Evaluation of boron fertilizers for a sunflower (Helianthus annuus L.) - green gram (Vigna radiata L) cropping sequence in Inceptisols
Field experiments were conducted at the Agricultural Research Station, Bhavanisagar, Tamil Nadu, India during 1999 to 2000 in Inceptisols to evaluate boron fertilizers (borax, boric acid, Agribor) and to assess the effect of the mode and level of B application on the total B uptake and yield of sunflower and green gram. The experimental field was found to be deficient in available B (0.35 mg kg-1). Sunflower was raised as the main crop. Different B levels (0.5, 1.0, 1.5and 2.0 kg B ha-1)as soil application and two levels of foliar spray (0.2% and 0.3%) were compared with the control. The treatments were superimposed on the recommended dose of NPK. After harvestingthe main crop of sunflower, the residual effect of B was studied by raising green gram on the same field. The results revealed that the application of all the levels of B resulted in a significant increase in the B uptake and yield of sunflower as compared to the control. The highest yield was recorded for the soil application of B at a rate of 2.0 kg ha-1. The yield increase of sunflower was 3.6 to 15.8% and 7.2 to 18.9% over the control for seed and stalk, respectively. The green gram grain yield increased by 4.2 to 13.5% after the application of 1.0 and 2.0 kg B ha-1 to the main crop. No residual effect was observed for the lowest level of B application (0.5 kg ha-1). Agribor is equally as effective as borax in influencing the B nutrition of both the crops.