1.1 Background

The purpose of this work is to develop soil standards for Uganda. This is part of the on-going activities of NEMA to improve the environment. It is generally believed that the development and enforcement of soil quality standards is
the most important requirement for the long term sustainability of the productive capacity on croplands, forest, wetlands and range ecosystems and overall environmental management.

Uganda enacted the National Environment Statute in 1995, to provide a framework for sustainable management of environment and consequently, established the National Environment Management Authority, (NEMA) to implement it. Section 31 of the Statute requires NEMA to develop soil quality standards and the criteria for monitoring the said standards.

Since the final preparation of this report, a draft Environmental Standards (minimum standards for the Management of the Quality of Soil) Regulations, 1999 have been drafted and are attached to this report.

1.1.2 The Context

Earlier work (the NEAP Process) in Uganda identified the following as the major environmental problems:
 Land Degradation (especially Soil Erosion)
 Deforestation
 Loss of Biodiversity
 Degradation of Wetlands
 Pollution
 Unsanitary Conditions

It is evident from the above list of issues that soil degradation ranked high. The main causes of land degradation were also identified as:
 Land Fragmentation
 Inappropriate farming systems and methods
 Overgrazing
 Poor management of agrochemicals use
 Deforestation
 Bush-fires

In order to improve the soil quality, through the development of standards, this work will focus on the major problem, namely, soil degradation and make an effort to address it.

1.1.3 The Soils

The country is underlain by some of the world's oldest rocks which have been modified and altered by deep-seated tectonic activity. These rocks are overlain by predominantly ferralitic soils, and to a lesser extent ferruginous soils, which are the most widely distributed soil types, occurring in both forest and savanna ecosystems in the country. The profile of these soils consists of a thin (20-30 cm) top-soil and a deep (5-10 m) sub-soil. Organic matter and nutrients are strongly concentrated in the top-soil. These soils range in texture from clay loams to sandy loams. Red clay loams tend to predominate in wetter regions and are reportedly more fertile, while in the drier northern parts of the country, sandier soils containing fewer nutrients are quite common. Hydromorphic, podsolic, high altitude and dark ferralitic soils are highly weathered and are thus acidic and deficient in plant nutrients. Where vertisols occur, they are characterised by water-logging and poor internal drainage. The holomorphic soil types are saline.

Generally, the productivity of soils depends on favourable rainfall, adequate depth and maintenance of the humic top- soil. Due to the country's latitudinal location and climate, the soils are very prone to geological and accelerated erosion.

1.1.4 Topography

The main topographical features to the north of the country lie towards the eastern and north-eastern borders and include three large Miocene volcanoes, namely, Moroto (3,890 m), Kadam (3,070m), and Napak (2,540 m), and a number of hills, which are composed of Basement complex rocks. Similar plateau elevations are found in West Nile to the North-west of the country. many of these volcanoes and mountains have been extensively scoured by erosion. Relative relief is low, seldom more than 20 - 30 metres.

South-ward from the northern plains, which range between 750 m and 1,110 m, the plateau level rises towards the Lake Victoria water-shed, through a narrow zone of flat- topped hills in the central and west-central parts of the
country. In this zone, the relative relief is in the order of 150 metres. While similar land-forms are found in the off- shore islands of Ssese, Kome and Buvuma, the hill-tops are generally lower, but to the west of the Lake, the hill-top level rises.

In the Masaka area, the hill-top level stands at 1320 metres, whereas it rises in Koki to 1380 metres and in other parts of Rakai and Mubende to 1500 m. South in Bushenyi, the hill-tops show a continuous rise to over 1800 m. In the south-west of the country, in Kabale and Kisoro, the plateau reaches its greatest heights with hill summit levels at about 2100 metres.

As the plateau level rises to the east and west, it is emphasized by the impressive mountainous topography found along the international border. To the west lie the Mufumbiro volcanoes, the Rwenzoris and part of the deep trough of the Western Rift Valley. To the east, the Uganda-Kenya border is marked (to the south) by Mt. Elgon (4,320 m) and the stump or plug of Tororo Rock and a complex of similar eroded volcanic plugs. Relief contrasts are greatest in the west; from the high peaks of Rwenzori to the hot arid flats around lake Albert to the north, there is a height difference of nearly 4500 metres.

The highest point in the country, the summit of Mt. Stanley, rises to 5,040 metres above sea level, while the lowest part is in the far north-west on the Sudan border, close to Nimule, where the valley of the Albert Nile drops to about 600 metres above sea level.

1.1.5 Drainage

Most of the drainage system of the southern part of the country drains into Lake Victoria, from where the waters escape through the Owen Falls Dam into the Victoria Nile, Lake Kyoga and to Lake Albert. The Kagera and Katonga rivers all rise at present in the swamp filled gaps in the upwarped rift rim of western Uganda and flow sluggishly east to the Lake Victoria and are joined along the river courses by a series of barbed tributaries.