Identification of terrestrial gastropods families found in district Swat, Pakistan

Very little is known about the malacofauna in district Swat of Khyber Pakhtunkhwa province, situated in the Northern part of Pakistan. The Swat valley possesses a variety of suitable environmental conditions, providing different types of habitats for both flora and fauna. Taken into consideration these points, the present study was conducted to explore the terrestrial snails diversity in agricultural and non-agricultural fields in the lower Swat valley. A total of 417 shells were collected from three sites: Kokarai, Kanju Township, and Deolai. Based on conchological features, three families: Bradybaenidae, Hygromiidae, and Zonitidae were identified using different terrestrial snail keys. In Kokarai and Deolai, shells of members of all the above-mentioned families were found from agricultural fields. In Kanju Township, shells of members of the family Bradybaenidae and Zonitidae were found. From these findings, it was concluded that district Swat possesses a significant malacofauna which was unexplored before and aided more to the existing literature on malacofauna. It also supports the idea that the agroecosystem is rich in species diversity. Further in-depth and extensive study is recommended to be carried out for a detailed taxonomy of the described terrestrial gastropod families.

Dryland irrigation increases accumulation rates of pedogenic carbonate and releases soil abiotic CO2

Agricultural fields in drylands are challenged globally by limited freshwater resources for irrigation and also by elevated soil salinity and sodicity. It is well known that pedogenic carbonate is less soluble than evaporate salts and commonly forms in natural drylands. However, few studies have evaluated how irrigation loads dissolved calcium and bicarbonate to agricultural fields, accelerating formation rates of secondary calcite and simultaneously releasing abiotic CO2 to the atmosphere. This study reports one of the first geochemical and isotopic studies of such “anthropogenic” pedogenic carbonates and CO2 from irrigated drylands of southwestern United States. A pecan orchard and an alfalfa field, where flood-irrigation using the Rio Grande river is a common practice, were compared to a nearby natural dryland site. Strontium and carbon isotope ratios show that bulk pedogenic carbonates in irrigated soils at the pecan orchard primarily formed due to flood-irrigation, and that approximately 20–50% of soil CO2 in these irrigated soils is calcite-derived abiotic CO2 instead of soil-respired or atmospheric origins. Multiple variables that control the salt buildup in this region are identified and impact the crop production and soil sustainability regionally and globally. Irrigation intensity and water chemistry (irrigation water quantity and quality) dictate salt loading, and soil texture governs water infiltration and salt leaching. In the study area, agricultural soils have accumulated up to 10 wt% of calcite after just about 100 years of cultivation. These rates will likely increase in the future due to the combined effects of climate variability (reduced rainfall and more intense evaporation), use of more brackish groundwater for irrigation, and reduced porosity in soils. The enhanced accumulation rates of pedogenic carbonate are accompanied by release of large amounts of abiotic CO2 from irrigated drylands to atmosphere. Extensive field studies and modelling approaches are needed to further quantify these effluxes at local, regional and global scales.

Estimation of soil organic carbon in agricultural fields: A remote sensing approach

Aim: In view of the importance of Soil Organic Carbon (SOC) in agricultural management, a study was conducted to develop a digital SOC map using remotely sensed spectral indices. The present study was conducted on the Tawdeehiya Farms, located in the central region of Saudi Arabia between Al-Kharj and Haradh cities. Methodology: Landsat-8 (L8) and Sentinel-2 (S2A) satellite images were used for the characterization of SOC stocks in the topsoil layer (0-10 cm) of the experimental fields. Soil samples were randomly collected from six (50 ha each) agricultural fields and analyzed in the laboratory for SOC (SOCA) following Walkley and Black method. While, vegetation indices (VI), such as the Normalized Difference Vegetation Index (NDVI), NDVIRedEdge, Enhanced Vegetation Index (EVI), Bare Soil Index (BSI), and Reduced Simple Ratio (RSR) were computed and subsequently used for the development of SOC prediction models. Results: Univariate linear regression technique was employed for the recognition of a suitable band/VI for SOC (SOCP) mapping. The SWIR-1 band of both L8 (R2 = 0.86) and S2A (R2 = 0.77) data was promising for predicting SOC with 16% (S2A) and 18% (L8) of BIAS. Interpretation: The NDVI and BSI (for L8 data) and BSI and RSR (for S2A data) were found most suitable VI in the prediction of SOC. The R2 values of linear regression models were 0.68 (BSI) and 0.78 (RSR), indicating that nearly 68% and 78% of the SOC could be predicted through L8 and S2A datasets, respectively.

Distribution of commensal rodents in rain-fed and irrigated areas of Swat district, Khyber Pakhtunkhwa, Pakistan

Distribution pattern and relative abundance of the agricultural rodent pests of rain-fed and irrigated areas of district Swat Khyber Pakhtunkhwa, Pakistan were recorded from April 2011 to November 2013 using wire mesh live traps. A total of 350 rodents (269 Rattus rattus and 81 Mus musculus) were captured under 2268 trap nights (trap success: 0.15). Regression of daily captures on cumulative captures revealed an estimate of 350 rodents from all the sampled structures with an average of 21.8 rodents per crop field. House rats (R. rattus; 76.8% of captures) were numerically dominant in almost all types of agricultural fields, and were significantly different from the mice (Mus musculus; 23.1% of captures). Both species were found together in some fields. The sex ratio revealed that males outnumbered the females in both of the reported species.

Characterization of Cypermethrin-degradation by a Novel Molybdenum-reducing Morganella sp. Isolated from Active Agricultural Land in Northwestern Nigeria

The increasing use of cypermethrin in agricultural fields, household and industrial applications for effective pest control had increased the global burden of the pollutant over the years. Consequently, there is an urgent need to devise techniques to eliminate this pollutant from the environment. A bacterium capable of degrading cypermethrin has been successfully screened and characterized. The bacterium was grown in a mineral salt medium (MSM) supplemented with cypermethrin as its sole carbon and energy source at an optimum pH 7.5, temperature 40 ºC, a carbon source concentration of 4 g/L, optimum incubation time of 24 h and an inoculum size of 400 µL. The potential of Morganella sp. to degrade cypermethrin makes it an important instrument for the degradation of cypermethrin. This knowledge may be useful for the optimization of environmental conditions for cypermethrin bioremediation and important for detoxification of cypermethrin polluted sites.

Effects of Cropping Pattern on Carbon Sequestration And Aggregate Stability of Soil in Long Term Agricultural Fields in Khulna, Bangladesh

Effects of cropping pattern on soil carbon sequestration and their aggregate stability in long term agricultural fields was investigated in 2018. Four cropping patterns were selected that have been cultivated for last ten years. Results showed that Soil organic carbon (SOC) value was improved for vegetable field from 4.06 to 9.11 g/kg and carbon stock (20.14 Mg C ha/yr) as well as soil carbon sequestration rate was the highest in vegetable field (1.12 Mg C ha/yr). The logarithmic relationship between the C input and C sequestration rate showed the strong correlation (r = 0.72, p < 0.05). In terms of aggregate stability, vegetable field put the best result (0.41 mm) (p > 0.05). The straight-line relation between aggregate stability and Cstock established that they are strongly correlated (r = 0.81, p < 0.05). Finally, results indicated that Vegetable-Vegetable-Vegetable cropping pattern was the best soil carbon sequester along with the best aggregate stability. Bangladesh J. Bot. 50(4): 1029-1034, 2021 (December)