Long-term analysis of soil water regime and nitrate dynamics at agricultural experimental site : field-scale monitoring and numerical modeling using HYDRUS-1D
Description:
•Glasshouse experiments on Sprayable Biodegradable Polymer Membrane (SBPM) Technology.•Water conservation using SBPM increased with increasing application rate.•Crop emergence decreased with increasing application rate.•The 150 mm width and 0.5 kg m-2 SBPM rate was most effective in reducing weeds.•SBPM band application had positive effects on soil water potential. With a rapidly growing global population, increased agricultural productivity is required to achieve future food security. Efficient use of water and other agricultural inputs such as nutrients and pesticides must underpin agronomic practices to improve crop establishment and increase crop yields. A glasshouse study was conducted to explore the potential of a newly developed sprayable biodegradable polymer membrane (SBPM) applied in bands to reduce soil evaporation and increase soil temperature, thus improving germination, emergence and crop establishment. The aims were two-fold: (i) to evaluate the effectiveness of the SBPM in reducing seedbed water loss and its effect on seedling emergence and (ii) to determine an effective band width (100 vs 150 mm) and application rate of SBPM to conserve seedbed water. Our study demonstrated that a high application rate (1 kg m-2) is effective at reducing soil water loss, but it reduces crop emergence (cotton, sunflower, sorghum, mung bean, carrot, capsicum and rockmelon). All three SBPM application rates (1, 0.5 and 0.25 kg m-2) showed increased soil water content compared to the control plot (bare soil surface). The applied bands, 100 and 150 mm width, limit evaporation and increased soil water potential and temperature compared to the control, however with no significant differences between the two treatments. Crop emergence was proportional to the application rate and decreased with increasing application rate (i.e., control < 0.25 kg m-2 < 0.5 kg m-2 < 1 kg m-2). The SBPM suppressed weed growth similar to conventional mulch film and was most effective at 0.5 kg m-2 and 150 mm width. Future research should focus on the field SBPM application management with an emphasis on crop emergence zones, biodegradability and comparing its effectiveness with other conventional mulches.
Description:
Greater understanding of the microbial activity role in metal mobilization processes in soil is of major importance. The objective was to study the effect of major Cd species in solution of a saline soil on dehydrogenase activity (DHA). Hypothesis is that (i) under increased soil salinity, more mobile Cd species with diverse effect on DHA may be generated (i.e., CdCl n 2-n ) and that (ii) DHA may correlate to organically complexed Cd species. In a greenhouse pot experiment, NaCl salinity (50 and 100 mM) was applied to control soil and soil spiked with Cd (5 and 10 mg kg -1 ). Soil total and available (CaCl 2 extractable) Cd concentrations were measured, and DHA determined using 2,3,5-triphenyltetrazolium chloride (TTC) method. Speciation was calculated from results of soil solution ion analysis using geochemical equilibrium model Visual MINTEQ. DHA was reduced with increased soil salinity and Cd contamination, but only compared with control soil. Although weak, negative correlation between DHA and CdCl n 2-n complexes in soil solution suggested their higher inhibitory effect on DHA than other Cd species. Positive correlation between DHA and organically complexed Cd indicated that raised microbial activity may increase the proportion of organically complexed Cd in the soil solution. Cd toxicity to soil microorganisms can be accentuated in a saline environment, which may be an issue of great importance for agricultural production in coastal areas. Microbial activity may via releasing organic substances in soil solution significantly change cadmium complexation and mobility in soil, an aspect which has often been overlooked. Graphical Abstract
Description:
Phytoremediation is an effective and low-cost method for the remediation of soil contaminated by potentially toxic elements (metals and metalloids) with hyperaccumulating plants. This study analyzed hyperaccumulator publications using data from the Web of Science Core Collection (WoSCC) (1992–2020). We explored the research status on this topic by creating a series of scientific maps using VOSviewer, HistCite Pro, and CiteSpace. The results showed that the total number of publications in this field shows an upward trend. Dr. Xiaoe Yang is the most productive researcher on hyperaccumulators and has the broadest international collaboration network. The Chinese Academy of Sciences (China), Zhejiang University (China), and the University of Florida (USA) are the top three most productive institutions in the field. China, the USA, and India are the top three most productive countries. The most widely used journals were the International Journal of Phytoremediation, Environmental Science and Pollution Research, and Chemosphere. Co-occurrence and citation analysis were used to identify the most influential publications in this field. In addition, possible knowledge gaps and perspectives for future studies are also presented.
