Concentrations Of Available Potassium Research Articles

Effect of Mg-Modified Waste Straw Biochar on the Chemical and Biological Properties of Acidic Soils.

Biochar is important for soil improvement, fertilizer innovation, and greenhouse gas reduction. In this paper, Mg-modified biochar was prepared from rice and corn straw and mixed with soil at a 1% (w/w) addition in an indoor soil simulation experiment to study the effect of Mg-modified biochar on the chemical properties of acidic soil. The results showed that the addition of Mg-modified biochar reduced soil acidity and improved soil fertility. Compared with the control group, the Mg-modified biochar treatment significantly increased the concentrations of available potassium, available phosphorus, total phosphorus, organic carbon and exchangeable calcium and magnesium in the soil, and effectively increased the concentration of total nitrogen. Rice straw Mg-modified biochar treatment was more effective in increasing the soil-available potassium, available phosphorus, total phosphorus and exchangeable magnesium concentration, while corn straw Mg-modified biochar was more effective in increasing the soil organic carbon and exchangeable calcium concentration. In addition, the high pyrolysis temperature of Mg-modified biochar was more effective in promoting the soil-available potassium, available phosphorus and total nitrogen concentration, while the low pyrolysis temperature of Mg-modified biochar was more effective in promoting soil alkaline nitrogen, exchangeable calcium and magnesium.

Effects of the Long-Term Continuous Cropping of Yongfeng Yam on the Bacterial Community and Function in the Rhizospheric Soil

Replant disease caused by continuous cropping commonly occurs in yam with consecutive monoculture. However, little is known about how the continuous cropping of yam affects the rhizospheric soil bacterial community structure. In this study, the effects of continuous cropping on rhizospheric soil characteristics, bacterial diversity, and community structure were investigated in the Yongfeng yam fields under monoculture for 1, 5, 10, 15, and 20 years. Long-term monoculture caused soil acidification and increased the concentration of available potassium (AK) and available phosphorus (AP), and soil bacterial richness, but decreased the soil bacterial diversity. An exception was for the field under monoculture for 20 years as it showed the highest bacterial diversity. The relative abundance of beneficial bacteria, such as Proteobacteria, Actinobacteria, and Chloroflexi decreased while the relative abundance of harmful bacteria, including Gemmatimonadetes and Acidobacteria, increased with an extended continuous cultivation time. The networks varied among yams with different cultivation years and became complex with the increase in cultivation years. However, after time in monoculture, the bacterial network decreased gradually and existed stably. These changes in bacterial community composition and co-occurrence of networks may increase the potential risk of soil-borne disease and reduce the yield and quality of Yongfeng yam.

Effects of vegetation restoration and environmental factors on understory vascular plants in a typical karst ecosystem in southern China

Understory vegetation is an important component in most forest ecosystems. It is very important for soil and water conservation in karst region, study on understory will provide valuable information for understanding the interaction mechanism between understory flora and karst environment. Thirty-two plots were sampled in three vegetation types along with a restoration gradient (shrubland, forest–shrub transition, and mixed-species broadleaf forest) in typical karst mountains in Southwest Guangxi, China. Overstory trees, understory vascular plants, soil nutrients, and topographic factors were recorded in each 400-m2 plot. Multivariate statistics were used, including the multi-response permutation procedure (MRPP), indicator species analysis, and canonical correlation analysis (CCA). MRPP showed understory species composition significantly differed among the three vegetation types, with the greatest difference between the shrubland and the mixed forest. Twenty-one understory species were identified as significant indicator species, with 13 species being identified as indicators of the shrubland, two of forest–shrub transition, and six of the mixed forest. Light-demanding herbaceous seed plants were common in shrubland, while shade-tolerant calcicole assembled under the mixed forest. Forward selection of CCA ordination revealed that understory plant distribution was most strongly influenced by elevation, followed by soil pH, the concentration of total potassium and exchangeable calcium, slope aspect, slope degree, and the concentration of available potassium. The result reveals that vegetation types affect understory species composition by modifying understory environments. Elevation affects the spatial distribution of vegetation and soil factors, and then the understory plants. Meanwhile, soil Ca content also plays a key role in the understory species distribution. Understory diversity increased with increasing canopy structure complexity from shrubland to mixed-species forest. Thus, it is necessary to take measures to promote natural vegetation restoration and to protect the mixed forests in degraded karst areas.

