Organic matter components and aggregate stability after the application of different amendments to a horticultural soil

The effects of usual or recommended rates of application of five organic amendments (24 t/ha yr of MSW compost, sewage sludge, and ovine manure, 2.4 t/ha yr of commercial vermicompost, and 100 l/ha yr of a commercial humic acids solution) on the soil contents of organic matter, total humified substances, humic acids, carbohydrates and microbial gums, and the structural stability of aggregates were investigated. Four and five years after the beginning of the experiment, significant increments in most of the parameters studied were found after the application of organic residues, whereas the two commercial amendments did not produce any significant change, suggesting that rates recommended by the producers and imposed by their high prices are too low to be useful. MSW compost yielded the highest increases, even if the amount of organic matter applied as ovine manure was very similar. Organic matter and carbohydrates appeared to be the parameters most closely related to soil aggregate stability.     

Effect of organic amendments on seedling infection of rice caused byRhizoctonia solani

Summary Soils amended with organic amendments such as rice chaff, mustard cake, neem cake, saw dust and farm yard manure significantly reduced the seedling infection of rice owing toRhizoctonia solani. Significant increase in shoot growth was noticed in soils amended with organic amendments while reduction in root growth of rice seedlings was also observed owing to the addition of organic amendments such as sunflower cake, mustard cake, coconut cake and farmyard manure.     

Environmentally safe substances for controlling the root-knot nematode,Meloidogyne arenaria infested potato and their influence on yield and alkaloidal content in Egypt

The nematicidal action of three seed mill wastes from cress (Eruca sativa Mill.), castor (Ricinus communis L.) and linseed (Linum usitatissimum L.) as soil additives were tested at three rates (on base lower rate, recommended rate and higher rate), under field conditions at the research and production station of the National Research Centre, El-Nubaria district, El-Beheira governorate, Western Nile Delta region, Egypt, to study the physiological influence of these substances on potato yield, their role against Meloidogyne arenaria infection and the alkaloidal content. All the evaluated treatments significantly (p???0.05 and/or 0.01) reduced the numbers of juveniles in soil and in roots, number of galls, egg masses, gall and egg mass indices and consequently rate of nematode build-up as compared to untreated plants(control). Statistical differences in the nematode stages were found within and between treatments. The percentage of reduction in the nematode stages was comparatively more with using of Linseed mill wastes followed by castor seed mill wastes, then cress seed mill wastes. Regarding to the potato yield, all the evaluated amendments achieved significantly (p???0.05 and/or 0.01) increased, total contents of alkaloidal content as compared to untreated plants. On the other hand, all the evaluated amendments achieved significantly (p???0.05 and/or 0.01) decreased the solanine values as compared to untreated plants. These results indicate that some natural compounds may be used as natural nematicides in controlling M. arenaria nematode and improving the quality and yield of potato plants.     

Influence of one or two successive annual applications of organic fertilisers on the enzyme activity of a soil under barley cultivation

The effect of cow manure and two rates of addition of municipal solid waste (MSW) compost on the enzymatic activity of a soil supporting barley cultivation was studied and compared with mineral fertilisation (MF). The experiment was carried out in unirrigated land in field conditions for two years. One set of plots was fertilised only once, at the start of the experiment, while another set of plots was fertilised annually (before each sowing). In general, the organic amendments stimulated soil enzyme activity but mineral fertilisation did not. The annual addition of large quantities of MSW compost, in general, led to lower levels of enzyme activity than similar rates of amendment in the plots receiving a single addition, probably because of the toxic effect which the heavy metals incorporated with the MSW compost had on microbial development. In the second year, plot receiving a single application of organic amendment showed higher protease hydrolysing casein, beta-glucosidase and dehydrogenase activities than control or soil with mineral fertilisation. This implied that the addition of organic waste, and particularly MSW compost, had a catalysing effect in the soil which lasted for the following years. Barley yields obtained with organic amendments were, in general, similar to, or even higher, than those obtained with mineral fertilisation. The annual addition of high doses of compost had an inhibitory effect on enzyme activity and barley yield (compared with the results obtained with the low addition of compost) due to the negative effect of the heavy metals incorporated with the compost.     

