10.THE ROLE OF THE PRIVATE SECTOR IN ENHANCING CONSERVATION TILLAGE PRACTICES IN AFRICA J.B.R. Findlay W.L.Haag, K. Boa-Amponsem, M. Descous, G.Rass and W.Modestus  

Introduction 

Conservation tillage systems, which prevent the erosion of the soil by wind and water with the resulting improved water penetration into the soil profile which gives greatly improved moisture utilisation by plants and thus subsequent improved crop profitability, are widely used in the United States of America, South America and Australia. Apart from large scale commercial farms in Kenya, South Africa, Zambia and Zimbabwe there is little or no conservation tillage practiced by small scale farmers in African countries, which all have a common problem of drought, extreme soil erosion by excess water run-off and soil nutrient deficiencies. 

Conditions that lead to soil erosion and excessive water run-off are the lack of vegetation or plant residue covering the soil surface and the use of agricultural implements that invert the soil and destroy the soil structure. By continual removal of plant material from the soil surface by livestock grazing or burning or cultivation, there is a gradual deterioration of soil quality and a loss of fertile top soil which results in reduced crop production. It is important that this soil loss, both physical and in quality, is stopped and conservation tillage systems adopted to rehabilitate the soil in crop producing areas with the objective of producing crops that create wealth for farmers and the country. 

Successful crop production is reliant on the knowledge and technology of many disciplines and agricultural development projects must be supported by all relevant parties. Conservation tillage has been practiced in the United States of America for over 50 years but it is only in the last 10 years when the benefits have been widely accepted by farmers. During this period, experience and knowledge have been gained by many people and organisations and they have combined their expertise with the result of conservation tillage practices being widely adopted. This success has been due to partnerships or team efforts which includes support from government politicians, government policy makers, government researchers, government extension services, private sector seed breeders, fertilizer suppliers, pesticide researchers and manufacturers, equipment manufacturers, produce marketers and processors, distribution agents, financial institutions and universities. 

Some objectives of the introduction of „new" farming technology must be to make crop production more profitable for the farmer and to create wealth within the nation. With the promotion of the use of certified seed, fertilizer, conservation tillage and herbicides, small scale farming can become profitable and create wealth. The following is an example of how an American company, Monsanto, combined forces with Non Governmental Organisations (NGOs) such as Sasakawa Global 2000 (SG 2000) and Winrock to develop and promote conservation and no tillage practices in certain African countries. 

The Conservation Tillage Project Concept 

Monsanto is a world leader in the development of conservation tillage practices due largely to the development of Roundup herbicide (360g glyphosate / l) to replace manual and mechanical seed bed preparation and weed control in row crops, both annual and perennial. Hand hoeing and plowing are basic weed control technologies that have been used for over 3000 years in agriculture and, with the discovery and introduction of Roundup in the late 1970s, weed control can be done far more efficiently and effectively without destroying the soil structure and mulch on the surface. This has revolutionized the productivity and profitability of farmers who have adopted this system of pre-plant weed control followed by the in-crop use of herbicides with minimal or no soil cultivation. 

This has been adopted by many large scale commercial farmers worldwide but there has been little acceptance by small scale farmers due mainly to a lack of exposure to the system and to herbicides. This was appreciated by Monsanto but there was also the problem of how to reach these small scale farmers who are in rural areas where new developments are not always readily accessible. 

There are many organisations funded by the United Nations, World Bank, private foundations and charity groups that are involved in agricultural projects with small scale farmers in Africa. Most of these organisations have offices and staff in selected countries where they work in close co-operation with local government agencies and with the political support of the government. Monsanto chose to work with Sasakawa Global 2000 in Ethiopia, Ghana, Mozambique and Tanzania and with Winrock in Senegal in the promotion of conservation tillage, which would easily be incorporated into existing programmes. 

This has lead to the implementation of conservation tillage programmes where Monsanto supplies the technical information and training; SG 2000 / Winrock supply on-the-ground management, supervision and specific project support; the government department of agriculture supplies the extension services to promote the practice among the farmers as well as the research services to give local technical support; the distribution services of the farmer’s inputs such as certified seed, fertilizer and pesticides must also be involved to ensure that the farmer’s requirements are readily available. 

