The Effect of Azolla on Nitrogen Use Efficiency in Rice-wheat Rotations of NepalCuvillier Verlag, 2004 - 113 pages The low productivity of the rice-wheat cropping system in Nepal is associated with a low efficiency of applied mineral N in rice. The aquatic fern Azolla was used to reduce N losses via ammonia volatilization from the flooded lowland rice in farmers' field conditions in Nepal. The Azolla cover changed the floodwater chemistry, thus reducing ammonia volatilization losses. The use of Azolla in combination with Urea increased rice yields by 15% and reduced urea-N losses from 17-38% to 2-8%. A combined use of Azolla and urea is a viable option to enhance the productivity of rice-wheat systems in Nepal. |
Common terms and phrases
15N excess 15N recovery 30 kg N Agricultural algae ammonia volatilization ammoniacal N concentration Analysis of Variance ANOVA applied urea atom Azolla and urea Azolla cover Azolla exchange Azolla-N Bhaktapur biomass chemical fertilizer Cissè Craswell Degree of Sum denitrification Dobermann dose of urea dry matter yield effect of Azolla Error A*B F-Value P-Value Freedom(df farmers field experiment flooded rice floodwater chemistry floodwater pH floodwater temperature g pot-1 grain dry matter grain yield green manure harvest higher increased kg ha-1 kg N ha-1 Khumaltar labeled Azolla lowland rice Macale maximum tillering Mean F-Value P-Value micro-plots NARC Ndff Nepal NH3 volatilization nitrogen-15 nutrient P-Value partial pressure Philippines pot experiment recovered rice crop rice fields rice plant rice-wheat system root second split significant Source Degree Square SS Square(SS Sum of Mean Table Total urea application urea Azolla urea-N Variance ANOVA Vlek Watanabe Wet season Wet seasons 2001 wetland rice