Loamy Sand Soil Research Articles

Transport of plastic particles in natural porous media under freeze-thaw treatment: Effects of porous media property.

Freeze-thaw (FT) cycles would alter physical and chemical properties of soil and thus influence the transport of plastic particles (one type of emerging contaminant with great concerns). This study was designed to investigate the effects of FT treatment on the mobility of plastic particles (nanoplastics as representative) in columns packed with natural soils (i.e. loamy sand and sandy soil, quartz sand employed as comparison). We found that FT treatment of different types of porous media would induce different transport behaviors of plastic particles. Specifically, FT treatment of quartz sand did not affect plastic particles mobility. While FT treatment of loamy sand and sandy soil increased plastic particles transport. The increased pore sizes and disintegration of small soil particles from soils (the detached soil would serve as mobile vehicle for the transport of plastic particle) led to the facilitated mobility of plastic particles in two types of soils after FT treatment. The presence of preferential flow paths induced by FT treatment also drove to the enhanced mobility of plastic particles in sandy soil with FT treatment. This study clearly showed that the mobility of model plastic particles in two types of natural soils was greatly enhanced by FT treatment.

Effect of age of seedling and spacing on yield attributes and yield of finger millet

An investigation was carried out to study the effect of age of seedling and spacing on yield attributes and yield of finger millet during kharif season of the year 2019 on loamy sand soil at College Agronomy Farm, B. A. College of Agriculture, Anand Agricultural University, Anand. The experiment was consisted of twelve treatment combination comprised of three age of seedling (A1: 14 days, A2: 21 days and A3: 28 days) and four spacing (S1: 20 cm x 15 cm, S2: 20 cm x 20 cm, S3: 30 cm x 10 cm and S4: 30 cm x 15 cm) tested under Randomized Block Design (Factorial) with four replications. The results of an experiment showed that number of fingers/earhead, length of fingers (cm), earhead weight (g), grain weight/earhead (g) and test weight (g) of finger millet were achieved significantly higher with transplanting of 21 days old seedling (A2). As far as spacing is concern, transplanting of finger millet at 30 cm x 15 cm (S4) recorded higher yield parameters. However, Grain and straw yield were recorded higher under treatment combination A2S3 (transplanting of 21 day old seedling at 30 cm x 10 cm).

Biomass, Essential Oil Yield, and Composition of Marjoram as Influenced by Interactions of Different Agronomic Practices under Controlled Conditions

Origanum marjorana L. has been valued for centuries for its flavoring attributes and therapeutic properties. The growing demand for its various applications necessitates optimizing agronomic practices for its production. A glasshouse pot trial was conducted to identify optimum agronomic practices for increased herbage and oil yield, as well as oil quality. The effects of varying air temperature regimes (low, medium, and high levels), irrigation (low, medium, and high levels), nitrogen fertilizer application (N = 100, 150, and 200 kg/ha), and soil type (sandy loam, sandy clay loam, and loamy sand) on the productivity of marjoram plants were investigated. The results showed an increase in plant growth and herbage yield as well as chlorophyll content under conditions of high air temperature, low irrigation, and moderate to high nitrogen level applied to sandy loam soil, with an increase in oil yield with loamy sand soil. The major compounds observed in marjoram essential oil were terpinene-4-ol (22.63-36.72%) and (Z)-β-terpineol (6.85-16.60%), in which terpinene-4-ol was not found to be within the International Organization for Standardization (ISO) limits of acceptability while (Z)-β- terpineol had no reference limits available. A promising performance of marjoram cultivation under high regimes of air temperature (16.7 to 36.6 °C), nitrogen fertilization (200 kg ha-1 N), and low irrigation (up to 60% soil water depletion from field capacity) on sandy loam soils was demonstrated for improved crop productivity.

