Types Of Organic Amendments Research Articles

Vermicompost as Organic Amendment: Effects on Some Soil Physical, Biological Properties and Crops Performance on Acidic Soil: A Review

One of the most precious natural resources is soil, which provides ecological functions necessary for life's survival and sustenance. Therefore, preserving and enhancing soil health is crucial for agricultural and ecological sustainability. However, careless application of mineral fertilizer lowers fertility and organic matter and has negative impacts on the environment, ground water quality, and soil health, whereas the use of organic amendments is essential for enhancing soil health. In order to improve the physical, biological, and crop productivity of acidic soil, this review emphasizes the potential of vermicompost as a soil conditioner. Thus, adding organic amendments to soil is a management tactic that can boost microbial populations, activity, and variety, enhances soil fertility and improve soil structure. Vermicompost (VC) is one type of organic amendment that is created when earthworms and soil microorganisms interact. The end product has a high degree of maturity, high porosity, aeration, drainage, water storage capacity, and microbial activity. As a result, applying this amendment encourages biological activity, which raises the soils' potential for production both directly through increased nutrient availability and indirectly through improved physical characteristics. Similarly, the addition of vermicompost (VC) to soil raised its pH levels, phosphorus, potassium, calcium, magnesium, and total organic carbon; it also enhanced the soil's cation exchange capacity, microbial biomass carbon, micronutrient content, and nitrogen content, all of which increased crop yield. In addition to raising crop yield and improving soil quality and nutrient availability, vermicompost also strengthens crop resistance to pests and diseases. By adding essential nutrients, humic acids, growth-regulating hormones, and enzymes to the soil, it acts as an organic fertilizer that improves plant nutrition, photosynthesis, and overall crop quality.

Effect of Environmental and Anthropic Conditions on the Development of Solanum peruvianum: A Case of the Coastal Lomas, Lima-Peru

Land degradation and the effects of climate change are increasing arid lands, accelerating desertification, and leading to the loss of ecosystem services worldwide. This research focused on evaluating how human impact and environmental factors affect the development of Solanum peruvianum in its natural habitat of coastal lomas. The study was carried out in the coastal lomas of Mangomarca-Peru, where phenotypic and ecological data on the plants were collected. Information was also gathered on human impacts on the nutritional characteristics of the soils. Then, five types of organic amendments were used to improve the physical and chemical characteristics of the degraded soil, and the development and photosynthetic activity of S. peruvianum were evaluated. As a result, under the study conditions, it was found that S. peruvianum was established approximately 33.74 cm from the rocks, in a range of 300 to 650 m asl. The maximum height of the plants was 90 cm, with a stem diameter at ground level of 2 cm. S. peruvianum produced fruits between January and July, with a seed germination rate of 36% in 25 days. On the other hand, the anthropogenic impact on the soil reduced 58% of organic material (OM), 71% of nitrogen, 40% of P2O5, and 13% of K2O and increased the concentration of magnesium oxide, calcium oxide, pH, and electric conductivity (EC). The organic amendments bokashi, compost, and biochar, when mixed with the degraded soil, increased the pH, OM, N, P, and EC; however, the plants died after 25 days. On the other hand, the application of the Premix5 substrate for 100 days favored the growth of 52.84 cm and 38.29 cm in the preserved soil and 23.21 cm in the black soil mixed with blond peat, and it should be noted that the substrates presented an acid pH and EC > 0.1. Regarding photosynthetic phenotyping, S. peruvianum plants grown in their natural habitat and in Premix5 showed a higher proton flux (vH+), linear electron flow (LEF), and maximum quantum yield (Fv’/Fm’). On the contrary, they showed a lower NPQt value than plants grown in preserved and black soil mixed with blond peat.

Selection of Suitable Organic Amendments to Balance Agricultural Economic Benefits and Carbon Sequestration.