Such a project must have the involvement and co-operation of all parties working together to upgrade the productivity and production of the small scale farmer, who has not received the support he needs in the past. 

Traditional Small Scale Farming Practices 

Hand Hoeing 

This is the most common technique for seedbed preparation and weeding. In most cases the land is hand cleared, all the organic material is burned and then the crop is planted followed by in-crop weeding. Often in the rainy season the rate of weeding can not keep up with the rate of weed growth and the crop yield potential is greatly reduced. 

Fallow Rotation 

Where land is available, a rotation of leaving land fallow for up to five years after a crop has been produced is common. Indigenous vegetation and weeds are allowed to grow for a number of years and then when the land is going to be planted again, the vegetation is hand cleared and burnt. This will enable the soil to marginally recuperate between crops but there will be a gradual deterioration of soil quality over the years. 

Animal Traction 

This is associated with plowing for a seedbed preparation and for weeding. In this process the soil is inverted and the structure destroyed as well as the organic material on the surface being greatly reduced. In some instances a rip can replace a plowing for seedbed preparation. Animal traction requires the year round maintenance of a healthy animal workforce. 

Mechanical Cultivation 

This is very limited in the small scale farming sector of Africa and when present, it is associated with plowing and the destruction of soil structure. 

Seed Production 

Most of the seed used by small scale farmers in Africa is home grown and of an inferior quality. There are a number of initiatives to improve seed quality and cultivar selections. An example of this is the introduction of a quality protein maize, Obatanpa, in Ghana which was part of the SG 2000 programme. It is important that high yielding cultivars are developed and made available to farmers. 

Fertilizer Use 

Generally little or no fertilizer is used in the small scale farming sector, due mainly to availability and cost. Lack of soil analysis facilities as well as the lack of a variety of fertilizer formulations being available is also a problem. Soils are generally deficient in nutrients and the use of fertilizer can have excellent results. 

Pesticide Availability 

Due to the lack of information and exposure to the benefits of pesticides, small scale farmers are not using these modern farming options. Also the market is seen by distributors as being limited and marketing will be expensive for a relatively small return. 

Other Issues 

Certain other issues such as land availability and ownership, illiteracy among farmers, lack of financial support, input / output systems and others that effect small scale farmers are generally receiving some attention by governments and donors. Many existing systems are based on low input technology giving low yields and low income, which maintains the farmer in poverty. 

The Conservation Tillage Project 

The objectives of this project are (i) to introduce new technology to the small scale farmer such as the use of certified seeds, improved crop cultivars, the use of fertilizer and the use of herbicides and pesticides; (ii) the introduction of conservation tillage systems with the elimination of „slash and burn" farming, increasing the organic material on and in the soil, reduction of hand labour and inefficient time utilization, and elimination of cultivations that destroy the soil structure; (iii) the development of local conservation tillage expertise and knowledge within the agricultural research institutions, extension services and academic institutions; and (iv) the development of small scale farmer input and output support systems and management skills. 

The project is based on showing the farmer by means of demonstrations what his system produces compared to the proposed conservation tillage system. This is done by research organisations such as the Crop Research Institute (CRI) in Ghana, Institut Senegalais de la Recherche Agronomique (ISRA) in Senegal and the Selian Research Institute (SRI) in Tanzania conducting trials and working with the extension services to develop recommendations that farmers can implement. Monsanto and the supporting organisation, SG 2000 or Winrock, will give specific training on conservation tillage, the effect of weeds on crops, the use of herbicides and other issues to address the concerns of extension staff and farmers. Because the conservation tillage system is beneficial to plant growth, the effective control of weeds is fundamental to the success of this farming practice and an integrated weed management system based on herbicides is essential. 

Demonstrations 

The recommended system includes the use of certified seed, the use of fertilizer at planting and as a top dressing, the use of pre-plant herbicide weed control and the use of in-crop residual herbicides which is compared to the current farmer practice. 

