Agricultural Sandy Soil Research Articles

Influence of friction velocity and saltation intensity on the particle‐size distribution of dust (PM32) emitted from an agricultural soil

AbstractThe size distribution of dust emitted from soils determines particle attributes such as the enrichment in elements that are important for biogeochemical cycles, global climate and human health. There is an ongoing discussion about the size distribution of dust and its relationship with saltation and wind speed. In this work, we present our own results and discuss them in the context of other studies, emphasizing on dust emission from agricultural soils, which is relatively complex and less studied. The objective of this work was to evaluate the particle size distribution of the emitted dust or particulate matter (PM) up to 32 μm in diameter (PM32) from an agricultural sandy soil under two saltation‐supply conditions, using a wind tunnel coupled to a dust‐suspension chamber. We found strong correlations between friction velocity, saltation flux and dust emission. Additional saltation supply increased the total dust PM32 emission at high wind speeds up to three‐fold. Correlation between wind speed and dust concentration was best explained by a power law, with exponents up to 12.04 for the 20 to 32 μm particle‐size range under high‐saltation conditions, but much lower (up to 4.34) for the 0.25 to 1 μm size range under low saltation. An increase of the wind speed affected significantly the concentration of the coarser dust fraction (PM > 10 μm), but affected less the concentration of fine dust (PM from 10 to 1 μm) and did not affect the concentration of the ultrafine (PM < 1 μm) fraction in the suspension chamber. Results found suggest that dust is mostly produced from particles less than 60 μm in diameter, both by fragmentation and direct wind lift. Results found herein reinforce one of the existent theories, but raise questions about the influence of the soil type, and the place and timing of the sampling arrangements.

Assessing the Effect of Intensive Agriculture and Sandy Soil Properties on Groundwater Contamination by Nitrate and Potential Improvement Using Olive Pomace Biomass Slag (OPBS)

The relationship between agricultural activities, soil characteristics, and groundwater quality is critical, particularly in rural areas where groundwater directly supplies local people. In this paper, three agricultural sandy soils were sampled and analyzed for physicochemical parameters such as pH, water content, bulk density, electrical conductivity (EC), organic matter (OM), cation exchange capacity (CEC), and soil grain size distribution. Major and trace elements were analyzed by inductively coupled plasma-optical emission spectrometry (ICP/OES) to determine their concentrations in the fine fraction (FF) of the soils. Afterward, the elemental composition of the soils was identified by X-ray powder diffraction (XRD) and quantified by X-ray fluorescence (XRF). The surface soil characteristics were determined by the Brunauer–Emmett–Teller (BET) method, whereas the thermal decomposition of the soils was carried out using thermogravimetric analysis and differential scanning calorimetric (TGA-DSC) measurements. The morphological characteristics were obtained by scanning electron microscopy (SEM). Afterward, column-leaching experiments were conducted to investigate the soil’s retention capacity of nitrate (NO−3). Parallelly, a chemical and physical study of olive pomace biomass slag (OPBS) residue was carried out in order to explore its potential use as a soil additive and improver in the R’mel area. The OPBS was characterized by physicochemical analysis, assessed for heavy metals toxicity, and characterized using (XRD, XRF, SEM, and BET) techniques. The results show that the R’mel soils were slightly acidic to alkaline in nature. The soils had a sandy texture with low clay and silt percentage (<5% of the total fraction), low OM content, and weak CEC. The column experiments demonstrated that the R’mel irrigated soils have a higher tendency to release large amounts of nitrate due to their texture and a higher degree of mineralization which allows water to drain quickly. The OPBS chemical characterization indicates a higher alkaline pH (12.1), higher water content (7.18%), and higher unburned carbon portion (19.97%). The trace elements were present in low concentrations in OPBS. Macronutrients in OPBS showed composition rich in Ca, K, and Mg which represent 10.59, 8.24, and 1.56%, respectively. Those nutrients were quite low in soil samples. Both XRD and XRF characterization have shown a quasi-dominance of SiO2 in soil samples revealing that quartz was the main crystalline phase dominating the R’mel soils. Oppositely, OPBS showed a reduced SiO2 percentage of 26,29% while K, Ca, and P were present in significant amounts. These results were confirmed by XRF analysis of OPBS reporting the presence of dolomite (CaMg, (CO3)2), fairchildite (K2Ca (CO3)2), and free lime (CaO). Finally, the comparison between the surface characteristic of OPBS and soils by BET and SEM indicated that OPBS has a higher surface area and pore volume compared to soils. In this context, this study suggests a potential utilization of OPBS in order to (1) increase soil fertility by the input of organic carbon and macronutrients in soil; (2) increase the water-holding capacity of soil; (3) increase soil CEC; (4) stabilize trace elements; (5) enhance the soil adsorption capacity and porosity.

