Composting to ensure food security: Learning by doing

V A Clottey, W A Agyare, K O Gyasi, M Schreurs*, A Maatman*, H Abdulai and R K Dinku**

Savanna Agricultural Research Institute, P. O. Box 52, Tamale, Ghana
^*International Centre for Soil Fertility and Agricultural Development, Africa Division, B. P. 4483, Lome, Togo
**Ministry of Food and Agriculture, Tolon-Kumbungu District, PO Box 1, Tolon, Ghana
catuq@yahoo.com

Abstract

Farmers from six villages in the peri-urban Tolon-Kumbungu District in the Northern Region of Ghana took part in a field school from 1999-2001, learning how to prepare and use compost on maize and groundnuts. They tried the heap, the pit and enclosure methods of preparing compost and made a decision to use mainly the pit method giving reasons for their choice. The farmers also made informed choices from their experiential learning on the best ways to store and apply the compost in the field. The farmers modified ways to transport the matured compost to their fields. The farmers tested three cropping patterns of growing maize and groundnuts - repeated monoculture cropping, rotating monoculture crops and intercrops- with the use of composts and mineral fertilizer and made a decision on growing the two crops as monoculture in rotation. Maize and groundnut grain yields under rotation with the use of compost (5 tonnes/ha) and half of the recommended rate (30:25:25) of mineral fertilizer on the maize were superior to other production systems.

The results of this Farmer Field school have shown how local communities that are located close to each other can come together to analyse their agro-ecological situation and decide on relevant issues to research through experimentation, based on assessment of knowledge from stakeholders outside the village. In the process they generated information which, when shared amongst them, helped to add to their indigenous knowledge to enrich their farming systems. A farmer-to farmer extension process is going on in the pilot area as farmers share their knowledge with others within their communities and in the neighbouring communities.

Keywords: Compost, farmers, field school, groundnuts, maize

Introduction

Soil fertility management is now an issue in the top brackets of African agricultural development policy. A decline in soil fertility across sub-Saharan Africa is evident and characterised mainly by nutrient mining and soil degradation (Stoorvogel and Smaling 1990; van der Pol 1992, Hilhorst and Muchena 2000). National maize yield levels in several African countries have not always increased and in some cases have even dropped although mineral fertilizer utilization has steadily increased from 1961 to 1997 (Scoones and Toulmin 1999).

In Ghana, apart from reduction in crop yield and livestock productivity, the ratio of rangelands to arable lands is dwindling in many farming communities. Most soils in Ghana have organic matter content below 1%, low available phosphorus and are highly acidic (pH of below 5).

To arrest reduced crop yield, increase livestock productivity and increase the ratio of rangelands to arable lands farmers need to be conscious of these trends before they can accept changes. This calls for processes that will take farmers through a self-discovery of the consequences of the processes they use in their farming system. An agroecological system analysis involving farmers, followed by a process of looking for solutions to the identified problems creates a fertile ground for participatory learning and action research.

In 1999 the Savanna Agricultural Research Institute (SARI), the Ministry of Food and Agriculture (MoFA) and the African division of the International Centre for Soil Fertility and Agricultural Development (IFDC-Africa Division) started activities that focus on Integrated Soil Fertility Management (ISFM) in the Northern Region of Ghana, more specifically in the peri-urban parts of the Tolon-Kumbungu District. The approach of the project was based on participation of all stakeholders involved so as to enhance farmers' decision-making capacities with respect to ISFM techniques through a process of mutual learning. Using the concepts of Participatory Technology Development (PTD) modified into a Farmers' Field School, farmers, researchers and extension workers put to test and developed technological packages adapted to improve fertiliser use efficiency that at the same time fitted into the farmers' socio-economic context.

Objectives

The objectives of the research were established after an analysis of the agro-ecology of the pilot area together with the community members. The objectives of the research were to (1) intensify maize production, (2) promote a better cropping pattern for maize production, (3) promote the use of compost to enhance chemical fertiliser uptake and (4) promote the use of chemical fertiliser, especially phosphorus on groundnuts.