Potential mineralization of nitrogen from organic wastes to ryegrass and wheat crops

Two-pot experiments with ryegrass and wheat plants were conducted in a Cambic Arenosol to test the reliability of N fate predicted by incubation experiments previously performed, with the same soil, to assess potentially mineralizable nitrogen from six organic wastes (municipal solid waste compost, secondary pulp mill sludge, horn meal, poultry manure, solid phase from pig slurry and composted pig manure). Two treatments, corresponding to 80 and 160 kgN/ha were tested, with or without mineral N fertilization. Experimental data obtained in the pot trials was consistent with nitrogen net mineralization trend observed in the aerobic incubations with all the wastes tested. Values of potentially mineralizable nitrogen (N(0)) from the equations obtained by model fitting, to the incubation data, were well correlated to ryegrass and wheat N uptake. Poultry manure was the most efficient N supplier to crops.     

Biochar co-compost improves nitrogen retention and reduces carbon emissions in a winter wheat cropping system

Organic amendments, such as compost and biochar, mitigate the environmental burdens associated with wasting organic resources and close nutrient loops by capturing, transforming, and resupplying nutrients to soils. While compost or biochar application to soil can enhance an agroecosystem's capacity to store carbon and produce food, there have been few field studies investigating the agroecological impacts of amending soil with biochar co-compost, produced through the composting of nitrogen-rich organic material, such as manure, with carbon-rich biochar. Here, we examine the impact of biochar co-compost on soil properties and processes by conducting a field study in which we compare the environmental and agronomic impacts associated with the amendment of either dairy manure co-composted with biochar, dairy manure compost, or biochar to soils in a winter wheat cropping system. Organic amendments were applied at equivalent C rates (8 Mg C ha⁻¹). We found that all three treatments significantly increased soil water holding capacity and total plant biomass relative to the no-amendment control. Soils amended with biochar or biochar co-compost resulted in significantly less greenhouse gas emissions than the compost or control soils. Biochar co-compost also resulted in a significant reduction in nutrient leaching relative to the application of biochar alone or compost alone. Our results suggest that biochar co-composting could optimize organic resource recycling for climate change mitigation and agricultural productivity while minimizing nutrient losses from agroecosystems.     

Agronomic properties of a volcanic ash-derived soil as affected by uncomposted organic materials

A sandy soil from the Vesuvian volcanic area, low in organic matter, was treated in pot experiments with raw farm-yard manure, green horse bean and wheat straw in order to study the effects of organic amendments on physical, chemical and biological properties. Farm-yard manure, rawly composted, caused a significant decrease of bulk density and improved water retention and the content of available phospate and potassium. It also showed the higher conversion co-efficient to stable humus during two years of the incubation period. It depressed the wheat seed germination and cotyledon growth for a one-year incubation period. Horse bean green manure was rapidly mineralized and did not remarkably improve the physical properties of the soil. Furthermore, it produced the lowest humus content and negatively affected seed development for eight months, but remarkably increased nutrient elements' contents (P and K). Wheat straw, added with N (2% urea form), improved humus formation and soil structure compared to horse bean; it increased K and P content and negatively affected seedling development for two months only.     

Phytotoxicity analysis of extracts from compost and their ability to inhibit soil-borne pathogenic fungi and reduce root-knot nematodes

Compost extracts are novel organic amendments, typically applied to suppress soil-borne diseases. This research evaluated the phytotoxicity of compost extracts and analyzed their ability to inhibit pathogenic fungal growth and reduce root-knot nematodes. The physical, chemical and biological characteristics of extracts from a pig manure and straw compost were analyzed. Three types of extracts were tested: direct extracts of compost (DEC), aerated fermentation extracts of compost (AFEC) and non-aerated fermentation extracts of compost (NAFEC). All compost extracts showed low phytotoxicity against lettuce and cress, but AFEC and NAFEC were more phytotoxic than DEC. All compost extracts significantly inhibited pathogenic fungal growth except for the fungus Rhizoctonia solania AG4. For two seasons, tomato root biomass of three compost extracts was 1.25–5.67 times greater than CK (water control), and AFEC and NAFEC showed the best tomato root growth promotion. The reduction ratio of root egg mass and density of soil nematodes were 34.51–87.77% and 30.92–51.37%, when applied with three compost extracts. The microbial population in compost extracts was considered to be the most significant factor of inhibition pathogenic fungal growth. No markedly correlations among bacterial community diversity, the inhibition of pathogenic fungal growth and the reduction of root-knot nematodes were observed. This information adds to the understanding of the growth-promoting and suppression effects of compost extracts and will help to enhance crop production.     

