Combination Of Soil Amendments Research Articles

Assessing Stachytarpheta jamaicensis (L.) Vahl growth response and rhizosphere microbial community structure after application of food waste anaerobic digestate as biofertilizer with renewable soil amendments

A combination of soil amendments (biochar, organic compost, and rice husk) and anaerobic digestate of food waste may ensure high cropland productivity and resource efficiency. This study evaluated the effectiveness of food waste anaerobic digestate (FWAD) as a replacement for commercial fertilizer in growing Stachytarpheta jamaicensis (L.) Vahl (ornamental plant) under different soil amendment conditions. The results of soil coupling amendments such as biochar, organic compost, and rice husk positively affected Stachytarpheta jamaicensis growth, with the added FWAD. Adding coupling soil amendments along with the added FWAD significantly enhanced the chlorophyll content index, height, and number of leaves in Stachytarpheta jamaicensis. Under the addition of FWAD, the chlorophyll content index of soil coupling biochar amendment revealed 53.08 ± 0.07, while soil coupling rice husk amendment revealed 53.68 as compared to the control soil growing medium with 52.58 ± 0.07. Meanwhile, the plant height and the number of leaves increased by up to 27%, for soil coupling biochar and rice husk amendment, respectively. The microbial community analysis of the rhizospheric zone of Stachytarpheta jamaicensis revealed the top phylum in all treatments is Acidobacteriota, Actinobacteriota, Bacteroidota, Cyanobacteria, Firmicutes, Fusobbacteria, Gemmatimonoadota, Halobacterota, Latescibacterota, Myxococcocccota, Proteobacteria, Spirochaetota, Synergistota, and Verrucomicrobiota. FWAD is shown to have significant effects on the growth of Stachytarpheta jamaicensis in this study, thereby providing practical implications for replacing commercial fertilizer with FWAD.

Soil Constraints in an Arid Environment—Challenges, Prospects, and Implications

Climate models project that many terrestrial ecosystems will become drier over the course of this century, leading to a drastic increase in the global extent of arid soils. In order to decrease the effects of climate change on global food security, it is crucial to understand the arid environment and the constraints associated with arid soils. Although the effects of aridity on aboveground organisms have been studied extensively, our understanding of how it affects soil processes and nutrient cycling is lacking. One of the primary agricultural constraints, particularly in arid locations, is water scarcity, due to which arid soils are characterized by sparse vegetation cover, low soil organic carbon, poor soil structure, reduced soil biodiversity, and a high rate of soil erosion via wind. Increased aridity will limit the availability of essential plant nutrients and crop growth, and subsequently pose serious threats to key ecological processes and services. The increasing rate of soil salinization is another major environmental hazard that further limits the agricultural potential of arid soils. These soil constraints can be ameliorated and the crop yields increased through case-specific optimization of irrigation and drainage management, enhancing the native beneficial soil microbes, and combinations of soil amendments, conditioners, and residue management. This review explores technologies to ameliorate soil constraints and increase yields to maintain crop output in arid soils.

Aided Phytoremediation in Fire-Affected Forest Soil

Wildfires are occurring with an increasing frequency, and substances they generate can negatively affect the environment. A pot experiment with Lolium perrene was performed on burnt soil supplemented with organic (biochar, compost) and inorganic (NPK fertilizer) supplements and combinations of soil amendments in order to assess the possibility of aided phytomanagement of fire-affected areas. Soil amendments affect more aboveground biomass growth than underground biomass growth. Organic amendment, biochar, and compost promoted aboveground biomass growth; however, they did not increase the bioconcentration of metal elements in the roots. Unamended burnt soil achieved the highest bioconcentration of metal elements in underground biomass, while it produced significantly less aboveground biomass than burnt soil amended with biochar and with compost. Based on the ash composition from this study, aided phytostabilization appears to be a suitable phytomanagement method, as the priority is to rapidly recover vegetation in order to prevent soil erosion. This study therefore recommends selecting a suitable phytoremediation method based on the composition of ash.

