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A field experiment was executed during the Rabi season at CSKHPKV, Palampur, to evaluate the effects of different weed control and nitrogen management practices on weed control, yield, nutrient content, dehydrogenase activity and the oil content of linseed. The experiment was set up in the RBD with 3 replicates consisting of fifteen treatment combinations comprising five weed controls (viz. isoproturon 1.25 kg/ha, clodinafop propargyl + metsulfuron methyl 60+4 g/ha, clodinafop propargyl + carfentrazone ethyl 60+10 g/ha, hand weeding twice and weedy check) and three nitrogen levels (i.e., FYM 5 t/ha, 75 and 100% RDN). The soil texture at the experimental site was silty clay loam, acidic and medium in available nitrogen, phosphorus and potassium. The results showed that the use of clodinafop propargyl + metsulfuron methyl 60+4 g/ha significantly decreased the count and dry matter content of the total weeds at the maximum count and dry matter stage. However, 1.25 kg/ha isoproturon was likewise effective at significantly reducing the total weed count and was the next best at reducing the dry matter content of the total weeds. The effective control of weeds by the application of isoproturon at 1.25 kg/ha (Post.) significantly increased plant growth without any toxicity, which contributed to increased nutrient uptake and increased seed, straw and oil yields in the linseed treatment. Among the nitrogen levels, a considerably lower count and dry matter content of the total weeds were recorded in the 100% RDN plots, followed by the 75% RDN treatment. The application of 100% RDN resulted in significantly greater NPK uptake than did the other treatments, which contributed to considerably greater seed, straw and oil yields. Thus, the application of isoproturon at 1.25 kg/ha (Post.) with 100% RDN was proven to be the most effective at realizing higher seed and oil yields with better weed control in linseed plants grown under utera conditions.

This study evaluated the changes in microbial activity in the course of time following the joint application of the herbicides S-metolachlor, foramsulfuron, and thiencarbazone-methyl to two soils (S1 and S2) under conventional tillage (CT) and non-tillage (NT) management in field conditions. The biochemical parameters of soil respiration (RES), dehydrogenase activity (DHA), microbial biomass (BIO), and the phospholipid fatty acid (PLFA) profile were determined at 1, 34, and 153 days during herbicide dissipation. In the absence of herbicides, all microbial activity was higher under NT than CT conditions, with higher or similar mean values for S1 compared to S2. A continuous decrease was detected for RES, while DHA and BIO recovered over time. In the presence of herbicides, a greater decrease in all microbial activity was detected, although the changes followed a similar trend to the one recorded without herbicides. In general, a greater decrease was observed in S1 than in S2, possibly due to the higher adsorption and/or lower bioavailability of herbicides in this soil with a higher organic carbon content. The decrease was also greater under CT conditions than under NT conditions because the herbicides can be intercepted by the mulch, with less reaching the soil. These changes involved evolution of the structure of the microbial community.

Oxime cholinesterase reactivators (oximes) are used to counteract organophosphate intoxication. Charged oximes are administered via intramuscular or intravenous injection when the majority of dose is unmetabolized and is excreted as urine. In this study, the effects of selected double charged oximes were determined in the HK-2 cell line as a model for renal toxicity screening. Some effects on dehydrogenase activity were found for obidoxime, asoxime (syn. HI-6), K027, and K203. The effects of K868 and K869 were found to be unreliable due to rapid degradation of both chlorinated oximes in the assay medium, resulting for K868 in an isoxazole-pyridinium product., Oximové reaktivátory cholinesterázy (oximy) se používají k potlačení intoxikace organofosfáty. Nabité oximy se podávají intramuskulární nebo intravenózní injekcí, dokud není většina z podané dávky nemetabolizována a je vylučována močí. V této studii byly účinky vybraných oximů s dvojitým nábojem stanoveny v buněčné linii HK-2 jako modelu pro screening renální toxicity. Některé účinky na aktivitu dehydrogenázy byly zjištěny u obidoximu, asoximu (syn. HI-6), K027 a K203. Bylo zjištěno, že účinky K868 a K869 jsou nespolehlivé v důsledku rychlé degradace obou chlorovaných oximů v testovacím médiu, což má za následek pro K868 isoxazol-pyridiniový produkt.