Long-term excessive use of fertilizers and intensive cultivation not only decreases soil organic carbon (SOC) and productivity, but also increases greenhouse gas emissions, which is detrimental to sustainable agricultural development. The purpose of this paper is to identify organic amendments suitable for winter wheat growth in the North China Plain by studying the effects of organic amendments on the economic benefits, carbon emissions, and carbon sequestration for winter wheat fields and to provide a theoretical basis for the wide application of organic amendments in agricultural fields. The two nitrogen rates were N0 (0 kg ha-1) and N240 (240 kg ha-1), and the four organic amendments were straw, manure, mushroom residue (M R), and biochar. The results showed that, compared to N0, N240 significantly increased the yield by 244.1-318.4% and the organic carbon storage by 16.7-30.5%, respectively, but increased the carbon emissions by 29.3-45.5%. In addition, soil carbon stocks increased with all three types of organic amendments compared to the straw amendment, with the biochar treatment being the largest, increasing carbon storage by 13.3-33.6%. In terms of yield and economic benefits, compared to the straw amendment, the manure and biochar amendments increased winter wheat yields by 0.0-1.5% and 4.0-13.3%, respectively, and M R slightly decreased wheat yield; only the economic benefit of the M R amendment was greater than that of the straw amendment, with an increase in economic benefit of 1.3% and 8.2% in the 2021-2022 and 2022-2023 seasons, respectively. Furthermore, according to the net ecosystem productivity (NEP), N0 was the source of CO2, while N240 was a sink of CO2. The TOPSIS results showed that N240 with a mushroom residue amendment could be recommended for increasing soil carbon stocks and economic benefits for winter wheat in the NCP and similar regions. Low-cost M R can increase farmer motivation and improve soil organic carbon, making a big step forward in the spread of organic materials on farmland.

Effect of soil organic amendments on sorption behavior of two insecticides and two herbicides

The effect of biochar, compost, peat and wheat straw at 1 and 5% on adsorption isotherm of chlorantraniliprole, dinotefuran, bispyribac-sodium, and metribuzin was studied in clay loam soil and sandy loam soil. Biochar, compost, peat and wheat straw (at a rate of 1 % in soil) improved the adsorption capacity of chlorantraniliprole and metribuzin in sandy loam soil. The sorption coefficients are higher for chlorantraniliprole and metribuzin whereas lower for dinotefuran and bispyribac-sodium in amended soil compared to unamended sandy loam soil. There is not a clear direct correlation between Freundlich parameters as well as Kd or Koc and type of organic amendment. The sorption of all tested pesticides on biochar was increased, whereas on compost was decreased. The order of pesticides sorption in soils and different organic amendments is generally inversely proportional to their aqueous solubilites. Adsorption of chlorantraniliprole increases on the sandy loam soil amendment at the rate of 1% in the following order: peat > compost > biochar > original soil. Also, the magnitude of adsorption on soil A amendment at the rate of 5% can be arranged for dinotefuran in the order; peat > biochar > compost > original soil and for bispyribac-sodium and metribuzin peat = wheat straw > biochar > original soil.

An Investigation into the Effects of Organic Amendments in a Saline Environment on Soil Chemical Characteristics, Growth, and Yield of Rice in the South of Senegal

Context of the Study: The use of organic amendments could help increase the resilience of lowland rice in Lower Casamance to salinity. The aim of this study was to test the effect of different organic amendments (biochar and compost) on the salinity tolerance of lowland rice in Basse Casamance.
 Objective: The aim was to test the effect of different organic amendments on the salinity tolerance of rice in the lowlands of the villages of Selecky and Essyl in Lower Casamance.
 Methodology: A split-plot design was adopted with two factors: the type of organic amendment with 4 treatments (biochar, compost, compost + biochar and the control) and salinity with two treatments (salted and unsalted zones). These treatments were repeated 3 times in two consecutive years, 2020 and 2021, at the Selecky and Essyl sites. Physico-chemical characteristics as well as rice growth and production parameters were studied.
 Results: In the saline zone, soil amendments significantly increased the number of tillers and the height of rice plants compared with controls (p<0.05). Average rice yield and plant biomass were significantly higher in the amended plots at Selecky in both experimental years (p<0.05). At Essyl, on the other hand, height, number of tillers, rice yield and plant biomass were lower in the 2nd year of experimentation. Organic amendments had a significant effect (p<0.05) on rice production and yield parameters in the salt zone.