Use of composts to manage corky root disease in organic tomato production

Corky root disease of tomato caused by Pyrenochaeta lycopersici is an economically important disease in organic tomato production. This study aimed to evaluate the effects of various composts consisting of green manure, garden waste and horse manure against corky root disease through bioassay under greenhouse conditions, where soil naturally infested with P. lycopersici was used as a root substrate. The various composts were mixed at a rate of 20% (v/v) with the infested soil. Disease severity (measured as infected roots) in the unamended soil was compared with that in the soil–compost mixtures. One of the composts made from garden waste significantly reduced the disease, whereas horse manure compost significantly stimulated it. Lower concentrations of NH₄‐N and total carbon and a higher concentration of Ca in the substrate were correlated with lower level of corky root disease. Addition of green manure or garden waste compost to the infested soil increased total microbial activity or population density of copiotrophic bacteria and actinomycetes, respectively. However, increased microbial activity or microbial population in soil–compost mixtures was not associated with a reduction in corky root disease severity in the present study.     

不同有机废弃物改良新复垦耕地的综合效果评价

由废弃地整理复垦形成的耕地存在土壤有机质和有效养分低、土壤板结、微生物活性弱和土壤耕作性状不良等问题,快速、有效地提高土壤肥力质量是全面提升该类耕地质量和生产性能的重要组成部分.本文通过田间小区试验研究了城郊有机废弃物对新复垦耕地土壤培肥的综合效果,并比较了不同类型城郊有机废弃物在培育耕地质量方面的差异.试验设置了施用等量猪粪、鸡粪、水稻秸秆、蔬菜收获残留物、城市污泥、沼渣、猪粪/水稻秸秆堆肥、生活垃圾堆肥和对照（不施有机肥）9个处理（年用量30 t·hm^-2）,连续进行3年的定点试验.结果表明： 施用任何有机物对改善土壤肥力均有明显的作用.其中,提升土壤碳库管理指数以施用猪粪、鸡粪、猪粪/水稻秸秆堆肥、水稻秸秆和沼渣的效果最为显著;增加土壤水稳定性团聚体和降低土壤容重以施用猪粪/水稻秸秆堆肥和沼渣的效果最佳;施用污泥、猪粪/水稻秸秆堆肥和生活垃圾堆肥可增强土壤保蓄能力;施用猪粪、鸡粪和猪粪/水稻秸秆堆肥对增加土壤有效态养分的效果最为明显;各类有机物均显著提高了土壤微生物数量和酶活性.长期施用污泥、生活垃圾堆肥及畜禽粪存在着土壤重金属污染的风险,但短期施用对土壤环境质量影响不明显.总体上,对土壤肥力的改善效果由大至小依次为：猪粪/水稻秸秆堆肥>鸡粪>猪粪>沼渣>生活垃圾堆肥>水稻秸秆>城市污泥>蔬菜收获残留物;对土壤的相对污染程度由大至小为：城市污泥>生活垃圾堆肥>猪粪>鸡粪>沼渣>猪粪/水稻秸秆堆肥>蔬菜收获残留物>水稻秸秆.     

