Mesorhizobium improves chickpea growth under chromium stress and alleviates chromium contamination of soil.

Environmental pollution has become a transnational issue that impacts ecosystems, soil, water, and air and is directly related to human health and well-being. Chromium pollution decreases the development of plant and microbial populations. It warrants the need to remediate chromium-contaminated soil. Decontaminating chromium-stressed soils via phytoremediation is a cost-effective and environmentally benign method. Using multifunctional plant growth-promoting rhizobacteria (PGPR) lower chromium levels and facilitates chromium removal. PGPR work by altering root architecture, secreting chemicals that bind metals in the rhizosphere, and reducing phytotoxicity brought on by chromium. The present study aimed to investigate the chromium bioremediation capacity of metal-tolerant PGPR isolate while promoting the growth of chickpeas in the presence of varying levels of chromium (15.13, 30.26, and 60.52 mg/kg of chromium). The isolate, Mesorhizobium strain RC3, substantially reduced chromium content (60.52 mg/kg) in the soil. It enhanced the root length by 10.87%, the shoot length by 12.38%, the number of nodules by 6.64%, and nodule dry weight by 13.77% at 90 days. After 135 days of sowing, more improvement in the root length (18.05), shoot length (21.60%)the chlorophyll content (6.83%), leghaemoglobin content (9.47%), and the highest growth in the crop seed yield (27.45%) and crop protein content (16.83%)The isolate reduced chromium accumulation in roots, shoots, and grains chickpea. Due to chromium bioremediation and its plant growth-promoting and chromium-attenuating qualities, Mesorhizobium strain RC3 could be used as a green bioinoculant for plant growth promotion under chromium stress.

Climate plays a dominant role over land management in governing soil carbon dynamics in North Western Himalayas.

The soil carbon (C) dynamics is strongly influenced by climate and land-use patterns in the Himalayas. Therefore, soils under five prominent land use [e.g., maize (Zea mays), horticulture, natural forest, grassland, and wasteland] were sampled down up to 30 cm depth under two climatic conditions viz., temperate and subtropical to assess the impacts of climate and landuse on soil C dynamics. Results demonstrated that irrespective of land use, temperate soil contains 30.66% higher C than subtropical soils. Temperate soils under natural forests had the higher total organic carbon (TOC, 21.90 g kg-1), Walkley-Black carbon (WBC, 16.42 g kg-1), contents, and stocks (TOC, 66.92 Mg ha-1 and WBC, 50.24 Mg ha-1), and total soil organic matter (TSOM, 3.78%) concentration as compared to other land uses like maize, horticulture, grassland, and wasteland. Under both climatic conditions, maize land use had the lowest TOC 9.63, 6.55 g kg-1 and WBC 7.22, 4.91 g kg-1 at 0-15 and 15-30 cm soil depth, respectively. Horticulture land use had 62.58 and 62.61% higher TOC and WBC over maize-based land use under subtropical and temperate climatic conditions at 0-30 cm soil depth, respectively. However, soils of maize land use under temperate conditions had ∼2 times more TOC than in subtropical conditions. The study inferred that the C-losses is more in the subtropical soil than in temperate soils. Hence, the subtropical region needs more rigorous adoption of C conservation farming practices than the temperate climatic setting. Although, the adoption of C storing and conserving practices is crucial under both climatic settings to arrest land degradation. Horticultural land uses along with conservation effective soil management practices may be encouraged to restore more soil C and to improve the livelihood security of the hill populace in the North Western Himalayas.

Seasonal variation of the quality of groundwater resources for human consumption and industrial purposes in the central plain zone of Punjab, India.

