازی بستر بذر، جاگذاری کود در زمین،
*پیش‌بر چین‌دار (fluted coulter)
3-خاکورزی نواری(عمقی)( Strip-tillage (deep)
- برچیدن بقایا، از بین بردن فشردگی، کاشت کود در عمق پایین‌تر، ایجاد پشته
*کولترها(پیش‌برها)، چاقوها، شاخه‌های زیرشکنی، دیسک‌های پوشاننده
مزایای خاکورزی نواری(Strip-tillage):
یکی از مشکلات بیخاکورزی این است که در این روش سرعت رشد اولیة بذر پایین آمده و ممکن است که زارعین به این سیستم ناامید شوند ولی در سیستم خاکورزی نواری سرعت رشد به دلیل گرمتر شدن شیارها، و مقدار محصول نهایی بسیار بهتر از بیخاکورزی می‌باشد.
شکل زیر نمودار دمایی دو سیستم را در عمق 2 اینچی مقایسه می‌کند.
همانطور که در شکل مشاهده می‌شود، دمای بخش نواری شبیه حالت چیزلی بوده و حدوداً 5 درجه گرمتر از سیستم بی‌خاک ورزی می‌باشند. نتیجتاً جوانه‌زنی و رشد اولیة بذر در سیستم بیخاکورزی دیر‌تر از این دو سیستم خواهد بود.
یکی از مزایای مهم خاکورزی نواری نسبت به خاک‌ورزی‌های رایج، کاربرد ادوات و زمان کمتر است که می‌تواند توجیه اقتصادی این روش باشد.
عملیات خاکورزی نواری یکبار بر روی مزرعه انجام شده(one-pass tillage) و نحوة کاشت نیز بستگی به سیستم انتخاب شده دارد. در مواقعی که زمان کاشت کوتاه می‌باشد، کشاورزان می‌توانند مقدار بیشتری از زمینهایشان را به این سیستم اختصاص دهند. نکتة دیگر اینکه ادوات این سیستم کوچکتر بوده و هزینه‌های نگهداری ادوات پایین می‌آید.
- نمودار بررسی مقدار بقایا در مرکز ردیف‌ها در هر دو سیستم(بیخاکورزی و خاکورزی نواری)
انتخاب سیستم خاکورزی نواری:
قبل از تبدیل سیستم خاکورزی به نوع نواری بایستی سیستم خاکورزی خود را بررسی نمائید. زیرا اغلب اصلاح یا تعویض یک سیستم نیاز به امکانات خاصی دارد(از قبیل کولتر یا پیش‌برها، ردیفکارها و و...).
قبل از تغییر به این سیستم سوالات سادة زیر را از خودتان بپرسید:
-
آیا اهداف ثابت و پایداری دارید؟
-
آیا خاکورزی شما وقت‌گیر بوده و هزینة تاخیر(Timeliness) متقبل می‌شوید؟
-
آیا پایداری و رشد اولیة گیاه در مزرعة شما رضایت‌بخش است؟
-
آیا مشکل فشردگی خاک دارید؟
انتخاب سیستم‌خاک‌ورزی نواری بستگی به سیستم برداشت، نوع خاک، و سیستم مدیریتی دارد. برای مثال:
در خاک‌های سرد و خیس، بایستی بقایا را کنار زد تا باعث سایه یا بازتابش نور نشده و زمین گرمتر شود.
جدول 2 سطح بقایای گیاهی را نشان می‌دهد که در ردیف‌های هر دو سیستم توسط پیش‌برهای انگشتی خاکورزی شده‌اند. قابل ذکر است که در هر دو سیستم مقادیر زیادی از بقایا در سطح زمین حفظ شده‌اند تا مقدار فرسایش کنترل شود.
خاک‌هایی که رس زیادی دارند، ممکن است که واکنش بیشتری نسبت به این سیستم داشته و در اثر خاکورزی سطحی نوارها (shallow in-row tillage) این بخش از خاک بهتر خشک شود. در این حالت تماس بذر با خاک بیشتر شده و همچنین بستر بذر و شرایط بهتری برای رشد فراهم می‌شود. اگر در مزرعه مشکل فشردگی خاک را نیز داشته باشیم، بایستی خاکورزی نواری را به صورت عمیق‌تر انجام دهیم(deep strip tillage). قابل ذکر است که در این گونه مواقع شناسایی لایة سخت و مناطق فشرده شده از اهمیت خاصی برخوردار است تا بتوان از روی آن عمق خاکورزی را تخمین زد. ابزارها و ادواتی که برای این منظور بکار می‌روند بایستی طوری تعبیه شوند که علاوه بر کار در عمق بالا، بقایا را بیش از حد مجاز زیرورو نکنند.