Materials and methods

Six villages from a part of the district near the town of Kumbungu that have the potential to adopt ISFM strategies were selected after a reconnaissance survey. These are: Bognayili, Mbanaayili, Nwogu, Naapagyili, Gumo and Kpilo.

Twenty-one farmer experimenters from the six villages volunteered to run the field schools on the following criteria.

• Farmer's preparedness to make and use compost;
• Farmer's willingness to follow the treatments of the experimental trials as defined and agreed upon for a period of (at least) four years;
• Farmer's continuous access to the same piece of land earmarked for the field school for a period of (at least) four years.

The farmers were taken through different methods of preparing compost. Emphasis was placed on materials that can be used for the preparation of compost and the changes that occur during composting and their significance. The farmers were given a free hand to experiment with the proportions of fresh and dry materials to use in the compost preparation, the storage and mode of application of the matured compost.

With the participation of the pilot farmers, the field school treatments were agreed upon and carried out on average plot sizes of one acre (i.e. 4,000 m²) divided into five equal parts. The integrated soil fertility management (ISFM) treatments were:

• Continuous cropping of maize with the full recommended rate (full-rate) of mineral fertiliser but without compost (control treatment);
• Maize - groundnut intercrop with compost and half of the recommended rate (half-rate) of mineral fertiliser;
• Continuous cropping of monoculture maize with compost and half -rate of mineral fertiliser;
• Monoculture maize with compost and half -rate of mineral fertiliser in rotation with monoculture groundnut;
• Monoculture groundnut with compost and half-rate of phosphorus in rotation with monoculture maize.

The last two treatments were alternated every year to realise the rotation effect. All treatments received inorganic fertiliser in the form of N from ammonium sulphate, P from single super phosphate and K from potassium sulphate, at the full-recommended rate of 60 kg N, 50 kg P and 50 kg K per ha (except for monoculture groundnut, receiving only P). Compost was applied at a rate of 2 tons per acre (4000m²). This is equivalent to 5 tons per hectare.

In the cropping season of 1999, the collaborating farmers did not apply compost to their fields. All treatments were imposed with the full rate of fertiliser. The full range of treatments was imposed in the years 2000 and 2001.

Results and discussion

Farmers' reflexions on compost and the experimentation

A participatory learning and action research was generated among the farmers. In 1999 the farmers received training on different ways of preparing compost using the heap and pit methods as well as composting in enclosures and containers. They decided to experiment on the seasons and methods for compost preparation, the storage and application of compost on the fields. The experiences of farmers are elaborated below.

Season for compost preparation

One group of farmers decided to prepare compost in the rainy season, another in the dry season and yet another group began at the tail end of the rainy season and overlapped into the dry season. There were some farmers who prepared compost during all or some of these periods. They shared their experiences on the advantages and disadvantages of making compost for each period (Table 1).

Method of compost preparation

Farmers made a comparison between the heap and pit method of preparing compost (Table 2). These two methods were the most adopted after the training. Only two farmers built compartments with mud. The farmers who use this method said it is the most difficult method when it comes to turning the compost, but it gives the best quality of compost. It is also more tedious to build the compartments than to just dig the pits.

After sharing this information amongst them, the farmers now found it more convenient to prepare compost in the dry season when they have enough time at their disposal because the harvest has ended. They mainly use the pit method around the homesteads. To them, a little effort made to dig the pits is worthwhile as the same pits can be used over and over. There were no disturbances from ruminants and poultry. Water was available unlike constructing the pits in the fields where they may reduce farmland areas as well.

Storage of compost

Farmers stored the matured compost either in heaps or in industrially woven-polypropylene sacks of various sizes indoors or outdoors. Some farmers stacked the sacks with compost in the open air and covered them with straw mats. These farmers reported that they saw few signs of algae growth around the base of plants to which they applied the compost stored in sacks lying on top and sides of the stacks. They attributed the loss in potency of compost to the fact that the rains permeated these sacks.