Physical and Chemical Properties of Limestone Quarry Technosols Used in the Restoration of Mediterranean Habitats

The lack of topsoil is frequently a limiting factor in limestone quarry restoration. This implies that new technosols for maintaining target habitats must be created using mining wastes as the main components. We designed three different technosols using different combinations of mineral materials (mining wastes, excavated soils and topsoil), organic amendment types (compost and digestate) and doses for the restoration of target habitats. Moreover, we monitored the main physicochemical indicators of the quality of the technosols. We observed not only an increase in soil organic carbon and plant nutrients related to the application of any type of organic amendment, but that the digestate mostly increased the soil resistance to erosion by improving soil aggregation even before the emergence of vegetation. Soil-water-retention capacity only improved in technosols built with organic amendments and topsoil. The combination of mining wastes, organic amendments and a superficial horizon of topsoil resulted in the most optimal technosol for the restoration of limestone quarries in the Mediterranean climate.

Gross nitrogen transformations and ammonia oxidizers affected by nitrification inhibitors and/or organic amendments in a calcareous soil: A 15N tracing study

Nitrification inhibitors (NIs) combined with organic amendments are considered effective strategies for improving soil nitrogen availability and reducing nitrogen loss. However, these effects might depend on the types of organic amendments and nitrification inhibitors, and whether their combined application could generate a synergistic effect on nitrogen transformation rate has not been well investigated. In this study, a 15N aerobic incubation experiment was conducted to investigate the effects of nitrification inhibitors (3,4-dimethylpyrazole phosphate [DMPP, 1 % of applied NH4+-N] or methyl 3-(4-hydroxyphenyl) propionate [MHPP, 5 % of applied NH4+-N]) and/or organic amendments (straw [1 %, w/w] or straw-derived biochar [1 %, w/w]) on the gross nitrification rates of mineralization, nitrification, and immobilization in calcareous soil. Our findings revealed that compared with the control treatment, biochar, straw, and MHPP_straw boosted gross mineralization rates by 1.19–2.69 times. The addition of nitrification inhibitors and/or organic amendments inhibited the gross nitrification rates by 15.8 %–89.7 %, which ranged from 0.85 mg N kg−1 day−1 to 8.28 mg N kg−1 day−1 across treatments. DMPP_straw showed the greatest inhibiting effect, whereas 5 % MHPP treatment had the least effect. Gross NH4+ immobilization rates increased by 4.12–18.18 times, where NO3− immobilization rates were only stimulated with the treatments of straw, DMPP_straw, and MHPP_straw. DMPP was more efficient in inhibiting nitrification than MHPP, but it also significantly enhanced ammonia (NH3) volatilization, which rose by 2.77 times over that in MHPP. The high C/N ratio and inorganic-N adsorption of straw and biochar might play prominent roles in affecting NH4+ content by stimulating mineralization and inorganic immobilization. The decrease in the abundances of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) can be partially explained by the inhibitory effects of DMPP and MHPP. Changes in the community of AOB were more sensitive to management measures than those of AOA. In conclusion, our study demonstrates that treatments with DMPP_straw and MHPP_straw efficiently promote inorganic nitrogen immobilization, mitigate NH3 volatilization, inhibit nitrification to the greatest extent, and thus yield the most positive synergistic effects on soil nitrogen retention.