بررسی اقتصادی یک سیستم کاری بسیار مشکل و پیچیده است. در این بررسی هزینه‌های ابتدایی، ادوات، سایز تراکتور، افت و استهلاک ادوات، هزینه‌های مربوط به کود و سم و ... بایستی مورد محاسبه قرار گیرند. زارعین در انتخاب یک سیستم بایستی تمام جوانب آن را بسنجند. برای مثال در زمینی ممکن است که تمام سیستم کاشت ذرت به سیستم خاکورزی نواری اختصاص یابد ولی گاه نیز ممکن است که در مزرعه‌ای(برای مثال سویا) این سیستم مردود اعلام گردد.
چکیده:
خاکورزی نواری تنها راه‌حل همة مشکلات مزارع نیست! این سیستم نیز همانند سیستم بیخاکورزی مشکلات مربوط به مدیریت علف‌های هرز، آفتها، PHخاک و ... را دارد. در این سیستم بقایای گیاهی بیشتری نسبت به سیستم‌های رایج در سطح مزرعه باقی می‌ماند، بطوریکه تفاوت این سیستم را با سیستم‌های رایج به چشم می‌توان در سطح مزرعه مشاهده نمود
Drivers effecting development and sustainability of no-till systems for smallholders
at watershed level in Brazil.
Summary
The adoption of the no-till conservation system in Brazil can be considered as a Bright spot of
improved land and water management for tropical soils prone to soil and water losses under
conventional land preparation methods. This system has contributed to enhancing the productivity
and sustainability of annual cropping systems of both large and small farming units of the
southern and Cerrados regions of the Brazil. Smallholders adopting the systems have benefited
through reductions in labor and increased profits produced by the system. Widespread adoption of
no-till in Brazil is associated with strong participation by farmers in the development and
implementation of the system and to policies and incentives to improve environmental land and
water quality at the watershed level. The case study included in this paper illustrates the positive
linkages that were developed between farmers, local goverment and the private sector to improve
public health, control soil erosion and reduce water pollution at the watershed level.
Background and justification of the study
The concept of no-till in agriculture is not new. It evolved during the last 100 years in temperate
areas of the world and was successfully adopted by large-scale farmers in many European
countries and the U.S. The expansion of this system was largely supported by the agribusiness
sector, which developed planting machines, effective weed control methods and cropping systems
to reduce labor and land preparation costs.
The adoption of no-till systems in Brazil has been remarkable. It is estimated that today, 20
million ha are routinely planted under this system in the southern part and the Cerrado regions of
the country. The system is under rapid expansion and adoption in flat areas of Argentina and
Paraguay.
Although a large proportion of the area under no-till in Brazil is confined to large-scale farming
enterprises that have the technical and financial capacity to effective adopt this changed
management system, there is an increasing number of smallholders using no-till systems.
The purpose of this paper is to illustrate the importance of smallholder agriculture in Brazil and to
describe the process by which they are adopting/adapting no-till within their own unique technical
and financial constraints. The paper also attempts to demonstrate the impact of programs of
improved land and water management at the watershed level on the adoption of no-till systems. A
case study from the Paraná region in Brazil was selected to illustrate these benefits and to identify
the exogenous and endogenous factors that motivated the adoption of no-till at the watershed
level.
Methodological approach
The present study started in October 2003 as part of the IWMI-led effort to identify examples of
Bright Spots of improved land and water management and to identify the main driving forces
associated with their development. The study commenced with a rapid assessment of the
importance of smallholder agriculture in Brazil. An initial constraint to this was the lack of a clear
identification of this group within the context of the Brazilian agriculture. Consequently, the first
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step included a survey among research and extension agents involved in rural development in
different regions of the country to identify these characteristics. This was followed by a review of
secondary information to determine the extent of smallholder agriculture in the country.
The study continued with the description of the evolution of no-till systems in Brazil and the
process of adoption by smallholders. Collected information was validated through visits and
interviews with small farmers in the southern region of Paraná, Brazil.
The last part of the document describes the impact of improved soil and water conservation at the
watershed level. To do this, we selected the Rio do Campo watershed, in Paraná Brazil. This
watershed has an area of 7,076 ha and it is located in the municipality of Campo Mourão, Paraná.