Description:
Phytoremediation is an effective and low-cost method for the remediation of soil contaminated by potentially toxic elements (metals and metalloids) with hyperaccumulating plants. This study analyzed hyperaccumulator publications using data from the Web of Science Core Collection (WoSCC) (1992–2020). We explored the research status on this topic by creating a series of scientific maps using VOSviewer, HistCite Pro, and CiteSpace. The results showed that the total number of publications in this field shows an upward trend. Dr. Xiaoe Yang is the most productive researcher on hyperaccumulators and has the broadest international collaboration network. The Chinese Academy of Sciences (China), Zhejiang University (China), and the University of Florida (USA) are the top three most productive institutions in the field. China, the USA, and India are the top three most productive countries. The most widely used journals were the International Journal of Phytoremediation, Environmental Science and Pollution Research, and Chemosphere. Co-occurrence and citation analysis were used to identify the most influential publications in this field. In addition, possible knowledge gaps and perspectives for future studies are also presented.
Description:
This study investigates the impacts of Acacia invasion on Bornean heath forest (HF) soils. Soil profiles and water properties at one soil depth (< 1 m) and physicochemical properties with Soil Fertility Index(SFI) and Soil Evaluation Factor (SEF) from the topsoil or three soil depths of Acacia-invaded and non-invaded HF were assessed. Acacia invasion modified soil profiles by producing thicker horizons O and B but waning horizon E. Thick leaf litter layer in invaded HF was associated with a significant decrease in soil bulk density, moisture, organic matter (OM), total organic carbon, water volume, and NH4+ but a significant increase in soil temperature, and soil water pH, NO3
Description:
This study investigates the impacts of Acacia invasion on Bornean heath forest (HF) soils. Soil profiles and water properties at one soil depth (< 1 m) and physicochemical properties with Soil Fertility Index(SFI) and Soil Evaluation Factor (SEF) from the topsoil or three soil depths of Acacia-invaded and non-invaded HF were assessed. Acacia invasion modified soil profiles by producing thicker horizons O and B but waning horizon E. Thick leaf litter layer in invaded HF was associated with a significant decrease in soil bulk density, moisture, organic matter (OM), total organic carbon, water volume, and NH4+ but a significant increase in soil temperature, and soil water pH, NO3
Biology, distribution and management of the globally invasive weed Solanum elaeagnifolium Cav (silverleaf nightshade): A global review of current and future management challenges
Description:
•Field scale experiments on Sprayable Biodegradable Polymer Membrane (SBPM) Technology.•SBPM application rate of 1 and 3 kg m−2 showed significant soil water conservation.•Soil temperature increase was significant in 3 kg m−2 and under 55 cm width SBPM.•SBPM outperformed plastic mulch film (PMF) treatment in the absence of crop.•Results proved effectiveness of SBPM technology under field conditions. Reducing soil evaporation, especially in temperate climate zones, increases crop production. Plastic mulch films (PMFs) are very efficient in conserving soil water conservation however, plastic pollution is raising environmental and human health concerns. Therefore, a newly developed Sprayable Biodegradable Polymer Membrane (SBPM) Technology was tested for its ability to conserve soil water, suppress weeds, modify soil temperature, and improve crop yields. Two-year field experiments were performed in tomato and watermelon cropping systems, where SBPM was compared to no mulch and PMF controls. SBPM loadings were 3.0, 1.0, 0.5, and 0.25 kg m−2, with fumigation (F) and without fumigation (NF) in tomato, and 1.5, 1.0, 0.5, and 0.25 kg m−2 in watermelon. In tomato, the soil volumetric water content (VWC) in the topsoil was significantly higher for all treatments compared to the control, in the following order: 1 kg m−2 F > 0.5 kg m−2 NF > 1 kg m−2 NF > 0.5 kg m−2 F > Control in 2016/17 and 3 kg m-2 NF > Control > 0.5 kg m−2 F > 3 kg m−2 F > 0.5 kg m−2 NF in 2018. With watermelon in 2017, VWC was lower in the topsoil of the SBPM treatments than with PMF, but higher during the 2018 trial when no crop was grown. The amount of conserved soil water appeared to be determined by the physical integrity (unevenness/holes/tears) of the SBPM and PMFs. Soil salinity increase/decrease was associated with the volume of infiltrating water in the different treatments. Soil temperature increased significantly under the highest SBPM loading of 3 kg m−2 NF, using a 55 cm width of polymer coverage. The yield responses across treatments were not significant. Field experiments proved the effectiveness of the SBPM technology, but also highlighted some limitations of it when compared with conventional PMFs. The SBPM technology needs ongoing refinement to improve its sprayability, durability, biodegradability, and cost-effectiveness.
