Effect of Sowing Date and Plant Density on Quantitative and Qualitative Yield of Brown Mustard (Brassica juncea) Under Saline and Non-Saline Soil Conditions

To investigate the effects of sowing date and plant density on quantitative and qualitative yield of forage brown mustard (S-83 line), a split-plot experiment based on a randomized complete blocks design with four replicates was carried out in 2015 and 2016. The experiment was done in saline (10 ds/m) and non-saline (2 ds/m) environments in the research farm of Mazraeh Nemooneh (Anbaralum township), Iran. The main factor was the sowing date at five levels (starting from Nov 6, with 15-day intervals), and plant density at three levels (208000, 277000 and 416000) was assigned to subplots. The results showed that the effects of year and sowing date on all traits were significant at p<0.01. Also, the effect of plant density on the number of branches, fresh forage yield, pods per plant and fresh pod weight was significant at p<0.01. Furthermore, the interaction effect of year × environment on plant height, fresh forage yield, pods per plant, dry forage yield, number of auxiliary branches, leaf fiber percentage and phenological traits of brown mustard was significant at p<0.01. The mean comparison showed that late sowing led to an increase in leaf protein and fiber percentage, whereas salinity significantly decreased shoot dry weight, plant height and fresh and dry forage yield. Also, soil salinity not only decreased the protein percentage but lowered forage quality and fresh forage yield by 7000 and 4000 kg/ha in the first and second years, respectively. The highest forage yield was 42593.5 kg/ha and obtained when the plant was sown on Nov 6, and late sowing decreased the yield. Overall, sowing on Nov 6 was optimum and later sowing dates lead to decreased fresh and dry forage yield.