Loess-Palaeosol Sequences in the Kashmir Valley, NW Himalayas: A Review

Loess deposits and intercalated palaeosols are widespread in the Quaternary record, and these have been extensively used to gain insights into continental paleoclimatic and paleo-environmental conditions and changes. Especially over Eurasia, loess geoarchives play an important role for our understanding of past changes. Loess covers almost 500 km2 of the Kashmir Valley in north-western India, it occurs dominantly in plateau positions, but also on terraces and sometimes forms slope deposits with thicknesses ranging from several to more than 20 m. For the time being, however, the timing of the initiation of the loess accumulation, the provenance, the grain size composition and also the paleo-environment have not been studied systematically and yet only little quantitative data is available. Yet it is clear that deposition rates are at least comparable to European loess, and that the presence of multiple palaeosols intercalated in the loess can provide valuable information on the history of the region. The limited available data hinders regional and continental correlation, and tapping its value as archive of past environmental changes in this sensitive region with influence from Westerlies and the Indian Monsoon. However, several characteristic palaeosol patterns can be traced throughout the Kashmir valley, which provide stratigraphic information. Several studies investigate physical and chemical properties of the loess-paleosol sequences and conclude to its aeolian origin and recording of past climates. The intensity of soil formation phases is traced through various proxies in low resolution and yet without conclusive age control. Here we review the exiting literature, available data, and interpretations from loess-palaeosol sequences in the Kashmir Valley. These are placed in the context of our own observations and loess from the Indian subcontinent. © Copyright © 2020 Dar and Zeeden

Pathogenic variability in Exserohilum turcicum and identification of resistant sources to turcicum leaf blight of maize (Zea mays L.)

Turcicum leaf blight of maize incited by Exserohilum turcicum (Pass.) Leonard and Suggs is the major limiting factor of maize production in temperate agro-ecologies. Disease management through host plant resistance is the most effective strategy. In the present study among 26 maize genotypes which were initially screened for resistance against E. turcicum under field conditions, 8 genotypes viz., PS 39, CML 451, CML 470, CML 472, VL 1030, VL 1018140, VL1018527 and SMI178-1 were found resistant when screened against twelve isolates of E. turcicum under artificial epiphytotic conditions. Eight genotypes viz., PS45, CML165, CML459, VL1249, VL0536, SMC-5, SMC-3 and KDL 211 were found moderately resistant with disease grade ranged from 2.1-2.5. These maize genotypes possess resistance to turcicum leaf blight can be used successfully in developing high yielding early maturing varieties for high altitude temperate agro-ecologies. The fungus E. turcicum is highly variable in nature. Variability studies on pathogenicity were conducted on twelve isolates of E. turcicum on eleven putative differential maize lines. During the present study a wide pathogenic variation was observed among the twelve isolates of E. turcicum. Cluster analysis on the basis of similarity or dissimilarity in reaction types exhibited by the differential hosts, clustered the isolates into 6 pathogenic groups. The isolates belonged to higher altitudes (Kti 10, Kti11, Kti5) were found to be more aggressive as compared to the isolates of low altitude areas

Phytoliths as proxies of the past

Phytoliths are silica casts of plant cells, created within and between living tissues across almost all plant clades. Because they are abundant, durable and distinctive, phytoliths are used to deduce historic vegetation patterns and human uses across the fields of archeology, paleoethnobotany, paleoecology, and historical ecology, particularly at sites where preservation of larger plant-derived samples is poor. Nonetheless, phytolith research has recently contributed to advances in biogeochemical cycling and carbon sequestration. Although much progress has been made over the past few decades, some basic methodological concerns in phytolith systematics and Si cycling still hamper the overall development of this emerging field of science. Here, we first review basic scenarios of phytolith studies across different disciplines of science and then advocate interdisciplinary phytolith research to overcome the challenges of phytolith systematics, inform the representation of Si and C cycling in biogeochemical models, and improve the utility of phytoliths as proxies in archeology and paleontology.This study has benefited from the support of the University Grants commission (UGC), India provided to Irfan Rashid under Raman fellowship Programme.Peer Reviewe

Dar in “Machine crushed animal bones as partial replacement of coarse aggregates in lightweight concrete

ABSTRACT An exploratory study on the suitability of the machine crushed animal bones as partial or full replacement for normal coarse aggregates in concrete works has been carried out. Physical and mechanical properties of machine crushed animal bones and locally available normal aggregate have been determined and compared. A large number of concrete cubes of size 150×150×50 mm with different percentages by weight of normal aggregate to crushed animal bones as coarse aggregate in the order 100:0, 75:25, 65:35, 50:50, 25:75 and 0:100 were cast, tested and their physical and mechanical properties were determined. Compressive strength tests showed that approximately 50% of the crushed animal bones in replacement for normal aggregate were quite satisfactory with no compromise in compressive strength requirements for concrete mix ratio 1:1.5:3. The study has been carried out at 25%, 35%, 50%, 75%, and 100% replacement levels of normal aggregate by crushed animal bone (CAB) aggregate by weight and a comparative study has been done between normal concrete and crushed animal bone (CAB) concrete