Savremena poljoprivredna proizvodnja podrazumeva neracionalnu upotrebu velikih količina pesticida, što narušava kvalitet i plodnost poljoprivrednih zemljišta. Visoke koncentracije teških metala u zemljištu predstavljaju veliki rizik po agroekosisteme i živi svet, a najčešći uzrok zagađenja je antropogeni uticaj i neadekvatna primena hemijskih sredstava. Usled dugotrajne i intenzivne primene fungicida na bazi bakra, zemljišta pod vinogradima posebno su ugrožena od zagađenja ovim metalom. Primena fungicida na bazi bakra, često je povezana sa smanjenom aktivnošću mikroorganizama i promenama u strukturi mikrobnih zajednica. U cilju globalne procene stanja zemljišta pod vinogradima ispitane su fizičke, hemijske i mikrobiološke osobine zemljišta i u vinogradarskom rejonu Vranje. Brojnost mikroorganizama i dehidrogenazna aktivnost u uzorcima sa kontrolnih parcela ukazuju da način iskorišćenja parcele nije uticao na mikrobiološke parametre zemljišta. Raznovrsnost, brojnost i aktivnost mikroorganizama zavisili su prvenstveno od pH reakcije i fizičko-hemijskih osobina zemljišta., Modern agricultural production implies irrational use of large amounts of pesticides, which impairs the quality and fertility of agricultural soil. High concentrations of heavy metals in the soil pose a great risk to agroecosystems and wildlife, and the most common cause of pollution is anthropogenic impact and inadequate use of chemicals. Due to long-term and intensive application of copper-based fungicides, soils under vineyards is particularly vulnerable to pollution by this metal. The use of copper-based fungicides is often associated with reduced activity of microorganisms and changes in the structure of microbial communities. In order to globally assess the condition of the soil under vineyards physical, chemical and microbiological properties of the soil in the wine-growing region of Vranje were examined. The abundance of microorganisms and dehydrogenase activity in the control plots indicate that the method of plot utilization did not affect the microbiological parameters of the soil. The diversity, abundance and activity of microorganisms depended primarily on the pH reaction and physical and chemical properties of the soil.

Digestates are commonly used as organic inputs in agriculture. This study aimed to answer four questions: (1) What are the immediate and longer-term impacts of digestates on soil microbial activity?; (2) How much of the digestates’ carbon is mineralized within the first months? (3) How do the nitrogen, lignin, cellulose, and hemicellulose contents of digestates influence microbial activity and carbon mineralization? (4) How does the soil type influence mineralization? To investigate this, dehydrogenase activity (DHA) was measured in a field trial and in laboratory experiments with five digestates (DGs), cattle slurry, and cattle manure. DHA measurements were supplemented with soil respiration experiments using two different soils. DHA was significantly increased by all organic inputs, but decreased back to the control level within seven months under field conditions. Twenty percent to 44% of the organic carbon (Corg) in the digestates was converted to CO2 after 178 days. Soil respiration was significantly negatively correlated to lignin content (r = −0.82, p < 0.01) and not correlated to nitrogen, cellulose, or hemicellulose content. On the basis of equal carbon application, slurry promoted soil respiration and DHA more strongly than digestates in the short term., Peer Reviewed

