Influence of foliar application of chemicals on the root exudations and rhizosphere microflora ofSorghum vulgare andCrotalaria juncea

The effect of foliar application of sodium nitrate (0.1%), disodium hydrogen phosphate (0.1%), 2,4-D (25 p.p.m.) and Dithane Z-78 (200p.p.m.) on the quantity, and quality of sugars and amino acids exuded by sorghum and sunnhemp and on the rhizosphere microflora were studied. The sodium oitrate spray adversely affected the amino acid exudation in sorghum but increased the same in sunnhemp; the disodium hydrogen phosphate and Dithane Z-78 sprays reduced amino acid exudations whereas the 2,4-D spray enhanced the same in both the plant species. The disodium hydrogen phosphate spray caused qualitative changes in sugars but enhanced the quantity only in sorghum; the 2, 4-D spray increased exudation of sugars in both plant species and the sodium nitrate and Dithane Z-78 sprays caused qualitative changes in both plant species. Increases in bacterial population by 2, 4-D spray, in actinomycetes by 2, 4-D, disodium hydrogen phosphate and sodium nitrate sprays, and in fungal population by 2, 4-D and sodium nitrate sprays were observed in sorghum rhizosphere whereas in sunnhemp 2, 4-D and sodium nitrate sprays increased the bacterial, actinomycetes and fungal populations.