Soil EC Values Research Articles

Biological soil conditioner with reduced rates of chemical fertilization improves soil functionality and enhances rice production in vegetable-rice rotation

Soil is an essential source of nutrients for crop growth, but excessive chemical fertilizer can lead to soil acidification and decreased sustainability. Organic fertilizer helps improve soil physicochemical properties and increase soil utilization efficiency. However, soil functionality and crop sustainability response to organic fertilizers need further research. In this study, multiple fertilizer practices (including different amounts of nitrogen fertilizer or soil conditioners, traditional organic fertilizer), various rice varieties, and other rotation systems were applied to test the effects of soil conditioners on crop yield and soil fertility. The results showed that crop yield sustainability and stability were significantly positively correlated with soil pH, EC value, and nitrogen (Pearson r > 0.5). In addition, improving soil quality was beneficial to increasing crop yield sustainability and stability (R2 > 0.5). Chemical fertilizers and soil conditioners can increase soil nutrient content and improve crop yield sustainability index (>0.8). Applying soil conditioners can enhance the activity of soil catalase and urease in paddy soil, especially in the 12 and 15 m3 ha−1 soil conditioner treatments due to soil microbial activity being affected by soil salinity and organic matter content. Soil conditioners increase the mass of Nitrospira species in soil, decompose nitrogen in the soil, and reduce soil nitrate and nitrite content, thereby improving soil pH and reducing the risk of soil acidification caused by excessive chemical fertilizer. Combining soil conditioners and chemical fertilizer (20 % less than traditional fertilization) can promote soil quality and fertility while improving crop yield sustainability and stability.

Application of Fe3[KG-*2/5]O4/Mulberry Stem Biochar Effects on Soil Arsenic Species and Rice Arsenic Content

The passivation effect of Fe3O4/mulberry pole biochar (Fe-MBC) prepared at different carbonization temperatures on soil available arsenic content was studied through soil culture experiments, and Fe-MBC-800 (prepared by carbonization at 800℃) with good passivation effect was selected and characterized. The effects of 1%-7% (mass fraction of biochar to soil) Fe-MBC-800, MBC-800, and Fe3O4 on soil pH value, soil electrical conductivity, soil arsenic form, rice biomass, and total arsenic (As) content in rice were studied using a pot experiment. The results showed that:①Fe-MBC-800 successfully loaded Fe3O4, and its main functional groups were C=O double bond, O-H bond, C-O bond, and Fe-O bond. The specific surface areas of Fe-MBC-800, MBC-800, and Fe3O4 were 209.659 m2·g-1, 517.714 m2·g-1, and 68.025 m2·g-1, respectively. ②The addition of Fe-MBC-800 could increase the soil pH value, decrease the soil EC value, increase the content of residual arsenic in soil, and reduce the content of water-soluble arsenic and available arsenic in the soil. Under the treatment using 7% Fe-MBC-800 (ω) amendments, the content of water-soluble arsenic and available arsenic in the soil decreased by 81.6% and 56.33%, respectively. ③When the addition ratio of Fe-MBC-800 in the soil was 5%-7%, it could promote the growth of rice plants, increase rice biomass, and reduce the bioaccumulation of arsenic by between 62.5% and 68.75%.

Effects of Phosphogypsum and Suaeda salsa on the Soil Moisture, Salt, and Bacterial Community Structure of Salinized Soil

