Most of these factors are explained in details below:

The irrigation system for the field or a farm must function alongside other farm operations such as land preparation, cultivation and harvesting. The use of the large mechanised equipment requires longer and wider fields. The irrigation systems should not interfere with these operations and may need to be portable or function primarily outside the crop boundaries.

The type of irrigation system selected is an important economic decision. Some types of pressurised systems have high capital and operating costs, but may utilise minimal labour and conserve water  (see table). Their use tends toward high value cropping patterns. Other systems are relatively less expensive to construct and operate, but have high labour requirements. Some systems are limited by the type of soil or the topography found on a field. The cost of maintenance and expected life of the rehabilitation along with an array  of annual costs like energy, water, depreciation, land preparation, maintenance, labour and taxes should be included in the selection of an irrigation system.

Topography is a major factor affecting irrigation. Of general concern are the location and elevation of the water supply relative to the field boundaries, the area and configuration of the fields and access by roads and utility lines. Field slope and its uniformity are two of the most important topographical factors.

The soil's moisture holding capacity, intake rate, and depth are the main criteria affecting the type of system selected. Sandy soils typically have high intake rates and low soil moisture storage capacities and may require an entirely different irrigation strategy then the deep clay soil with low infiltration rates but high moisture storage capacities. Sandy soil requires more frequent, smaller applications of water, whereas clay soils can be irrigated less frequently and to a larger depth. The distribution of soils may vary widely over a field and may be an important limitation on some methods of applying irrigation water.

The quality and quantity of the source of water can have a significant impact on the irrigation practices.  Salinity is generally the most significant problem. A poor quality water supply must be utilised more frequently and in larger amounts then one of good quality.

The yields of many crops can be as much affected by how water is applied as the quantity delivered. Irrigation systems create different environmental conditions, such as humidity, temperature and soil aeration. They affect the plant differently by wetting different parts of the plant. Some crops have high economic value and allow the application of more capital intensive practices. Deep rooted crops are more amenable to low frequency, high application rate systems than shallow rooted crops.

Beyond the confines of the individual field, irrigation is a community enterprise. Individuals, groups of individuals and often the water authorities and state governments must join together to construct, operate and maintain the irrigation system as a whole. Irrigation often means a technological intervention in the agricultural system even if irrigation has been practised locally for generations. New technologies mean new operation and maintenance practices. If the community is not sufficiently adaptable to change, some irrigation systems will not succeed.

The designer, consultant or manager of irrigation systems should be aware of the broader setting in which irrigated agriculture functions. Ignorance has led to many more failures or inadequacies then has poor judgement or poor training. One needs to be reminded that much of the engineering practice is art rather than science. Experience is often a more valuable resource then computational skills, but both are needed.