Within a 30-day incubation laboratory study, the polycyclic aromatic hydrocarbon (PAH) degradation profile of two bacteria, Planomicrobium sp. RNP01 and Rhodococcus sp. RNP05 were studied by three microtiter plate assays to reveal the combination of certain biological and biochemical characteristics which are reliable indicators in evaluation of bacterial biodegradation abilities. The three assays, which are hydrocarbon growth assay, 2,6-DCPIP assay and dehydrogenase activity assay revealed that Rhodococcus sp. RNP05 exhibited better potential for PAH degradation than Planomicrobium sp. RNP01. Differences between initial and final optical density and specific growth rate constants were significantly higher (r = 0.995, P < 0.05) in case of Rhodococcus sp. RNP05 on all tested substrates, as compared to Planomicrobium sp. RNP01. This was confirmed by GC-FID analyses. Dehydrogenase activity of Rhodococcus sp. RNP05 was higher (r = 0.9995, P < 0.05) than Planomicrobium sp. RNP01 and correlated positively with the hydrocarbon growth assay (r = 0.999, P < 0.05, for Rhodococcus sp. RNP05, r = 0.986, P < 0.05 for Planomicrobium sp. RNP01). This study has shown that the combination of these assays could be used for determining the bioremediation potential of PAHs in petroleum contaminated soil with the ability of screening a large number of bacterial strains., Degradacija policikličnih aromatičnih ugljovodonika (polycyclic aromatic hydrocarbons - PAH) ispitivana je testovima u mikrotitar pločama pomoću dva bakterijska soja Planomicrobium sp. RNP01 i Rhodococcus sp. RNP05, u periodu od 30 dana. Rezultati ispitivanja su ukazali da se kombinacijom određenih bioloških i biohemijskih karakteristika mogu kreirati dobri indikatori u proceni bakterijskog degradacionog potencijala. Tri testa, 2,6-DCPIP test, test dehidrogenazne aktivnosti i test rasta na ugljovodonicima pokazali su da Rhodococcus sp. RNP05 ima veći potencijal za degradaciju PAH jednjenja u odnosu na Planomicrobium sp. RNP01. Razlike u početnoj i krajnjoj optičkoj gustini i specifične konstante rasta bile su značajno više (r = 0,995, P < 0,05) u testu sa Rhodococcus sp. RNP05 na svim testiranim supstratima, u poređenju sa Planomicrobium sp. RNP01, a dobijeni rezultati su potvrđeni gasno-hromatogafskom-FID analizom. Dehidrogenazna aktivnost soja Rhodococcus sp. RNP05 bila je viša u odnosu na Planomicrobium sp. RNP01 (r = 0,9995, P < 0,05) i u pozitivnoj korelaciji sa testom rasta na ugljovodonicima (r = 0,999, P < 0,05, za Rhodococcus sp. RNP05, r = 0,986, P < 0,05 za Planomicrobium sp. RNP01). Rezultati prikazanog istraživanja ukazuju na to da se kombinacija ovih testova može koristiti za određivanje bioremedijacionog potencijala za razgradnju PAH jedinjenja u zemljištu zagađenim naftom, pri čemu se dobija i mogućnost testiranja velikog broja bakterijskih sojeva.

This article was supported by the German Research Foundation (DFG) and the Open Access Publication Fund of Humboldt-Universität zu Berlin., Digestates are commonly used as organic inputs in agriculture. This study aimed to answer four questions: (1) What are the immediate and longer-term impacts of digestates on soil microbial activity?; (2) How much of the digestates’ carbon is mineralized within the first months? (3) How do the nitrogen, lignin, cellulose, and hemicellulose contents of digestates influence microbial activity and carbon mineralization? (4) How does the soil type influence mineralization? To investigate this, dehydrogenase activity (DHA) was measured in a field trial and in laboratory experiments with five digestates (DGs), cattle slurry, and cattle manure. DHA measurements were supplemented with soil respiration experiments using two different soils. DHA was significantly increased by all organic inputs, but decreased back to the control level within seven months under field conditions. Twenty percent to 44% of the organic carbon (Corg) in the digestates was converted to CO2 after 178 days. Soil respiration was significantly negatively correlated to lignin content (r = −0.82, p < 0.01) and not correlated to nitrogen, cellulose, or hemicellulose content. On the basis of equal carbon application, slurry promoted soil respiration and DHA more strongly than digestates in the short term., Peer Reviewed