The improvement of saline soil is an important issue that cannot be ignored in the farmland soil environment. The change in soil salinity will inevitably affect the soil bacterial community. This experiment was based on moderately saline soil in the Hetao Irrigation Area, conducted by applying phosphogypsum (LSG), interplanting Suaeda salsa with Lycium barbarum (JP) and applying phosphogypsum and interplanting S. salsa with L. barbarum (LSG+JP),and the local unimproved soil of a L. barbarum orchard was used as the control (CK), to explore the effects of different improvement methods on soil moisture, salinity, nutrients, and bacterial community structure diversity during the growth period of L. barbarum. The results showed that compared with that under CK, the LSG+JP treatment significantly decreased the soil EC value and pH value from the flowering stage to the deciduous stage (P<0.05), with an average decrease of 39.96% and 7.25%, respectively; the LSG+JP treatment significantly increased soil organic matter (OM) and available phosphorus (AP) content during the whole growth period (P<0.05), with an average annual increase of 81.85% and 203.50%, respectively. The total nitrogen (TN) content was significantly increased in the flowering and deciduous stages (P<0.05), with an annual average increase of 48.91%. The Shannon index of LSG+JP in the early stage of improvement was increased by 3.31% and 6.54% compared with that of CK, and the Chao1 index was increased by 24.95% and 43.26% compared with that of CK, respectively. The dominant bacteria in the soil were Proteobacteria, Bacteroidetes, Actinobacteria, and Acidobacteria, and the dominant genus was Sphingomonas. Compared with that in CK, the relative abundance of Proteobacteria in the improved treatment increased by 0.50%-16.27% from the flowering stage to the deciduous stage, and the relative abundance of Actinobacteria in the improved treatment increased by 1.91%-4.98% compared with that in CK in the flowering and full-fruit stages. Redundancy analysis (RDA) results showed that pH, water content (WT), and AP were important factors affecting bacterial community composition, and the correlation heatmap showed that Proteobacteria, Bacteroidetes, and EC values were significantly negatively correlated (P<0.001); Actinobacteria and Nitrospirillum were significantly negatively correlated with EC values (P<0.01). In conclusion, the application of phosphogypsum and interplanting S. salsa with L. barbarum (LSG+JP) could significantly reduce soil salinity, increase nutrients, and improve the diversity of soil bacterial community structure, which is beneficial to the long-term improvement of saline soil in the Hetao Irrigation Area and the maintenance of soil ecological health.

Variation of Physico-Chemical Properties among Different Soil Orders under Different Land Use Systems of the Majha Region in North-Western India

The impact of different soil orders and land use systems on the distribution of physico-chemical properties is the most critical matter to address in order to maintain sustainable agricultural production. Hence, the present investigation was carried out to study the variation in the physico-chemical characteristics of soil in diverse land use systems (LUSs), i.e., agriculture, horticulture, and forestry, under major soil orders (entisol, inceptisol, and alfisol) in the Majha region of Punjab. A total of 225 depth-wise (at 0–20 cm, 20–40 cm, 40–60 cm, 60–80 cm and 80–100 cm) soil samples were collected from three land-use systems under different soil orders. The mean values of the physico-chemical properties ranged from 6.80–7.50, 7.64–8.34 and 6.94–7.87 for pH; 0.13–0.42, 0.19–0.54 and 0.19–0.46 dS m−1 for EC; 0.14–0.99, 0.21–0.69 and 0.15–0.72% for OC; 0.75–2.07, 1.07–3.32 and 0.93–2.29% for CaCO3; 7.77–41.84, 10.56–40.23 and 7.24–39.51 kg ha−1 for P; and 98.37–334.68, 94.51–230.18 and 93.01–367.39 kg ha−1 for K under different land uses in soil orders entisols, inceptisols and alfisols, respectively. Soil parameters including pH, CaCO3, and phosphorus (P) distribution differed significantly among soil orders; however, soil EC, organic carbon (OC) and available potassium (K) did not. The inceptisols under the agricultural land use system (ALUS) had the highest soil pH, EC, and CaCO3 values. The highest soil OC content was found in entisols under forest land use systems (FLUS), followed by horticultural land use systems (HLUS). The highest values of soil-available phosphorous (P) were found in FLUS under inceptisols, while the highest amounts of soil-available potassium (K) were found in entisols and alfisols under ALUS and FLUS, respectively. Thus, the distribution of physico-chemical properties under different LUSs in each soil order is highly variable and does not follow any particular trend. In general, soil properties such as OC, P, and K content decreased with an increase in soil depth, while pH and CaCO3 values increased with depth in all land uses and soil orders. There was a positive correlation between soil OC and EC, as well as available P and K in the soils investigated. The available P and K are negatively correlated with soil pH and CaCO3 content in the soil. The principal component analysis (PCA) revealed that soil pH and OC were the most variable soil parameters, which influence the availability of other physico-chemical properties under different soil orders and land use systems. Therefore, it is suggested that the land use systems play an important role in the distribution of physico-chemical properties of soil in different soil orders. The results of the study will help students, researchers, and agricultural management staff in managing different land uses for maintaining soil fertility and productivity in alluvial soils of North-western India.