Growth and yield performance of castor hybrids under different methods of planting and fertility levels in North Gujarat Agro-climatic region

A field experiment was conducted to evaluate the yield performance of castor hybrids under different methods of planting and fertility levels at Agronomy Instructional Farm, C P College of Agriculture, Sardarkrushinagar, Gujarat in loamy sand soil. The experiment consisted eight treatment combinations with two hybrids (GCH 7 and GCH 8), two planting methods (Direct seed sowing and Transplanting) and two fertility levels(75% RDF and 100% RDF) were undertaken in randomized block design with factorial concept and replicated four times. Significantly higher number of capsules (88.63) on primary spike, seed yield per plant (686.30 g), 100-seed weight (32.49 g), number of spikes (20.01) per plant, seed yield (3220 kg/ha) and stalk yield (5340 kg/ha) were recorded with GCH 8 hybrid. In plantingmethods, significantly higher number of capsules (89.09) on primary spike, seed yield per plant (688.65 g), number ofspikes (19.60) per plant, seed yield (3230 kg/ha), stalk yield (5361 kg/ha) and available P2O5 (48.7 kg/ha) and S (13.01 mg/kg) after harvest of crop were recorded under direct seed sown castor. 100% RDF registered significantly higher plant height (86.14 cm) at harvest, number of nodes (18.58) per plant, number of capsules (88.60) on primary spike, length of primary (74.57 cm) spikes, seed yield per plant (688.53 g), 100-seed weight (32.00 g), number ofspikes (19.66) per plant, seed yield (3190 kg/ha), stalk yield (5281 kg/ha) and available N, P2O5and S (156 kg/ha, 49.8 kg/ha and 13.35 mg/kg, respectively).

Optimization of Irrigation and Nitrogen Levels in Chickpea ( L.) under Loamy Sand Soil of North Gujarat

Optimization of Irrigation and Nitrogen Levels in Chickpea ( L.) under Loamy Sand Soil of North Gujarat

Effect of Organic and Liquid Manures on Yield, Yield Attributes and Economic of Urdbean

A field experiment was carried out in 2020 kharif season, on loamy sand soil at the S.K.N. College of Agriculture's Agronomy Farm in Jobner (Rajasthan). It included two foliar sprays of each of four liquid manures (control, 100% RDP panchgavya @ 5%, 100% RDP vermiwash @ 10%, and 100% RDP cow urine @ 5%), totaling sixteen treatment combinations. It included four treatments of organic manures (control, 100% RDP through FYM, through vermicompost, and through poultry manure) and two foliar sprays of each of four liquid manures. Three replications of the experiment were set up using a Randomized Block Design. 'Krishna' variety of urdbean was sown as on July 13, 2020, a test crop with a 30-cm row spacing. The results showed that two foliar sprays of 5% panchgavya were the most effective liquid manure treatment in raising the maximum seed production (942 kg/ha), straw yield (2,121 kg/ha), and biological yield (3,063 kg/ha) of urdbean. The highest levels of nitrogen, phosphorous, and potassium were found in seed and straw under this liquid manure treatment, which was comparable to two foliar sprays of 10% vermiwash. However, applying 100% RDP through FYM was the most lucrative strategy, for obtaining higher yield, net returns of '36,314/ha and a B:C ratio of 2.68. Foliar spraying with 5% panchgavya also generated an extra 36,798/ha in net returns over the control, which had the highest B:C ratio of 2.37.

Comparative growth analysis of cumin plants (Cuminum cyminum L.) treated with glycerol and talc based phosphate solubilizing bacterial consortia

Cumin (Cuminum cyminum L.) is a versatile annual herb cultivated in the Middle East, India, China, and Tunisia. The seeds of this plant are primarily used in cooking as common food additives and traditional medicines to treat hypolipidemia, cancer and diabetes. However, cumin plants have poor germination and weak establishment rate, particularly under drought stress. The present study aimed to examine the growth promotion potential of cumin plants treated with talc and glycerol-based phosphate solubilizing bacteria (PSB) consortia. Four efficient PSB were isolated from the rhizosphere of Calotropis procera and Solanum lycopersicum and identified through 16S rRNA sequencing as Pseudomonas nitritireducens MF351819, Klebsiella pneumoniae MF351845, Erwinia sp. MF351846 and Pantoea dispersa MF351847. In a nursery experiment on cumin (Cuminum cyminum) plants, 15 treatments of single, dual, triple and quadruple combinations of four PSB isolates were formulated on glycerol and talcum powder-based bacteriological carriers. The 100-day pot experiment was initiated during the winter of 2016 (the last week of October) containing loamy sand soil of Sardarkrushinagar, Gujarat. The formulations were applied to pot soil containing seven-day-old cumin seedlings. With glycerol-based PSB inoculations, the P14 treatment containing a consortium of K. pneumoniae MF351845, Erwinia sp. MF351846, and P. dispersa MF351847 provided the highest per plant seed yield of 0.19 g. With talc-based PSB inoculations, the P11 treatment containing a consortium of K. pneumoniae MF351845, Erwinia sp. MF351846, and P. nitritireducens MF351919 produced the highest per-plant cumin seed yield of 0.42 g. Overall, talc-based PSB consortial treatments improved height, dry weight, 100 seed weight and yield of the cumin plant.

