EFFECTS OF PLANT DENSITY, ORGANIC MATTER AND NITROGEN RATES ON RICE YIELDS IN THE SYSTEM OF RICE INTENSIFICATION (SRI) IN THE "OFFICE DU NIGER" IN MALI

Abstract

A study was conducted to determine influence of combined application of farmyard manure and different levels of inorganic fertilizer on growth, yield and yield components in the System of Rice Intensification in Mali. Three types of experiments were conducted at the agronomic research station of the Regional Centre of Agronomic Research of Niono (CRRA-N) in the Office du Niger zone, which extends in the North-eastern direction (between 13° and 15° latitudes North and 4°-6° Western longitudes). The materials used comprised a rice variety, mineral fertilizers and organic matter. The rice variety used was Kogoni 91-1 also called (Gambiaka Suruni) which is an improved variety with a cycle of 120 days. The mineral fertilizers used were, triple superphosphate (TSP), Di-Ammonium Phosphate (DAP, urea and potassium chloride. The potassium chloride was uniformly applied to all plots, while the rate of application of TSP, urea and DAP depended on the treatments described in the research protocol. The organic matter (OM) source was animal manure coming from the animal park of the research station. This manure was characterized by low content of nitrogen (0, 34 %N), phosphorus (0.16% P) and potassium (0.65% K). The results indicated significant yield benefit of the SRI system although the drainage system not efficient. Significant interaction between row spacing and soil fertility level occurred showing that row spacing as wide as 30cm x 30cm can be used in SRI system when soil fertility is high. However, when soil fertility level is low, it is reasonable to use row spacing of 25cm x 25cm or narrower as certain studies have already shown it. Although good yield can be obtained using farmyard manure, addition of mineral fertilizer still increase rice yield showing that combination of organic and inorganic fertilizer should be considered to sustain rice yield.