Immobilization of Cd by mercapto-palygorskite in typical calcareous and acidic soil aggregates: Performance and differences

The microscale spatial heterogeneity and complexity of soil aggregates affect the properties and distribution of heavy metals (HMs). It has been confirmed that amendments can alter the distribution of Cd in soil aggregates. However, whether the Cd immobilization effect of amendments varies across soil aggregate levels remains unknown. In this study, soil classification and culture experiments were combined to explore the effects of mercapto-palygorskite (MEP) on Cd immobilization in soil aggregates of different particle sizes. The results showed that a 0.05–0.2% MEP application decreased soil available Cd by 53.8–71.62% and 23.49–36.71% in calcareous and acidic soils, respectively. The Cd immobilization efficiency of MEP in calcareous soil aggregates was in the following order: micro-aggregates (66.42–80.19%) > bulk soil (53.78–71.62%) > macro-aggregates (44.00–67.51%), while the efficiency in acidic soil aggregates was inconsistent. In MEP-treated calcareous soil, the percentage change in Cd speciation in micro-aggregates were higher than that in macro-aggregates, whereas there was no significant difference in Cd speciation between the four acidic soil aggregates. Mercapto-palygorskite addition in micro-aggregates of calcareous soil increased the available Fe and Mn concentrations by 20.98–47.10% and 17.98–32.66%, respectively. Mercapto-palygorskite had no effect on soil pH, EC, CEC, and DOC values, while the difference in soil properties between the four particle sizes was the main influencing factor of MEP treatments on Cd in calcareous soil. The effects of MEP on HMs varied across soil aggregates and soil types, but had strong specificity and selectivity for Cd immobilization. This study illustrates the influence of soil aggregates on Cd immobilization using MEP, which can be used to guide the remediation of Cd-contaminated calcareous and acidic soils.

Magnetic Treatment of Irrigation Water and Seeds and Its Effect on the Productivity and Quality of Wheat (Triticum aestivium L.) Grown in Saline Soil

ABSTRACT The current research was carried out to evaluate the impact of treating wheat (Triticum aestivum c.v Sakha 93) seeds and irrigation water magnetically in combination with different sources and rates of nitrogen on wheat productivity and grain quality under saline soil conditions. Two field experiments were carried out during the winter seasons 2018–2019 and 2019–2020 in a split split randomized complete block design with four replicates at El-Rabaa village, Bir Al-Abd, North Sinai Governorate, Egypt. Main plots were assigned to N-sources, urea, and compost; sub-plots were N-rates 0, 119, 179, and 238 Mg N ha−1, while magnetic treatment of irrigation water and wheat grains was in sub-subplots. The highest chlorophyll and carbohydrate contents (3.12 mg g−1 f.w. and 783 g kg−1, respectively) were observed due to compost, N4+ (MS + MW) treatment representing an increasing percentage of 189% and 220%, respectively. The maximum plant height, spike length, No. spike plant−1, and spike weight values were 82.0 cm, 15.1 cm, 13.9, and 24.9 g plant−1. The results were due to the addition of compost at a rate of 238 kg N ha−1 in combination with magnetized seeds and water treatment with 224, 643, 546, and 845% over the untreated treatment. The maximum straw and grain yields (11.7 and 7.29 Mg ha−1, respectively) were achieved due to the application of compost at a rate of N3 + (MS + MW), and the corresponding increments over the non-treatment plants were 718 and 846%, respectively. However, treatment of compost (179 Mg N ha−1 + magnetized seeds and water) resulted in the maximum increases in the No. grains spike−1, grains weight, 1000-grains weight, protein content, N, P, K, Fe, Mn, and Zn-uptake by grains. Soil pH and EC values were decreased, especially for plants treated with compost (238 kg N ha−1 + magnetized seeds and water treatment).

Effect of foliar application of varying doses of salicylic acid at different growth stages on growth, quality and nutrient uptake efficiency of French bean (Phaseolus vulgaris L.)

