The life-form and primary productivity of a grassland community of Rangamatia (210 56' N ; 860 41' E) situated at a distance of 15 kms away from North Orissa University and 11 kms from Baripada, the District headquarter of Mayurbhanj in the state of Orissa was analysed. The experimental site was protected from grazing and human interferences for a period of 1 year prior to start of the investigation. The soil of the experimental site was moderately acidic (pH = 5.5). The climate of the locality is monsoonal with three distinct seasons viz. rainy (July to October), winter (November to February) and summer (March to June). The total rainfall during the study period was 1906.2 mm of which a maximum of 499.8 mm was recorded during July. The minimum and maximum atmospheric temperature during the study period was found to be normal.
The floristic composition of the grassland community comprises of 36 species (15 were grasses and 21 were non - grasses). Cynodon dactylon, Digitaria abludens, Eleusine indica, Vetiveria zizanioides among the grasses and phyllanthus fraternus and Sida cordifolia among the non-grasses were found dominant during the study period. The life-form of the community consisted of the class chamaephyte (27.78%), hemicryptophyte (25%), cryptophyte (16.67%) and the therophyte (30.55%). Out of 36 species, 9 species were top strata, 10 were middle strata and 17 species were found to be lower strata. The frequency, density, abundance etc. of the experimental grassland community were determined month wise using 1m x 1m size quadrats as determined by species area curve. All the dominant species exhibited higher percentage of frequency through out the sampling period. The community represented high density value in the month of September and less in the month of April. The grasses showed highest density values as compared to that of the density of non-grasses. The total basal cover of the experimental site showed minimum during April and maximum in the month of September. The grasses showed higher important value index than that of the non - grasses. The dominance index based on density value showed an opposite trend compared to diversity index value. A negative correlation was found between diversity and dominance indices.
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