Within a 30-day incubation laboratory study, the polycyclic aromatic hydrocarbon (PAH) degradation profile of two bacteria, Planomicrobium sp. RNP01 and Rhodococcus sp. RNP05 were studied by three microtiter plate assays to reveal the combination of certain biological and biochemical characteristics which are reliable indicators in evaluation of bacterial biodegradation abilities. The three assays, which are hydrocarbon growth assay, 2,6-DCPIP assay and dehydrogenase activity assay revealed that Rhodococcus sp. RNP05 exhibited better potential for PAH degradation than Planomicrobium sp. RNP01. Differences between initial and final optical density and specific growth rate constants were significantly higher (r = 0.995, P < 0.05) in case of Rhodococcus sp. RNP05 on all tested substrates, as compared to Planomicrobium sp. RNP01. This was confirmed by GC-FID analyses. Dehydrogenase activity of Rhodococcus sp. RNP05 was higher (r = 0.9995, P < 0.05) than Planomicrobium sp. RNP01 and correlated positively with the hydrocarbon growth assay (r = 0.999, P < 0.05, for Rhodococcus sp. RNP05, r = 0.986, P < 0.05 for Planomicrobium sp. RNP01). This study has shown that the combination of these assays could be used for determining the bioremediation potential of PAHs in petroleum contaminated soil with the ability of screening a large number of bacterial strains., Degradacija policikličnih aromatičnih ugljovodonika (polycyclic aromatic hydrocarbons - PAH) ispitivana je testovima u mikrotitar pločama pomoću dva bakterijska soja Planomicrobium sp. RNP01 i Rhodococcus sp. RNP05, u periodu od 30 dana. Rezultati ispitivanja su ukazali da se kombinacijom određenih bioloških i biohemijskih karakteristika mogu kreirati dobri indikatori u proceni bakterijskog degradacionog potencijala. Tri testa, 2,6-DCPIP test, test dehidrogenazne aktivnosti i test rasta na ugljovodonicima pokazali su da Rhodococcus sp. RNP05 ima veći potencijal za degradaciju PAH jednjenja u odnosu na Planomicrobium sp. RNP01. Razlike u početnoj i krajnjoj optičkoj gustini i specifične konstante rasta bile su značajno više (r = 0,995, P < 0,05) u testu sa Rhodococcus sp. RNP05 na svim testiranim supstratima, u poređenju sa Planomicrobium sp. RNP01, a dobijeni rezultati su potvrđeni gasno-hromatogafskom-FID analizom. Dehidrogenazna aktivnost soja Rhodococcus sp. RNP05 bila je viša u odnosu na Planomicrobium sp. RNP01 (r = 0,9995, P < 0,05) i u pozitivnoj korelaciji sa testom rasta na ugljovodonicima (r = 0,999, P < 0,05, za Rhodococcus sp. RNP05, r = 0,986, P < 0,05 za Planomicrobium sp. RNP01). Rezultati prikazanog istraživanja ukazuju na to da se kombinacija ovih testova može koristiti za određivanje bioremedijacionog potencijala za razgradnju PAH jedinjenja u zemljištu zagađenim naftom, pri čemu se dobija i mogućnost testiranja velikog broja bakterijskih sojeva.

Biobeds bioremediation systems are effectively used for minimizing pesticide point-source contamination. For keeping the biobed effectiveness, its biomixture needs to be replaced every so often. The exhausted biomixtures can contain pesticide residues and so they require a special treatment before being discharged into the environment. In this study, we explore the potential of vermiremediation for cleaning up biobed biomixtures contaminated with pesticides. Two biomixtures composed of soil:peat:straw (P) and soil:vermicompost of wet olive cake: olive tree pruning (O), contaminated with high loads of four pesticides, were used. Vermicomposting was carried out by Eisenia fetida earthworms for 12 weeks. Results showed that 50% and 70% of the earthworms colonized the contaminated P and O biomixtures, respectively, but the number of alive earthworms decreased with time just as their weight. The colonization of biomixtures did not significantly affect the dissipation of imidacloprid and tebuconazole, but increased 1.4 fold the dissipation of oxyfluorfen in both biomixtures and that of diuron in biomixture P. Although the presence of high loads of pesticides and the composition of the biomixtures limited the vermiremediation, satisfactory results were obtained for diuron and oxyfluorfen. Complementing vermiremediation with other remediation practices could improve the efficiency of this technology