Description:
Organic amendments are often reported to improve soil properties, promote plant growth, and improve crop yield. This study aimed to investigate the effects of the biochar and compost produced from sewage sludge and olive pomace on soil hydraulic properties, water flow, and P transport (i.e., sorption) using numerical modeling (HYDRUS-1D) applied to two soil types (Terra Rosa and Rendzina). Evaporation and leaching experiments on soil cores and repacked soil columns were performed to determine the soil water retention, hydraulic conductivity, P leaching potential, and P sorption capacity of these mixtures. In the majority of treatments, the soil water retention showed a small increase compared to the control soil. A reliable fit with the modified van Genuchten model was found, which was also confirmed by water flow modeling of leaching experiments (R2 0.99). The results showed a high P sorption in all the treatments (Kd 21.24 to 53.68 cm3 g−1), and a high model reliability when the inverse modeling procedure was used (R2 0.93–0.99). Overall, adding sewage sludge or olive pomace as compost or biochar improved the Terra Rosa and Rendzina water retention and did not increase the P mobility in these soils, proving to be a sustainable source of carbon and P-rich materials.
Description:
Organic amendments are often reported to improve soil properties, promote plant growth, and improve crop yield. This study aimed to investigate the effects of the biochar and compost produced from sewage sludge and olive pomace on soil hydraulic properties, water flow, and P transport (i.e., sorption) using numerical modeling (HYDRUS-1D) applied to two soil types (Terra Rosa and Rendzina). Evaporation and leaching experiments on soil cores and repacked soil columns were performed to determine the soil water retention, hydraulic conductivity, P leaching potential, and P sorption capacity of these mixtures. In the majority of treatments, the soil water retention showed a small increase compared to the control soil. A reliable fit with the modified van Genuchten model was found, which was also confirmed by water flow modeling of leaching experiments (R2 0.99). The results showed a high P sorption in all the treatments (Kd 21.24 to 53.68 cm3 g−1), and a high model reliability when the inverse modeling procedure was used (R2 0.93–0.99). Overall, adding sewage sludge or olive pomace as compost or biochar improved the Terra Rosa and Rendzina water retention and did not increase the P mobility in these soils, proving to be a sustainable source of carbon and P-rich materials.
Description:
Preformed biodegradable and next generation sprayable biodegradable polymer membrane (SBPM) formulations, which biodegrade to non-harmful products (water, carbon dioxide and microbial biomass), have been introduced as an alternative to plastic mulch films in order to mitigate plastic pollution of the environment. In this preliminary field study on cotton (Gossypium hirsutum L.), a novel SBPM technology was compared to preformed slotted oxo-degradable plastic (ODP) mulch film and no mulch control (CON) in terms of yield, crop water productivity (CWP), and soil temperature. The first results showed higher CWP and crop yield, and increased soil water content under the SBPM cover. This study indicates that SBPM technology could perform at similar level as ODP or comparable films under field conditions and, at the same time, provide environmentally sustainable agricultural cropping practices. Additionally, the fully treated, non-replicated SBPM plot had a wetter soil profile throughout the entire crop season. This innovative technology has shown a high potential even at this early stage of development, indicating that advances in formulation and further testing can lead to significant improvements and thus increased use in crop production systems.