P S Ramakrishnan
Articles written in Proceedings – Plant Sciences
Volume 87 Issue 8 August 1978 pp 243-253
The interference between wheat and
Volume 89 Issue 5 October 1980 pp 421-427
The present study reveals a variety of competitive interactions between the two species of
Volume 90 Issue 6 December 1981 pp 547-553
The seeds of
Volume 91 Issue 1 February 1982 pp 61-68
Three categories of secondary successional herbaceous communities subsequent ot slash and burn, viz., early successional non-sprouting, early successional sprouting and late successional populations were investigated for their reproductive efficiency considering leaf component since it is the chief organ of photosynthesis. Early successional non-sprouting populations were found to be reproductively the most efficient whereas the early successional sprouting populations allocated more to vegetatively reproducing organs. While the high reproductive potential of early successional non-sprouting species was associated with vigour and production efficiency of the species, this relationship was stronger with the latter characteristic. On the other hand, early successional sprouting populations showed inverse relationship between vegetative and sexual reproductive effort. The strategy of late successional species seems to be to maximize vegetative growth in a closed habitat. The significance of these strategies is discussed in the paper.
Volume 91 Issue 3 June 1982 pp 241-253
The peripheral disturbed zone of a 50-year old stand of the forest at Lailad was dominated by
Volume 91 Issue 3 June 1982 pp 255-268
The litter production in a 50 year old humid sub-tropical forest at Lailad was found to be 5.5 t/ha/yr, 77% of which was through leaf and the remainder through wood. Litter production was more in the peripheral disturbed zone compared to the undisturbed central zone which is related to the successional status of the community. Species differences in the rate of decomposition of litter was noted. Besides litter production and decomposition pattern were related to seasonal differences in temperature and humidity. The present results have been discussed in the light of the data from other studies done elswhere.
Volume 91 Issue 3 June 1982 pp 269-280
This paper deals with water and nutrient flow through incident rainfall, throughfall and stemflow through a 50-year old stand of forest at Lailad. A larger proportion of water was accounted as throughfall and stemflow in March-April and was related to canopy density and this was inversely related to interception loss which was maximum in December. Many of the nutrient concentrations like that of N, K, Ca, etc. increased with the maturation of the leaves during October–November. Though concentration of nutrients was higher in stemflow, the total quantity was more
Volume 91 Issue 5 October 1982 pp 397-407
Seed germination of
Volume 93 Issue 3 July 1984 pp 379-400
Rotational bush fallow agriculture variously termed as shifting agriculture, slash and burn agriculture are commonly known in India as
Volume 96 Issue 1 March 1986 pp 25-36
Three year old open grown pine saplings were selected. Three whorls of shoots were begun in one year. The species thus exhibits a recurrent flushing pattern. Two orders of shoots were recognised on the main leader during the study period of one year. Shoots produced at lower canopy levels attained less extension growth and fewer and shorter needles compared to shoots at higher canopy levels. The growth characteristics of shoots indicated shade intolerant nature of the species. The fascicles of 3 flushes appearing at different times of the year had different patterns of fall and life expectancy. The adaptive strategy of the growth pattern with recurrent flushing and short longevity of the needles are discussed and related to faster growth rate of
Volume 97 Issue 2 April 1987 pp 165-176
Coexistence of closely related
At their altitudinal limits at 950 m elevation,
Volume 97 Issue 2 April 1987 pp 177-183
The competitive relationships between
Volume 98 Issue 1 February 1988 pp 13-23
Growth and allocation patterns of biomass and nutrients of herbaceous species from grasslands at Cherrapunji in north-eastern India were studied under varied nutrient stress situations. Though populations from a nutrient richer soil had better growth rate than those from nutrient poor sites, this difference was not reflected in the tissue concentration of nutrients. Populations in nutrient deficient soils had high allocation to the belowground organs of reproduction than for aboveground parts. Though
Volume 98 Issue 2 April 1988 pp 121-133
Two bamboo species,
Volume 99 Issue 3 June 1989 pp 199-210
Village ecosystem function of the Khasis in Meghalaya was studied. The land has been desertified around Cherrapunji as the traditional slash and burn agriculture (jhum) has been replaced by plantation systems. Apart from mixed plantations with areca nut, orange, jackfruit, bay leaf, black pepper and betel leaf, broom grass, thatch grass and bamboo are also raised in the village. All the systems generally are economically viable and have a high energy efficiency with labour as the major input. Poultry and swine husbandry are two animal husbandry systems in the village. Both are largely detritus based. About 9% of the produce from mixed areca nut plantation, 50% from the bamboo and entire produce of thatch grass is utilized within the village and the rest is exported. In the absence of agriculture much of the food for consumption is imported from outside the village boundary. The possibility of further useful changes needs evaluation with scientific inputs.
Volume 99 Issue 3 June 1989 pp 211-221
Energy and economic analysis of cash crops (coffee, tea, ginger and pineapple mixed cropping system) are contrasted with shifting agriculture under a 10-yr cycle in north-eastern India. Though ginger gave maximum monetary return, followed by tea, the output/input ratio was higher for pineapple mixed cropping system. Coffee is not successful in this area of study. Some of the cash crop systems had high energy efficiencies though the shifting agriculture had high output/input ratio of 43·5. Nutrient losses through water was high under cash crops with maximal losses under ginger; compared to shifting agriculture the losses were substantial. It is suggested that plantation crops should be sustained in the region basing it, to the extent possible, on the concept of recycling of organic wastes.
Volume 99 Issue 4 August 1989 pp 343-351
Two early successional shrubs
Volume 99 Issue 4 August 1989 pp 353-362
Growth and architecture of early versus late successional shrubs are compared and contrasted to evaluate their leaf display characteristics. Early successional shrubs had a higher growth rate over an extended period of time compared to late successional shrubs. Inter-branch length and branch angle were greater for late successional species as compared to early successional ones. First- and second-order branch production over third-order branches was greater in late successional shrubs, whereas the reverse was the case for early successional ones. On the other hand, length contribution by all branch orders was higher for the early successional species. The bifurcation ratio was significantly higher for early successional species growing in the open as compared to late successional shrub species growing in shade. Early successional shrubs follow an exploitive strategy and make faster growth whereas late successionals have a conservative strategy for survival in shade.
Volume 99 Issue 5 October 1989 pp 431-436
The two early successional shrubs (
Volume 100 Issue 1 February 1990 pp 23-31
Cation budgeting was done under 4- and 12-year old terraces at higher elevation of Meghalaya (960 m) in north-east India. Cation addition occurred after burning the biomass arising from the weed and the crop residue prior to cropping. While nutrient removal through weeds was more under 12-year old terrace than under 4-year old one, the reverse was true for that removed by crop. Nutrient deficit, particularly potassium, was obvious under 12-year old terrace. Decline in soil fertility and increase in weed potential are implicated in the reduced crop yield.