The effects of olive mill waste compost and poultry manure on the availability and plant uptake of nutrients in a highly saline soil

The effects of a compost (produced from by-products of the olive oil industry) and a poultry manure on mineral ion solubility and exchangeability in a highly saline agricultural soil (electrical conductivity for a 1:5 soil:water extract=1.85 dS m(-1)) from Murcia (SE Spain) were studied. The organic amendments did not change significantly the soil electrical conductivity or the soluble Na(+), Ca(2+) or Mg(2+). Only soluble K(+) increased, due to the K(+) supplied by the amendments. The cation exchange capacity increased in treated soils, the exchange complex being mainly saturated with Ca(2+), Mg(2+) and K(+). However, Na(+) was not retained in the exchange sites, and the sodium absorption ratio remained low. The compost and manure increased markedly the shoot growth of the salt-tolerant Beta maritima L. (sea beet) and Beta vulgaris L. (sugar beet). For B. maritima, this seemed to be related to decreases in the shoot concentrations of Na(+) and Cl(-) and increases in K(+) and H(2)PO(4)(-). In the case of B. vulgaris, increases in shoot H(2)PO(4)(-) and B and, for manure-treated soil, a decrease in shoot Na(+) may have been involved. Cultivation of tomato (Lycopersicon esculentum Mill. cv. Moneymaker) in the soil used previously for B. vulgaris indicated that the effects of the manure on tissue cation concentrations were longer-lasting than those of the compost.     

Growth response of selected vegetable crops to spent mushroom compost application in a controlled environment

Summary Snap bean, cucumber, radish, spinach, and tomato seedlings and plants were grown in soils amended with 0, 10, 20, 30 and 50% spent mushroom compost (SMC) under greenhouse conditions. While total seedling emergence was not affected by the addition of SMC, the rate of seedling emergence was delayed. Increased growth was observed in the range of 30 to 50% SMC. The elemental content in seedling tissue indicated an antagonism among K, Ca, and Mg for ion uptake. Increased plant growth and yield were obtained with addition of 20 to 30% SMC; those grown at 50% SMC exhibited some stunting. The limiting factor in the use of SMC appeared to be its high soluble salts content.     

Comparison of Suppressiveness of Vermicomposts Produced from Animal Manures and Sewage Sludge against Phytophthora nicotianae Breda de Haan var. nicotianae

The degrees of suppression produced by vermicomposts produced from cattle manure, sheep manure or horse manure and by vermicomposts produced from sewage sludge were compared in greenhouse experiments. The effect of these vermicomposts on the growth and infection of tomato seedlings by Phytophthora nicotianae var. nicotianae was studied. The density of the pathogen and the number of micro-organisms in container media amended with vermicomposts were also analysed. The vermicomposts produced from animal manure significantly reduced the infection of tomato seedlings by the pathogen. The density of P. nicotianae in media which included these vermicomposts was similar to that in infested peat substrate (control treatment). The vermicomposts from sewage sludge did not protect tomato seedlings against P. nicotianae . They also significantly inhibited growth of the plants as well as decreasing the density of the pathogen in container media. In general the vermicomposts had no effect on total number of micro-organisms in potting media compared with control. They only had higher levels of actinomycetes but this did not appear to correspond with their ability to suppress the pathogen.     

Long term effects of manure, charcoal and mineral fertilization on crop production and fertility on a highly weathered Central Amazonian upland soil

Application of organic fertilizers and charcoal increase nutrient stocks in the rooting zone of crops, reduce nutrient leaching and thus improve crop production on acid and highly weathered tropical soils. In a field trial near Manaus (Brazil) 15 different amendment combinations based on equal amounts of carbon (C) applied through chicken manure (CM), compost, charcoal, and forest litter were tested during four cropping cycles with rice (Oryza sativa L.) and sorghum (Sorghum bicolor L.) in five replicates. CM amendments resulted in the highest (P < 0.05) cumulative crop yield (12.4 Mg ha⁻¹) over four seasons. Most importantly, surface soil pH, phosphorus (P), calcium (Ca), and magnesium (Mg) were significantly enhanced by CM. A single compost application produced fourfold more grain yield (P < 0.05) than plots mineral fertilized in split applications. Charcoal significantly improved plant growth and doubled grain production if fertilized with NPK in comparison to the NPK-fertilizer without charcoal (P < 0.05). The higher yields caused a significantly greater nutrient export in charcoal-amended fields, but available nutrients did not decrease to the same extent as on just mineral fertilized plots. Exchangeable soil aluminum (Al) was further reduced if mineral fertilizer was applied with charcoal (from 4.7 to 0 mg kg⁻¹). The resilience of soil organic matter (SOM) in charcoal amended plots (8 and 4% soil C loss, mineral fertilized or not fertilized, respectively) indicates the refractory nature of charcoal in comparison to SOM losses over 20 months in CM (27%), compost amended (27%), and control plots (25% loss).     

