Rice Drought Effects

Drought and its effect to crops

Water is a primary factor in determining the world’s rice production. It is necessary for several metabolic reactions, and its restriction can affect all the aspects of growth and development in plants the available fresh water resources in the world are constant and the population of the world is exponentially increasing, the available water per capita continuously decreases which result to water scarcity and stress in some area.

Total rice production in Asia has more than doubled over the past 50 years; however, drought and floods remain the main sources of risk and uncertainty for farmers. It is estimated that in Asia some 23 million ha of rice are affected by drought. Most of these areas are rainfed, although

In rice, research reports demonstrate that drought not just reduction in grain yield, but also grain quality. Drought is related to constraints in plants causing several negative effects to metabolic processes, including water relations, nutrient uptake and metabolism, and photosynthetic assimilates. Also, it causes the formation of reactive oxygen species ROS, denaturation of protein and damage to nucleic acids. As a result, leaf expansion, photosynthetic rate, tillering process, plant growth and development, and grain productivity and quality are limited. Plants have various defenses against drought stress, including photosynthetic activity reduction, stomatal closure, transpiration decrease, antioxidative enzymes activation, carbohydrate metabolism changes, and organic acids, antioxidants and osmolites accumulation. Drought resistance in rice mainly depends on the capacity for osmotic adjustment, allowing plants to maintain turgor and to control water

Throughout the world, the best agricultural land is already fully utilized and hence marginal land including saline soil is being brought to agriculture. Salinity is an environmental challenge that severely limits plant growth, reduces cultivatable land area, crop productivity and quality worldwide (Hossain et al., 2012 and Shrivastava & Kumar, 2015) and according to FAO survey as cited by Plaut et al. (2013) that over 800 million ha in near future will be affected by salinity, making it a major constraint to food production for a steadily increasing population.

Soil salinity refers to the content of water soluble mineral salts primarily sodium, potassium, magnesium, calcium and chloride, in the soil. Soil salinity could be a result of either the intrusion of seawater into the agricultural area, or of a raise in salt-affected groundwater. Apart from this, salination also commonly occurs as a result of human activities such as irrigation, residual of soil and water amendments, use of animal waste and chemical fertilizers (Kader,