Efficacy of cattle manure in improving the productivity of peanut (Arachis hypogaea) in sandy soil of Central Vietnam

Peanut is an important annual crop in sandy soil of Central Vietnam. Organic fertilizer application plays a key role in improving peanut yield and soil quality. However, research on cattle manure is still limited in sandy soil for peanut crop. Trial consisted of 10 fertilizer treatments with two factors including two application methods and five ratios of inorganic fertilizer and manure and rice straw combinations. They were arranged in a split plot design with three replicates during the spring and summer season of 2021 on the sandy soil at Cat Trinh commune, Phu Cat district, Binh Dinh province, Vietnam. The aims of the study were to evaluate the efficiency of different combinations of organic amendments on the yield of peanut and to examine possible short-term changes in soil characteristics as a result of organic amendments application. The study results showed that application methods and different organic treatments gave higher yields compared with application of inorganic fertilizer alone. The highest peanut yield was found in the application of organic fertilizer from cattle manure+rice straw (1:0.5) and row application with (2.80-3.85 t/ha), increasing (21-27%) compared with application of inorganic fertilizer alone in surface application method and seasons. Cattle manure application improved some soil chemistry properties after the experiment such as OC, CEC, total N, P2O5 and K2O. In conclusion, incorporation of different types of organic amendments improved peanut yield and soil properties more than application of inorganic fertilizer alone.

Wetting and drying cycles, organic amendments, and gypsum play a key role in structure formation and stability of sodic Vertisols

Abstract. In the natural environment, soils undergo wetting and drying (WD) cycles due to precipitation and evapotranspiration. The WD cycles have a profound impact on soil physical, chemical, and biological properties and drive the development of structure in soils. Degraded soils are often lacking structure, and the effect of organic amendments and WD cycles on structure formation of these soils is poorly understood. The aim of this study was to evaluate the role of biotic and abiotic factors on aggregate formation and stabilization of sodic soils after the addition of gypsum and organic amendments (feedlot manure, chicken manure, lucerne pallets, and anionic poly acrylamide). Amended soils were incubated at 25 ∘C over four WD cycles, with assessment of soil microbial respiration, electrical conductivity, pH, sodium adsorption ratio (SAR), aggregate stability in water (ASWAT), aggregate size distribution, and mean weight diameter. Our results demonstrate that WD cycles can improve aggregate stability after the addition of amendments in sodic Vertisols, but this process depends on the type of organic amendment. Lucerne pellets resulted in highest soil microbial respiration, proportions of large macroaggregates (>2000 µm), and mean weight diameter. In contrast, dispersion was significantly reduced when soils were treated with chicken manure, whilst anionic polyacrylamide only had a transient effect on aggregate stability. When these organic amendments were applied together with gypsum, the stability of aggregates was further enhanced, and dispersion became negligible after the second WD cycle. The formation and stability of small macroaggregates (2000–250 µm) was less dependent on the type of organic amendments and more dependent on WD cycles as the proportion of small macroaggregates also increased in control soils after four WD cycles, highlighting the role of WD cycles as one of the key factors that improves aggregation and stability of sodic Vertisols.

Interaction Between Mycorrhizae and Organic Amendments to Improve Growth and Phosphorus Uptake in Brinjal

Phosphorus (P) is the second most important macronutrient both for plants and other living organisms. However, due to its fixation with soil collides; it becomes unavailable to plants and hence cannot enter the food chain. The effect of combination of mycorrhizae and different organic amendments on P uptake and plant growth of brinjal (Solanum melongena) was evaluated in a pot trial, conducted at wire house of Institute of Soil and Environmental Sciences, University of Agriculture Faisalabad. Each treatment was composed of one type of organic amendment (i.e. farmyard manure (FYM), biogas slurry (BGS), poultry manure and compost) at the rate of 1.5% w/w and mycorrhizae. Results showed that the combined application of mycorrhizae and organic amendment improved plant growth and enhanced P uptake. Improved root length, shoot height and leaf canopy was observed in FYM+mycorrhizae and BGS+mycorrhizae combinations. Similarly, enhanced P uptake improved photosynthetic activity and high biomass was observed in BGS+mycorrhizae combinations. The use of mycorrhizae and organic amendments appeared to be efficient in improving P uptake up to 53.45% and plant growth 64.32%. It is concluded that practicing this in the field can be cost effective approach and reduce environmental risk by reducing application of chemical fertilizers.