A Review of Soil-Improving Cropping Systems for Soil Salinization

A major challenge of the Sustainable Development Goals linked to Agriculture, Food Security, and Nutrition, under the current global crop production paradigm, is that increasing crop yields often have negative environmental impacts. It is therefore urgent to develop and adopt optimal soil-improving cropping systems (SICS) that can allow us to decouple these system parameters. Soil salinization is a major environmental hazard that limits agricultural potential and is closely linked to agricultural mismanagement and water resources overexploitation, especially in arid climates. Here we review literature seeking to ameliorate the negative effect of soil salinization on crop productivity and conduct a global meta-analysis of 128 paired soil quality and yield observations from 30 studies. In this regard, we compared the effectivity of different SICS that aim to cope with soil salinization across 11 countries, in order to reveal those that are the most promising. The analysis shows that besides case-specific optimization of irrigation and drainage management, combinations of soil amendments, conditioners, and residue management can contribute to significant reductions of soil salinity while significantly increasing crop yields. These results highlight that conservation agriculture can also achieve the higher yields required for upscaling and sustaining crop production.

Restoring ecological properties of acidic soils contaminated with elemental sulfur

Elemental sulfur (S0) accumulates in the environment from anthropogenic sources as a byproduct from oil and gas refining and from trap and skeet shooting targets. Bacteria can oxidize S0 to H2SO4, which acidifies soil. We explored whether combinations of soil amendments can be used to remediate acidic soils contaminated with S0 by restoring soil chemistry, plant growth, and bacterial communities in a greenhouse. Results were compared to a contamination gradient in a field that had been limed with CaMg(CO3)2 two years prior. Amendments in the greenhouse included CaCO3 by itself, and in combination with fertilizer, compost, biochar, and chitin. Amended soils were incubated for one week and half of all containers were planted with Poa nevadensis. We sequenced bacterial DNA from a subset of amended soils and along the field gradient. CaCO3 additions in the greenhouse initially raised the pH of contaminated soil to values found in uncontaminated soils. However, pH decreased over time, which was likely caused by the oxidation of S0 to H2SO4. This was also apparent in the field, where CaCO3 additions raised pH to 4 but not to the desired value of 5 or higher. Plants in the greenhouse failed to grow in the unamended contaminated soil, but CaCO3 alone reduced concentrations of toxic cations and resulted in more plant growth than in the uncontaminated soil. CaCO3 also partially restored the bacterial communities in the greenhouse and in the field by increasing richness and diversity to near values found in uncontaminated soil, suggesting that bacteria can be resilient to prolonged acidic conditions. Organic amendments did not provide a significant benefit to restoration. This study demonstrates that acid neutralization alone can restore abiotic and biotic components and productivity of soils contaminated with S0, but multiple CaCO3 applications may be required to avoid future acidification.

Impact of coal mining on soil properties and their efficient eco-restoration

Coal mining is one of the core industries that contribute to the economic development of a country but deteriorate the environment. Being the primary source of energy, coal has become essential to meet the energy demand of a country. Mining of mineral resources results in extensive soil damage, altering microbial communities and affecting vegetation leading to destruction of vast amount of land. In the present study, attempts have been made to assess the impact of coal mining on soil nutrients and their efficient restoration through different combination of soil amendments. The physico-chemical and biological properties of mine spoil before and after treatment were analysed. Results indicated that the applications significantly improved the physico-chemical and microbiological properties (which were practically absent) of the coal mine spoil dump. A great variety of microorganisms have been found in mine wastes and microbiological processes that are usually responsible for the environmental hazard created by mine wastes. The findings of this study can be utilised by the mine management programs in the large scale revegetation of several adjacent coal mining overburden dumps for eco-friendly mining.

Soil Organic Carbon Fractions and Enzymes Activities as Affected by Organic and Inorganic Amendments in an Acid Soil of Meghalaya

Soil organic carbon (SOC) and its fractions (labile and non-labile) are important for sustainability of any agricultural production system as they govern most of the soil properties, and hence soil quality and health. Being a food source for soil microorganisms, they also affect microbial activity, diversity and enzymes activities. The present paper reports the results from a three years (2011–14) field experiment to elucidate the effect of soil amendments (lime and FYM) on SOC fractions and enzymes activity. Results revealed that integrated soil management comprising 50% NPK+FYM @ 5 t ha−1+Lime @ 0.5 t ha−1 significantly improved the SOC fractions, and the proportional changes were more in the labile SOC fractions. Soil enzymes activities were also better correlated with the labile SOC fractions. Rhizosphere soil had proportionally more amount of labile organic carbon (LBC) over total organic carbon (TOC), and also had better enzymatic activities than non-rhizosphere soil. This experiment shows that proper combination of soil amendments improves the SOC fractions, and changes would be more readily reflected by the labile SOC fractions. Soil enzymes activity, which is directly related with the labile SOC fractions, is a good indicator of changes induced by various management practices. Relative changes in the SOC fractions and soil enzymes activity are more pronounced in the rhizosphere than in non-rhizosphere soil.

