C P Kushwaha | Banaras Hindu University, Varanasi (original) (raw)

Papers by C P Kushwaha

Applied Soil Ecology, 2001

Changes in the proportions of water-stable soil aggregates, organic C, total N and soil microbial... more Changes in the proportions of water-stable soil aggregates, organic C, total N and soil microbial biomass C and N, due to tillage reduction (conventional, minimum and zero tillage) and crop residue manipulation (retained or removed) conditions were studied in a tropical ...

Annals of Botany, 2005

Background and Aims In the dry tropics, vegetative phenology varies widely with tree characterist... more Background and Aims In the dry tropics, vegetative phenology varies widely with tree characteristics and soil conditions. The present work aims to document the phenological diversity of flowering and fruiting with reference to leafing events in Indian dry-tropical tree species. Methods Nine tree species, including one leaf-exchanging and eight deciduous showing varying leafless periods, were studied. Monthly counts of leaves, flowers and fruits were made on 160 tagged twigs on ten individuals of each species for initiation, completion and duration of different phenological events through two annual cycles. Key Results Variation in flowering relative to leaf flushing (which occurred just prior to or during a hot, dry summer) revealed five flowering types: summer flowering (on foliated shoots), rainy-season flowering (on foliated shoots following significant rains), autumn flowering (on shoots with mature leaves), winter flowering (on shoots undergoing leaf fall) and dry-season flowering (on leafless shoots). Duration of the fruiting phenophase was shortest (3-4 months) in dry-season and winter-flowering species, 6-9 months in rainy-and autumn-flowering species, and maximum (11 months) in summer-flowering species. A wide range of time lag (<1 to >8 months) between the start of vegetative (first-leaf flush) and reproductive (first-visible flower) phases was recorded in deciduous species; this time lag was correlated with the extent of the leafless period. A synthesis of available phenological information on 119 Indian tropical trees showed that summer-flowering species were most abundant (56 % of total species) amongst the five types recognized. Conclusions The wide diversity of seasonal flowering and fruiting with linkages to leaf flush time and leafless period reflect the fact that variable reproductive and survival strategies evolved in tree species under a monsoonic bioclimate. Flowering periodicity has evolved as an adaptation to an annual leafless period and the time required for the fruit to develop. The direct relationship between leafless period (inverse of growing period) and time lag between onset of vegetative and reproductive phases reflects the partitioning of resource use for supporting these phases. Predominance of summer flowering coupled with summer leaf flushing seems to be a unique adaptation in trees to survive under a strongly seasonal tropical climate.

Tropical trees exhibit variations in leaf initiation, maturation and leaf fall patterns. This stu... more Tropical trees exhibit variations in leaf initiation, maturation and leaf fall patterns. This study has demonstrated the diversity of these leaf events in various tropical trees and their possible ecological adaptive mechanism of these species to survive in extreme events. The results of the study has strong implication for global climate change scenario on changing pattern of leafing of tropical trees in Vindhyan dry tropical region which is experiencing high degree of environmental change due to increased industrial intensification.

Ecological Indicators, 2016

In tropical forests, deciduousness is an outcome of integrated effect of drought, tree characteri... more In tropical forests, deciduousness is an outcome of integrated effect of drought, tree characteristics and soil moisture conditions and thus it is a reliable indicator of seasonal drought experienced by different tree species. Variations in the deciduousness are associated with several ecophysiological characteristics, such as varying allocation pattern of metabolic products, resource capture and conservation, water relations and stem water storages, annual carbon sequestration, timing of reproductive event initiation, extent of separation of vegetative and reproductive events and leaf strategies, and it helps in maintenance of water balance and protection of tree organs during the seasonal drought. Tropical forests support mosaics of tree functional types showing marked differences in the duration of deciduousness (from leaf exchanging to >8 months deciduous), as a result of varying degree of water stress experienced by physiognomy, distribution and wood anatomy of tropical trees. Wide variations in deciduousness in the same species growing at different sites suggest the high sensitivity of tropical trees to small changes in growing habitat. In the present review we have explored the ecological significance of deciduousness in tropical trees with emphasis on: (a) inter-and intraspecies plasticity in deciduousness, (b) various capacity adaptations related with the duration of deciduousness, (c) relationship between tree stem water status and deciduousness, and (d) probable effect of impending climate change on tropical trees. An attempt has also been made to establish deciduousness as climate change indicator in the dry tropics. There is need to develop capabilities to detect and predict the impact of climate change on deciduousness through long-term phenological network in tropics. Remote sensing techniques can generate valuable ecological information such as leaf level drought response and phenological patterns. Deciduousness has the potential to emerge as an important focus for ecological research to address critical questions in global modeling, monitoring, and climate change.