The comparative plot parameters are as follows: A plot of a minimum of 1000 sq m (= 0.1 ha; 20 x 50m or 30 x 33m etc.); certified seed for this area (3000 maize seed per plot); fertilizer such as 12-24-12 NPK at planting followed at 4 to 6 weeks later with urea (both at 10 kg per plot); a 15 l knapsack which is calibrated to spray 15 l per plot (= 150 l / ha); Roundup® post emerge herbicide either as the Dry formulation (420 g glyphosate per kg) at 2 sachets (annual weeds) or 3 sachets (perennial weeds) per 15 l per plot or as the solution (360 g glyphosate / l) at 250 ml (annual weeds) or 400 ml (perennial weeds) per 15 l per plot; Lasso® EC or MT (480 g alachlor / l) at 350 ml per plot for legumes etc. or Lasso+atrazine SC (350 g alachlor + 200 g atrazine / l) at 600 ml per plot for maize or sugarcane. 

The sequence of events is to rip if necessary, spray existing weeds with Roundup, plant certified seed with fertilizer, apply residual Lasso herbicide, apply fertilizer top dressing, harvest with the objective of leaving crop residue on the plot. 

Sites are chosen that have a good chance of success in that both farmer and extension officers must learn the system by experience. Areas with agronomic problems should be avoided initially and only tackled once experience has been gained. It is advisable to have 3 to 5 participating farmers in a village to facilitate mutual support and discussions. If animal traction is involved, it should be limited to a rip for seedbed preparation. The choice of crop is wide but consideration must be given to those crops that yield a good crop residue to form a mulch on the soil surface and with a strong root system to develop the soil structure. Maize is generally a reliable crop to start with. It is important that records of each comparison site are kept to enable correct decisions to be made at a later stage. Crop residue on the soil surface is a fundamental requirement and activities that reduce this such as grazing and burning are counter productive and should be discouraged at all costs. 

Number of Demonstration Plots conducted 

The project relies on showing the small scale farmers what the benefits of the conservation tillage system are by putting out small demonstration plots on their land. The more farmers that are exposed to these plots, the greater the chance of adoption of the technique. Although there were also numerous replicated small plot trials conducted by research institutes to support the demonstration programme, they have not all been documented. Table 1 gives an indication of the number of demonstration plots conducted in the various countries. Due to time restraints and cost management, these programmes were often concentrated in a region or area and not widely dispersed, such as in Ghana the demonstrations were almost entirely in the Ashanti and Brong Ahafo regions and in Tanzania they were in the Arusha, Magugu and Babati areas. 

Table 1: The number of reduced and no tillage demonstration plots conducted per year in each of the focus countries on maize, legumes and rice.(X = not finalised). 

* Ghana - Trials started in 1992; 1994 was the first commercial year.  ** Tanzania - Roundup Dry registered in 1997 after 5 years of government trials.

Results 

Time Saving 

By using a Roundup pre-plant weed control spray, a farmer takes two days, one hour and 40 minutes to prepare and plant 0.1 ha with maize [ 22 days and 40 minutes per ha] compared to the traditional hand hoeing to clear the land and in-crop weeding taking 14 days and 40 minutes per 0.1 ha [140 days, 6 hours and 40 minutes per ha] as in Table 2. By using the pre-plant herbicide spray system, approximately 6.0 ha can be cropped by one man in the time that it would take him to produce maize on one ha when all preparation and weeding is done by hand. 

Table 2 : The time required to prepare and plant maize on a 1000 sq m demonstration plot. 

In Senegal, the reduction in hand labour in rice production was between 53.2 to 60.0 % when a pre-plant herbicide was used in place of manual labour (Table 3.).  Table 3: Manday requirements per ha for rice planting-bed preparation and in-crop weed control in 5 trials and 23 demonstrations; manual labour vs pre-plant herbicide application; Senegal 1993 and 1994. 
 

Crop Yields  The maize yield improvements achieved in Ghana with hybrids and the quality protein maize cultivar, Obatanpa, when the traditional „slash and burn" technique is compared to reduced tillage in the closely monitored CRI plots (32) where the seed and fertilizer was standard over all plots, shows that a pre-plant weed control herbicide can give an increase of 39 - 55 % and by adding a residual herbicide treatment to this, yield increases of up to 79 - 92 % above that which the farmers obtain traditionally can be obtained. (See Table 4).  Table 4: The average maize yield from demonstration plots (32) receiving either „slash & burn"or Roundup pre-plant, or Roundup pre-plant and residual herbicide, all with 1 x hand weeding*; Crop Research Institute, Ghana, 1997 
 

