The Effect of Urea and Urea with Urease Inhibitors on TuberYields and Starch Content in Potatoes

摘要

Volatile losses of NH ( originating from urea may be reduced by the application o urease inhibitors. The objective of the work was to compare the effect of three rates o nitrogen applied in two different fertilisers - urea and urea with urease inhibitoi (NBPT). The effect of the fertiliser on tuber yields and starch content in potatoes wa: monitored. Two-year small-plot field experiments were established with the earh cultivar 'Red Anna'. The experiment involved seven treatments (with 4 replications)including a control unfertilised treatment. The N rates were as follows: 54, 72 and 9( kg N ha1. The yields differed statistically significantly in the respective years, i.e. 29.3-40.5 t ha 1 in 2010 and 17.3-23.7 t ha 1 in 2011. The effect of both fertiliser: and/or nitrogen rates on tuber yields was irregular. Higher yields were achieved ii treatments where higher rates of urea were applied as compared to the same rates o urea with the inhibitor only in 2011. On the other hand treatment with the lowest rat* of urea with urease inhibitor showed yields comparable to or higher than all the othei treatments in both years. The year-on-year fluctuation in the starch content of the tubers was minimal, i.e., 12.48-15.00% (2010) and 11.79-13.60% (2011). Thelowesi starch content in tubers was achieved with the lowest rate of N in urea. No difference; in the starch content were observed in terms of the N rates applied in urea with tin urease inhibitor in the two years. The results showed that the effectiveness of both fertilisers was affected primarily by the year.