Assessment of Water requirements for Horticultural Crops in Arid Regions

Arid regions have very low precipitation values (usually less than 250mm), consequently there is little water availability, so in these regions efficient management of this resource is imperative. This study aims to assess the water needs of some horticultural crops and a fruit tree on the island of São Nicolau, Cape Verde. Twelve crops were selected among the most used by farmers in the area and three scenarios related to precipitation were created. The water needs of the crops in the three scenarios were assessed using the previously calibrated Hargreaves - Samani method. The water balance to determine irrigation consumption was made for the following 3 rainfall conditions: scenario 1 corresponds to the year with the lowest rainfall; scenario 2 is the average of the values recorded over the series; and scenario 3, the year with the highest rainfall. The consumption of water by the crops was not significantly different in the 3 scenarios, the difference being in the amount of water resulting from the precipitation that can be stored and, thus, determining which area can be dedicated to irrigated agriculture. The lettuce, cucumber, pepper and carrot cultures, since the cultures studied were those with the lowest water requirements. The cultivation of banana cultivation should be the subject of a study on its adaptability, due to its high consumption, namely the possibility of applying deficient irrigation in order to increase water productivity.