Inland salt areas of Southeast Serbia: ecological preferences of certain representatives of flora

Simultaneous monitoring of vegetation and soil of inland salt areas of Southeastern Serbia was performed in order to assess the univariate response of species along the environmental gradients. Five habitat types were recognized by classification analysis based on physicochemical characteristics of soil. Ecological preferences of 9 species recognized as diagnostic of established habitats were estimated by Huisman-Olff-Fresco models. Carex distans, Cynod on dactylon and Plantago coronopus are diagnostic species of habitat type I which is characterized by electrical conductivity lower than 500 μScm−1, slightly alkaline reaction and low concentration of nutrients. Habitats of type II with alkaline soil, where concentration of available potassium (53 mg K2O/100 g soil) and phosphorus (19 mg P2O5/100 g soil) is high and electrical conductivity is in range of 608 to 860 μScm−1, are suitable for Carex divisa, Juncus compressus and Limonium gmelinii. Puccinellia festuciformis shows affinities to habitats of type III, characterized by electrical conductivity of 1200–2800 μScm−1 and low water and nutrient content. Presence of Camphorosma monspeliaca on habitats (type IV) indicates high concentration of OH− ions, salts (>3000 μScm−1) and chlorides in soil. Puccinellia distans shows affinities to strongly saline, alkaline and nutrient rich habitats (type V) with fluctuating water regime during the vegetation season. Information on objectively assessed ecological preferences of plant species represents a suitable foundation for defining local or regional indicator systems, calibration of existing ecological indices and realization of procedures with the goal of conservation and enhancement of threatened ecosystems such as inland salt areas.

Geo-spatial variability in soil health of Biwan watershed located at Mewat district of Haryana, India

A study was carried out to evaluate the geo-spatial variability of soil health parameters in Biwan watershed located in the Mewat district of Haryana in 2012-13. The main objective of this study was to determine spatial variability of selected soil health parameters that influence crop growth and yield. Soil samples (100) with GPS co-ordinates were collected on random basis from Tapkan, Biwan, Shonkh, Palla and Palladi villages of Biwan watershed during pre-monsoon period (May 2012). Soil health parameters such as pH2, electrical conductivity (EC2), organic carbon, available NPK and micronutrient (Zn, Fe, Cu and Mn) were analyzed from each sample by the standard methods. The spatial variability maps for different soil health parameters were prepared through GIS software (ArcGIS 9.0). Results indicated that the pH2 (6.0-8.59) and EC2 (<1.0 dS/m) were normal in about 80% of soil samples in watershed area. Comparatively, higher soil salinity was observed in Palladi village. Organic carbon and available nitrogen were low in the soils of whole watershed. The available phosphorous was low in 57% soil samples and rest was in medium. The lower concentration of available phosphorous was in most of the part of watershed, whereas medium concentration was in some part of Biwan and Palladi villages. The available potassium was low in 23%, medium in 67% and high in 10% soil samples. The higher concentration of available potassium was in some parts of Biwan, Shonkh and Palla villages. The Zn concentration was deficient (<0.6 mg/kg) in 70% of soil samples and 30% samples were in sufficient. The higher concentration of Zn was in Tapkan and Palladi villages. 84% soil samples showed the iron (Fe) deficiency. The sufficient Fe concentration was in the scattered patches of the watershed. The Cu and Mn concentrations in most of the soils of Biwan watershed were sufficient. It was concluded from the study that the soil health of Biwan watershed was poor.

Diversity and Structure of Diazotrophic Communities in Mangrove Rhizosphere, Revealed by High-Throughput Sequencing.

Diazotrophic communities make an essential contribution to the productivity through providing new nitrogen. However, knowledge of the roles that both mangrove tree species and geochemical parameters play in shaping mangove rhizosphere diazotrophic communities is still elusive. Here, a comprehensive examination of the diversity and structure of microbial communities in the rhizospheres of three mangrove species, Rhizophora apiculata, Avicennia marina, and Ceriops tagal, was undertaken using high-throughput sequencing of the 16S rRNA and nifH genes. Our results revealed a great diversity of both the total microbial composition and the diazotrophic composition specifically in the mangrove rhizosphere. Deltaproteobacteria and Gammaproteobacteria were both ubiquitous and dominant, comprising an average of 45.87 and 86.66% of total microbial and diazotrophic communities, respectively. Sulfate-reducing bacteria belonging to the Desulfobacteraceae and Desulfovibrionaceae were the dominant diazotrophs. Community statistical analyses suggested that both mangrove tree species and additional environmental variables played important roles in shaping total microbial and potential diazotroph communities in mangrove rhizospheres. In contrast to the total microbial community investigated by analysis of 16S rRNA gene sequences, most of the dominant diazotrophic groups identified by nifH gene sequences were significantly different among mangrove species. The dominant diazotrophs of the family Desulfobacteraceae were positively correlated with total phosphorus, but negatively correlated with the nitrogen to phosphorus ratio. The Pseudomonadaceae were positively correlated with the concentration of available potassium, suggesting that diazotrophs potentially play an important role in biogeochemical cycles, such as those of nitrogen, phosphorus, sulfur, and potassium, in the mangrove ecosystem.

