Quantitative assessment of soil quality is required to determine the sustainability of land uses in terms of environmental quality and plant productivity. Our objective was to identify the most appropriate soil quality indicators and to evaluate the impact of six most prevalent land use types (natural forestland, cultivated lowland, cultivated upland terrace, shifting cultivation, plantation land, and grassland) on soil quality in eastern Himalayan region of India. We collected 120 soil samples (20 cm depth) and analyzed them for 29 physical, chemical, and biological soil attributes. For selection of soil quality indicators, principal component analysis (PCA) was performed on the measured attributes, which provided four principal components (PC) with eigenvalues >1 and explaining at least 5% of the variance in dataset. The four PCs together explained 92.6% of the total variance. Based on rotated factor loadings of soil attributes, selected indicators were: soil organic carbon (SOC) from PC-1, exchangeable Al from PC-2, silt content from PC-3, and available P and Mn from PC-4. Indicators were transformed into scores (linear scoring method) and soil quality index (SQI) was determined, on a scale of 0-1, using the weighting factors obtained from PCA. SQI rating was the highest for the least-disturbed sites, i.e., natural forestland (0.93) and grassland (0.87), and the lowest for the most intensively cultivated site, i.e., cultivated upland terrace (0.44). Ratings for the other land uses were shifting cultivation (0.60) > cultivated low land (0.57) > plantation land (0.54). Overall contribution (in percent) of the indicators in determination of SQI was in the order: SOC (58%) > exch. Al (17.1%) > available P (8.9%) > available Mn (8.2%) > silt content (7.8%). Results of this study suggest SOC and exch. Al as the two most powerful indicators of soil quality in study area. Thus, organic C and soil acidity management holds the key to improve soil quality under many exploitatively cultivated land use systems in eastern Himalayan region of India.

This report summarizes the findings of a geochemical investigation of the Pahute Mesa-Oasis Valley groundwater flow system in southwestern Nevada, funded by the Underground Test Area project of the U.S. Department of Energy, National Nuclear Security Administration Nevada Operations Office. This work is intended to provide geochemical data and interpretations in support of flow and contaminant transport modeling for the Western and Central Pahute Mesa Corrective Action Units. The principal conclusions of this study are as follows: Geochemical and isotopic data in the Oasis Valley flow system are consistent with a direct groundwater flowpath between Pahute Mesa and Oasis Valley. This conclusion is in accord with hydraulic gradients and current hydrogeologic framework models of the area. The geochemical and isotopic data indicate that groundwater discharge in central Oasis Valley consists predominantly of deep regional groundwater flow beneath Pahute Mesa mixed with a smaller amount of local recharge. Geochemical signatures in the Oasis Valley discharge area are further affected by shallow groundwater recirculation or gas exchange through the unsaturated zone. Available data suggest that groundwater in northwestern Oasis Valley originates from north of Oasis Valley, and that groundwater from southeastern Pahute Mesa flows both into the Beatty Wash area of Oasis Valley and down Fortymile Canyon. The lack of tritium in groundwater indicates that travel times from Pahute Mesa to Oasis Valley are greater than 50 years. Corrected dissolved inorganic carbon and dissolved organic carbon 14 C groundwater ages indicate that average travel times from Pahute Mesa to Oasis Valley range from modern (greater than 50 years) to 8,500 years. Trace element data and U and Sr isotopic data are consistent with the proposed source areas, flowpaths, and mixing of groundwaters that discharge in Oasis Valley.

Changes in soil organic carbon, dehydrogenase activity, nutrient availability and leaf nutrient concentrations in a mango orchard soil was evaluated from four years (2007)(2008)(2009)(2010)(2011) field experiment on a Typic Ustocrepts soil of subtropical region in Lucknow, India. Organic (FYM, vermicompost, mulching, Azotobacter, PSM and Trichoderma harzianum) and inorganic (N, P, K) substrates were applied each year within the tree basin. It was observed that soil and leaf nutrients concentrations significantly increased in organic and inorganic amended soils as compared to control. Vermicompost, organic mulching and microbial inoculation significantly enhanced soil organic carbon content, available nutrients, dehydrogenase activity and leaf nutrient concentrations. Dehydrogenase activity was highest (1.85 µg TPF g -1 h -1 ) in organically treated soils. Surface soil (0-10 cm depth) showed higher dehydrogenase activity (1.29 to 1.85 µg TPF g -1 h -1 ) as compared to lower soil depths in all the treatments.

The goal of this study was to assess the influence of different organic fertilisers -vermicompost, mulching, Azotobacter, phosphate solubilising microbes (PSM) and Trichoderma harzianum added each year to mineral fertilisers containing NPK and to farmyard manure (FYM) on leaf nutrient status, tree growth, fruit yield and quality of guava grown in low fertile soil. The results revealed that vermicompost, bio-fertilisers and organic mulching resulted in yield and fruit quality boosters, as compared to application of NPK and FYM as the only organic fertiliser. Significant differences in plant height, canopy spread and stem girth of guava plants were obtained in combination, where Azotobacter, T. harzianum, PSM and organic mulching were applied. The leaf nutrient contents (N, P, K, Ca, Mg, Fe, Cu, Mn and Zn) were within sufficient ranges. Fruit yields and quality were highest in combination, where vermicompost, Azotobacter, T. harzianum, PSM and organic mulching was applied. Fruit quality parameters viz. soluble solid concentration, titratable acidity, total sugars and ascorbic acid showed positive correlation with the available macro-and micronutrients in the soil.

The hilsa shad <em>Tenualosa ilisha</em> (Hamilton, 1822), is a commercially important and highly relished food fish. This paper presents the length-weight relationships (LWR) and condition factor of hilsa, throughout its geographical distribution in India. A total of 910 samples of <em>T. ilisha</em>, comprising 404 males and 288 females collected from various locations of east and west coasts of India were used for analyses. Heterogeneity in the LWR of males, females and pooled population was noticed. The regression coefficient (b) ranged from 2.07-3.68 for pooled, 0.75-3.03 for males and 1.78-2.97 for females. The coefficient of determination (R2) varied between 0.72-0.98 in pooled, 0.73-0.94 in males and 0.76-0.97 in females. Fulton’s condition factor (K) ranged from 0.47-3.05 in pooled, 0.47-1.63 in male and from 0.77-3.05 in female samples whereas relative condition factor (Kn) varied from 0.48-2.51 in pooled population, from 0.47-1.56 in males and 0.76-2.33 in females. Mean Fulton’s condition factor (K) ranged from 0.7-1.33 in pooled population, 0.92-1.28 in males and from 0.95-1.39 in females whereas the mean relative condition factor (Kn) varied between 0.98-1.04 in pooled population, 0.98-1.04 in males and 0.98-1.03 in females. These parameters (b, K, Kn) have been found useful in evaluating the well-being of different populations of this species. Most of the populations under study showed concordance to ideal value of b, thereby indicating isometric growth. However, significant negative allometric growth was observed for pooled samples from Padma, Hoogly and males from Padma and significant positive allometric growth was observed in the pooled samples collected from Hoogly. Comparative study of recent data with the decadal old data (1999-2000) revealed differences in mean size of the fish. This study also indicates overexploitation of the species in the recent years, which might be due to intensive fishing efforts.