Response of cassava (Manihot esculenta Crantz) to calcium and potassium in a humid tropical upland loamy sand soil

Calcium (Ca) and potassium (K) are essential nutrients for plant growth but the antagonistic effect between these nutrients may reduce crop yield. A two–year field trial was carried out in a loamy sand soil to evaluate cassava response to Ca (0, 50, 100, and 200 kg ha−1, as ground limestone, GL) and K (0, 50, 100, and 200 kg K2O ha−1, as potassium chloride, KCl). Calcium addition, especially 200 kg Ca ha−1, adversely affected soil K availability with more pronounced on water–soluble K than on exchangeable and non–exchangeable K from day–7 onwards. Both Ca and K had no antagonistic impact on cassava. However, growth and yield responded positively to K more promptly than to Ca. Combined rates, except 100 kg Ca ha−1 with no K fertilizer, significantly increased fresh tuber yield by 7.6–41.1 % over the control. To gain the highest fresh tuber yield by adding 200 kg Ca ha−1, 200 kg K2O ha−1 must be implemented. This light–textured soil was physically preferable for cassava tuberization, and the optimum yield can be achieved by proper Ca and K fertilization.

The Effect of P2O5 Fertilizer, Zeolite, and Volcanic Soil Media from Different Altitudes on the Soil Mineral, Growth, Yield, and Asiaticoside Content of Centella asiatica L.

Centella asiatica is an herbal plant with many health benefits due to the content of asiaticoside compounds. Factors affecting asiaticoside content are altitude, soil texture, and soil nutrient status. This research aimed to identify the effect of zeolite, P2O5 fertilizer, and soil media from different altitudes on C. asiatica. The research was conducted in a greenhouse from August 2017–June 2018. The experimental design was a factorial, completely randomized design with three factors and four replications. The first factor was soil media that originated from 100, 450, and 900 m above sea level (asl), the second factor was the dose of P2O5 fertilizer (0, 27, 54, and 81 kg ha−1), and the third was the dose of zeolite (0, 3, and 6 t ha−1). The results showed that applying zeolite minerals at all altitudes increased nutrient availability and soil cation exchange capacity (CEC) by up to 70%. The novelty of this study is that the soil from an altitude of 900 m asl, with a P2O5 fertilizer dose of 54 kg ha−1, has a loamy sand soil texture and produces the highest asiaticoside content (3.61%) and the largest plant dry weight (19.24 g). These results did not significantly differ from those obtained from the soil 450 m asl with a sandy loam soil texture (the most suitable soil texture for C. asiatica), that is 3.37% asiaticoside and 19.87 g plant dry weight. This study concluded that C. asiatica could develop in loamy sand soil by giving it 54 kg ha−1 P2O5 fertilizer.

Effect of continuous cultivation and soil texture on some soil properties

The effects of soil continuous cultivation and soil texture on some of its properties, electrical conductivity, total porosity, and calcium carbonate content and soil penetration resistance. Six samples of soil material for a layer of 0-30 cm were collected from three different texture sites are Clay, Loam and Loamy Sand in Basra Governorate for three sites Abi al-Khasib, Karma and Zubair. Three of these samples represented the treatment of soil continuous cultivation, soil planted with alfalfa crop (Medicago sativa) for 7 consecutive years, and the other three samples from the same sites for uncultivated soil with three replications for each sample. The results showed a decrease in the values of electrical conductivity, calcium carbonate, soil penetration resistance, and an increase in soil porosity values in cultivated soils. The lowest EC values were 4.1, 5.3 and 6.2 dS. m-1 for soils with textures Loamy sand, Loam and Clay, respectively, and for CaCO3 of 182.3 g. kg-1 in Loamy sand, 266.7 g. kg-1 and 310 g. kg-1 for Loam and Clay soils, respectively, and for resistance to penetration of 550 KN.m-1 for clay soils. While it was 620 KN.m-1, and 714 KN.m-1, for loam soil and loamy sand soil, respectively, compared to uncultivated soil. While the soil porosity values increased for cultivated soils compared with uncultivated soils and the values of 43%, 48.53% and 53.4%, for soils with textures Loamy sand, Loam and Clay respectively, And for the average weighted diameter of 0.2537 mm, 0.2817 mm, 0.3640 mm, for soils with textures Loamy sand, Loam and Clay, respectively.