Due to environmental pollution, climate change, and anthropogenic activities, the judicious use and regular assessment of the quality of groundwater for industrial, agricultural, and drinking purposes had gained a lot of attention across the globe. To assess the seasonal suitability of groundwater based on hydrochemistry and different quality indices, groundwater samples were collected and analyzed for different physicochemical parameters. Our findings indicated that the pH, electrical conductivity (EC), total dissolved solids (TDS), total hardness (TH), and calcium ion (Ca2+) content of groundwater were within acceptable limits of WHO and Bureau of Indian Standards (BIS) guidelines for drinking water. However, chloride content exceeded the acceptable levels, accounting for about 29.1% during the pre-monsoon and 15.3% during the post-monsoon period. Based on the water quality index (WQI), none of the water samples were deemed unsuitable for drinking purposes. However, when considering the synthetic pollution index (SPI), 100% of the samples were categorized as moderately polluted during both the pre-monsoon and post-monsoon periods. For industrial purpose suitability, 39.8 and 30.6% of the water samples had high corrosion tendency for pre-monsoon and post-monsoon seasons, respectively. Additionally, 77.5-93.4% of the total water samples were slightly affected by salinization on the basis of Revelle index. Generally, the groundwater quality for drinking purposes meets the WHO and BIS guidelines, with high corrosion potential for industrial use and slight salinization concerns in the area.

Landfill leachate a new threat to water quality: a case study from the Temperate Himalayas.

Landfills are commonly seen as the most cost-efficient and practical approach to waste management in various regions around the world. Nonetheless, the infiltration of hazardous materials from poorly managed dumping sites remains a significant environmental issue in most developing countries such as India. Leachate serves as a prominent point source of contamination in many environmental media like soil, groundwater, and surface water around the world. So the prime issues humans are experiencing are associated with water quality. Thus, the investigation was undertaken to assess the impact of leachate from the Achan landfill on surface water quality in the Temperate Himalayas. Monitoring was done during in all four seasons, viz., spring, summer, autumn, and winter. Among the sites, the leachate outflow site was found to have the highest mean value of pH (7.95), EC (2.16 dS/m), total nitrogen (2.64 mg/l), P (4.75 mg/l), K (1.41 mg/l), Ca (107.45 mg/l), Mg (54.93 mg/l), Zn (0.8 mg/l), Fe (1.78 mg/l), Cu (0.66 mg/l), Mn (0.81 mg/l), BOD (21.47 mg/l), COD (66.24 mg/l), temperature (14.22 °C), turbidity (14.29 NTU), while lowest mean values of all parameters were recorded at control site. Among the seasons, summer season was found to have maximum value of pH (7.9), EC (2.36 dS/m), total nitrogen (2.54 mg/l), P (4.0 mg/l), K (0.89 mg/l), Ca (85.94 mg/l), Mg (43.91 mg/l), Fe (1.4 mg/l), Cu (0.52 mg/l), Mn (0.64 mg/l), BOD (22.82 mg/l), COD (65.87 mg/l), temperature (18.99 °C), and turbidity (8.49 NTU). The maximum mean value of Zn (0.66 mg/l) was recorded during winter season, while other parameters were found to be minimum during winter season. From this study, we concluded that a decreasing trend was observed during all the seasons in the concentration of all physico-chemical parameters with an increase in distance from the landfill. So it is recommended that the leachate should be treated at the source before disposing into the water body and the landfill should be lined properly to prevent the entry of leachate into water sources.

Land-use systems regulate carbon geochemistry in the temperate Himalayas, India.