Other farmers stored their compost in heaps or in the woven-polypropylene sacks in rooms or pens and under trees or sheds. They explained that they believe the heaps of stored compost to be less potent than the compost stored in sacks. The indicator used by the farmers to check the richness was the amount of algae that formed at the base of plants the compost was applied to. The more algae that were formed at the base of the plants, the better the richness of the compost. Farmers have experienced that when compost is kept in woven-polypropylene sacks; the sacks tear so the farmers have begun to store the compost in rooms and in heaps covered with mats woven from straw.

Transport of compost

Transportation of materials for composting and of matured compost to and from the fields has been and is still a problem to farmers. Indeed it is the determining factor of wide scale adoption of composting in many communities.

The first demand for support from the farmers to transport materials and compost was to put wheelbarrows at their disposal. However the farmers soon did not find it convenient for carting compost or composting materials over a long distance. They preferred to use bicycles although the volume they could cart on the carriers was far less than the wheelbarrows could. Some farmers later hired pushcarts to cart their compost to the fields.

Since the bicycle is a utility vehicle in the communities and every household has at least one, the project in collaboration with the Tamale Implement Factory modified a hand-drawn cart to be pulled by bicycles. This was preferred to animal drawn carts because of the extra responsibility of animal care and more importantly the frequent occurrence of bullock theft in the area that makes investment into these animals risky.

Application of compost

In the first year of applying compost on the fields, the farmers put several methods of application to trial. They tried spot application to emerged plants, burying and not burying the compost. Others tried broadcasting the compost immediately before ploughing whiles others applied it in bands across the field and ploughed them in.

The farmers quickly realised in the very first year that when compost was left uncovered, the plant does not reap the full benefits of it. They also noted that when using spot application, the weeds that grow around the crop stood taller than those growing between the rows. Finally, they noted that weeds grew more vigorously on fields where the compost was broadcasted than where it was applied to the base of the emerged plants.

Farmers observed that maize plants stood taller and the leaves were greener on the fields where the compost was broadcasted and ploughed in than where it was spot applied to the emerged plants. However one old farmer, when sharing his experience on the use of mineral fertiliser and organic manure, mentioned that when organic manure and mineral fertiliser are applied to maize, the leaves are lighter in colour but the stem girth is bigger than that of maize that received only mineral fertiliser.

On the whole, the farmers observed that the soil was moister on fields where compost was broadcasted and ploughed in than where it was spot applied. They also noticed the disappearance of certain weeds associated with poor soils (eg. Striga and Cynodon spp. which locally is called kpunkpagon) and the appearance of weed species they normally see on the relatively more fertile, compound fields. One such weed they mentioned is Amaranth sp.

They all agreed that broadcasting compost before ploughing it in is easier than spot application to plants however more labour is used to control the weeds.

Cropping patterns

The field trials for the ISFM strategies, where compost and mineral fertiliser were used for monoculture repeated cropping of maize (MzFCmp), in maize-groundnut intercrops (Intcrop), a rotation of maize and groundnut (MzRotCrop) and a control treatment of monoculture repeated cropping of maize with only mineral fertiliser (Mzfert), were also aimed at generating action research and sharing of knowledge. The investigative theme was how the use of compost will benefit each cropping pattern.

The mean maize grain yield among the farmers in 1999 when the farmers did not apply compost to their fields but rather imposed all the treatments with the full rate of fertiliser was 1354 kg ha^-1 and that of groundnuts was 294 kg ha^-1 for the monoculture crop and 177 kg ha^-1 for the intercrop. The crops in the subsequent two years when the ISFM strategies (full treatments) were imposed were better in all respects as most farmers obtained yields higher than the 1999 mean yield values of maize and groundnuts (Figure 1 and Figure 2).

The Box-Whisker plots (Figures 1 and 2) showing the median and range of yields is also estimating the stability of the treatments across the farmers, their socio-economic and biophysical environments as well as the years that the treatments have been imposed (Baum et al 1999). A line at the median of the data set bisects the box. The vertical lines at the top and bottom of the box are the whiskers and they indicate the range of typical yield values recorded on the farmers' fields. The dot in Figure 2 shows an outlier, which is an extreme yield value that is outside the box by more than 1.5 times the size of the box (Statistix for Windows 1996).

