A report of Siwalik forest around Letang Raja-Rani wetland, Morang, eastern Nepal

Species composition, phytosociological status and soil characteristics of Siwalik forest occurring around Raja-Rani wetland, Letang municipality, eastern Nepal was studied. A total of 47 tree species belonging to 40 genera and 26 families were reported. Dominant and co-dominant trees were Shorea robusta (IVI=133.4) and Schima wallichii (IVI=70.6), respectively. In the forest total tree density, basal cover area, seedling density, fallen dead density and dead standing density were 378.4 trees ha-1, 163.7 m2 ha-1, 105250 individual ha-1, 4 trees ha-1 and 1.6 trees ha-1, respectively. Irregular girth class distribution and high stump density (136.8 tree ha-1) denote disturbance. Soil physicochemical characteristics were: acidic soil (pH 4.8), moisture (12.5%), water holding capacity (50.05%), bulk density (1.17 g cm-3), porosity (0.55%), humus (8.6%), organic carbon (0.52%), nitrogen (0.1%), phosphorus (33 kg ha-1), and potassium (300 kg ha-1). Regulating human encroachment to ensure natural regeneration of species to maintain the viability of the Letang Raja-Rani wetland site and integrity of the local ecosystem is strongly recommended.

Sustainable Conservation Tillage Technique for Improving Soil Health by Enhancing Soil Physicochemical Quality Indicators under Wheat Mono-Cropping System Conditions

An improved understanding of the effect of conservation tillage on soil physicochemical quality indicators is obligatory to manage and conserve soil in a climate change scenario. Tillage strategies change soil physicochemical characteristics, consequently modifying crop yields. Conservation tillage is generally used to improve the soil physicochemical characteristics globally. However, the impact of conservation tillage on different soil depths under wheat cultivation is not well documented. A 3-year study was conducted using a randomized complete block design (RCDB). The objective of this research was to specifically study soil physicochemical indicators (soil bulk density, porosity, hydraulic conductivity, water content, temperature, nitrogen, phosphorous, potassium, C:N ratio, pH) and (crop yield) in conventional tillage (CT), straw incorporation into the conventionally tilled soil (CTS), no-tillage (NT), and stubble-retention to the no-tilled soil (NTS) measures under wheat monocropping system across different soil layers. Averaged over 0–40 cm soil layer, the results depicted scarce differences among the tillage practices regarding soil bulk density, porosity, water content and hydraulic conductivity. CT increased soil temperature over conservation tillage systems. Overall, conservation tillage improved soil total nitrogen, available phosphorous, total potassium, C:N ratio and yield than CT, whilst it decreased soil pH. We conclude that NTS and CTS are the best strategies to enhance soil health under wheat mono-cropping system conditions.

The Rhizosphere Microbial Community of Tobacco and Its Relationship With The Properties of Leaves and Rhizosphere Soils

BackgroundRhizosphere microbes possess important effects on plant growth and quality. Here we collected tobacco roots and leaf samples from ten places in Yunnan province to investigate the interaction of the rhizosphere microbes, the soil physicochemical characteristics, and the tobacco leaf properties. ResultsA high-throughput sequencing method was used to sequence the V3–V4 region of 16S rRNA genes, and the operational taxonomic units (OTUs) were clustered using QIIME under 97% identity. A total of 4571 OTUs were obtained from the 30 tobacco root samples, and the top three phyla were Proteobacteria, Acidobacteria, and Actinobacteria, while the top three annotated genera were Gp6, Gemmatimonas, and Gp4. Redundancy analysis (RDA) showed that most of the soil physicochemical properties (10 out of 17) had a significant influence on the rhizosphere microbial community. Both correlation analysis and RDA analysis revealed that quick potassium (K) and Acidobacteria_Gp3 had a significant correlation with the tobacco leaf properties. The variance partitioning analysis showed that rhizosphere microbes had a bigger influence on the tobacco leaf properties. ConclusionsOur results showed great differences in the rhizosphere microbial diversity of tobacco and complex interaction among the microbial diversity, soil physicochemical characteristics, and tobacco leaf properties.

Correction to: Effects of organic amendment on some soil physicochemical characteristics and vegetative properties of Zea mays in wetland soils of the Niger Delta impacted with crude oil

In the original publication of the article, the author’s name Reuben N. Okparanma was misspelled.