Legumes can increase the yield of subsequent wheat with or without grain harvesting compared to Gramineae crops: A meta-analysis

Legumecereal crop rotation is considered a sustainable intensive rotation model that can reduce nitrogen (N) inputs, improve soil quality, increase biodiversity and reduce environmental pollution risks. However, compared with Gramineaecereal rotations, quantitative assessment of the effects of legumecereal rotations on grain yield and N use of subsequent cereal crops are lacking. There is also no comprehensive analysis of factors explaining the change in yield effects of subsequent cereal crops, or the differences in these effects, depending on whether the grains of the legume crops are harvested. Here, a meta-analysis of the effects of legumewheat (LW) and Gramineaewheat (GW) rotations on wheat yield and N use was conducted based on 453 observations from 62 studies published worldwide. Our results suggested that compared with GW rotations, LW rotations had a positive effect on wheat yields. Wheat yield was significantly increased by 21.28 % and 31.71 % (P < 0.05) under legume-harvested grainwheat (LHGW) rotation and legume that non-harvested grainwheat (LNHGW) rotation systems, respectively. The positive benefits of legume crops on wheat yield were reduced to some extent by their harvest. The main factors affecting wheat yield were fertilization rates and climate and soil types, with weight ratios of 0.32, 0.21 and 0.16, respectively. For fertilization rates, wheat yield benefits decreased with increases in N fertilizer inputs, and we identified significant positive benefits in temperate, subtropical and Mediterranean climates (P < 0.05). For soil types, sandy and loamy sand soils with low clay contents generally had the best wheat yield benefits. Furthermore, compared with GW rotations, LW rotations increased N use efficiency by 8.57 % on average, which was significantly affected by N inputs (P < 0.05). Therefore, the introduction of legume crops into the GW rotation system can increase wheat yields and reduce N applications regardless of whether legume grains are harvested. Moreover, legume crops have the best wheat yield benefits under low N input conditions, which can make an important contribution to the sustainable intensification of global wheat production.

Effects of sewage sludge hydrochar on emissions of the climate-relevant trace gases N2O and CO2 from loamy sand soil

This work explores the effects of amending a loamy sand soil with hydrochars having different physicochemcial characteristics. The effects of different hydrochars on emissions of the greenhouse gases nitrous oxide (N2O) and carbon dioxide (CO2) were investigated together with the relationship between the hydrochar's mineral nitrogen content and the soil microbial biomass. Soil samples were amended with eleven different hydrochars and feedstocks having different carbon and nitrogen contents at application rates of 5 t ha−1 and 25 t ha−1. Microbial immobilization was the main mineral nitrogen sink in soil following hydrochar application. Moreover, the processing conditions applied during hydrochar production (i.e., the pyrolysis temperature and residence time) had significant effects on N2O and CO2 emissions: treatment with incubated hydrochars yielded significantly lower N2O emissions than treatment with non-carbonized feedstocks, particularly at the highest level of hydrochar application (25 t ha−1). Further analysis revealed that increasing the process temperature and residence time during hdyrochar production significantly increased the final product's total organic carbon content but reduced its content of hot water extractable carbon. Hydrochars produced with higher process temperatures and longer residence times therefore yielded lower CO2 emissions during a 44-day incubation experiment than raw feedstocks or hydrochars produced under less severe conditions. Hydrochars formed from sewage sludge at high process temperatures and with long residence times are thus promising soil additives for reducing GHG emissions.

Response of FYM and Split Application of Nitrogen on Growth and Green Yield of Fodder Maize (Zea mays L.)