When compost substituted a half rate of chemical fertiliser either under rotation (MzRotCrop) or repeated cropping (MzFCmp), the range of maize yields (Figure 1) skewed more towards the upper boundaries than the yields of monoculture repeated cropping of maize using exclusively fertiliser (Mzfert). The MzRotCrop yield values had the highest median and the greatest skew towards higher values (Figure 1). The yield values of the Mzfert and Intcrop treatments looked the more compact implying a higher stability or better adaptability (Baum et al 1999), however the farmers' most preferred choice was the rotation treatment (MzRotCrop) under which most of them got higher maize yields.

This choice was probably buttressed by the fact that grain yields of groundnuts from the intercrops (Intcrop) with maize were generally lower than the monoculture crops in rotation (Gnut rot). Most of the yields were below 500 kg ha^-1 in the intercrops while in the rotational monoculture crops they were in excesses of 600 kg ha^-1 with some getting close to 1500 kg ha^-1 (Figure 2). Groundnut yields of about 75% of the farmers doubled from the initial year average of 294 kg ha^-1 when rotated with maize and some (about 30%) had yields in excesses of 1000 kg ha^-1.

The results above are very significant to the farmer. Farmers buy mineral fertiliser and use it exclusively on maize, rice and pepper in the pilot area. Farmers in the pilot area apply only 1 bag per acre (4000 m²) of either 15-15-15 or Sulphate of Ammonia to their maize crop. This is about 18 kg each of N, P and K per hectare or 26 kg of N per hectare respectively which are just less than the half rates used at this ISFM field school. To a large extent, the real life situation in the farming systems of the pilot areas had been stimulated making the results very relevant to the farmers to make decisions. This put the already adopted ISFM situation into a research perspective.

Farmers now find monoculture rotation of the two crops, maize and groundnut, as the cropping pattern that they will apply compost to because they have realised a stable increment in maize yields planted on fields that had groundnut grown on it in the previous season.

Farmers also applied compost to pepper that was not a test crop in the experiment. They have found the increment in yield very significant and this has brought more meaning to the rotational patterns involving maize, groundnut and pepper that are dominant in the study area.

Conclusions

• The farming systems in the Tolon-Kumbungu District which - like in most parts of Africa - are characterised by inadequate return of nutrients to the soil, when crops and their residues are harvested and taken somewhere else, now have the potential to reverse this trend or at least minimise the impact of this phenomenon.

• The results of this study have shown how local communities that are located close to each other can come together to analyse their agro-ecological situation, decide on what to experiment on, based on assessment of knowledge from outside. In the process they generated information which, when shared amongst them, had helped them to add on their indigenous knowledge to enrich their farming systems.

• There was a considerable variation in soil fertility among the field school sites as well as variation in the way each farmer prepares, stores, and utilises compost. By sharing of information during the farmer field schools, the farmers are heading towards perfection of the technology of preparing organic matter from plant residue, animal droppings and household waste. A wave of farmer-to-farmer extension of the technology had been triggered and this must be sustained with complementary technological packages and socio-economic measures that will really make farmers' enterprise grow profitably.

References

Baum E, Gyiele L A, Drechsel P and Nurah G K 1999 Tools for the economic analysis and evaluation of on-farm trials. IBSRAM Global Tool Kit Series No. 1. International Board for Soil Research and Management, Bangkok, pp 31-32.

Hilhorst T and Muchena F M (Editors) 2000 Nutrients on the move-Soil fertility dynamics in African farming systems. International Institute for Environment and Development, London, 146p.

Scoones I and Toulmin C 1999 Policies for soil fertility management in Africa. Institute of Development Studies, Sussex and International Institute for Environment and Development, London, 128p.

Statistixfor Windows 1996 User's Manual, Analytical software, Tallahassee, Fl, USA, pp 105-106.

Stoorvogel J and Smaling E M A 1990 Assessment of soil nutrient depletion in sub-Saharan Africa 1983-2000. The Winand Staring Centre, Wageningen.

van der Pol F 1992 Soil mining: an unseen contributor to farm income in Southern Mali. Bulletin 325, Royal Tropical Institute, Amsterdam, 42p.

Received 22 May 2006; Accepted 26 July 2006; Published 2 October 2006

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