*All plots were planted with certified seed; received fertilizer at planting and as a top- dressing; Roundup Dry at 15 sachets and Lasso+atrazine SC at 5.0 l /ha. In Mozambique, maize yields were considerably improved over traditional methods when conservation tillage principals were used. Due to data details only distinguishing between high and low inputs, it is difficult to accurately contribute all yield increases to the reduced and no till systems but the dramatic increases recorded must be due largely to the use of herbicides and the resulting lack of weed pressure on the crop, which gave up to a 2.9 ton / ha or 513 % increase in Monapo, a 2.4 ton / ha or 646 % increase in Ribaue and a 3.8 ton / ha or 402 % increase in Malema (See Table 5).  Table 5 : Maize yields from low and high cost input production methods (See text) in Mozambique, 1996 - 97. 
 

The use of Roundup as a pre-plant weed control treatment in rice in Senegal, resulted in between an 11.3 and 30.3 % yield increase over the traditional manual cultivation method in trials and a 35.1 % increase when measured in commercial farmer demonstrations (See Table 6).  Table 6 The average yield from 5 replicated field trials and 23 commercial demonstration sites where a pre-plant Roundup spray was compared to manual weed control; Senegal, 1993, 1994

Crop Costs and Profitability 

In Ghana the 32 closely monitored tillage comparison plots, where the seed, planting and fertilizer costs were standard, the treatment that gave the best weed control with a complete pre and post plant herbicide programme gave a net profit of US $ 713-00, which is US $ 353-31 more than the traditional method which gave US $ 359-69, for an additional US $ 29-00 outlay on herbicides (See Table 7).  Table 7: The variable costs of maize production under three tillage systems and the profit per ha from 32 comparison plots; Crop Research Institute, Ghana, 1997. 
 

In Senegal rice production demonstrations in 1994, the additional outlay of US $ 25-00 above the cost of manual seedbed preparation and in-crop weeding, resulted in a yield increase over the manual method of 1.23 tons grain / ha which gives an additional US $ 197-68 / ha income for a total per ha net profit of US $ 695-16 or 40 % above the accepted standard (See Table 8). In 1995 this was repeated where the rice yield gain was an additional 40.0 % over that of the standard treatment and with a 65.5 % gain in net profit of US $ 1115-50 against $ 673-92 per ha. 

Table 8: The average input costs, yield, gross income and net profit of manual rice bed preparation and weed control compared to a Roundup pre-plant weed control spray; [Average of 5 trials and 23 demonstration plots]; Senegal, 1994. 
 

In Tanzania, the yields of no till maize and rice were increased in the no till sites by only 12.7 % and 6.0 % over the conventional manual method but the overall income per ha was increased by US $ 112-30 (+24.5 %) for maize and US $ 165-24 (+11.0 %) for rice (See Table 9). 

Table 9:The average maize and rice yields from demonstration plots comparing 4 manual hoeings for seedbed preparation and weeding with a Roundup pre-plant no- till system; Tanzania, 1994 - 1997. 

Conclusions 

The data presented support a significant productivity improvement in small scale farming with the introduction of no till cropping techniques, which are based on effective pre-plant herbicide weed control in the seedbed followed by the use of residual herbicides to greatly reduce the negative effect of weed pressure on the crops, to replace manual methods. This technology has shown to give the benefits of enhanced moisture utilization and soil structure improvement. However, this also has the benefit of more efficient time utilization, increased areas under cultivation, increased yields and increased profitability. 

Acknowledgments 

The authors acknowledge the tremendous effort put in by field staff from many organizations in all areas of this ambitious project in the four countries discussed above. Without them the plots would not have been sprayed and progress in crop production would not have taken place.  We would like to thank the following and their teams;  Ghana - Vincent Anchirinah, Osei Bonsu, Joe Manu (Crop Research Institute), Ben Dzar, Sydney Seho-Ahiable, Tommy Asare-Baffour (SG 2000) and the staff of Dizengoff Ghana Ltd..  Mozambique - Min. Jose Pacheco, Antonieta Ferrao, Alberto Matavele, Custodio Mucavele, David Mariotte, Aguinado Neves, Luciano Rafael (MAP and DNER), Carlos Pieres (Agroquimicos).  Senegal - Dr.Alphone Faye (Winrock International), Dr. Souleymane Diallo (ISRA), and the SODAGRI field staff. 
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