A comparison of the fate of diflufenican in agricultural sandy soil and gravel used in urban areas.

Diflufenican is used in both agricultural and urban areas to control weeds. However, in Europe pesticides are regulated using agricultural soil data only. Urban soils where the top layer is replaced by gravel (e.g. driveways, outdoor tiled areas) can evidently differ from agricultural soils in many biotic and physical properties. In the present study, we compared the degradation, mineralization, sorption and aging of diflufenican between an agricultural sandy soil to a gravel used in urban areas. Both diflufenican and its two main aerobic metabolites were investigated. Diflufenican and the metabolites degraded slower in gravel than in agricultural soil. One of the metabolites, 2-[3-(Trifluoromethyl)phenoxy]nicotinic acid (AE B107137 as identified by EFSA; further abbreviated as AE-B), was formed from the incubation of diflufenican in both soil and gravel, however, showing different formation patterns in the two materials: No accumulation of AE-B was determined in the soil, whereas in gravel, an accumulation of AE-B was determined over the full study period of 150days. After 150days, approximately 10% of the applied diflufenican was mineralised in the soil (cumulative), while it was not mineralised in the gravel. Diflufenican showed much stronger sorption to the soil than to the gravel, while the sorption of the metabolites was weaker than diflufenican in both soil and gravel. Within the experimental period, the influence of aging on the fate of diflufenican in soil and gravel is limited (<0.9 and <1.4%, respectively) when compared to the amount of compound still present in the soil. Overall, the results imply shortcomings in the risk assessment procedures requested for the registration of pesticides for urban areas.

Mitigation of sodium risk in a sandy agricultural soil by the use of natural zeolites.

Na+ contamination of irrigation waters represents a global environmental issue for soil structure and plant production. Notwithstanding several techniques for the reduction of Na+ have been proposed in recent years, they generally exhibit disadvantages, including low recyclability and relatively high operational/maintenance costs. In this paper, we propose a natural and eco-friendly solution for the reduction of Na+ risk in coastal agricultural sandy soil (SS), vulnerable to salinity stress. A series of column leaching experiments have been conducted to assess the influence of Italian zeolite-rich tuff (natural zeolites, NZ) addition to soil (NZSS) on Na+ removal, SAR, and CROSS index, under three different salinity scenario. Result showed that the Na+ removal efficiency varied between 46.4 and 54.3% in soil amended with NZ, and analogously SAR index was significantly reduced from 7 to up 13 points. SAR and CROSS indexes resulted better correlated in SS rather than NZSS due to the influence of K+ released by NZ. In conclusion, soil amendment with NZ represents a natural and eco-friendly solution for increasing sandy soil resilience to Na+ risk.

The relations between the rainfall erosivity index AI and the hydraulics of overland flow and sediment concentration in sandy soils

The purpose of this study is to investigate the effects of rainfall erosivity index AI on the hydraulics of overland flow parameters such as the flow velocity, the flow depth, the flow regime, overland flow power and on soil surface characteristics, such as surface roughness and sediment concentration. The erosivity index AI represents six rainfall intensities, 31.40 mm·h-1; 37.82 mm·h-1; 69.49 mm·h-1; 81.85 mm·h-1; 90.39 mm·h-1 and 101.94 mm·h-1 generated by a rainfall simulator. To simulate the soil plot, a soil tray was filled with remolded agricultural sandy soil. The results found have shown that the AI represents better the rainfall than rainfall intensity and related to drop diameter with a power function. Overland flow never exceeded the laminar and subcritical regime; the Reynolds number reacted differently with AI and rainfall intensity, whereas the Froude number has similar reaction with both parameters. Re, Fr and n follow with AI logarithmic, linear and power functions respectively. Finally, AI is a good predictor of soil erosion.