Background: The ubiquitous presence of salicylic (SA) acid in plant systems has been confirmed by many scientists. Salicylic acid is widely distributed throughout the plant and is proposed to affect a number of phyto-physiological activities. As an endogenous plant growth factor or a hormone SA has number of functions including florigenic and thermogenic role, part in plant-pathogen interaction, signal transduction, etc. Method: The present investigation was conducted at the Experimental Farm of the Division of Vegetable Science, SKUAST-K, during Kharif 2020 to find out the effect of foliar spray of varying doses of salicylic acid (SA) applied at different plant growth stages on growth and quality attributes of French bean var. Shalimar French Bean-1. The experiment was laid out in split plot design with twelve treatment combinations and three replications. Result: The investigation revealed that the treatment combination T1D2 (250ppm of SA applied at plant emergence stage) recorded minimum values for days taken to 50 per cent flowering and days taken to pod formation. Moreover, the same treatment combination T1D2 also recorded maximum values for plant height, number of primary branches plant-1, number of leaves plant-1 et al., leaf area and shoot dry weight plant-1. It was further revealed that in the treatment combination T1D2 maximum values of vitamin C content, TSS, protein content, leaf chlorophyll content and pod dry matter content were also recorded, while pod anthocyanin content was maximum in the treatment combination T2D2 (250ppm of SA applied at vegetative stage). The treatment combination T1D2 also significantly enhanced nutrient uptake efficiency of the plants and resulted in lowest values for the available nitrogen, phosphorus and potassium, soil EC and maximum values for organic carbon as compared absolute control. than absolute control D0.

Effects of Soil Amendments on the Bacterial Diversity and Abundances of Pathogens and Antibiotic Resistance Genes in Rhizosphere Soil Under Drip Irrigation with Reclaimed Water

Due to reclaimed water, irrigation can cause human health and environmental risks. Soil amendments are applied to reveal the abundance of pathogens and antibiotic resistance genes in rhizosphere soil irrigated by reclaimed water and to better understand the effects of environmental factors on the rhizosphere soil bacterial composition, which has guiding significance for the reasonable use of soil amendments. In this study, the effects of biochar, bioorganic fertilizer, humic acid, loosening soil essence, and corn vinasse on bacterial community diversity and certain gene abundances in rhizosphere soil under drip irrigation with reclaimed water were studied using high-throughput assays and quantitative PCR. The results showed that biochar significantly increased pH, organic matter, and total nitrogen contents in the rhizosphere soil. The corn vinasse significantly decreased soil pH and increased the contents of total nitrogen and total phosphorus but significantly increased the soil EC value (P<0.05). The effects of the five soil amendments on the α-diversity of rhizosphere bacteria were not significantly different. The bacterial community structure and diversity of rhizosphere bacteria were similar at different taxonomic levels, but their relative abundance was different. α-Proteobacteria, γ-Proteobacteria, Bacteroidia, Actinobacteria, Acidimicrobiia, and Anaerolineae were the dominant bacteria in all treatments. The dominant genera consisted of Pseudomonas, Sphingobium, Sphingomonas, Cellvibrio, Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium, Flavobacterium, and Algoriphagus (relative abundance>1%). Correlation analysis of environmental factors showed that the composition of the rhizosphere bacterial community was strongly correlated with pH, EC, total nitrogen, and total phosphorus content. The abundances of pathogenic bacteria and antibiotic resistance genes were 103-107 copies·g-1 and 104-108 copies·g-1, respectively. There were significant differences in the detection levels of pathogens and antibiotic resistance genes. Bioorganic fertilizer, loosening soil essence, and corn vinasse significantly increased the abundances of some antibiotic resistance genes, whereas humic acid and corn vinasse significantly decreased the abundances of Pseudomonas syringae, Ralstonia solanacearum, and total coliforms (P<0.05). A significant correlation was found between pathogens (Arcobacter, Bacillus cereus, Pantoea agglomerans, and Fecal bacteroidetes) and antibiotic resistance genes (tetA, tetB, tetO, tetQ, sul1, ermB, and ermC). In conclusion, while monitoring pathogens and antibiotic resistance genes in the agricultural environment under reclaimed water irrigation, attention should be paid to the rational application of soil amendments to avoid exacerbating the spread of biological contamination.

Impact of NPK fertilization on hazelnut yield and soil chemical-microbiological properties of Hazelnut Orchards in Western Georgia

In this study, the effects of ground and foliar applications of the NPK fertilizers in hazelnut orchards on the soil chemical and microbiological properties and hazelnut yield were investigated. The fertilization practicesses from ground were done two times using NPK (20:10:10 +trace elements) on March and May while the fertilization practices from leaf were done three times using NK (15:12 +trace elements) on May, June and July at six different hazelnut orchards located on Samegrelo, Guria and Adjara regions in Western Georgia in 2018. The alkaline characterized fertilizer applications from soil generally increased soil reaction (pH), nutrient contents and EC values in different magnitude depends on the soil characteristics of locations. The lowest soil pH (4,40) and EC (0,107 dS m-1) values showed the highest increment (10,7% and 77,6%, respectively) over the control. The basal soil respiration and Cmic values of all hazelnut orchards were generally increased by the NPK ferilization. Increasing soil pH and EC by the fertilization also increased CA and DHA activity. The mean values of percent increase in yield and yield parameters by the NPK fertilization were obtained as 8,3% in yield, 13,3% in shelled nut weight, 10,0% in kernel weight and 5,1% in percent kernel efficiency. The hazelnut yield value had significant positive correlation with soil pH (0,669*), EC (0,652*) and Cmic (0,620*) values. The foliar fertilization and improving the soil properties of hazelnut orchards by the application of alkaline characteristic NPK fertilizer from soil increased hazelnut yield and yield parameters compare with the farmer applications or control treatments. The increments in soil microbiological properties and nutrients are considered as a desirable result in terms of sustainable soil management and plant nutrition for hazelnut orchards.

