the female organs of the plant. Optimum factors for ideal pollination are a relative humidity rate of 50–70% and temperature of 24.4 °C. If the humidity rate is higher than 90%, the pollen would not shed. Increasing air circulation is a favourable method of keeping humidity levels under control. Irrigation Irrigation is the process of artificially applying water to soil to allow plant growth. This term is preferably used when large amounts of water is applied to dry, arid regions in order to facilitate plant growth. The process of irrigation not only increases the growth rate of the plant but also increases the yield amount. In temperate and tropical areas rainfall and snowfall are the main suppliers of irrigation water, but in dry places with unfavourable weather conditions, groundwater serves as an essential source. Groundwater collects in basins made up of gravel and aquifers, which are water-holding rocks. Dams also act as an essential distributive source of irrigation water. Underground wells also play an important role in storing water for irrigation, specifically in America, and Arizona, in particular. Water and debris from streams filled by water accumulated during storms also collect into underground basins. There are two types of irrigation techniques: spray irrigation and drip irrigation. Drip irrigation is regarded as more efficient as less water evaporates than in spray irrigation. References Agriculture Crops