A field experiment was conducted at Main Forage Research Station, Anand Agriculture University, Anand (Gujarat) to study the effect of FYM and split application of nitrogen on the growth and yield of fodder maize in loamy sand soil during rabi season of 2021-22. The experiment was laid out in a randomized block design (factorial) with three replications. There ten treatment combinations comprising two levels of FYM i.e., F1 (No FYM) and F2 (10 t FYM/ha) and five levels of nitrogen split i.e., N1 (Control: Common Practices, 50% Basal + 50% 30 DAS), N2 (20% N at Basal + 80% N in three equal splits), N3 (30% N at Basal + 70% N in three equal splits), N4 (40% N at Basal + 60% N in three equal splits) and N5 (50% N at Basal + 50% N in three equal splits). Application of 10 t FYM/ha were improved the growth, quality and yield attributes like periodical plant height, leaves/plant, leaf-stem ration, green and dry fodder yield, crude protein and dry matter content, NPK content and uptake, Acid Detergent Fiber (ADF) and Netural Detergent Fiber (NDF) as compared to control treatment of fodder maize. Response of FYM on soil EC, pH was found to be non-significant and soil available phosphorus potassium was found significant. Split application of nitrogen (50% N at Basal + 50% N in three equal splits) reported significant response on growth parameters like periodical plant height, number of leaves per plant, green fodder yield and quality parameters like dry matter content, crude protein content, dry fodder yield, crude protein yield, neutral detergent fiber and acid detergent fiber of fodder maize. Response of split application of nitrogen on post-harvest soil parameters like pH, EC, organic carbon, available phosphorus and potassium.

Draft Genome Sequences of Pseudomonas sp. Strains MWU13-2100 and MWU13-2105 Isolated from Wild Cranberry Bog Soil in the Cape Cod National Seashore.

ABSTRACTPseudomonas sp. strains MWU13-2100 and MWU13-2105 were isolated from a wild cranberry bog with Pipestone loamy coarse sand soil in Truro, Massachusetts, and taxonomically assigned based on whole-genome sequences. The draft genomes are most closely related to P. batumici (41.4% and 41.8% dDDHd4), but with only 50.8 dDDHd4 to each other.

Effects of Carboxymethyl Cellulose/Nano-Calcium Carbonate Hydrogel Amendment of Loamy Sand Soil for Maize Growth

Water unavailability and shortage are severe problems in agriculture, particularly in loamy sandy to sandy soil, since they inhibit plant growth, resulting in a low crop yield. Using biocompatible hydrogels with good water absorption and retention properties is essential to improve plant growth under unfavorable situations. This work aimed to investigate the influence of the carboxymethyl cellulose/nano-calcium carbonate (CMC/NCC) composite amended in the loamy sand soil on maize growth in a pot experiment. Two types of CMC hydrogels with 1 or 5% wv–1 of NCC, designated as CMC/NCC1 and CMC/NCC5 composite hydrogels, respectively, were selected in this study. Incorporating NCC nanoparticles into the physically crosslinked CMC hydrogel networks exhibited the ability to increase water absorption of the pristine and nanocomposite CMC hydrogels. We investigated the properties of hydrogels of different compositions and dosages added to cause increased water absorption capacity (WAC), water holding capacity (WHC), and carbon dioxide (CO2) evolution. The CMC/NCC hydrogels had better swelling capacity than those of the pristine CMC hydrogels at all pHs. The amendment of hydrogels in loamy sand soil enhanced the soil WHC. The CO2 evolution gradually increased with incubation time in the order of CMC > CMC/NCC1 > CMC/NCC5 > the control soil. The chlorophyll contents, the biomasses of the above- and below-ground parts, and root length were observed as the determining parameters of maize growth. Although the total chlorophyll contents of maize leaves did not significantly change with hydrogel supplementations, the root biomass and cumulative root length of the maize grown in the soil amended with hydrogels were significantly lower than that of untreated soil without changing the above-ground biomass. This suggests that the maize plant growing in the loamy sand soil amended with CMC/NCC hydrogels could affect the allocation of carbon without changing the overall crop yield. Thus, the CMC/NCC hydrogels can be used as an alternative soil amendment for agricultural applications in the loamy sand soil to maintain plant growth.

Cadmium phytoremediation potential of Brassica genotypes grown in Cd spiked Loamy sand soils: Accumulation and tolerance.