Biochar and Compost Application either Alone or in Combination Affects Vegetable Yield in a Volcanic Mediterranean Soil

The aim of this work was to compare the application of biochar, compost, and their mixtures on soil fertility and crop yields using a volcanic Mediterranean soil. For this reason, three types of organic amendments (OAs) were selected: compost1, made from olive mill waste and orchard pruning residues; compost2, made from olive mill waste, animal manure and wool residues; and biochar made from beech wood pyrolyzed at 550 °C. When selected, the OAs were characterized chemically for organic carbon (OC), total N, pH, electric conductivity (EC) and the bulk fraction of organic matter using 13C CPMAS NMR spectroscopy. In addition, soil chemistry was analysed at the end of each year for the following parameters: pH, OC, total N, CaCO3, P2O5, NH4, FDA and EC. Results showed that biochar had the highest OC and the lowest N and EC compared to both composts. Moreover, 13C CPMAS NMR showed that biochar had the lowest content of O-alkyl, methoxyl- and alkyl-C and the highest content of aromatic-C. On the other hand, compost2 and compost2+biochar mixture reduced Aubergine yield by −60% and −40%, respectively, and tomato yield by −50% and −100%, respectively. Nevertheless, a significant increase in onion and rape yields were observed when compost1, compost1+biochar and compost2 were applied, while biochar and compost2+biochar significantly decreased the yield of these crops. Overall, our results highlight that the effect of OAs on crops yield is largely variable and influenced by the interaction with soil chemistry.

Response of Biofertilizer and Foliar Spray of Organic Amendments on Economics and Yield Attributes of Cowpea (Vigna unguiculata L.)

Field experiment was conducted on cowpea during Kharif 2021 at (CRF) Crop Research Farm, Department of Agronomy, Naini Agricultural Institute. SHUATS, Prayagraj (U.P) India. The experiment entitled as “Response of biofertilizer and foliar spray of organic amendments on economics and yield attributes of cowpea (Vigna unguiculata L.)”, to study treatments consisting of three kinds of biofertilizers viz.Rhizobium, PSB and Rhizobium + PSB and three types of organic amendments viz. Panchagavya, Jeevamrutha and Beejamrutha. Each of the nine treatments was replicated three times and laid out in a Randomized Block Design with various treatment combinations. T1: Rhizobium 20 g + Panchagavya 3% foliar spray, T2: Rhizobium 20 g + Jeevamrutha 5% foliar spray,T3: Rhizobium 20 g + Beejamrutha 2% foliar spray ,T4: PSB 20 g + Panchagavya 3% foliar spray,T5: PSB 20 g + Jeevamrutha 5% foliar spray,T6: PSB 20 g + Beejamrutha 2% foliar spray, T7: Rhizobium + PSB 20g + Panchagavya 3% foliar spray,T8: Rhizobium + PSB 20g + Jeevamrutha 5% foliar spray,T9: Rhizobium + PSB 20g + Beejamrutha 2% foliar spray. The results revealed that treatment 9 (Rhizobium + PSB 20g + Panchagavya 3% foliar spray) recorded maximum on no. of pods per plant (15.43), length of pod (19.53), seeds per pod (10.68), test weight (133.40), seed yield (1025.50), harvest index (41.74), and B:C ratio (2.42).It is concluded that seed treatment with Rhizobium + PSB 20g + Panchagavya 3% foliar spray was found more productive and economical.