Three years of phytostabilisation experiment of bare acidic soil extremely contaminated by copper smelting using plant biodiversity of metal-rich soils in tropical Africa (Katanga, DR Congo)

Copper smelting has created large surfaces of bare soil contaminated by trace metals (TMs: e.g., total Cu: 42,500mgkg−1 in bare soil vs. 220mgkg−1 in remote forest) in the Lubumbashi suburbs of the ‘Cité Gécamines/Penga Penga’ (Katanga, D.R. Congo). Human exposure to trace metals at the site has become a primary environmental concern. This study evaluated different strategies (spontaneous and assisted phytostabilisation) to promote plant establishment on bare soil at the contamination site for soil reclamation/remediation. First, soil chemical properties were assessed in three vegetation units (bare soil, metallophytic grassland patches, and termite mounds). Results showed lower nutrients, organic matter content, and pH in bare soil; however increased metal concentrations were not detected. Limestone (0, 2.5, 5, and 10tha−1) and compost (0, 45, and 225tha−1) were applied in a factorial design. Plant establishment was monitored for three years; and leaf TM concentration was assessed during the third year. Soil amendments improved bare soil conditions (higher pH and nutrients and lower TMs), and facilitated spontaneous plant establishment, with compost exhibiting the largest positive effects. Colonisers were primarily annual species; either true metallophytes or weedy taxa, which were sporadically present at the study site. However, only the perennial Microchloa altera survived during the 6-month dry season. Following three years of phytostabilisation experiment with M. altera by planting, substantial growth and high survival was observed in M. altera. A combination of soil amendments (lime and compost) was most effective to improve plant fecundity, and reduce metal uptake by leaves. Our results show promise for reclamation of bare soil contaminated by the mining industry in tropical climate.

Significance of Some Soil Amendments and Phosphate Dissolving Bacteria to Enhance the Availability of Phosphate in Calcareous Soil

A field experiment was carried-out on a private farm at the Salah El-Din village, El-Bostan district, Nobaria, El-Behera Governorate, Egypt. The aim of this study was to evaluate the best combination of rock phosphate (RP), sulphur (S), organic manure, and phosphate dissolving bacteria (PDB) inoculation to enhance the availability of phosphorous from rock phosphate and their effects on yield of broad bean plants (cv. Luz doe Otono L.). It was found that either sulphur application or PDB inoculation with RP had a significant effect on broad bean yield and its quality. Application of RP and different soil amendments individually or together increased N, P, and K contents in straw and seeds of broad bean plant. The highest contents of the studied nutrients were found when the plants were fertilized by a mixture of RP and different soil amendments. Results also showed the important role of organic matter, sulphur, and PDB for releasing phosphorus from rock phosphate. The combination of soil amendments with RP as a natural P-source, has the possibility of saving significant quantities of industrialized inorganic phosphate fertilizers.

Utilisation of chemically stabilized arsenic-contaminated soil in a landfill cover

The aim of the study was to determine if an As-contaminated soil, stabilized using zerovalent iron (Fe0) and its combination with gypsum waste, coal fly ash, peat, or sewage sludge, could be used as a construction material at the top layer of the landfill cover. A reproduction of 2 m thick protection/vegetation layer of a landfill cover using a column setup was used to determine the ability of the amendments to reduce As solubility and stimulate soil functionality along the soil profile. Soil amendment with Fe0 was highly efficient in reducing As in soil porewater reaching 99 % reduction, but only at the soil surface. In the deeper soil layers (below 0.5 m), the Fe treatment had a reverse effect, As solubility increased dramatically exceeding that of the untreated soil or any other treatment by one to two orders of magnitude. A slight bioluminescence inhibition of Vibrio fischeri was detected in the Fe0 treatment. Soil amendment with iron and peat showed no toxicity to bacteria and was the most efficient in reducing dissolved As in soil porewater throughout the 2 m soil profile followed by iron and gypsum treatment, most likely resulting from a low soil density and a good air diffusion to the soil. The least suitable combination of soil amendments for As immobilization was a mixture of iron with coal fly ash. An increase in all measured enzyme activities was observed in all treatments, particularly those receiving organic matter. For As to be stable in soil, a combination of amendments that can keep the soil porous and ensure the air diffusion through the entire soil layer of the landfill cover is required.