The municipality has a total population of 82,318 inhabitants, with 88% of them living in the
urban area. All water consumed by population is supplied by the Rio do Campo River watershed
that comprises of the Rio do Campo and Rio das Barras Rivers respectively.
The watershed has 182 farms and 167 households. The topography is mostly hilly with smooth
slopes. Almost the entire agricultural area of the watershed is under no-till. Soils are mostly
classified “Latossolos Vermelhos” in the Brazilian soil classification and as “Oxisols” according
to the FAO system. Mean annual rainfall is 1730mm.
Results
Characteristics of smallholders in Brazil
The definition of smallholders in Brazil is generally applied to farmers that: i) own small parcels
of land; ii) the dominant source of labor on the farm is from family members; iii) live on their
own properties; iv) have little access to credit; v) explore soils of low fertility and; 6) have more
diversified production systems. They are also known as small family farms or family producers.
The results of the survey revealed that in spite of the great diversity of climate, soil and
socioeconomic conditions of the country there are an increasing number of small farmers using
no-till systems, particularly those agrarian communities in the southern region of the country.
This region was strongly influenced by European and Japanese communities that migrated to the
country to settle after the Second World War. They brought with them a set of cultural traits that
have profoundly influenced smallholder agriculture in this part of the country. Most of these
farmers have practiced diverse forms of soil conservation in the past. During the last ten to twenty
years some of these communities have move to the Cerrado region contributing to the
dissemination of improved soil and water practices.
Importance of smallholder agriculture in Brazil
According to the Brazilian Institute of Statistics (IBGE, 2003) there were 353 million ha under
agricultural production on 4.8 million farms in 1996. Almost 50% of the total number of these
farms had less than 10 ha (Table 1). More recent reports indicate that small farms contribute 35%
of the total production output of the agribusiness sector in Brazil, own 25% of cultivated land and
involve approximately 14 million people (EMBRAPA, 2003). Overall, they contribute 11% to the
total Brazilian GDP. In the State of Paraná, that produces 23% of total soybean crop of Brazil,
41% of farms are less than 10 ha (Iapar, 2004).
Comprehensive Assessment Bright Spots Project Final Report
No-till was adopted in temperate regions of the world (i.e. Europe and the US) as a means of
reducing fuel consumption and labor costs associated with land preparation. In contrast, Brazilian
farmers adopted no-till to counteract soil erosion problems caused by conventional land
preparation methods. The first machinery used for this purpose in Brazil was a planter introduced
in 1972 by a farmer called Herbert Bartz. He was interested in planting annual crops with
minimum soil disturbance on his farm. Since then, hundreds of farmers have abandoned
conventional land preparation methods and adopted new planting machines, cover crops and
weed control methods without soil disturbance.
The adoption of no-till production systems by farmers paved the way for the formation of the
farmer-led clubs and associations devoted to the dissemination of the information on the no-till
systems at the regional and national level. Figure 1 shows these linkages with research and policy
groups. These linkages gave farmers a stronger voice with respect to initiatives at the country
level. Simultaneously, there was strong support from the agro-industrial sector through the
manufacture of new planters, sprayers and harvesters for no-till management systems. On the
other hand, research institutions developed new crop components for improved rotation systems
and selected green manure and cover crops species adapted to no-till systems (Borges Filho,
2001). New maize, sorghum and wheat varieties were developed for improved rotation systems
with soybeans as the main crop. This change improved profitability of the system and reduced risks
of mono-cropping systems dominating the agricultural landscape.
A key factor favoring the adoption of no-till systems by small farmers was the development of
animal traction machines for planting, fertilization and herbicide application. The Instituto
Agronomico do Parana (IAPAR) was one of the institutions developing this type of machinery.
Numerous field days were organized by staff of the institution to demonstrate to small farmers the
feasibility of this system even on sloping lands. Later in the process other research institutions
including the French institution CIRAD and the Brazilian Institution EMBRAPA continued
improving the system. More recently, several commercial enterprises in Brazil started assembling
and distributing small tractor-mounted implements adapted to no-till operations on small farms.