Istraživanje je obuhvatilo utvrđivanje brojnosti pojedinih sistematskih i fizioloških grupa mikroorganizama, kao i određivanje aktivnosti enzima dehidrogenaze u zemljištima vinograda. Mikrobiološke karakteristike zavisile su od fizičkih i hemijskih osobina zemljišta na pojedinim parcelama. Najpovoljniji uslovi za razvoj i aktivnost mikroorganizama karakterisali su zemljišta neutralne i slabo alkalne reakcije, dok je najmanja brojnost većine mikroorganizama i enzimatska aktivnost zabeležena u kiselim zemljištima. Prisustvo lakopristupačnog bakra iznad 50 mg/kg zabeleženo je samo u 4% ispitivanih zemljišta, stoga dobijeni rezultati ne mogu potvrditi uticaj bakra na mikrobiološke karakteristike., The study included the determination of the abundance of specific systematic and physiological groups of microorganisms, as well as the determination of the activity of the enzyme dehydrogenase in vineyard soils. Microbiological characteristics depended on the physical and chemical properties of the soil in individual plots. The most favorable conditions for the development and activity of microorganisms were characterized by soils of neutral and slightly alkaline reactions, while the lowest abundance of most microorganisms and enzymatic activity was recorded in acidic soils. The presence of readily available copper above 50 mg / kg was recorded in only 4% of the tested soils, therefore the results obtained cannot confirm the influence of copper on microbial characteristics.

Soil is a non-renewable resource, and its degradation compromises human health, 2 natural ecosystems, and even the climate. The application of organic amendments and 3 herbicides is commonplace in agriculture, and their impact on soil fertility needs to be 4 evaluated. Therefore, the objective was to evaluate the effect on soil microbial activity 5 and structure of amendments, sewage sludge (SS) and green compost (GC), and the rate 6 of herbicide pethoxamid applied (2, 10 and 50 mg kg-1). Herbicide dissipation kinetics, 7 soil dehydrogenase activity (DHA) and the profile of phospholipid-derived fatty acids 8 (PLFAs) extracted from the soil have been determined in unamended (S) and amended 9 (S+SS and S+GC) soils. The dissipation curves of pethoxamid applied at the three rates 10 closely fitted a single first order kinetics model in all the soils. The dissipation rate 11 decreased with the rate applied in the order 2 mg kg-1 > 10 mg kg-1 > 50 mg kg-1 in 12 unamended and amended soils. However, the half-life or time required for 50% 13 dissipation (DT50) of pethoxamid was not significantly different in unamended and 14 amended soils when applied at 2 and 10 mg kg-1, but it was lower in the amended soils 15 than in the unamended one when the herbicide was applied at the highest rate. The 16 highest DHA mean values were obtained in S+GC treated with pethoxamid at 2, 10 and 17 50 mg kg-1; however, DHA was lower in S+SS than in S. Peak DHA values were 18 observed in S and S+GC soils treated with pethoxamid at 2 mg kg-1 at 15 days of 19 incubation, and in S, S+GC and S+SS treated with the herbicide at 10 and 50 mg kg-1 at 20 35 days of incubation. These peak DHA values are close to 50% of herbicide 21 dissipation. A statistical analysis of the PLFA results has revealed significant effects for 22 sampling time in all the soils, for the pethoxamid rate, and for the interaction between 23 time and pethoxamid rate only in S+GC and S+SS. The application of organic 24 amendments