Phytoremediation acts as an efficient methodology for management of toxic elements spiked soils. The accumulation and tolerance potential of hyper-accumulator plants for toxic elements act as an index for in-situ removal of toxic elements. Extraction of cadmium (Cd) through its accumulation in harvestable parts of plants has attracted attention as the economic and environment friendly technique. Brassica genotypes have greater potential to accumulate Cd when grown in Cd spiked soils. Therefore, for evaluation of comparative efficiency of three Brassica genotypes (B. juncea, B. campestris and B. napus) in phytoremediation of Cd spiked soils, a pot study was carried out in Cd contaminated soil with 6 levels as 0, 5, 10, 20, 40, and 80mgkg-1 soil. Results indicated that dry biomass production of Brassica genotypes declined with the enhanced Cd contamination in soil. The reduction in grain and shoot yield varied from 2.87 to 1.85 and 11.85 to 8.00g pot-1 with increased Cd contamination from 5 to 80mgkg-1 soil. Similarly, increased levels of Cd contamination resulted in enhanced concentration and accumulation in grains as well as shoots of all Brassica genotypes. Among Brassica genotypes, B. juncea recorded the highest production of dry biomass (12.8g pot-1), Cd accumulation (736.0μg pot-1). Also, the bioaccumulation coefficient and tolerance index indicated that B. juncea is the most tolerant genotype to Cd contamination in soil. Therefore, B. juncea could act as the most potential genotypes for decontamination of Cd spiked soils by preventing its entry into food chain.

Soil chemical extractions can alter potassium coordination in agricultural soils: A combined wet chemical and X-ray absorption spectroscopic approach

• Potassium XANES spectroscopy from soils is paired with six wet chemical extractions. • Dampening of post-edge XANES oscillations was caused by the Mehlich III extraction. • XANES indicates Mehlich III can dislodge K from inner-sphere siloxane bonds. • Dampening was more significant in the loamy sand soil versus the sandy clay loam soil. • Dampening increased the LCF component of K associated with montmorillonite by 25% Soil wet chemical extractions are used to determine plant available potassium (K); yet problems with K bioavailability still persist in soils. Bioavailability is directly related to how elements are bonded and coordinated to the solid phases of soil. However, there is a critical knowledge gap with respect to identifying the in situ, solid-phase K coordination environments in soils treated with wet chemical extractions. Synchrotron-based X-ray absorption spectroscopy (XAS) measures the molecular coordination environment of elements and has been used here to study K chemistry in two agricultural field soils. The objective of this work is to pair XAS with wet chemical K extractions and analyze changes in the coordination environment of K throughout the soil profile. Soil profiles collected down to 1.2 m of a loamy sand and a sandy clay loam were treated with six different extraction methods: (1) Mehlich III, (2) ammonium acetate, (3 & 4) Haney, Haney, Hossner, and Arnold 1 and 2, (5) citrate dithionite, and (6) water extractable potassium. The residual solid was analyzed using XAS and X-ray diffraction (XRD). Citrate dithionite extracted the largest amount of K (1860 mg kg −1 ), and the water extraction removed the least (30 mg kg −1 ). XAS and XRD indicate K sources in these soils are illite, illite–smectite, smectite, and potassium feldspar. A Linear Combination Fit (LCF) approach indicated changes of interest in the post-edge region of the K, K-edge XANES spectra due to the Mehlich extraction. XANES data indicate that the Mehlich extraction can remove loosely bound K and dislodge a portion of K from interlayer space of illite and illite–smectite. This is significant because the Mehlich extraction is effectively decreasing the number of coordinating O atoms surrounding K and causing a dampening in the oscillations of the XANES spectra in the post-edge region (3,620–3,650 eV). The dislodgement of K due to the Mehlich III extraction indicates that the inner-sphere bonds that K forms to the siloxane surfaces in the interlayer space can be broken, and K can become more hydrated with water molecules also present in the interlayer space. This dampening was dependent on soil texture, was more significant in the coarser textured soil, and would indicate an increased accommodation of K by montmorillonite or an increase in K hydration in illite–smectite. The dampening resulted in an average increase in K intercalated in montmorillonite interlayer spaces by 25% in Mehlich treated samples according to the LCF results. Future studies involving K sorption to silicon and aluminum oxides will further clarify behavior of K on mineral surfaces, particularly during surface precipitation.