These equipments are able to perform land preparation and herbicide applications at low cost
resulting in improved labor efficiency. Farmers are currently purchasing these implements
through small farmer cooperatives. More innovative farmers are purchasing commercial no-till
planters to plant soybeans in their own fields. In one of the visited municipalities of Paraná we
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found a group of smallholder farmers that had combined their capital reserves and efforts to
purchase and share a no-till planter and harvester. This has resulted in a greater degree of
participation in the soybean market, less labor and greater income. Family members are now
engaged in other on-farm business to increase income.
Southern region Cerrado region
Farmers Farmers
Associations Associations
(clube amigos da terra) (clube amigos da terra)
Research and technical assistance
Agroindustry and private sector
(Grupo de Plantio Direto)
APDC
(Associação Plantio Direto no Cerrado)
FEBRAPDP
(Federação Brasileira de Plantio Direto na Palha)
CAAPAS
(Confederação das Associações Americanas para uma Agricultura Sustentável)
Figure 1. Development model of no-till in Brazil (Borges Filho, 2001).
Example of improved land and water management at the watershed scale: the Rio do
Campo case study.
Evolution of the production systems in the watershed
During late 70´s agricultural activities in the State of Paraná expanded relatively rapidly due to
the growing importance of the soybean crop in the international market. New soybean varieties,
coupled with intensive use of conventional tillage and fertilizer made it possible to develop
profitable production systems in the region. However, this led to the generation of high soil
erosion loses and contamination of water sources due to the extensive use of insecticides and
herbicides. Farmers commonly reported cases of intoxication. Because of this, local government
and urban population started to perceive the potential hazards of this problem on the general
health of the community (Folha de Londrina, 1984). Municipalities then, started discussing
alternatives to preserve the quality of water of the watershed. However, it was realized that to
solve the problems, farmers had to be included in the development of solutions. State research
and development agencies started to develop a soil and water conservation program with the
active participation of farmers. The program consisted initially of the construction of contour
terraces to control soil erosion and the implementation of biological control programs to reduce
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207
use of agrochemicals. Lately, no-till systems were introduced by farmers to reduce even further
degradation problems.
In 1984, the municipality of Campo Mourão made an important step towards the reduction of soil
erosion and contamination in the watershed. All local loans provided to farmers by the Banco do
Brasil were tied to the use of soil conservation practices. This motivated farmers to adopt no-till
practices.
Collective action to improve land and water management
Farmer-led organizations and local authorities of the municipality of Campo Mourão initiated
discussions in ways of improving environmental quality of the watershed without compromising
profits to farmers. Successes and lessons learnt from similar experiences in other countries were
analyzed collectively. This resulted in a plan that included the following activities:
• Construction of sixteen water supply systems for chemical sprayers. These facilities reduced
contamination of clean water from pesticide residues and eliminated their discharge into the
river. In some cases farmers used their own resources to build these structures.
• Implementation of a biological control program to control pests of soybean and maize. By
1998 there were 16 private enterprises in the region devoted to the multiplication of natural
enemies and to the monitoring of pest and diseases dynamics in soybean and maize crops.
• Development of riparian zones along major rivers to reduce water contamination. Farmers
gradually adopted this practice as they became aware of the need to have buffer zones to
counteract contamination problems associated with the use agro-chemicals in their own
fields. As a result of this activity buffer zones increased from 5 to 30 m wide have been
constructed.
Government support
In 1974 the government of Paraná State initiated a program to control soil erosion. This was
followed by the launching of the National Program for Soil Conservation in 1975. Between 1984
and 1987 the State Government invested US$ 1,921 million to implement soil conservation
programs in 680 micro watersheds. Sixty percent of the resources were allocated to improve onfarm
machinery, 15% to support aspects of soil fertility, and 15% to improve road infrastructure,
7% to reforestation initiatives and 1% to the adoption of green agricultural systems. During the
period 1989 to 1997 the State of Paraná allocated an additional US$ 148 million to implement
soil conservation practices on 7.1 million ha including the Rio do Campo watershed. The
following activities were undertaken:
1. Improvement of 79.8 km of roads and construction of rainfall outlets (culverts).
2. Construction of contour terraces on 6,127 ha.
3. Incentives to adopt cover crops and no-tillage systems.
4. Incentives to improve soil fertility.
5. Reforestation of 380 ha.
Private support to improved land and water management
Besides efforts undertaken by farmers and local government to improve land and water
management there was also strong support from the private sector to support adoption of
improved practices. Cooperatives, retail outlets of agrochemicals and machinery factories met
regularly with farmer associations and extension agents to understand farmer needs and demands
to reduce soil erosion and water contamination risks. They also visited farmer fields to identify
individual problems. This led to the development of appropriate machinery and technical
assistance.