Biochar and compost from cotton residues inconsistently affect water use efficiency, nodulation, and growth of legumes under arid conditions

There is an urgent global need to expand crop cultivation into arid and semiarid lands to guarantee food security. Thus, limited irrigation strategies and soil amendments are promising strategies for conserving water in arid and semi-arid crop production. Soil amendments, such as compost and biochar can improve soil water relationships, nitrogen (N) fixation, soil fertility, and crop productivity. A study was designed to evaluate the effect of biochar and compost applications on soil water relationships, nutrient uptake, plant growth, and N-fixation. A greenhouse pot experiment was conducted in two soils using a complete factorial design. The main effect, i.e., water content of each soil, was maintained at either 40% or 60% water filled porosity. The sub-effect, organic amendment type, was applied as biochar or compost. The sub-sub effect was rate of application (0, 5, and 10 Mg ha−1). Plant height and root length were significantly affected by the rate of amendment applied, whereas shoot and root mass differences were explained by irrigation strategy. Whole plant N uptake was moderately affected by water content only (p = 0.0818). Phosphorus and Potassium uptake were highly affected by amendment type and rate. Biochar moderately improved plant available water (0.061 %Vol Mg−1 ha−1) over the range of 0–20 Mg ha−1 in the sandier soil. Compost did not improve plant available water in either soil. Nodulation was affected by soil type only. The benefits of biochar or compost for plant were inconsistent and depended upon irrigation strategies, soil type, application rate, and plant species.

Soil and Plant Responses to Phosphorus Inputs from Different Phytase-Associated Animal Diets

The over-supplementation of animal feeds with phosphorus (P) within livestock-production systems leads to high rates of P excretion and thus to high P loads and losses, which negatively impact the natural environment. The addition of phytase to pig and poultry diets can contribute to reducing P excretion; however, cascading effects of phytase on plant–soil systems remain poorly understood. Here, we addressed how three different diets containing various levels of exogenous phytase, i.e., (1) no-phytase, (2) phytase (250 FTU), and (3) superdose phytase (500 FTU) for pigs (Sus scrofa domesticus) and broilers (Gallus gallus domesticus) might affect P dynamics in two different plant–soil systems including comfrey (Symphytum × uplandicum) and ryegrass (Lolium perenne). We found that differences in phytase supplementation significantly influenced total P content (%) of broiler litter and also pig slurry (although not significantly) as a result of dietary P content. P Use Efficiency (PUE) of comfrey and ryegrass plants was significantly higher under the intermediate ‘phytase’ dose (i.e., commercial dose of 250 FTU) when compared to ‘no-phytase’ and ‘superdose phytase’ associated with pig slurry additions. Soil P availability (i.e., water soluble P, WSP) in both comfrey and ryegrass mesocosms significantly decreased under the intermediate ‘phytase’ treatment following pig slurry additions. Dietary P content effects on P losses from soils (i.e., P leaching) were variable and driven by the type of organic amendment. Our study shows how commercial phytase levels together with higher dietary P contents in pig diets contributed to increase PUE and decrease WSP thus making the plant–soil system more P conservative (i.e., lower risks of P losses). Our evidence is that dietary effects on plant–soil P dynamics are driven by the availability of P forms (for plant uptake) in animal excretes and the type of organic amendment (pig vs. broiler) rather than plant species identity (comfrey vs. ryegrass).

Benefits of applying organic amendments from recycled wastes for fungal community growth in restored soils of a limestone quarry in a semiarid environment