Identification of saline landscapes from an integrated SVM approach from a novel 3-D classification schema using Sentinel-1 dual-polarized SAR data

This study presented an integrated SVM classification method that investigated the relationship between intrinsic scattering attributes of the surface features and the conductivity characteristics of the soil in the newly proposed two- and three-dimensional classification (2D and 3D) schema to classify the saline landscape. The study was conducted in the Vellore district, Tamil Nadu, which is composed of heterogeneous saline landforms due to the active geological processes and anthropogenic activities. The intensity products of Sentinel-1 data (VV + VH) of C-band frequency were employed in the present study. The SVM with linear kernel has outperformed the other models, namely random forest (RF), naive Bayes (NB), and K-Nearest Neighbour (k−NN), in performing the broad level of classification from the 2D classification schema (SVMOA = 84.2%, RFOA = 80.4%, k-NNOA = 78.8%, NBOA = 68.4%). The soil EC values derived from the dielectric loss measurements (R2 = 0.79, ρ = 0.018, and α=95%) were used to introduce the integrated SVM approach in the 3D schema to further breakdown the mapped classes into non-saline (NS) (soil EC ≤ 2 ds/cm), slightly saline (SS) (soil EC = 2.1 to 4 ds/cm) and moderately saline (MS) (soil EC = 4.1 to 8 ds/cm) categories. The overall performance of the integrated SVM approach implemented for the 3D classification schema (F1 = 0.80) was found to be satisfactory, but with an associated uncertainty majorly from MS (Precision = 0.52, F1 = 0.69), SS (Recall = 0.09, F1 = 0.15), and NS waterbodies (Recall = 0.18, F1 = 0.29) as shown in the Precision-Recall graph (AUCPR3D = 0.62). However, with the promising performance level demonstrated for the other nine classes such as NS, SS, and MS wet soil (F1 = 0.92, 0.92, 0.96), healthy plants (F1 = 0.83), salt-tolerant plants under SS and MS conditions (F1 = 0.83, 0.88), and waterlogged vegetation under NS, SS, and MS conditions (F1 = 0.82, 0.83, 0.83), the proposed classification scheme becomes an effective method to map saline and non-saline features from dual-polarimetric SAR data.

Salt tolerance of Papaya (Carica papaya), Indian spinach (Basella alba L.) and Okra (Abelmoschus esculentus) in the south central coastal region of Bangladesh

A study was conducted on saline tolerant vegetables with their mineral constituents for nutritional security during July 2020 to June 2021. Edible portions of the three summer vegetables, such as papaya, Indian spinach and okra were collected from Barguna and Patuakhali districts. The locations were Sawdagarpara, Taltoli, Barguna district, Pakhimara of Khepupara upazila and Dumki of Patuakhali district. Sawdagarpara (saline soil, EC=6.2 dSm-1), Taltoli, Barguna district and Pakhimara (saline soil, EC=3.8 dSm-1), Khepupara, Patuakhali district were selected as the saline areas and Dumki (non-saline soil, EC=0.9 dSm-1), Patuakhali was a non-saline area on the basis of soil EC levels. The vegetables were analyzed for P, K, Ca, Mg and S. In saline areas, comparatively lower accumulations of P and higher accumulations of K, Ca, Mg and S were found in non-saline areas. Considering the achieved findings, studied vegetables can tolerate moderate salinity (soil EC value up to 6.2dSm-1) and they can be recommended to grow commercially in the study area for nutritional security. The accumulation trend in the vegetables was Ca&gt;Mg&gt;P&gt;K&gt;S. On the basis of total mineral ingredients, the trend of vegetables was found to be Indian spinach&gt; papaya&gt; okra. Therefore, the study recommended that Carica papaya, Basella alba L. and Abelmoschus esculentus are the moderately saline tolerant vegetable crops.