The Himalayan ecosystem is critical for ecological security and environmental sustainability. However, continuous deforestation is posing a serious threat to Himalayan sustainability. Changing land-use systems exert a tenacious impact on soil carbon (C) dynamics and regulate C emissions from Himalayan ecosystem. Therefore, this study was conducted to determine the changes in different C pools and associated soil properties under diverse land-use systems, viz. natural forest, natural grassland, maize field converted from the forest, plantation, and paddy field of temperate Himalaya in the surface (0-20 cm) and subsurface (20-40 cm) soils. The highest total organic carbon (24.24 g kg-1) and Walkley-black carbon contents (18.23 g kg-1), total organic carbon (45.88 Mg ha-1), and Walkley-black carbon stocks (34.50 Mg ha-1) were recorded in natural forest in surface soil (0-20 cm depth), while soil under paddy field had least total organic carbon (36.45 Mg ha-1) and Walkley-black carbon stocks (27.40 Mg ha-1) in surface soil (0-20 cm depth). The conversion of natural forest into paddy land results in 47.36% C losses. Among the cultivated land-use system, minimum C losses (29.0%) from different pools over natural forest system were reported under maize-filed converted from forest system. Land conversion causes more C losses (21.0%) in surface soil (0-20 cm depth) as compared to subsurface soil. Furthermore, conversion of forest land into paddy fields increased soil pH by 5.9% and reduced total nitrogen contents and microbial population by 28.0% and 7.0%, respectively. However, the intensity of total nitrogen and microbial population reduction was the lowest under maize fields converted from the forest system. The study suggested that the conversion of natural forest to agricultural land must be discouraged in the temperate Himalayan region. However, to feed the growing population, converted forest land can be brought under conservation effective maize-based systems to reduce C loss from the intensive land use and contribute to soil quality improvements and climate change mitigation.

Pyrolyzed and unpyrolyzed residues enhance maize yield under varying rates of application and fertilization regimes.

Biochar is increasingly gaining popularity due to its extensive recommendation as a potential solution for addressing the concerns of food security and climate change in agroecosystems, with biochar application for increased carbon sequestration, enhanced soil fertility, improved soil health, and increased crop yield and quality. There have been multiple studies on crop yield utilizing various biochar types and application amounts; however, none have focused on the influence of diverse biochar types at various pyrolysis temperatures with different application amounts and the integration of fertilizer regimes in maize crops. Therefore, a two-year factorial field experiment was designed in a temperate Himalayan region of India (THRI) to evaluate the residual effect of different biochar on maize yield under different pyrolysis temperatures, various application rates and fertilizer regimes. The study included three factors viz., amendment type (factor 1), rate of application (factor 2) and fertilizer regime (factor 3). Amendment type included 7 treatments: No biochar- control (A1), apple biochar @ 400 °C pyrolysis temperature (A2), apple biochar @ 600 °C pyrolysis temperature (A3), apple residue biomass (A4), dal weed biochar @ 400 °C pyrolysis temperature (A5), dal weed biochar @ 600 °C pyrolysis temperatures (A6), and dal weed residue biomass (A7). The rate of application included 3 levels: Low (L- 1 t ha-1), medium (M- 2 t ha-1), and high (H- 3 t ha-1). At the same time, the fertilizer regimes included 2 treatments: No fertilizer (N) and recommended dose of fertilizer (F). The results revealed that among the various amendment type, rate of application and fertilizer regimes, the A3 amendment, H rate of application and F fertilizer regime gave the best maize growth and productivity outcome. Results revealed that among the different pyrolyzed residues used, the A3 amendment had the highest plant height (293.87 cm), most kernels cob-1 (535.75), highest soil plant analysis development (SPAD) value (58.10), greatest cob length (27.36 cm), maximum cob girth (18.18 cm), highest grain cob yield (1.40 Mg ha-1), highest grain yield (4.78 Mg ha-1), higher test weight (305.42 gm), and highest stover yield (2.50 Mg ha-1). The maximum dry weight in maize and the number of cobs plant-1 were recorded with amendments A4 (14.11 Mg ha-1) and A6 (1.77), respectively. The comparatively 2nd year of biochar application than the 1st year, the H level of the rate of application than the L rate and the application and integration of the recommended dose of fertilizer in maize results in significantly higher values of growth and productivity in maize. Overall, these findings suggest that the apple biochar @ 600 °C pyrolysis temperature (A3) at a high application rate with the addition of the recommended dose of fertilizer is the optimal biochar for enhancing the growth and productivity of maize in the THRI.

Management of Green Mold Disease in White Button Mushroom (Agaricus bisporus) and Its Yield Improvement.

