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T. C. Pokhriyal , B. C. Ramola , M. S. Bisht , H. O. Nautiyal , K. P. Unnikrishnan

Abstract

Nitrate contents in the leaf, litter and soil upto 60 cm depth were investigated in the natural sal (Shorea robusta) forest, Jhajra, DehraDun. Significantly more soil nitrate was observed in the upper depths (0-30 cm) as compared to 30-60 cm depth. The nitrate contents in the top and middle portion of canopy were significantly higher as compared to the nitrate content in the bottom portion. The nitrate content in the leaves have also responded to the seasonal variations. Though there was no significant correlations observed among the variables when data was pooled for the whole year, significant correlations were available within the seasons.

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T. C. Pokhriyal , B. C. Ramola , A. S. Raturi

Abstract

In the present study, seasonal changes in the moisture and N contents of the leaf, litter and soil upto 60 cm depth were carried out in the natural sal (Shorea robusta) forest, Jhajra, Dehra Dun. A significantly higher soil moisture contents were observed during the rainy seasons (July, Aug., Sept.) and lowest in the months of June. The maximum litter fall was observed in the months of April, March followed by May. The remaining months have poor litter fall and they do not differ among themselves signlficantly. The upper part of crown have significantly higher N contents as compared to middle and bottom. No slgnificant changes in the soil N was observed upto 60 cm depth. A negative correlation was observed between soil moisture and litter production rate and green leaf N and litter N. Whereas a positive correlation was noticed between soil N and litter production, this relationship was more pronounced during summer months.

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B. K. Subba Rao , B. C. Ramola , V. N. Sharda

Abstract

The paper deals with the effect of thinning (20%) on peak flow and fort-nightly runoff in a forested mountainous watershed near Dehra Dun, U.P. India. It has been found that the peak rate of flow increased by 8.6% in the first year (significant at 5% level) but the effect was insignificant in the second year after thinning. There was no significant effect on the total volume of fort-nightly runoff either in the first year or in the second year after thinning.

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R. C. Ghosh , B. K. Subba Rao , B. C. Ramola

Abstract

This paper presents the results of interception studies carried out during 1977 in coppice sal forest at Rajput Forest Experiment Station, (Rajpur Forest Block, West Dehra Dun Division) to evaluate the effect of thinning on the interception loss. This study is one of a series of hydrological studies that are being carried out at Forest Research Institute, Dehra Dun. It is proposed develop mathematical models by using the results of these studies, to predict hydrological behaviour of forested watersheds. These models also enable us to predict the effect of management operations and biotic influences on the hydrological behaviour. Present study has shown that the interception loss decreases with increasing amount of rainfall and that a reduction of crown density by 22% has resulted in a reduction of interception by 5% in coppice sal forest. Also, it has been observed that interception loss depends upon rainfall and vegetation characteristics.

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B. K. Subba Rao , B. G. Dabral , B. C. Ramola

Abstract

Regular hydrological studies are in progress since 1967 in the two experimental watersheds in the hill sal coppice forest of Rajpur Forest Block in the Debra Dun Forest Division. This paper presents the preliminary observations on runoff, sediment discharge and guality of water, made in one of the experimental watersheds (watershed No. 1) during 1967-70. It has been observed that the water flowing out is of high purity, pH was 7, tending to be slightly acidic. Among the dissolved chemicals CaO ranged highest. The total silt washed out during the monsoon months varied from 49 to 153 tonnes/km².

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