Using Zeolite and Vermicompost Amendments to Improve Water Productivity of Wheat Irrigated by Low-quality Water in the Northern Nile Delta

Aims: In the long run, reusing low-quality water in Egypt's agricultural sector directly or after mixing with fresh water to compensate for water supply constraints can be hazardous to plants and soil. As a result, some appropriate management must be considered. For this reason, a field experiment was implemented in winter seasons 2018/2019 and 2019/2020 at Sakha Agric. Res. Station Farm, Kafr El-Sheikh Gov., Egypt. This study aims to assess the impacts of zeolite and vermicompost as well their combinations on alleviation of low-quality water impacts on physicochemical properties of clayey soil and wheat productivity.&#x0D; Study Design: complete randomized block design with three replicates.&#x0D; Results: The application of 2.40 Mg Z ha-1 was found to be the most effective on soil properties and plant growth. This treatment reduced soil EC, Na+, Ca2+, Mg2+, Cl-, SO42-, and ESP values the most (52.90 percent, 83.21 percent, 30.43 percent, 6.04 percent, 91.82 percent, 19.83 percent, and 70.73 percent, respectively), while increasing the K+ value by 32.47 percent. It also achieved the highest increases in plant height, 1000-grain weight, grain, and straw yields (35.92%, 9.60%, 42.77%, and 25.61%, respectively) when compared to untreated soil. With 2.40 Mg VC ha-1, the greatest changes in bulk density, total porosity, and CEC (-9.23, 9.30, and 10.54 percent, respectively) were obtained. The applications of 1.80 Mg Z with 0.6 Mg VC ha-1 and 0.6 Mg Z ha-1 with 1.80 Mg VC ha-1, on the other hand, resulted in the greatest increases in soil moisture content, drainable pores (DP), and water holding pores (WHP). Furthermore, 0.6 Mg Z combined with 1.80 Mg VC ha-1 significantly increased the available N, P, and K in the soil. The addition of 2.4 tons Z/ha increased the WP and resulted in a high economically appealing wheat.&#x0D; Conclusion: It could be concluded that the application of Z and VC is a new strategy for alleviating abiotic stress and improving wheat growth. Z application was more effective than VC on improving soil physicochemical properties and improving the water productivity and achieve high economical attractiveness wheat irrigated by low-quality water.

Application of ITC cucumber fertilizer and water control system

In order to optimize the environmental factors for cucumber growth, a fertilizer and water control system was designed based on the Internet of Things (IoT) system. The IoT system monitors environmental factors such as temperature, light and soil Ec value, and uses image processing to obtain four growth indicators such as cucumber stem height, stem diameter size, number of leaves and number of fruit set to establish a single growth indicator model for temperature, light, soil Ec value and growth stage, and the four growth indicators were fused to obtain the comprehensive growth indicator Ic for cucumber, and calculates its deviation to determine the cucumber growth status. Based on the integrated growth index Ic of cucumber, a soil Ec control model was established to provide the optimal environment and fertilizer ration for cucumber at different growth stages to achieve stable and high yield of cucumber.

Potential of Landsat 8 OLI for mapping and monitoring of soil salinity in an arid region: A case study in Dushak, Turkmenistan.

Soil salinity is the most common land degradation agent that impairs soil functions, ecosystem services and negatively affects agricultural production in arid and semi-arid regions of the world. Therefore, reliable methods are needed to estimate spatial distribution of soil salinity for the management, remediation, monitoring and utilization of saline soils. This study investigated the potential of Landsat 8 OLI satellite data and vegetation, soil salinity and moisture indices in estimating surface salinity of 1014.6 ha agricultural land located in Dushak, Turkmenistan. Linear regression model was developed between land measurements and remotely sensed indicators. A systematic regular grid-sampling method was used to collect 50 soil samples from 0–20 cm depth. Sixteen indices were extracted from Landsat-8 OLI satellite images. Simple and multivariate regression models were developed between the measured electrical conductivity values and the remotely sensed indicators. The highest correlation between remote sensing indicators and soil EC values in determining soil salinity was calculated in SAVI index (r = 0.54). The reliability indicated by R2 value (0.29) of regression model developed with the SAVI index was low. Therefore, new model was developed by selecting the indicators that can be included in the multiple regression model from the remote sensing indicators. A significant (r = 0.74) correlation was obtained between the multivariate regression model and soil EC values, and salinity was successfully mapped at a moderate level (R2: 0.55). The classification of the salinity map showed that 21.71% of the field was non-saline, 29.78% slightly saline, 31.40% moderately saline, 15.25% strongly saline and 1.44% very strongly. The results revealed that multivariate regression models with the help of Landsat 8 OLI satellite images and indices obtained from the images can be used for modeling and mapping soil salinity of small-scale lands.