NEMATODE COMMUNITY RESPONSE TO VARIED PROPORTION OF DECOMPOSING PLANT LITTER

The research objectives were to investigate nematode community response to decomposing plant litter of varying proportions, and to measure the litter decomposition rate. This greenhouse experiments included three treatments of decomposing plant litter with proportions of 30:70, 50:50, and 70:30 (leaf litter to stem-paddy litter, weight to weight), and two controls (commercial organic fertilizers and no-organic matter). We applied the prepared plant litter and organic fertilizers on the surface of the agricultural sandy soil. Soil samples were taken after two, seven, 14, 28, 49, and 77 days to follow nematode temporal changes. Nematodes were assigned to functional groups and family level of a taxon. We used Anova to test the significance of nematode abundance among the treatments, exponential decay model to measure decomposition rates of the plant litter, and canonical correspondence analysis to investigate the correlation of varying plant proportion and nematode community composition. The results showed that nematode functional groups and family did not differ among soils of various plant litter proportions. Bacterivorous Rhabditidae and Cephalobidae, fungivorous Aphelenchidae, and fungivorous-root feeder Tylenchidae inhabited plant litter amended soils. Their abundance, however, differed significantly (p<0.001) and revealed two temporal patterns, i.e., linear (50:50) and unimodal (30:70 and 70:30). No nematodes were observed in organic fertilizer amended soil and no-organic matter soil. Nematode community composition changed over time according to the litter proportion, in which by the end of experiments, community of 50:50 and 30:70 were the least similar (r: 0.57 of axis-1 and 0.54 of axis-2, CPV: 89.06). We concluded that all litter proportions retained similar quality and supported the growth of similar nematode groups. The litter proportion, however, appeared to influence nematode abundance, their temporal patterns, and community compositions.

ESTIMATING SHORT- AND MEDIUM-TERM AVAILABILITY TO CEREALS OF NITROGEN FROM ORGANIC RESIDUES

Overused soil resources and the build-up of organic residues from industrial processes have resulted in increased risk of environmental contamination. Recycling of organic residues from industry by incorporation into agricultural soil, can provide valuable organic amendment as well as supply nutrients to crops. The effect of applying organic amendments to an agricultural sandy soil on the nitrogen nutrition of wheat (Triticum aestivum L.) and residual effects on the growth of a following maize crop (Zea mays, L.), were assessed under semi-controlled environmental conditions and were compared to nitrogen mineralization prediction obtained from an aerobic incubation. Six different organic residues (composted municipal solid waste, secondary pulp-mill sludge, hornmeal, poultry manure, the solid phase from pig slurry and composted pig manure) were added to a Cambic arenosol, incubated or used in pot experiments, to evaluate and try to predict the availability to crop plants of nitrogen released from these materials. Poultry manure was the most effective amendment in making nitrogen available and enhancing nitrogen uptake by wheat plants resulting in greater dry matter yield. The dried solid phase from pig slurry and hornmeal were also beneficial to wheat growth. There was a greater recovery of nitrogen (N), from organic materials studied, by a maize crop. Poultry manure was the residue that provided a greater residual effect on N supply to maize.

Changes of Physical Properties of Sandy Soil And Growth of Physic Nut (Jatropha Curcas L.) Due to Addition of Clay and Organic Matter

Agricultural sandy soil in Situbondo, East Java province, Indonesia which is used as a center garden for physic nut seed production has poor physical properties of soil indicated by low capacity to retain water. For plant growth of physic nut, the sandy soil physical properties need to be improved. In this study, the influence of addition of clay together with organic matter and intervals of irrigation to sandy soil on aggregate stability, bulk density, total soil porosity, water available content and plant growth of physic nut was investigated. The rates of clay and organic matter incorporated to top sandy soil were 5% clay + 0.8% organic matter and 1O% clay + 1.6% organic matter. Two intervals of irrigation tested were 10 days and 20 days. The results showed that incorporation of clay together with organic matter increased aggregate stability, total soil porosity, available water content and plant growth of physic nut. Intervals of irrigation had no influence of soil physical properties and plant growth. Keywords: agricultural, sandy soil, clay, organic matter, soil properties, physic nut