Winter warming effects on soil nitrate leaching under cover crops: A field study using high-frequency weighing lysimeters

Leaching of nitrate (NO3−)—a reactive nitrogen form with impacts on ecosystem health—increases during the non-growing season (NGS) of agricultural soils under cold climates. Cover crops are effective at reducing NGS NO3− leaching, but this benefit may be altered with less snow cover inducing more soil freezing under warmer winters. Our objective was to quantify the effect of winter warming on NO3− leaching from cover crops for a loamy sand (LS) and a silt loam (SIL) soil. This research was conducted over 2 years in Ontario, Canada, using 18 high-precision weighing lysimeters designed to study ecosystem services from agricultural soils. Infra-red heaters were used to simulate warming in lysimeters under a wheat-corn-soybean rotation planted with a cover crop mixture with (+H) and without heating (-H). Nitrate leaching determination used NO3− concentration at 90 cm (discrete sampling) and high temporal resolution drainage volume measurements. Data were analyzed for fall, overwinter, spring-thaw, post-planting, and total period (i.e., November 1 to June 30 of 2017/2018 and 2018/2019). Warming significantly affected soil temperature and soil water content—an effect that was similar for both years. As expected, experimental units under + H presented warmer soils at 5 and 10 cm, along with higher soil water content in liquid form than –H lysimeters, which translated into higher drainage values for + H than –H, especially during the overwinter period. NO3− concentrations at 90 cm were only affected by winter heating for the LS soil. The drainage and NO3− concentrations exhibited high spatial variation, which likely reduced the sensitivity to detect significant differences. Thus, although absolute differences in NO3− leaching between LS vs. SIL and +H (LS) vs. –H (LS) were large, only a trend occurred for higher leaching in LS in 2018/2019. Our research demonstrated that soil heating can influence overwinter drainage (for LS and SIL soils) and NO3− concentration at 90 cm in the LS soil—important NO3− leaching controlling factors. However, contrary to our initial hypothesis, the heating regime adopted in our study did not promote colder soils during the winter. We suggest different heating regimes such as intermittent heating to simulate extreme weather freeze/thaw events as a future research topic.

Effect of Brown Algae (Fucus vesiculosus L.) on Humus and Chemical Properties of Soils of Different Type and Postgermination Growth of Cucumber Seedlings

The possibility of using brown algae in agriculture as an alternative source of nutrients is currentlyunder study and discussion. Our study aimed to evaluate the effect of F. vesiculosus on the agrochemical properties of four soil types: Retisol loamy sand soil, Retisolloam, Retisol clay, and Histosol. The F. vesiculosus waste was added to soil samples at a rate of 0, 0.5, 1.0, 2.0, 5.0, and 10 wt%. The brown algaewaste application significantly decreased soil acidity in the substrates of all soil types, with the larger increasesfor Retisol loamy sand and Retisol clay than for Retisol loam and Histosol. The application of F. vesiculosus waste products increased the C content in all soil types except Histosol. The N and P content in soil substrates were not significantly affected by algaewaste application regardless of soil type. This study showed that the effect of F. vesiculosus waste application varies depending on the soil type, with the strongest impact on Retisol clay and the lowest on Histosol.

Nitrogen dynamics and carbon sequestration in soil following application of digestates from one- and two-step anaerobic digestion

Anaerobic digestion (AD) is an important tool for reducing greenhouse gas emissions from agricultural production. A prolonged retention time by adding an extra anaerobic digestion step can be utilized to further degrade the digestates, contributing to increased nitrogen mineralisation and reducing decomposable organic matter. These modifications could influence the potential N fertiliser value of the digestate and soil carbon sequestration after field application. This study investigated the effects of prolonging retention time by implementing an additional anaerobic digestion step on carbon and nitrogen dynamics in the soil and soil carbon sequestration. Two digestates obtained from two biogas plants operating at contrasting hydraulic retention times, with and without an additional digestion step, were applied to a loamy sand soil. N mineralisation dynamics were measured during 80 days and C mineralisation during 212 days. After 80 days of incubation, the net inorganic N release from digestates obtained from a secondary AD step increased by 9–17 % (% of the N input) compared to corresponding digestates obtained from a primary AD step. A kinetic four-pool carbon model was used to fit C mineralisation data to estimate carbon sequestration in the soil. After 212 days of incubation, the net C mineralisation was highest in undigested solid biomass (68 %) and digestates obtained from the primary AD step (59–65 %). The model predicted that 26–54 % of C applied is sequestered in the soil in the long-term. The long-term soil C retention related to the C present before digestion was similar for one- and two-step AD at 12–16 %. We conclude that optimizing the anaerobic digestion configurations by including a secondary AD step could potentially replace more mineral N fertiliser due to an improved N fertiliser value of the resultant digestate without affecting carbon sequestration negatively.