Applying organic amendments to recover physical, chemical, and biological qualities of soil may enable recovery of soils degraded by mining in semiarid climates. This study's aim was to investigate the development and changes in the composition of fungal communities in restored soils with five different types of organic amendments (two types of vegetable compost and sewage sludge compost, and a mixture of both) compared with unamended soils and surrounding natural soils and to examine the relationships between the fungal taxa, the new physico-chemical and biological soil properties of technosoils after 18 months of restoration, and natural soils. Restoration improved soil quality and fungal diversity, placing these soils in an intermediate position between unrestored soils (with no fungi present) and undisturbed reference soils, which were the most fungal diverse. Sewage-treated soils and their mixtures showed high nitrogen and carbohydrate content as well as high basal respiration and fatty acid content, suggesting that they provided readily biodegradable organic matter. In contrast, greenhouse compost-treated soils showed high total organic carbon and polyphenol content, whereas garden compost-treated soils showed intermediate values. The biological soil properties of both composts showed were similar to those of the reference soils, suggesting that composts contained more resilient organic matter. Organic amendments of dissimilar origin caused significantly different fungal soil communities at the genus level among the restored soils. Results indicated that soil pH, electrical conductivity, total nitrogen content, soil basal respiration, fungi/bacteria-PLFA ratio, and dehydrogenase and β-glucosidase activities, together with Pearson's correlations, revealed that these properties and nutrient content (total organic carbon, C/N ratio, carbohydrates, and polyphenols) influenced 40 soil fungal taxa. Therefore, the organic amendments led to changes in soil properties that favoured plant cover by promoting the soil fungal community growth beneficial to the carbon cycle and symbiotic with plants.

Nitrogen Release in Soils Amended with Different Organic and Inorganic Fertilizers under Contrasting Moisture Regimes: A Laboratory Incubation Study

Understanding nitrogen (N) release patterns and kinetics is a key challenge for improving N use efficiency in any agroecosystem. An incubation experiment was done to study the N release pattern and kinetics of contrasting soils amended with compost (CO), poultry manure (PM), rice husk biochar (RHB), poultry manure biochar (PMB) and cowdung (CD) combined with chemical fertilizer (integrated plant nutrient system, IPNS approach) under two moisture regimes, viz. field capacity (FC) and continuous standing water (CSW) at 25 °C for 120 days. Our results revealed that NH4+-N was the dominant under CSW conditions, whereas NO3−-N was dominant under FC conditions. Net mineral N data fitted well to the first order kinetic model. Both N release potential (N0) and rate constant (k) were greater in acidic soil than those of charland soil. The maximum N release varied between 24.90–76.29% of input depending on soil type and moisture status. N mineralization was strongly correlated with urea N application. PM and PMB mineralized in all soil and moisture conditions whereas N immobilization was observed in the case of RHB. N mineralization was strongly correlated with urea N application. Gaseous N losses were different for the organic amendments exhibiting more gaseous N losses in PM, CD and CO based IPNS whereas the lowest gaseous N loss was observed in PMB based IPNS. Biochar based IPNS increased soil pH in all conditions. Thus, the present study suggests that N release depends on soil type, soil moisture and type of organic amendment. However, CO, PM and CD based IPNS can be recommended for both acidic and charland soils in terms of N release as short duration crops will suffer from N deficiency if biochar based IPNS is used in the field.

Phytoremediation Of a Polluted Soil by Purple Plant (Tradescantia pallidaL.) Under Different Organic Amendments

Present investigation was performed to determine the ability of purple plant (Tradescantia pallida L.) for removing heavy metals from a contaminated soil particularly nickel, with the aid of different types of organic amendments. Results of soil heavy metal content after application of different fertilizers were: maximum values (ppm) of V, Cr, Ni, Mn, Cu, Zn, As, Mo, Cd, Pb and Ag were respectively: 275.437, 284.807 (control 1), 265.073, 1071.32, 60.0671 (control 2), 77.8288, 9.5162, 8.5267 (control 1), 5.7943 (control 1), 7.5076 (control 2) and 37.8868 (control 1). Whereas, the minimum values (ppm) of V: 104.644, Cr: 85.7222 (commercial fertilizer), Ni: 164.92, Mn: 711.155 (cow dung), Cu: 15.5141 (cow dung), Zn: 43.3929 (commercial fertilizer), As: 3.7819 (cow dung), Mo: 0.000 (plant residue composite and bird manure), Cd: 0.000 (plant residue composite and bird manure), Pb: 4.1535 (bird manure) and Ag: 2.9181 (plant residue composite). This indicate that the use of organic amendment induce the phytoremediation of polluted soils.