Mulch type and application of manure and composts in strawberry (Fragaria × ananassa Duch.) production: impact on soil fertility and yield

The objective of this research was to quantify the effect of the application of organic fertilizers: farmyard manure, vermicompost, spent mushroom compost, under two different ground cover management systems (black polyethylene and wheat straw mulch) on soil nutrient levels and strawberry yield during a two-year production cycle. The application of organic fertilizers, in the amounts equivalent to 170 kg ha -1 N, had the greatest impact on the concentration of available phosphorus, which was significantly higher on fertilized plots than on the control even two years after the application. The plots fertilized with farmyard manure and mushroom compost had higher concentrations of available potassium than the control, while the application of vermicompost did not affect the concentration of available potassium in the soil. The application of composts did not affect the concentration of available microelements in the soil, while the concentrations of Fe, Zn and Cu in the year of the organic fertilizers application were significantly higher on farmyard manure fertilized plots than on the control. The application of all three organic fertilizers had a significant effect on the mineral N concentration in the soil only in the year of the application and the following spring. However, the plots covered with polyethylene mulch had a higher mineral N concentration than the control at all sampling times. The concentration of available microelements was significantly higher in soil covered with black polyethylene mulch than in soil covered with straw mulch. Preplant application of organic fertilizers led to increase of yield, ranging from 14.3% in vermicompost treatmet to 17.3% in the farmyard manure treatment in relation to the control, only in the 1 st fruiting year. However, the application of polyethylene mulch facilitated a higher strawberry yield than straw mulch in both fruiting years.

Status of Soil Fertility in a Community Forest of Nepal

Soil is a complex mixture of mineral nutrients, organic matter, water, air and living organisms. The primary nutrients for plant growth are organic matter, nitrogen, phosphorus and potassium. In order to find the status of pH, organic matter (C), total nitrogen (N), available phosphorus (P) and available potassium (K) in forest soil, the study was conducted in Ghwangkhola Sapaude Babiyabhir Community Forest in Putali Bazaar Municipality-8, Syangja, Nepal. Soil parameters are analyzed through different standard methods followed worldwide by many soil scientists. Soil pH of sample in all three strata was slightly acidic and varies from 5.7 to 7.18. The carbon percentage was high and varies from 0.65% to 2.39%. The total nitrogen in soil was medium and varies from 0.09% to 0.12%. The concentration of available phosphorus in soil was high and varies from 73.71 kg/ha-93.23 kg/ha. The concentration of available potassium on soil was quiet low and varies from 2.54 kg/ha-4.23 kg/ha. Higher organic matter in the forest land indicate low activities of nitrogen losing process, which is due to the closed nutrient cycling and minimal disturbance in the natural forest system. So, addition of fertilizer rich in potassium and increasing pH is recommended to maintain potassium fertility and neutral pH in the forest soil. DOI: http://dx.doi.org/10.3126/ije.v1i1.8528 International Journal of Environment Vol.1(1) 2013: 56-67

Analysis of Macro and Micronutrients in Soils from Palestine Using Ion Exchange Membrane Technology

Ion Exchange membrane technology (IEM) is a method that allowed a single extraction process and a single subsequent measurement of different elements that are available in soil. The values of the available forms of the different macro- and micronutrients obtained by IEM extraction were compared with the values of the soluble form obtained by conventional extraction methods. In surface soil sample, the concentrations of available potassium, nitrate, phosphate, iron and boron were 37.7 mg kg–1, 17.5 mg kg–1, 3.6 mg kg–1, 171.0 μg kg–1, and 4.2 μg kg–1 respectively were greater than that of soluble forms of the same elements which were 7.0 mg kg–1, 9.2 mg kg–1, 0.4 mg kg–1, 109.0 μg kg–1, and 1.9 μg kg–1 respectively.

Potassium, Calcium, and Magnesium Distribution in an Oxisol under Long‐Term Potassium‐Fertilized Apple Orchard

Most Brazilian soils do not possess sufficient concentrations of available potassium (K) to produce maximum apple yield. Potassium distribution was evaluated with a depth profile of a Humic Xanthic Hapludox receiving K fertilization in an apple orchard, cv. Gala/MM106, at Vacaria, Rio Grande do Sul, Brazil. Treatments consisted of four rates of annual maintenance K fertilization. After 12 years of cultivation, soil was sampled in eight depth increments. Potassium, calcium (Ca), and magnesium (Mg) contents were extracted by Mehlich I, ion‐exchange resin, and ammonium acetate pH 7.0. Long‐term application of K fertilizer resulted in K accumulation mainly in the 0‐ to 30‐cm surface layer, with low K mobilization to deeper layers. Increasing rates of K fertilizer did not affect soil Mg concentration but induced a lower Ca concentration extracted by Mehlich I, especially in the 0‐ to 20‐cm layer. The estimated K2O rate for maximum apple yield was 86.5 kg/ha/year.