EVALUATION OF THE EFFECTS OF FLOODING ON THREE VARIETIES OF RICE
Background of the Study: The damaging effects of flooding remain as major sources of concerns among millions of rice farmers worldwide. The weather change due to various reasons causing unexpected and sudden flood recently in Nigeria has negative impacts on rice farming and people’s life. This research project is to evaluate the effect of flooding on the growth of three varieties of rice grown in Abakaliki Ebonyi State and to see how it influences people and agriculture.
The extent of the damage of flooding on rice is related to at least three factors. The temperature of the water, the amount of water motion and the duration of the flood. Temperature affects the speed of respiration. The faster the respiration, the quicker the oxygen is depleted and the sooner fermentation begins. Warm water speeds respiration, oxygen use and cell death. The faster water moves the greater the degree of turbulence. This water turbulence oxygenates the water slightly. Increasing oxygen content of the water slightly decrease’s the impact of flooding on plants. Duration of the flood is important because many of the effects of low oxygen on plants are reversible of the duration is not too long. Long durations allow for increased oxygen depletion and build up of harmful chemicals. Although local conditions influence the effects, 36 to 48 hours is often the tolerable limit.
In general rice cannot tolerate flooding better than other plants. But, if flooding occurs in the spring, the rice growing point is near the soil surface (below or above) making it likely to be submersed longer. Soil water logging and submergence (collectively termed flooding) are abiotic stresses that influence species composition and productivity in various type of rice, worldwide.
In rice farming, flooding species are manipulated (e.g. Ofada, upland and Nerica rice) or are accommodated by genotype selection. There have also been recent advances towards developing cultivators for low land areas prone to short-duration flash flooding. For most of this rice, excess water is a constraint to growth and productivity in many regions and this adversely affecting the growth of various types of rice.
Finally, rice are often damaged and thus, more susceptible to disease organisms. Disease symptoms may not appear until several weeks or even months after the flood event.