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Conservation Activities for Sustainable Agriculture in Northern ZAMBIA          

 

By Given Sikasote.

 

 

INTRODUCTION.

 

In many areas of Mbala district, Northern Zambia, woodlands have been cleared for farming through Chitemene System which is a slash and burn shifting cultivation method, where trees and bushes are cut, gathered together at certain points and burnt. This farming practice has not spared even the protected areas and affects the Chambeshi catchment areas, a situation which is feared could in the long run result into the drying up of rivers and streams.

 

The soils have been left bare after the bush fires, which are usually burnt late. Even crop residues are burnt out in the fields leaving the ground bare, with little realization that vegetation and crop cover are of big importance for the prevention of soil erosion, addition of organic matter to the soil and the regulation of soil temperatures etc.

 

Methods of plowing where the patterns of cultivation have always been the same over many years have been noticed. A good number of farmers still cultivate along the slopes rather than across. This has resulted into large amounts of soils being washed away, leading to reduced soil fertility..

 

The land ecology has been further affected through the uncontrolled human settlements, which too have encroached the catchment areas. The situation is further worsened by the uncontrolled cutting of forest trees for charcoal burning, which has become the main source of livelihood for most rural communities.

 

 

CONTROL MEASURES

 

So far a number of control measures to the above problems have or are still being tried through the various government institutions, with the Department of Agriculture being one the leading institutions.

 

 

1. Soil fertility Improvement. 

 

In order to prevent continous migration in search of fertile lands, the following practices have been initiated;

 

• Use of green manure: This has been done through the growing and incorporation of sunhemp and velvet beans into the soil. This in itself is an improvement to the traditional 'fundikila system' where grass of any type (which adds very few nutrients to the soil) is instead incorporated. The tendency is to bury the grass under mounds around April and May, just before the end of the rain season. These (mounds) are later spread just before the onset of the rains, in time for planting. However, farmers are being discouraged from this practice of spreading the mounds but to plant right on top of these mounds, for maximum use of the nutrients by the plants.

• Agroforestry practices: a number of demonstrations have been put up on the use of luceania, tephrosia and of late lablab beans.

• Use of kraal manure: although a number of farmers have regarded use of kraal manure as a practice which is tedious and one that introduces stubborn species of weeds to their fields, those that have tried to use it have realized that once properly applied allows the soil to remain fertile for many years, hence no need to shift.

 

 

2. Land Degradation.

 

Land degradation has been tried to be checked through the following farming practices:

 

 

• Tree planting: in recent years, the Forestry Department has been raising tree nurseries and a number of farmers have made tree plantings, whilst still being encouraged to maintain woodland indigenous species within their farming areas.

• Fuel wood: a programme to promote the growing of a certain tree type called Croton has just been started. The idea is to grow a lot of this tree type, which grows faster than the indigenous trees, so as to spare the natural trees which are always cut for fuel.

• Improved Fallows: this is where the land is left uncultivated for at least 3 years. However, with this practice farmers are encouraged not to allow fire into these fallow lands. This is sometimes combined with agro forestry where woody plants like Tephrosia vogeli and Cajanas cajan are grown while the area is being spared from cultivation.

• Control of soil erosion: Mbala has a land with a lot of steep landscapes. Farmers have therefore been encouraged to plant their crops across the slopes and in certain farm areas, contour lines have been established. Veitiver grass has been planted along these contours and large nurseries for this grass have been established.

 

 

3. Intergrated Fish Farming.

 

Fish farming, through construction of fish ponds along water furrows, is becoming prominent. This is making most farmers stay in one place for a long time. Alongside fish farming, farmers are growing vegetables which they sell for their income while at the same time feeding some to the fish. Manures from cattle and pigs are as well fed to the fish which in turn provides food and income for farmers.

 

 

4. Research Activities.

 

Northern Zambia falls in region III of the Agroecological Zone. This zone experiences the highest amounts of rainfall, of more than 1000mm p.a between the months of November and April. As a result, the soils are heavily leached with a very low soil pH,

<4.5 ( CaCl2 ), and consequently toxic with aluminum.

 

The National Wheat Research Programme, through its breeding programme, has over the years developed wheat varieties that are not only tolerant to aluminum toxicity but also resistant to diseaces, mostly Helminthosporium sativum, Xanthomonas campestri, rusts etc.

 

 

However, to enhance the productivity of these varieties, appropriate crop production technologies need to be used. The wheat agronomy programme carried out some research activities in order to come up with some of these production technologies through  the use of legume green manures and crop rotation.

 

 

The following trials were thus conducted:

 

1.Green manure trial:

 

which was conducted with three major objectives. First to compare the effect of short ( 2.5 months ) and long ( 4 months ) duration green manure crops on the yield of a following wheat crop: second, to compare the effect of grain crops of velvet beans, sunhemp and soybeans; and third to compare the effect of four four rates of top dressing fertilizer. The trial was conducted at Katito resaerch station for four rainy seasons.

From the data obtained from the trial it was concluded that wheat planted after long duration green manure crops of velvet beans and sunhemp results in an increase in yields and that wheat following grain crop of soybean, sunhemp and velvet beans gives even much better yields. There is potential of increasing  and sustaining wheat yields in Northern Zambia.

 

 

 

2. Crop rotation trial:

 

which was conducted for six years at Katito, near Mbala district. Wheat, maize, soybeans and groundnuts were included in the rotations. The main focus was however on wheat.

From the trial, it was found that wheat yielded better when it followed a legume crop in rotation- soybeansor g/nuts and to a lesser extent common beans. The results are in agreement with those obtained in the green manuring trial. Fertilizer effects were more apparent from the fertilizer applied in the same season rather than from the previous season

 

 

REFERENCES

 

Siwale, J.1998. Sustainable Dryland Wheat Production through Green Manuring.PP 356-358. The Tenth Regional Wheat Workshop for Eastern, Central and Southern Africa.

 

Siwale, J. 1998. The impact of Crop Rotation on the Grain Yield of Rainfed Wheat in Northern Zambia. PP 350-352. The Tenth Regional Wheat Workshop for East, Central and Southern Africa, University of Stellenbosch, S Africa.

 

 

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