Cropping pattern of Konkan region on the basis of probabilistic rainfall and soil characteristics

ABSTRACT- Cropping pattern at any place of humid tropics basically depends on soils and efficient management of abundant rainfall. Climate of Konkan region IS warm and humid. Rainfall is very high and varies usually from 200 to 350 cm. Rainfall probability has been computed at different levels of 16 stations of this region by fitting Gamma distribution model to weekly rainfall total. The existing cropping pattern was studied in relation with assured rainfall at different probability levels. Suitable cropping patterns based on assured rainfall and soils of the region have been suggested to increase production.

NEW AMS 14C DATES OF A MULTICULTURAL ARCHAEOLOGICAL SITE FROM THE PALEO-DELTAIC REGION OF WEST BENGAL, INDIA: CULTURAL AND GEO-ARCHAEOLOGICAL IMPLICATIONS

ABSTRACT This study is on the absolute age dating of a multicultural site of Erenda, East Medinipur district, in coastal West Bengal, India. Charcoal samples were collected and measured using the accelerator mass spectrometry (AMS) facility at the Inter-University Accelerator Centre, New Delhi, India. These samples were collected from secured stratigraphic context of two excavated trenches. A careful collection of samples from two trenches provided us with the first calendar dates, 950 BCE and 1979 BCE, of protohistoric sites in coastal West Bengal. These calibrated calendar dates not only have wider significance in terms of archaeology but also methodological implications to understand the relevance of application of AMS from the dynamic coastal landscape in the humid tropics during the late Holocene period.

Weather extremes and plantation crops in the humid tropics

Monsoon rainfall across the State of Kerala was declining since last 60 years (cyclic trend of 40-60 years is also noticed with annual/monsoon rainfall) while rise in temperature is evident. Of course, rate of increase in temperature was alarming across the High ranges (where cardamom, coffee and tea are grown) due to deforestation. It is also true to some extent along the Coast (low land) due to increase in sea surface air temperature. The decade 1981-90 was the driest and warmest decade. The year 1987 was the warmest year across Kerala. The State as a whole was moving from wetness to dryness within the Humid Climate ((B4-B3 as per the Thornthwaite’s climate classification). Among weather extremes, summer drought, monsoon flood, strong wind (blows in Palghat Gap from November to February, other than cyclonic wind across the State), hailstorms, unusual rains, landslides and warming may adversely affect plantation crops’ production and its quality. Heat wave and cold waves are not relevant with reference to plantation crops under the Humid Tropics. The effect of summer drought on coconut yield was noticed in 1983, 2004 and 2013. In the case of coffee, it appears that crop matures early in recent years due to increase in temperature and climate change. The quality of coffee and black pepper, nut size in coconut and cashew are also influenced due to global warming and climate change. In the case of black pepper, the mortality rate is high in young pepper vines due to prolonged summer drought as noticed in summer 1983, 2004 and 2013. Mixed cropping/integrated farming is suggested to sustain crop income against adverse weather on long run under projected climate change scenario.

Modeled forest conversion influences humid tropical watershed hydrology more than projected climate change

In the humid tropics, forest conversion and climate change threaten the hydrological function and stationarity of watersheds, particularly in steep terrain. As climate change intensifies, shifting precipitation patterns and expanding agricultural and pastoral land use may effectively reduce the resilience of headwater catchments. Compounding this problem is the limited long-term monitoring in developing countries for planning in an uncertain future. In this paper, we asked which change, climate or land use, more greatly affects stream discharge in humid tropical mountain watersheds? To answer this question, we used the process-based, spatially distributed Soil Moisture Routing model. After first evaluating model performance (Ns = 0.73), we conducted a global sensitivity analysis to identify the model parameters that most strongly influence simulated watershed discharge. In particular, peak flows are most influenced by input model parameters that represent baseflow and shallow subsurface soil pathways while low flows are most sensitive to antecedent moisture, macropore hydraulic conductivity, soil depth and porosity parameters. We then simulated a range of land use and climate scenarios in three mountain watersheds of central Costa Rica. Our results show that deforestation influences streamflow more than altered precipitation and temperature patterns through changes in first-order hydrologic hillslope processes. However, forest conversion coupled with intensifying precipitation events amplifies hydrological extremes, reducing the hydrological resilience to predicted climate shifts in mountain watersheds of the humid tropics. This finding suggests that reforestation can help mitigate the effects of climate change on streamflow dynamics in the tropics including impacts to water availability, flood pulses, channel geomorphology and aquatic habitat associated with altered flow regimes.