Impact of Organic Amendment with Alternate Wetting and Drying Irrigation on Rice Yield, Water Use Efficiency and Physicochemical Properties of Soil

A pot experiment was executed to investigate the impact of biochar and compost with water-saving irrigation on the rice yield, water use efficiency, and physicochemical properties of soil. Two irrigation regimes—namely alternate wetting and drying (AWD) and continuous flooding (CF)—and four types of organic amendments (OA)—namely rice husk biochar (RHB), oil palm empty fruit bunch biochar (EFBB), compost and a control—were applied to evaluate their effects. Under the AWD irrigation regime, the maximum grain was produced by RHB (241.12 g), whereas under the same organic amendments, both AWD and CF produced a similar grain yield. Under the same organic amendment, a significantly higher water use efficiency (WUE) was observed from the AWD irrigation with RHB (6.30 g L−1) and EFBB (5.80 g L−1). Within the same irrigation regime, soil pH, cation exchange capacity, total carbon, total nitrogen and available phosphorus were enhanced due to the incorporation of biochar and compost, while higher soil exchangeable potassium was observed under CF irrigation for all treatments. RHB and EFBB significantly reduced the soil bulk density (up to 20.70%) and increased porosity (up to 16.70%) under both irrigation regimes. The results imply that the use of biochar with AWD irrigation could enhance the nutrient uptake and physicochemical properties of soil and allow rice to produce a greater yield with less water consumption.

Contrasting Organic Amendments Induce Different Short-Term Responses in Soil Abiotic and Biotic Properties in a Fire-Affected Native Mediterranean Forest in Chile

This study aimed to evaluate contrasting organic amendments as a strategy to promote the recovery of biotic and abiotic edaphic conditions central to the reestablishment of soil ecosystem functions at a site in south-central Chile affected by megafires in the 2016–2017 summer season. We analyzed the effects of the application of fresh (poultry and swine manure) and stabilized (compost of agricultural waste origin) organic amendments on microbial parameters, including basal respiration, microbial biomass, the carbon mineralization coefficient, and the microbial metabolic quotient, along with soil physicochemical properties related to soil fertility and stability. All organic amendments improved soil fertility and stimulated soil microbial activity. Fresh amendments, particularly swine manure, promoted the immediate recovery of the microbial conditions evaluated. However, greater mineralization rates and thus presumably shorter periods of carbon (C) source consumption were related to the application of such organic amendments. Soils treated with compost accumulated the most organic carbon and nitrogen, ensuring long-term nutrient release and thus long-term soil function recovery. Choosing the type of organic amendment to use to sustain ecosystem resilience will highly depend on the restoration goals over time.

Chitin- and Keratin-Rich Soil Amendments Suppress Rhizoctonia solani Disease via Changes to the Soil Microbial Community.

Enhancing soil suppressiveness against plant pathogens or pests is a promising alternative strategy to chemical pesticides. Organic amendments have been shown to reduce crop diseases and pests, with chitin products the most efficient against fungal pathogens. To study which characteristics of organic products are correlated with disease suppression, an experiment was designed in which 10 types of organic amendments with different physicochemical properties were tested against the soilborne pathogen Rhizoctonia solani in sugar beet seedlings. Organic amendments rich in keratin or chitin reduced Rhizoctonia solani disease symptoms in sugar beet plants. The bacterial and fungal microbial communities in amended soils were distinct from the microbial communities in nonamended soil, as well as those in soils that received other nonsuppressive treatments. The Rhizoctonia-suppressive amended soils were rich in saprophytic bacteria and fungi that are known for their keratinolytic and chitinolytic properties (i.e., Oxalobacteraceae and Mortierellaceae). The microbial community in keratin- and chitin-amended soils was associated with higher zinc, copper, and selenium, respectively.IMPORTANCE Our results highlight the importance of soil microorganisms in plant disease suppression and the possibility to steer soil microbial community composition by applying organic amendments to the soil.