Vegetation Characteristics and Recent Successional Trends of Sand Dune Habitats at the Bulgarian Black Sea Coast

Coastal dunes are valuable and vulnerable habitats that require scientific exploration and understanding of their natural processes; therefore, the aims of this study were to determine the current vegetation characteristics of dune habitats along the Bulgarian Coast in terms of species richness and cover of typical psammophytes and different non-psammophytic plant groups, and to analyze how they respond to certain environmental drivers. Data were collected from 12 dune systems. The research was focused on embryonic, white and grey dunes. The field work was conducted throughout July and August 2017. The vegetation was sampled at 154 phytosociological plots (5 m × 5 m). To understand how the vegetation responds to different drivers, we tested the correlation of defined species group richness and cover in relation to (1) the soil pH and EC values, (2) the distance from inland to the sea and (3) the range of different categories of land cover in the surrounding area. In order to track temporal vegetation changes, we compared the cover of defined species groups between 2003 and 2017. We registered a total number of 269 vascular plants, 12 bryophytes and 5 lichens. The strongest presence in all dune types, both in species richness and cover, was the group of grass- and shrubland plants. Weeds and ruderal plants had significant coverage in grey dunes, while the richness and cover of forest and alien plants were negligible among the studied dune habitats. The comparison of data between 2003 and 2017 revealed a substantial decline in the cover of psammophytes. We observed a clear pattern regarding the share of species richness of psammophytes and non-psammophytes among different locations. We detected that grey dunes were the most affected by the penetration of non-psammophytes.

Effect of Organic Fertilizers and Foliar Application of some Stimulants on Barley Plants Under Saline Condition. تأثير الأسمدة العضوية والرش الورقي لبعض المنشطات على نباتات الشعير تحت ظروف ملحية

Salinity stress is one of the most deleterious abiotic stress factors that affect the growth, productivity, and physiology of plants. So, two field experiments were implemented aiming at assessing the influence of three types of organic fertilizers as main plots i.e. farmyard manure (FYM), plant compost (PC) and animal compost (AC) and foliar application of different stimulants i.e. proline, ascorbic acid and salicylic acid as sub-plots on the performance of barley plants grown on soil having EC value of 6.5 dSm-1. The results showed that the barley plants fertilized with animal compost (AC) possessed the best performance under soil salinity stress followed by that fertilized with plant compost (PC) then plants fertilized with farmyard manure (FYM), while barley plants untreated with organic fertilizers possessed the lowest performance. The investigated organic fertilizers increased the nutrient's availability and uptake and enhanced the synthesis of chlorophyll in the plant tissues and this may be the reason for increasing the ability of barley to tolerate salinity. Regarding the foliar application of stimulants, proline treatment was the superior one followed by ascorbic acid then salicylic acid and lately control treatment. Concerning the interaction effect, the highest values of barley growth criteria, as well as yield and its components, were realized when plants treated with plant compost (PC) and sprayed with proline, while the lowest values were recorded when barley plants were not treated with both organic fertilizer and antioxidants. Also, the organic fertilizers positively affected soil available nutrients (N, P and K) and EC values.

Short-term Effects of Food Waste Compost on Soil Properties and Chinese Cabbage Growth in Upland Soil

More than 5 million tons of food waste (FW) has been annually produced in Korea. Approximately 40% of FW is recycled through composting process. The aim of this study was to investigate the potential of using food waste compost (FWC) as a nutrient source and a soil amendment for Chinese cabbage cultivation. This study was carried out 1) to test effect of FWC application rates (0, 20, 40, and 60 Mg ha-1) on crop yield and soil property for two years and 2) to present a regression equation for predicting the yield from soil EC value under FWC application condition. The result showed that 40 Mg ha-1 or more decreased yield; however, pH, EC, total nitrogen, organic matter, available P2O5 and exchangeable sodium percentage (ESP) were increased with application rates of FWC. As a result of confirming the correlation between soil characteristics and yield, EC showed the highest correlation with other factors. Therefore, the regression equation between yield and EC was determined as the equation (y = log (x) × 5.2 + 122.3), and the soil EC value could be used as an indicator to predict the yield of Chinese cabbage under FWC application. Yield of Chinese cabbage according to application level of food waste compost during 2 years.