Acta Ecologica Sinica, 2011

Recent phenological studies in tropical deciduous forests revealed a mosaic of vegetation compose... more Recent phenological studies in tropical deciduous forests revealed a mosaic of vegetation composed of several pheno-phases that are evolved as an adaptation by the species to overcome seasonal drought in different ways. These pheno-phases represent extent of annual deciduousness (leaflessness) and triggering factors for buds break (e.g. vegetative and flower). Thus, studying patterns of various phenophases (phonological diversity) in tropical forest have been thought to provide a potential tool to address critical questions related to climate change modeling and monitoring. In tropics, tree species represent a gradient of deciduousness (from leaf-exchanging species to >6 months deciduous species) and flowering initiation (breaking of flower buds in various part of annual cycle). Both processes are mostly triggered by variation in day length and/or temperature during late dry season/autumn, and/or first significant rain during rainy season. In addition, few factors like drought induced leaf fall and sporadic winter rains are supposed to affect these processes temporarily. Besides, the abundances of pheno-phases (i.e. leafing and flowering) also vary among tropical deciduous forest trees. Presence of such variations in tropical tree pheno-phases and their abundances are reported to vary due to micro-climatic variables and has specific implications in tropical forests. Present paper discusses the existing information on various pheno-phases and their abundances in tropical forests and role of climatic factors on tree phonological diversity. Further, we emphasized the need to develop predicting understanding of impending climatic change (i.e. precipitation and temperature) on diversity of pheno-phases by collecting long-term data on tree pheno-phases through a network of phonological stations in dry tropics.

academic, research, Extension and regulatory service for the state and beyond. Akridge replaces R... more academic, research, Extension and regulatory service for the state and beyond. Akridge replaces Randy Woodson who was named Purdue’s provost last May. “Jay is an excellent leader who has a clear vision for Purdue Agriculture, ” Woodson said in announcing the appointment. “He is a very positive force who has the ability to build on the outstanding quality of one of the nation’s leading agricultural institutions.” “Agriculture plays an important role in Indiana’s economic vitality, ” Akridge said. “The state looks to us to grow leaders to create new enterprises, provide expertise to help the industry remain globally competitive, and be a valued partner in youth and rural development. This is our charge and is what the people of Purdue Agriculture are passionate about.” Akridge had been serving as interim dean, and previously served as the university’s interim vice provost for engagement and was director of the Center for Food and Agricultural Business, which provides professional deve...

$Research paper thumbnail of Application of fractal theory in assessing soil aggregates in Indian tropical ecosystems$

Journal of Forestry Research

Soil aggregation varies according to climatic and management factors, and is difficult to measure... more Soil aggregation varies according to climatic and management factors, and is difficult to measure because of irregular shapes and sizes of soil aggregates. We applied fractal theory to assess soil aggregation as affected by (1) land use change from forest to savanna, (2) nutrient additions in forest, ecotone, and savanna ecosystems, and (3) tillage practice and residue treatments in an agro-ecosystem. We used fractal dimensions nonlinear (D non-lin) and linear (D lin) based on number of aggregates (N) and mass of aggregates (M) (the range of values were 2.6− 2.89 and 2.69− 3.41, respectively) to capture the variations in the sizes of soil aggregates due to land use and treatments/management in these ecosystems. The variation in the values of non-linear fractal dimension based on mass (D Mnon-lin) was smaller in forest and savanna ecosystems with and without nutrient additions, while the variation was wider in agro-ecosystems with different management practices. Linear fractal dimensions based on number (D Nlin) and mass (D Mlin) of aggregates varied marginally in these ecosystems and did not capture the variations in soil aggregates well. The variations in non-linear fractal dimension indicate that continued nitrogen loading in forest accelerates the formation of macro-aggregates, whereas in savanna the situation was reversed. The values of non-linear fractal dimensions did not show significant change after 6 years of nutrient additions in the ecotone; reflecting a buffering mechanism of this system in soil aggregate formation. On the basis of non-linear fractal dimension values, we conclude that residue retention and minimum tillage are appropriate for proper maintenance of soil aggregate stability for sustained crop production in the Indian dry land

Current Science, 2015

Changes in ecosystems are highly complex, heterogeneous and are extremely difficult to measure th... more Changes in ecosystems are highly complex, heterogeneous and are extremely difficult to measure through single scale. Fractal geometry has been used to quantitatively estimate the extent of irregularity in ecosystem changes. However, in some cases it has been overly used giving misleading results. To avoid this, other metrics are also being used in studying changes in forest ecosystems. In this article, we review use of fractal geometry in measuring ecosystem components in a range of ecological conditions. Further, case studies from forest fragmentation and soil aggregates stability in different Indian tropical ecosystems with respect to management practices and environmental change have been described using fractal dimension. We have tried to point out some instances where fractals can more appropriately be used in assessing ecosystems properties and where it could not be successfully used. Characterization of ecological situations where fractals can effectively be used in general remains an important issue.

Applied Soil Ecology, Jan 1, 2001

Soil and Tillage Research, Jan 1, 2000

Annals of Botany, Jan 1, 2006

Current Science, Jan 1, 2005

Journal of tropical ecology, Jan 1, 2005

Abstract: Patterns of leaf phenological diversity were documented in nine key tree species of a t... more Abstract: Patterns of leaf phenological diversity were documented in nine key tree species of a tropical deciduous forest in the Vindhyan region of India. Monthly leaf counts on 160 tagged twigs on ten individuals of each species were made through two annual cycles. Tree ...

Current Science, Jan 1, 2005

Experimental Agriculture, Jan 1, 2005

SUMMARY To understand the impact of residue and tillage management on crop productivity of rice a... more SUMMARY To understand the impact of residue and tillage management on crop productivity of rice and barley (including grain yield) and soil fertility in a tropical dryland agro-ecosystem, the following six treatments were established: (a) conventional tillage ...