Mycoparasites cause serious losses in profitable mushroom farms worldwide. The negative impact of green mold (Trichoderma harzianum) reduces cropping surface and damages basidiomes, limiting production and harvest quality. The goal of the current study was to evaluate new generation fungicides, to devise suitable management strategies against the green mold disease under prevailing agro-climatic conditions. Six non-systemic and five systemic fungitoxicants were evaluated for their efficacy against pathogen, T. harzianum, and host, Agaricus bisporus, under in vitro conditions. Among non-systemic fungicides, chlorothalonil and prochloraz manganese with mean mycelium inhibition of 76.87 and 93.40 percent, respectively, were highly inhibitory against the pathogen. The least inhibition percentage of 7.16 of A. bisporus was exhibited by chlorothalonil. Under in vivo conditions, use of captan 50 WP resulted in a maximum yield of button mushroom of 14.96 kg/qt. So far, systemic fungicides were concerned, carbendazim proved extremely inhibitory to the pathogen (89.22%), with least inhibitory effect on host mycelium (1.56%). However, application of non-systemic fungitoxicants further revealed that fungicide prochloraz manganese 50 WP at 0.1-0.2 percent or chlorothalonil 50 WP at 0.2 percent, exhibited maximum disease control of 89.06-96.30 percent. Moreover, the results of systemic fungitoxicants showed that carbendazim 50 WP or thiophanate methyl 70 WP at 0.1 percent reduced disease to 2.29-3.69 percent, hence exhibiting the disease control of 80.11-87.66 percent. Under in vivo conditions, fungicide myclobutanil at 0.1 percent concentration produced the maximum button mushroom production of 12.87 kg/q.

Morpho-Cultural and Pathogenic Variability of Sclerotinia sclerotiorum Causing White Mold of Common Beans in Temperate Climate.

The present systematic research on cultural, morphological, and pathogenic variability was carried out on eighty isolates of Sclerotinia sclerotiorum collected from major common bean production belts of North Kashmir. The isolates were found to vary in both cultural and morphological characteristics such as colony color and type, colony diameter, number of days for sclerotia initiation, sclerotia number per plate, sclerotial weight, and size. The colony color ranged between white and off-white with the majority. The colony was of three types, in majority smooth, some fluffy, and a few fluffy-at-center-only. Colony diameter ranged between 15.33 mm and 29 mm after 24 h of incubation. The isolates took 4 to 7 days for initiation of sclerotia and varied in size, weight, and number per plate ranging between 14 and 51.3. The sclerotial arrangement pattern on plates was peripheral, sub peripheral, peripheral, and subperipheral, arranged at the rim and scattered. A total of 22 Mycelial compatibility groups (MCGs) were formed with seven groups constituted by a single isolate. The isolates within MCGs were mostly at par with each other. The six isolates representing six MCGs showed variability in pathogenicity with isolate G04 as the most and B01 as the least virulent. The colony diameter and disease scores were positively correlated. Sclerotia were observed to germinate both myceliogenically and carpogenically under natural temperate conditions of Kashmir. Germplasm screening revealed a single resistant line and eleven partially resistant lines against most virulent isolates.

Biochar as a tool for effective management of drought and heavy metal toxicity.

Drought and heavy metal stress undesirably disturb soil fertility and plant growth. Heavy metals pose severe biological toxic effects. Biochar, a carbon rich source application ameliorates this stress by increasing the plant growth, biomass, nutrient uptake and improves gaseous exchange in drought stress. Application of biochar reduces drought stress by increasing water holding capacity of soil through modification of soil physio-chemical properties that in turn increases water availability to plants and also enhances mineral uptake and regulation of stomatal conductance. Biochar mediates the retention of moisture, nutrients, inhibits harmful bacteria, absorbs heavy metals, pesticides, prevents soil erosion, increases soil pH, improves cationic exchange and boosts soil fertility. Drought and heavy metal stress often lead to production of reactive oxygen species. However, biochar significantly modifies the Reactive Oxygen Species (ROS) scavenging enzymes and provides an efficient electron transferring mechanism to tackle the toxic effects of ROS in plants. Biochar is regarded as a tool for the effective management of agricultural productivity and various environmental issues. This review provides insights on the potential role of biochar in ameliorating drought and heavy metal stress.