Effects of Soil Amendments on Coastal Saline-Alkali Soil Improvement and the Growth of Plants

Soil salinization is one of the major land degradation types and has greatly influenced sustainable agricultural development. Interest is growing in the use of soil amendments to reclaim saline and sodic soils. According to the practical soil conditions in the Yellow River Delta and the special characteristics of the coastal saline soil, in order to find the effects of combined applications of desulfurization gypsum, humic acid and polyacrylamide on saline-alkali soil, pot experiment was conducted to analyze the chemical properties and plant yields. L8(27) design was selected to engage in orthogonal experiment with first class interaction of three factors at two levels. The results demonstrated that applying soil amendments significantly increase the total salt content, decreased the soil pH and SAR. The effect on treatment 8(30g/kg desulfurization gypsum , 2g/ kg of humic acid , 0.025g/kg PAM) was the most significant, cotton soil pH and SAR decreased to 7.63 and 7.22, corn soil pH and SAR decreased to 7.57 and 7.34. The effects of soil amendments on crop growth showed that the treatment 7, combination of soil amendments (30g/kg desulfurization gypsum ,2g/ kg of humic acid , 0.01g/kg PAM) could promote the growth of cotton most significantly. Compared with the control, plant height, leaf area fresh weight and dry weight increased 33.4%,41.7%,82.2% and 237.8% respectively. The combination 8 of soil amendments (30g/kg FGD gypsum, 2g/ kg of humic acid ,0.025g/kg PAM) could promote the growth of corn most significantly. Compared with the control, plant height, leaf area fresh weight and dry weight increased 20.7%, 35.9%, 49.9%和47.9% respectively. There was no significant interaction between the three soil amendments.

Environmental and Economic Benefits of Saline‐Sodic Soil Reclamation Using Low‐quality Water and Soil Amendments in Conjunction with a Rice–Wheat Cropping System

AbstractA combination of appropriate crop rotation(s) and management interventions has the potential to transform saline‐sodic soil and water resources from an environmental burden into an economic asset. We carried out 2‐year field studies in the Indus Basin of Pakistan to evaluate different irrigation and soil management options of using saline‐sodic waters (SSW) and soils for reclamation and for growing salt‐tolerant cultivars of rice (SSRI‐8) and wheat (SIS‐32). These soils have variable levels of salinity and sodicity (ECe 9–44 dS m−1 and SAR 83–319). The treatments on both the sites were the same and consisted of: (1) Irrigation with SSW, (2) Irrigation with freshwater (FW), (3) Soil application of gypsum at 100 % gypsum requirement of soil + SSW (G + SSW), (4) G + one irrigation with SSW and one with FW (G + 1SSW + 1FW), (5) G + two irrigations with SSW and one with FW (G + 2SSW + 1FW), (6) Farm manure at 25 Mg ha−1 each year before rice + one irrigation with SSW and one with FW (FM + 1SSW + 1FW) and (7) FM + two irrigations with SSW and one with FW (FM + 2SSW + 1FW). Rice was grown as the first crop. After harvesting final wheat crop (fourth in sequence), maximum decrease in bulk density and increase in infiltration rate was observed with G + 1SSW + 1FW while FM + 1SSW + 1FW treatment showed higher decrease in pHs and ECe. Significantly the highest decrease in SAR occurred at both sites with G + 1SSW + 1FW. Maximum yields of rice and wheat were generally observed with G + 1SSW + 1FW. The crop yield and economic benefits with treatments showed a positive correlation with that of improvement in soil physical and chemical properties. Overall, the greatest net benefit was obtained from G + 1SSW + 1FW treatment. We also found that the farmers’ management skills were crucial in the overall success in improving crop yields during reclamation of saline‐sodic soils. Based on the results of this study, we propose that SSW could be used to reclaim saline‐sodic soils by using a rice–wheat rotation and a site‐specific combination of soil amendments and water application strategies.