Leaching Behavior of Heavy Metals In Biosolids Amended Sandy Soils

Use of biosolids in agriculture to improve crop production and soil quality have created concerns due to content of heavy metals that may affect surface or ground water quality. A column leaching study was conducted to evaluate the leaching potential of copper (Cu), lead (Pb), zinc (Zn), cdmium (Cd), cobalt (Co), chromium (Cr), and nickel (Ni) from two typical agricultural sandy soils in South Florida (Spodosol and Alfisol) with increasing application of pelletized biosolids (called PB) at the rates of 0, 1.25, 5.0, 10.0 g kg−1, respectively together with chemical fertilizer (CF). Elevated PB rate resulted in reduced leaching loss of Cu, Pb, Zn, Cd, Co, Ni from Spodosol, but resulted in increased loss of Pb, Zn, Cd, and Co from Alfisol. Significant reduction in Cu loss occurred in both soils, which can be attributed to the strong binding of Cu with organic matter from the applied PB. Percentage of Cd loss as of total Cd was 13% – 41%, the highest in all the heavy metals, whereas loss of Pb as of total Pb was less than 6.6%, though the concentrations of Pb, Cd, Co, and Ni in leachate were mostly above the limits of U.S. EPA drinking water standards or the national secondary drinking water standards. These results indicate that soil properties, PB application rates, and chemical behavior of elements jointly influence the leachate total loads of heavy metals in sandy soils applied with biosolids. Application of CF together with BP at a rate higher than 10.0 g kg−1 for sandy soils may pose potential threats to water quality due to enhanced leachate loads of Cr and Ni in Spodosol and Pb, Zn, Cd, Co and Ni in Alfisol.

LEACHING BEHAVIOR OF PHOSPHORUS IN SANDY SOILS AMENDED WITH ORGANIC MATERIAL

Transport of phosphorus (P) from agriculture often causes eutrophication of surface water systems, which is particularly a concern in sandy soil regions because of low holding capacity of the soil for nutrients and moisture. Soil amendment is considered to be one of the best management practices in reducing P loss to water. A column leaching study was conducted to evaluate the effectiveness of organic amendment applied together with water-soluble fertilizer in reducing P leaching in two typical agricultural sandy soils (Spodosol and Alfisol) in south Florida. The Spodosol is an Alfic Alaquod, whereas the Alfisol is an Arenic Glossaqualf. Both soils have the same texture with sandy, siliceous, and hyperthermic properties. Organic material (OM) used in this study is marketed as a slow release organic fertilizer (GreenEdge; JEA Inc., Jacksonville, FL), which supplies essential nutrients for plant growth. The treatments consisted of chemical fertilizer (CF) alone, CF + 1.25 g kg -1 OM, CF + 5.0 g kg -1 OM, and CF + 10.0 g kg -1 OM. A control receiving no CF or OM was also included. Leaching of orthophosphate-P (PO 4 -P) and dissolved total P was similar. After seven leaching events, application of CF together with 10.0 g kg -1 OM reduced PO 4 -P and dissolved total P loss by 25.4% and 21.4% in the Spodosol and by 45.3% and 22.6% in the Alfisol and increased soil Olsen-P and Mehlich 3-extractable P by 54% and 31%, respectively, in the Spodosol and by 50% and 94% in the Alfisol, compared with CF alone. Increasing OM application rates increased NaHCO- and NaOH-extractable P but decreased water-extractable P in the two soils. Soil microbial biomass P (MBP) and the percentage of MBP in Olsen-P (MBP/Olsen-P) increased by 585% and 350%, respectively, in the leached Spodosol and by 190% and 127%, respectively, in the leached Alfisol with the treatment of CF together with 10.0 g kg -1 OM, compared with CF alone. It appears that the reduction in P leaching by OM amendment was related to the stimulation of microbial activities, which incorporate water-soluble P from applied CF into organic fractions and retained more P in soil against leaching but available to plants. These results indicate that organic amendment in combination with CF in a 10 g OM kg -1 soil level can increase P utilization efficiency by reducing P leaching and maintaining a larger available P pool in sandy soils.

ASSOCIATION BETWEEN COLLOIDAL IRON, ALUMINUM, PHOSPHORUS, AND HUMIC ACIDS

In temperate regions a distinct part of phosphorus (P) in soils is associated with organic matter. Organic macromolecules can desorb from the soil matrix and, consequently, act as carriers for P in environments where it would otherwise be immobile. However, not all organic forms of P in soils have yet been characterized, and there is much debate about the involvement of Fe and Al in the association between organic matter and P. We studied the association between P, dissolved organic carbon (DOC), Al, and Fe in alkaline and aqueous extracts of an agricultural sandy soil. In these extracts, the high molecular weight fraction of the DOC was precipitated by adding CaCl2 or HCl. This selective precipitation of the humic fraction of the DOC resulted in the complete removal of Al and Fe from solution, whereas the removal of total P was only partial. The molar ratio for organic carbon (C) over (Al + Fe) in the precipitate was ∼1. This low ratio makes it highly unlikely that most of the Al and Fe are covalently bound to the humic material; rather, it suggests that Al and Fe oxides are, in colloidal form, associated with the humic macromolecules. Another important conclusion was that Al and Fe and a large fraction (more than 50%) of total P were associated with the humic and not the fulvic fraction of the DOC. The different chemical and physical characteristics of these two DOC fractions give them different transport behavior in soils, and this difference is expected to affect the behavior of at least a part of the "organic" P in the soil environment.

