Biochemical characteristics and microbial association of Isabgol (Plantago ovata Forks.) growing soils in Western Arid region of India

Isabgol (Plantago ovata Forks.) is one of the important cash crops in arid and semi-arid regions of India. The husk of Isabgol seeds are primarily used as laxative in medicinal preparations. The cultivation of Isabgol crop is very much dependent on soils and weather conditions as this crop is highly susceptible to many biotic and abiotic stress parameters. Soil microbial population is involved in many direct and indirect interactions with crop plants. The type of microbes present in the soils also affects the plant health. Soil samples from the rhizospheric zone of the plants were collected from Barmer, Jalore and Ajmer Districts of Rajasthan State in western arid region of India. The soil EC and pH (1:2.5) recorded were in the range of 0.12 to 0.46 dS/m and 7.4 to 8.9, respectively, depicting neutral to alkaline soils, the macro nutrient viz; N, P, K were found to be in the range of 128.0 to 192.54, 19.4 to 80.4 and 149.8 to 338.8 kg/ha, respectively. The DTPA extractable micronutrients Cu, Zn, Mn and Fe were in the range of 0.29 to 3.50, 0.26 to 1.5, 0.51 to 4.51 and 1.0 to 5.38 ppm, respectively, in the soil samples of Isabgol growing regions of Rajasthan. Total viable count (TVC) gives a quantitative idea about the presence of microorganism such as bacteria and fungi in samples. The total bacterial count of soil microorganisms varied from 0.8x107 to 1.96x107 cfu/g whereas, total fungal count varied from 1.52x106 to 2.85x106 cfu/g. Beneficial microorganism population in terms of total Azotobacter count (0.1x105 to 1.0 x105 ) psuedomonads counts (3.33x105 to 5.8x105 cfu/g) and phosphate solubilizing bacterial count (0.1x103 to 1.0x103 cfu/g) varied highly in different soils.