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Overall impact
The management of Rio do Campo watershed has been recognized as an appropriate model for
watershed management in Brazil. It has produced the following outputs: 1) installation of farm
demonstrations units to continually updated producers and extension personnel in new
technologies; 2) resulted in an increase of 12% in the productivity of water during the last 10
years; 3) Reduction of flood risk; 4) a steady reliable water supply to the city; 5) a reduction of
water turbidity from 286 to 33 NTU in 12 years; 6) expansion of no-till activities in the
watershed; 8) expansion of the area under agriculture (16% for soybeans and 63% for maize); and
9) an increase by 7% in the am the forested area within the confines of the catchment.
Lessons learnt
Widespread adoption of no-till systems and soil and water conservation practices by large and
smallholders in the Rio do Campo watershed was possible because of the synergy between
different sectors involved in the development of agricultural activities in the region. A key
component in the process of adoption was the development of strong farmer associations. They
served as the melting pot of issues and constraints for large and small-scale farmers to adopt
improved practices of soil and water management. Besides, they served to promote and
disseminate technologies and to mobilize support from the government and private sectors. This
in particular was a useful mechanism to improve the visibility of smallholders. For these reasons
it is important that every project of rural development spend time and resources stimulating the
creation/strengthening of farmer organizations.
Technical and extension personnel from national, private enterprises and NGO´s were also
important sources of knowledge for farmers. They developed technical solutions to solve
bottlenecks that inhibited the implementation of soil conservations programs. Many times
scientific experience can anticipate effects of practices to be adopted and reduce the time of
response of the projects
Although short-term profits is the main driving force for most of enterprises providing inputs and
machinery for the agricultural sector, they were instrumental in the adoption process since they
adapted their products to the demands of small and large scale farmers. There were clear
examples of the development of appropriated machinery for no-till systems for smallholders. The
most difficult part of any initiative on soil and water conservation is to get resources for its
implementation. However, when agricultural problems are connected to issues that are of interest
of urban population, then the chances for funding are improved. Projects on agricultural
sustainability have wide effects on a diverse range of components within the community and
therefore close interaction between all of these components is required. In this case, improved
land and water management was strongly related to public health concerns.
General conclusions
The adoption of improved soil and water conservation practices by large and small-scale farmers
in the Rio do Campo watershed was a response to pressure from urban populations and local
authorities to reduce soil erosion and potential health hazards due to water contamination with
agro-chemicals. Research institutions developed improved soil conservation practices and
alternatives to reduce the magnitude of the problem. Farmers started to evaluate these practices
by themselves and adapted them to their own conditions. Collective action also was fundamental
Comprehensive Assessment Bright Spots Project Final Report
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in the control of soil erosion and pollution of water bodies by agro-chemicals. No less important
was the placement of incentives and enforcement actions to promote land use change. No-till
systems provided direct benefits to large scale and small-scale farmers. They improved water
availability for crops, enhanced soil fertility and therefore increased agricultural productivity.
Risks of crop failures and unstable crop productivity yields were significantly reduced. This
ensured a more constant income to farmers. Adoption of new land management systems was
facilitated through the catalytic role of farmer associations. Eventual resistance to change was
counteracted by the development of the collective consciousness to attain community rather than
individual goals. More innovative farmers were encouraged to test and adapt no-till practices
with the support of research institutions and agribusiness enterprises.
Although adequate policies and economic incentives accelerated the adoption of no-till systems
at the landscape level, the system itself was initially tested and implemented by farmers almost
independently of governmental initiatives. The greatest asset in the process of change is the local
capacity and knowledge of local people. However, there must be an incentive for collective
participation.
Smallholders have benefited from technological advances brought about through the adoption of
no-till systems. They also shared with large scale farmers the benefits of reduced soil erosion,
improved crop productivity and reduced labor. Technical and financial support played a key role
in the development of feasible options for small scale agriculture. Smallholders indicated that the
adoption of animal traction and appropriate technologies allowed family members more time to
engage in other income generation activities and social events.
References
1. Amado. T.J.C. 2000. Manejo da palha, dinâmica da matéria orgânica e ciclagem de
nutrientes em plantio direto. In: Proceedings of the ENCONTRO NACIONAL DE
PLANTIO DIRETO NA PALHA, Foz de Iguaçu. Resumos. Ponta Grossa: Federação
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