Bio farming in vegetables : effect of biofertilizers in amaranth

Abstract

An experiment was conducted at the Instruction farm attached to the College of Agriculture, Vellayani, during April - Sept 1996 with objectives of finding out the impact of biofertilizers Arospirillum , AMF and dual inoculation under varying and varied levels of fertilizer on amaranthus. Study also aimed to note the economics of the integrated approach and to identify the best economic combinations which improve yield and quality of amaranth varieties Arun and Kannara local. The study had three controls and two number of replications. The results of the study revealed that yield attributing characters like no: of harvests, yield harvest", marketable yield and dry weight were highest in plots applied with dual inoculation of Azospirillum and AMF with 75 per cent dose of p.op. Azospirillum with 50 per cent POP also gave good results. Both these treatments were on par and was better than our state recommendation. Growth characters viz: Seedling growth rate, plant height, number of leaves per plant, number of branches per plant, LAI were highest. for Azospirillum inoculation at early stages. While AMF inoculation gave notable results at later stages. Physiological parameters namely Biomass, NAR, Root dry weight were significantly improved with dual inoculation and higher dose of chemical fertilizer. Leaf dry weight, RGR and CGR responded most to inoculation with Azospirillum at early stages, while at later stage AMF performed well. Kannara local was superior to

148 Arun at early stages. But Arun performed superior to Kannara local with the progress of time. Stem dry weight was significantly influenced by application of AMF. Vermicompost gave high biomass till 45 DAT. Quality of amaranth improved when biofertilizer was given with higher dose of chemical fertilizer in almost all parameters discussed. Dual inoculation with 75 per cent POP gave maximum content of total mineral and moisture. Ascorbic acid content was highest for the treatment dual inoculation with 25 per cent POP. AMF with 75 per cent POP recorded high protein content, the same bioagent with 50 per cent POP gave lowest content of oxalates. Less fiber flush of amaranth w.as got from plots given Azospirillum + 75 per cent POP. Uptake of major nutrients namely Nand P was influenced by inoculation of Azospirillum along with higher dose of chemical and AMF with lower inorganics respectively. Major nutrient status in the soil after the experiment was more in case N,P,K for dual inoculation, Arospirillum and AMF respectively. Irrespective of biofertilizer higher dose of inorganic gave greater residual amount of nutrients. Dual inoculation with 75 per cent dose and Azospirillum along with 50 per cent dose gave maximum l?:C ratio and net returns. Vermicompost recorded minimum disease score. Lower levels of chemical fertilizers recorded less infection.