Dynamics of acidity and electrical conductivity due to seawater amelioration in total reclaimed acid sulphate soils, South Kalimantan

The objective of our research was to determine the effect of inundation using seawater on the pH and EC of acid sulphate soils This research consisted of 2 stages, an incubation experiment carried out in the greenhouse, Indonesian Swampland Agricultural Research Institute (ISARI), Banjarbaru South Kalimantan and in the field of Handil, Maluka village, Bumi Makmur District, Tanah Laut Regency, South Kalimantan. The incubation experiment used several seawater concentrations of 0, 12.5, 25, 37.5 and 50%, with randomized complete design with 3 replications. The field experiment used a raise bed system with two treatment applications: (i) without brackish water and (ii) with brackish water. The results of the incubation experiment showed that the longer the incubation period and the higher seawater concentration caused a decrease in the soil pH while increasing EC values. Conversely, incubation of potential acid sulphate soils using well water (0% seawater) resulted in increasing soil pH and EC values. Field experiments showed that the application of brackish water on acid sulphate soil gave lower soil pH than that without brackish water. Contrary, EC values of acid sulphate soil applied with brackish water were higher than those without brackish water application.

Experimental Study on Soil Electrical Conductivity Inversion by Ground Spectral Measurement and SAR Data

In this paper, the ground-measured spectral reflectance was combined with C-band microwave radar quadrupolarized backscattering data, and the characteristic bands were selected using partial least squares and correlation coefficient methods, and a model was developed to evaluate the degree of soil salinization. Using the spectral reflectance and its logarithmic, first-order and second-order derivatives of the four spectral data, correlation analysis was performed and found that the first and second order derivatives of the spectra were better correlated compared to the first two. The correlations of soil EC values in the four bands of 1584-1588 nm, 1802-1806 nm, 2201-2205 nm, and 2344-2348 nm transformed by second-order derivatives were 0.27, 0.34, 0.33, and 0.35, respectively, and there existed two bands of 1802-1806 nm and 2344-2348 nm that both had better soil EC correlation. The bands selected by the partial least squares method are more backward than those selected by the correlation coefficient method, and there are extremely sensitive bands, and the fit of the second-order derivative transformation model is better compared with that of the correlation coefficient method. By combining the second-order derivatives of reflectance, surface roughness and radar backscatter coefficients, the neural network model with the second-order derivatives of reflectance and radar backscatter characteristics was the best prediction model, and its R2 for soil EC was 0.8666.

Management of phosphorus and potassium in bidi tobacco (Nicotiana tabacum L.) under rainfed conditions

A field experiment was undertaken at Regional Agriculture Research Station, Nandyal, Andhra Pradesh for four consecutive seasons from 2015-16 to 2018-19 on Vertisols under rainfed condition to find out the economics and management of phosphorus and potassium in bidi tobacco (Nicotiana tabacum L.) for higher cured leaf yield and quality. The experiment was laid out in a randomized block design with 8 treatments and replicated thrice. The data pooled over four seasons revealed that significantly higher leaf length (42.8 cm) and leaf width (17.3 cm) was recorded with 100% RDF (110 kg N + 70 kg P2O5+ 50 kg K2O ha-1) every year. Significantly higher cured leaf yield (1551 kg ha-1) and net returns (Rs 63,375 ha-1) were recorded with application of 110 kg N + 70 kg P2O5+ 50 kg K2O ha-1every year and on par with 100% RDN (110 kg N ha-1) +PK (70 kg P2O5+ 50 kg K2O ha-1) once in two years (1408 kg ha-1and net returns of Rs 59,275 ha-1). Leaf chemical constituents namely nicotine, reducing sugars and chlorides did not differ significantly due to different treatments and were in permissible limit. Post harvest soil analysis indicated that soil available N, P2O5 and K2O differed significantly due to different treatments and maximum amounts of available N (158.9 kg ha-1), available P2O5 (56.3 kg ha-1) and available K2O (537.3 kg ha-1) were recorded under treatment T5, T3 and T5, respectively. Soil pH and EC values were not affected significantly with the various treatments.