DEVELOPMENT OF MECHANICAL UREA BRIQUETTE APPLICATOR FOR SYSTEM OF RICE INTENSIFICATION TECHNIQUE

India is the second largest consumer of fertilizers in the world, after China. The total annual nitrogen consumption in Indian agriculture is 16.56 Mt, of which about 40% is consumed by rice. There is increasing trend in consumption and production of nitrogen in India. Nitrogen fertilizer is usually broadcast as prills in paddy fields prior to transplanting, followed by one or more topdressing in the floodwater within the period from transplanting to flowering. In wetland paddy cultivation, only 30-40% of nitrogen applied is fruitfully utilized as about two-third part is lost through gaseous losses, runoff, and leaching or is immobilized in the soil. One means to reduce nitrogen losses and improve fertilizer efficiency is to deep place fertilizer nitrogen as urea briquette (UB) of compacted prilled urea. Placement of UB may be done by hand after conventional line transplanting at the rate of one UB near the centre of each four rice hills and at soil depth of 7–10 cm, but is a time consuming process and requires lot of labour. Fertilizer deep placement has been proven to be effective in increasing fertilizer use efficiency in wetland rice production, but because of typical properties of fertilizer granule properties, machines developed to place them gave inconsistent results. Thus, physical and engineering properties of urea briquettes UB1 (3g) and UB2 (2g) were studied in relevance to the design of mechanical urea briquette applicator. Size and shape of metering cup were designed on the basis of maximum size of briquettes. Free flow of urea briquettes in the briquette hopper was influenced by angle of repose of UB and coefficient of static friction between UB and hopper material. Performance of metering mechanism of the applicator for uniformity of placement was tested in the laboratory on sticky belt, and performance parameters as average spacing, multiple index, missing index, quality of feed index and precision were evaluated. The metering device was tested for different cup sizes of 6.5mm (CS1), 3.5mm (CS2) and 2.5 mm (CS3) with hemi-spherical shape of cup. The average spacing was significantly influenced by different sizes of cup and types of briquette at 5 % level of significance. Miss index was highly influenced by different cup sizes at 5% level of significance. The cup size (CS) also significantly influenced missing index. It was also observed that multiple index was significantly influenced by cup size, urea briquette types at 5% level of significance, and briquette size had maximum influence on multiple index. Quality of feed index was highly influenced by UB type, followed by CS of the metering mechanism. General mean of quality of feed index was 94.77 per cent. The effect of urea briquette and cup size was found to be nonsignificant in case of precision. UB1 application rate was 112.4kg.ha -1 , whereas in case of UB2 the application rate was 71.2 kg.ha -1 . Since UB1 could provide recommended rate of N, optimum metering cup size for the briquette size was selected as 6.5 mm for final development of the applicator.