Water use efficiency, productivity, photosynthesis and sustainability of pressurized irrigation systems for Indian mustard [Brassica juncea (L.) Czern and Coss.] under semi-arid conditions of Rajasthan

An experiment was conducted to find out the effect of micro-irrigation and fertigation on water use efficiency, productivity, photosynthesis and sustainability of mustard crop during rabi seasons of 2009-10 and 2010-11. The treatments consisted of five irrigation systems in main plot viz., micro-sprinkler (MS), micro-sprinkler followed by check basin (MS+CB), drip irrigation system (DS), drip followed by check basin (DS+CB) and check basin (CB) alone. In sub-plot, four treatments of N doses viz., control (0 kg/ha N), 40, 80 and 120 kg/ha of N were taken. The soi pH and EC varied from 8.5-9.5 and 1.5-2.5 dS/m, respectively. The soil was poor in available N (125 kg/ha), medium in available P (20 kg/ha) and available K (245 kg/ha). Micro-sprinkler, drip systems and their combination with check basin method resulted in significantly higher growth attributes like plant height, dry matter accumulation and chlorophyll concentration and photosynthetic rate as compared to check basin alone during both the years of the experimentation. The similar trend was recorded for biological, seed and oil yield. Other sustainability parameters like sustainability yield index, water use efficiency and production efficiency were recorded highest in pressurized irrigation systems. During the first year, the irrigation water use efficiency and gross water use efficiency were recorded highest under drip system being at par with the micro-sprinkler, but in the subsequent year the highest water use efficiency was produced under micro-sprinkler system due to uniform moisture distribution in the soil profile. Among sub-plots, growth parameters and yield attributes were improved with increasing dose of nitrogen up to 120 kg/ha, while the days to 50% flowering reduced with higher N doses. The enhanced yield under 120. kg N/ha also resulted in higher sustainability index, production efficiency and water use efficiency.