Background Study 1.0 - Oryza sativa sp. (Rice Cultivation)
Rice (Oryza sativa sp.) is an important food crop that serves as a major carbohydrate source for nearly half of the world’s population (Mohanty, 2013). In order to meet the requirement of global rice demands, synthetic nitrogen (N) fertiliser and pesticides have been used in modern rice technology. Indiscrimination of pesticide usage could result in (1) contamination of ground and surface waters through runoff and seepage, (2) reduction of microorganism in paddy soil and water which results in soil infertility and (3) health impairment of farmers due to direct or indirect exposure to hazardous chemical (Peng et al., 2012).
In previous study, it was shown that rice farmer in China are over-applying 40% of pesticides compared to the amount needed and leads to the yield reduction – due to pest outbreaks which resulted from disruption of biodiversity in rice ecosystem (Huang et al., 2003). In 2002, total consumption of the annual N fertiliser in China was 25.4 million metric tons; quarter of it was used in for rice production (FAOSTAT, 2007). Due to overfertilisation, only 20-30% is taken up by the plant; remaining 70-80% is leached out to the environment – resulted in eutrophication in river. In addition, over-application of synthetic N fertiliser could lead to reduction of grain yield due to increasing susceptibility to lodging and damage from pests and diseases. This includes the emergence of Bacterial blight (BB) disease which caused by Xanthomonas oryzae pv. oryzae (Xoo) and resulted in losses of yields in rice cultivation. BB causes loses in rice cultivation, averaging from 20%-30% nevertheless severe cases can result in reduction of yield up to 80% (Horgan and Henderson 2015).
In conclusion, modern cultivation of rice have caused detrimental effects to the environment and emergence of diseases which resulted in reduction of rice grains yield and soil infertility. Thus, improvisation of current farming in rice cultivation need to be done in order to overcome these problems.