The Importance Of Environment And Patterns Of The Environment

1. Recognise patterns and processes of the environment and how they relate to the sustainable utilisation of agricultural land.

Introduction

In order to be a successful crop grower, you must be able to recognise the patterns of the environment, such as rainfall, climate, dry cycles, original vegetation, seasons, the movement patterns of animals so that you can apply these in implementation of your agricultural enterprise.

The processes of the biophysical environment include the interactions and relationships between food webs, human activities, soil, climate, water, plants, animals and solar energy.

We all live in an environment where certain basic requirements are provided. No matter how much technology or money we have if those basic

There is, however, wide regional variation in annual rainfall (Figure 3), from less than 50 mm in the Richtersveld on the border with Namibia, to more than 3000 mm in the mountains of the South-Western Cape, however only 28% of the country receives more than 600 mm (Table 1). The uncertainty of the rainfall is best expressed by the co-efficient of variation in annual rainfall (Figure 4).

The low rainfall regions have the highest co-efficient of variation. Annual rainfall distribution is skewed such that there are more below average than above average rainfall years, and the median is a more meaningful than the mean. The high seasonal variations are accompanied by high spatial variability, and the annual potential evapo-transpiration may exceed annual precipitation by ratios of up to 20:1, hence drought conditions are a common phenomenon (Schulze 1997). The declaration of drought status to a magisterial district has historically been used by the Department of Agriculture & Land Affairs to intervene in exceptional circumstances. Since 1994 this intervention has been discontinued and graziers are encouraged to plan their production system within the long-term production expectations of their farms.

Table 1. Annual rainfall distribution and climatic classification in South Africa

Rainfall (mm) Classification Percentage of land surface

<200 Desert