Management considerations for organic waste use in agriculture

Organic wastes are utilized in agriculture mainly for improving the soil physical and chemical properties and for nutrient sources for growing crops. The major source of organic waste used in agriculture is animal manure, but small amounts of food processing and other industrial wastes (along with municipal wastes) are also applied to land. In the last 35 years, and especially in the last 10 years, there have been increasing environmental regulations affecting farms that have resulted in more animal manure treatment options, and thus affecting characteristics of residues that are subsequently applied to land. Farms are being assessed for nutrient balances, with the entire nutrient and manure management system evaluated for best management alternatives. Because of inadequate available land on the animal farm in some cases, organic wastes must be treated and/or transported to other farms, or utilized for horticultural or other uses. This paper discusses the various factors and challenges for utilizing organic wastes in agriculture.     

On-farm production of AM fungus inoculum in mixtures of compost and vermiculite

On-farm production of arbuscular mycorrhizal (AM) fungus inoculum can reduce the cost of the inoculum and increase utilization of this symbiosis in plant production. Bahiagrass (Paspalum notatum Flugge) seedlings, colonized by AM fungi, were transplanted into raised bed enclosures. Media within the enclosures was vermiculite mixed with either field soil or yard clippings compost in Experiment I and vermiculite mixed with yard clippings compost or dairy manure/leaf compost in Experiment II. Compost and vermiculite mixtures yielded more propagules of AM fungi than soil-based mixtures in Experiment I. Growth of plants in a 1:4 (v/v) mixture of yard clippings compost and vermiculite produced more inoculum (503 propagules cm(-3)) than growth in 1:9 and 1:99 (v/v) mixtures (240 and 42 propagules cm(-3), respectively). Water, inorganic nutrient solution minus P, and fish protein digest were added to inoculum production enclosures in Experiment II. Results indicated that supplemental nutrient addition was unnecessary. This method produces a concentrated inoculum of AM fungi in a form readily used as an amendment to horticultural potting media for the production of vegetable seedlings.     

Recycling of manure nutrients: use of algal biomass from dairy manure treatment as a slow release fertilizer

An alternative to land spreading of manure is to grow crops of algae on the N and P present in the manure and convert manure N and P into algal biomass. The objective of this study was to evaluate the fertilizer value of dried algal biomass that had been grown using anaerobically digested dairy manure. Results from a flask study using two soils amended with algal biomass showed that 3% of total algal nitrogen (N) was present as plant available N at day 0. Approximately 33% of algal N was converted to plant available N within 21 days at 25 degrees C in both soils. Levels of Mehlich-3 extractable phosphorus (P) in the two soils rose with increasing levels of algal amendment but were also influenced by existing soil P levels. Results from plant growth experiments showed that 20-day old cucumber and corn seedlings grown in algae-amended potting mix contained 15-20% of applied N, 46-60% of available N, and 38-60% of the applied P. Seedlings grown in algae-amended potting mixes were equivalent to those grown with comparable levels of fertilizer amended potting mixes with respect to seedling dry weight and nutrient content. These results suggest that dried algal biomass produced from treatment of anaerobically digested dairy manure can substitute for commercial fertilizers used for potting systems.     