Effectiveness of immediate and delayed AFCF application in reducing radiocaesium transfer to ryegrass

Following encouraging results obtained with the surface application of ammonium-ferric-hexacyano-ferrate (AFCF) to reduce radiocaesium transfer to ryegrass grown on surface-contaminated sandy soil, its efficacy as a countermeasure was investigated when recently deposited or ‘aged’ radiocaesium was homogeneously mixed with the soil. It was demonstrated that surface application of AFCF (1 and 10 g m -2) on a sandy soil decreased the transfer factor (TF) of radiocaesium immediately after surface contamination by a factor of 2·3 and 17·1, respectively. Distributing the deposit homogeneously with the soil led to a decrease by a factor of 2·3. Surface application at rates of 1 and 10 g AFCF m -2 further reduced the radiocaesium TF by a factor of 1·2 and 1·8, respectively. In the absence of AFCF treatment, two-year ageing contributes to a radiocaesium transfer factor decrease of mixed radiocaesium from 1·32 to 0·56 Bq g -1 DW/Bq g -1 soil (factor 2·4). Surface application of AFCF in amounts of 1 and 10 g m -2 reduced the TF of the aged radiocaesium, mixed with the soil, by a factor of 1·9 and 3·5, respectively. The presence of ‘aged’ AFCF (10 g m -2), surface applied immediately after deposition and mixed with the radiocaesium in the soil two years after treatment, still resulted in an about five times lower transfer factor compared to the ‘aged’, untreated control. AFCF did under no circumstances negatively affect plant growth. The results obtained strengthen previous results, showing that AFCF is an effective, long-lasting and non-toxic countermeasure for radiocaesium uptake on agricultural sandy soil.

Algae removal by sand filtration and reuse of filter material

Integrated pond systems consisting of facultative and high-rate ponds operating in series can produce an effluent low in dissolved organic material, nutrients, and hazardous bacteria. However, the effluent is rich in algae, and cannot meet stringent water-quality criteria on suspended solids. The algae, therefore, must be removed before final discharge or reuse of the effluent. This study reports on the efficiency of slow sand filtration in removing algae from high-rate pond effluents. When agricultural sandy soil with an effective grain size of 0.08 mm was used as the filter medium, an average filtration rate of about 1.3 m 3/m 2 .d was obtained. If filtration was preceded by sedimentation, the duration of a filtration run was about 100 h. At the end of each run, the filter was cleaned by scraping off the top few centimeters of the filter bed. The filtered effluent consistently had a biochemical oxygen demand (BOD) value less than 20 mg/L and undetectable fecal coliforms. The filter media, being rich in organic matter and having moisture-retaining properties, can be used as a soil conditioner.

Nachweis der Wirkung einer KMg-Düngung auf den Stoffkreislauf von Kiefernbeständen unter besonderer Berücksichtigung des Zellulosetests: Ascertaining the Effect of KMg Fertilization on the Organic Matter Cycle in Pine Stands with Special Reference to the Cellulose Test

The biological nutrient cycle was activated by applying KMg in relatively young and older pine stands growing in the plain of the GDR on former agricultural sandy soils with substrats from the Younger Pleistocene. Application of KMg stimulated tree growth and had a persistent effect on the microbiological processes of organic matter conversion in the A 0 horizon and in the humous mineral soil. The cellulose test proved to be suitable for assessing the formation and conversion processes of soil organic matter caused by fertilization as to their effect on soil fertility. Auf vormals ackergenutzten jungpleistozänen Sandstandorten im Tiefland der DDR wurde der biologische Stoffkreislauf durch KMg-Düngung in jüngeren und älteren Kiefernbeständen aktiviert. KMg-Düngungen erhöhten das Baumwachstum und förderten nachhaltig die mikrobiologischen Stoffumsetzungsprozesse im Auflagehumus und humosen Mineralboden. Der Zellulosetest erwies sich als geeignet, die durch die Düngung ausgelösten Stoffbildungs- und Stoffumwandlungsprozesse hinsichtlich ihrer Wirkung auf die Bodenfruchtbarkeit zu beurteilen.