Rice yield nutrient uptake as affected by cyanobacteria soil amendments—a pot experiment

AbstractRice production and cyanobacterial N in acid soil can be improved by liming. There is evidence that the organic amendments can increase the soil pH. The aim of this study was to find appropriate combination of soil amendments and cyanobacteria capable for enhancing nutrient uptake and improving rice yield in acidic paddy soil. Three soil amendments (rice straw, sewage‐sludge composts, NPK) with and without inoculation of cyanobacteria were studied for rice plants (Oryza sativa L.) in a pot experiment. The sludge compost had significantly reduced soil acidity from 5.44 to 6.67. The plant N and K uptake increased significantly with sludge and cyanobacteria application. The yield components increased significantly with sludge, but decreased thereafter, an exception was the number of panicles, with straw compost. These characters were also significantly affected by inoculation with cyanobacteria except 100‐grain weight, filled‐grain percentage, and harvest index. The combination of sludge compost and cyanobacteria improved the yield components and consequently grain yield (138 g pot–1) compared with sludge treatment only (132 g pot–1). The amount of cyanobacterial N absorbed (N‐difference method) by rice plant under sludge compost was higher than that of soils amended with either rice straw or NPK treatments. Therefore, the addition of sewage sludge to acid paddy soil not only amended the soil properties but also activated the cyanobacteria and consequently improved rice plant nutrition and grain yield.

Effects of soil amendments on survival and early growth of three timber species grown on sand tailings in the peninsular Malaysia

Existing large tracts of tin tailings are problematic soils that were created from natural lowland rainforests of high biodiversity in Peninsular Malaysia. These ex‐mining sites are low in biodiversity with poor natural succession. Especially, isolated patches of tin tailings trapped in agricultural and urban developments have virtually very little natural regeneration. Hence artificial regeneration needs to be carried out. Successful tree planting techniques developed for greening sand tailings have been recorded. Yet, there is a lack of scientific data to support the soil amendment treatments recommended. This study was embarked with the aims to determine the effects of soil enrichment on survival and growth of Acacia mangium × Acacia auriculiformis (Acacia hybrid), Swietenia macrophylla (mahogany) and Khaya ivorensis (khaya). The study plots were established as a 3x4 factorial combination of soil amendments, fertilizer treatments and tree species in a completely randomized design. Fertilizer treatments including control, 120 g chicken manure point-1 at six‐month interval and 120 kg empty fruit bunch (EFB) point-1. The soil amendments assessed were control and application of 60 kg of mineral soil point-1. The seedlings were planted at 3x3 m spacing. Weeding and fertilization were carried out at three months interval. Soils were systematically and properly sampled for chemical analysis. The data of survival, vegetative growth, biomass and physiological responds of the three species were collected for analysis. Net photosynthesis and transpiration with leaf temperature of timber species were measured using a portable H2O/CO2 analyzer and LICOR super porometer, respectively. All the data collected were statistically analysed. The results show that Acacia hybrid had the highest survival, vegetative growth and biomass among the three species. The significantly greater survival, growth and high biomass accumulation of Acacia hybrid is due to its high adaptability by producing abundant leaves that enlarges the photosynthetically‐active leaf area. In addition, this study shows that at optimum temperature, the net photosynthesis, stomatal conductance and transpiration of Acacia hybrid were significantly greater than khaya and mahogany. This study also shows that soil treatment increased the growth of the three timber species on sand tailings. Chicken manure is a better type of fertilizer than EFB for timber species grown on sand tailings. Acacia hybrid treated with soil plus EFB or chicken manure had significantly the highest growth rates resulted in greatest biomass. Khaya ivorensis requires site preparation using soil plus chicken manure or EFB. Swietenia macrophylla treated with chicken manure or soil plus chicken manure grew better than other treatments. This study shows that the right species choice with viable site preparation technique and treated with suitable organic fertilizer are crucial to ensure the success of growing the timber species on impoverished ex‐mining sites.