ABSTRACT

The main objective of this Thesis was to determine the impact of the irrigation system and agricultural production on water quality in an irrigation scheme. The investigate irrigation system was located in the village of Chókwé, Mozambique. The irrigation system extends up to 28 600 hectares of agricultural land area. Fields in Chókwé produce mainly rice (half of the area) and other crops (cereals, cotton) and mainly vegetables during winter time. In the Thesis was focused on the Mozambican part of the Limpopo Basin.

In our Thesis were measured six different water quality parameters: nitrate, phosphorus, pH, conductivity, turbidity and dissolved oxygen. In order to determine the exact pH- value the water temperature was measured, too. We investigated The samples examined in the Thesis were taken from 40 sites. All together there were 98 sampling sites. The measured data was analyzed by using the SPSS software. According to this research the most significant differences between the irrigation and the drainage canals occur in the pH -values and in the conductivity levels of the water. Nitrate and phosphorus concentration, turbidity and dissolved oxygen concentration seem to have no statistical significances. Nitrate and phosphorus concentrations are very low, below Mozambican standards.

This study is made in the cooperation with Universidade Eduardo Mondlane and Savonia University of Applied Sciences as a part of North&Shouth Higher Education Institution Network Programme. In March 2008 there was the first intensive course shared by four countries Mozambique, Kenya, Finland and South Africa. The next intensive course will be held in Kenya in the fall 2009.

1  INTRODUCTION

1.1 Background

Many people think that Africa is a humid, tropical continent. In reality, 65% of the continent’s land area is classified as arid or semi-arid. Six of the driest countries in the world are found in Africa and this number is expected to double by the year 2025. The majority of Africa’s population live in the continent’s tropical greenbelt, which includes the Congo River basin and the coastal forests in the west and east Africa, so the distribution of water resources is linked to the distribution of the people. The quality and quantity of water is a vital factor in determining the well-being of the population. The fact that the population is concentrated to the tropical greenbelt is also related to the availability of land suitable for cultivation. In the African continent, there is 0,7 ha of arable land per person, which is lower than in any other part of the world except Asia. (Atlas 2003, p.13.)