An Asian Journal of Soil Science

A. Lalita Kumari ¹, G. Swarajya Lakshmi ²

Affiliations
1 Department of Soil Science, Regional Research Unit (Chemistry) Regional Agricultural Research Station, Lam, Guntur (A.P.), IN
2 Department of Bioresources and Environmental Studies, College of Agriculture, Acharya N.G. Ranga Agricultural University, Hyderabad (A.P.), IN

Abstract

A survey was conducted in chilli growing areas of Guntur district on soil properties, nutrient status and microbial populations besides collection of rhizosphere samples for isolation of Azospirillum inoculants.The survey indicated that out of 50 rhizosphere soils surveyed, 40 samples were heavy black or mixed black, the rest of 10 were sandy or red sandy loams. All the soils were neutral to alkaline in reaction, non saline and high in potassium status. Only 12 and 18 per cent of the surveyed samples were medium in organic carbon and available nitrogen, respectively. Rest were low in both the parameters. Only 8 per cent of samples recorded medium in available P₂O₅ and the rest were high. Population of Azospirillum ranged from 3.53 to 5.82 log₁₀ CFU. High population of Azospirillum (>5 log₁₀ CFU) was noticed in rhizosphere of chilli grown in heavy black soils. Comparatively, higher populations of other bacteria, fungi and actinomycetes were noticed where the crop was grown on heavy black soils under high level of input utilization. A non significant negative correlation was observed between the soil pH and EC and microbial population. Significant positive correlation was noticed between organic carbon and population of Azospirillum, other bacteria and fungi. Similar significant positive correlation was noticed between soil N and Azospirillum, other bacteria and fungi.

Keywords

Chilli, Rlizosphere Soils, Available Nutrients, Microbial Population, Azospirillum, Bacteria, Fungi, Actinomycetes.

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A. Lalita Kumari ¹, G. Swarajya Lakshmi ¹

Affiliations
1 Regional Agricultural Research Station, Lam Farm, Guntur (A.P.), IN

Abstract

An experiment was conducted at ARS, Amaravathi to isolate the native strains of Azospirillum from the rhizosphere of chillies and to study their efficiency on growth, nutrient content, uptake, nitrogen forms and microbial population in soil. Chilli seedlings were grown for 45 days in the pots and were then removed carefully along with ischolar_mains. Dry weights of plant samples were recorded and were analyzed for nitrogen, phosphorus and potassium concentrations and N, P and K uptake in the seedlings were computed. Rhizosphere samples were analyzed for nitrogen forms and microbial population. Inoculation with different native isolates of Azospirillum significantly increased nutrient uptake by the chilli seedlings and also nitrogen content in soil. Among the different native isolates tested, SCH₁₈ was superior to all other native isolates and was at par with the standard strain ICM 1001.

Keywords

Native Strains of Azospirillum, Rhizosphere, N, P and K Uptake in the Seedlings, Nitrogen Forms.

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