Effectiveness of municipal waste compost and its humic fraction in suppressing Pythium ultimum

The effect of addition of a municipal solid waste (MSW) compost and its water-soluble and humic fraction to suppress the effect of Pythium ultimum on pea plants was studied and compared with that of a chemical pesticide (metalaxyl). The biotic and abiotic characteristics of compost involved in the biocontrol effects of these materials were also evaluated. The addition into soil of whole composts and their humic fractions reduced the effect of the pathogen on pea plants, significantly reducing the number of root lesions and Pythium populations and avoiding reductions of plant growth. The greatest pathogen suppression was achieved with the chemical pesticide. However, it also caused a significant decrease in the number of nontarget bacteria and fungi and on beneficial soil microorganisms such as Trichoderma and Pseudomonas. Addition of organic amendments increased population size of nontarget and specific biocontrol microorganisms. The humic fraction showed similar results to compost. All this suggests that metalaxyl has a nonspecific effect, producing adverse effects on aspects of soil quality. This was avoided if the chemical pesticide was reduced and replaced by organic amendments such as an MSW compost or its humic fraction.     

Effectiveness of biochar and compost on improving soil hydro-physical properties,crop yield and monetary returns in inceptisol subtropics

Organic manures in combination with biochar might improve efficacy of biochar in improving soil functions related to hydro-physical properties and a field experiment was conducted over the course of two years with two levels of biochar @ 0 and 2tha⁻¹ and four levels of compost (100% recommended dose of N through farm yard manure, 100% recommended dose of N through vermicompost, 50% recommended dose of N through farm yard manure, and vermicompost each, and unfertilized control). Each treatment was replicated three times in factorial randomized block design (RBD). The objective of this research was to determine the effects of biochar and compost on soil hydro-physical properties, water use efficiency, monetary returns and yield of knolkhol (Brassica oleracea var. gongyloides L.) under sub-tropics of North West India. Compared with no-biochar, application of biochar significantly increased knolkhol yield by 7.8% and soil properties (infiltration rate, aggregate stability, maximum water holding capacity and hydraulic conductivity). Similarly, integration of compost significantly enhanced the soil water retention, aggregate stability, hydraulic conductivity and crop yield and gave highest infiltration rate, water retention, hydraulic conductivity and crop yield under M3 (50 % N through farm yard manure, +50 % N through vermicompost) treatment. Furthermore, synergetic positive effect of biochar and compost were noted for soil infiltration rate (4–38%), water retention (0.9–13.7%), aggregate stability (6–10.7%) and yield (6–11.9%) over the sole application of compost. Combined use of farm yard manure, and vermicompost accompanied by biochar resulted in highest net returns and B:C ratio. Biochar in combination with farm yard manure, and vermicompost can enhance soil hydraulic properties resulting in increased crop yield and maximum monetary returns under subtropical conditions.     

Vermicompost derived from mushroom residues improves soil C/P cycling,bacterial community, and fungal abundance

The utilization of agricultural waste organic materials through composting technology has gained significant traction in agricultural production as an effective means of crop nutrient management. However, the differences in the impact of organic amendments prepared by traditional composting and vermicomposting on soil properties still deserve further research. Based on field experiments conducted in greenhouse, compared to chemical fertilizer treatments as control, we utilized traditional compost (OF) and vermicompost (VcF) derived from agricultural organic waste edible mushroom bran and cow manure (2:8). Variations in soil physiochemical properties, activities of soil enzymes related C and P cycling, abundances and diversities of bacterial 16S rRNA and fungal ITS gene at total DNA level were analyzed. Both compost treatments enhanced soil organic carbon, soil total phosphorus, and soil available P content significantly and also increased the activities of soil α-glucosidase, β-glucosidase, acid phosphomonoesterase, and alkaline phosphomonoesterase significantly. The above results suggested that soil C and P transformations were stimulated effectively by both organic amendments. OF and VcF increased the fungal ITS absolute abundances significantly while diversity indices of soil bacterial community increased significantly under both treatments. Correlation analysis indicated that bacterial community composition was strongly correlated with several soil property indexes while fungal community composition was only significantly correlated with soil total phosphorous content. In conclusion, similar to traditional compost, vermicompost significantly improved soil nutrient cycling (especially C and P aspects). In terms of soil microbes, bacteria and fungi showed different responding mechanism to vermicompost: bacteria adjust microbial structure, while fungi tend to proliferated. In consideration of the advantages of vermicompost in technology and economic cost, it could be applied in the subsequent agricultural production more frequently.