Certain agricultural practices, such as the repeated application of herbicides or organic amendments to soil, can influence herbicide dissipation. This research has studied the effects of two repeated applications of mesotrione, pethoxamid, and triasulfuron on their dissipation rates in unamended soil (S) and soil amended with green compost (S+GC) or sewage sludge (S+SS). The dissipation experiment has also included an evaluation of the adsorption of the three herbicides by soils and of changes in soil dehydrogenase activity (DHA). The adsorption of the three herbicides by amended soils (Kf range 0.83–2.98) was higher than by unamended soil (Kf range 0.20–0.64). The adsorption coefficients (Kd) of mesotrione and triasulfuron were higher for S+SS, while that of pethoxamid was higher for S+GC, but no relationship between values for the time to 50% degradation (DT50) and adsorption coefficients could be determined. The repeated application of mesotrione decreased its dissipation rate in unamended soil (DT50 increased from 4.75 to 8.15 days) and amended soils (DT50 increased from 11.7 to 28.2 days in S+GC and from 17.7 to 37.9 in S+SS), whereas the repeated application of pethoxamid increased its dissipation rate in all the treatments, and the rate for triasulfuron increased only in amended soils. The highest DT50 values for pethoxamid (12.3 days) and triasulfuron (57.1 days) were in S+GC, and the lowest in S+SS (8.35 and 24.7 days). Soil DHA was stimulated by the presence of GC in the soil and by the first application of mesotrione. The second application of mesotrione and pethoxamid positively affected soil DHA, but this did not occur for triasulfuron. The repeated applications of herbicides and soil organic amendments have different effects on herbicide dissipation, adsorption, and soil DHA, and they should be taken into account when assessing soil quality and other potential environmental implications of pesticide use.

Certain agricultural practices, such as the repeated application of herbicides or organic amendments to soil, can influence herbicide dissipation. This research has studied the effects of two repeated applications of mesotrione, pethoxamid, and triasulfuron on their dissipation rates in unamended soil (S) and soil amended with Green compost (S+GC) or sewage sludge (S+SS). The dissipation experiment has also included an evaluation of the adsorption of the three herbicides by soils and of changes in soil dehydrogenase activity (DHA). The adsorption of the three herbicides by amended soils (Kf range 0.83–2.98) was higher than by unamended soil (Kf range 0.20–0.64). The adsorption coefficients (Kd) of mesotrione and triasulfuron were higher for S+SS, while that of pethoxamid was higher for S+GC, but no relationship between values for the time to 50% degradation (DT50) and adsorption coefficients could be determined. The repeated application of mesotrione decreased its dissipation rate in unamended soil (DT50 increased from 4.75 to 8.15 days) and amended soils (DT50 increased from 11.7 to 28.2 days in S+GC and from 17.7 to 37.9 in S+SS), whereas the repeated application of pethoxamid increased its dissipation rate in all the treatments, and the rate for triasulfuron increased only in amended soils. The highest DT50 values for pethoxamid (12.3 days) and triasulfuron (57.1 days) were in S+GC, and the lowest in S+SS (8.35 and 24.7 days). Soil DHA was stimulated by the presence of GC in the soil and by the first application of mesotrione. The second application of mesotrione and pethoxamid positively affected soil DHA, but this did not occur for triasulfuron. The repeated applications of herbicides and soil organic amendments have different effects on herbicide dissipation, adsorption, and soil DHA, and they should be taken into account when assessing soil quality and other potential environmental implications of pesticide use.

Certain agricultural practices, such as the repeated application of herbicides or organic amendments to soil, can influence herbicide dissipation. This research has studied the effects of two repeated applications of mesotrione, pethoxamid, and triasulfuron on their dissipation rates in unamended soil (S) and soil amended with green compost (S+GC) or sewage sludge (S+SS). The dissipation experiment has also included an evaluation of the adsorption of the three herbicides by soils and of changes in soil dehydrogenase activity (DHA). The adsorption of the three herbicides by amended soils (Kf range 0.83–2.98) was higher than by unamended soil (Kf range 0.20–0.64). The adsorption coefficients (Kd) of mesotrione and triasulfuron were higher for S+SS, while that of pethoxamid was higher for S+GC, but no relationship between values for the time to 50% degradation (DT50) and adsorption coefficients could be determined. The repeated application of mesotrione decreased its dissipation rate in unamended soil (DT50 increased from 4.75 to 8.15 days) and amended soils (DT50 increased from 11.7 to 28.2 days in S+GC and from 17.7 to 37.9 in S+SS), whereas the repeated application of pethoxamid increased its dissipation rate in all the treatments, and the rate for triasulfuron increased only in amended soils. The highest DT50 values for pethoxamid (12.3 days) and triasulfuron (57.1 days) were in S+GC, and the lowest in S+SS (8.35 and 24.7 days). Soil DHA was stimulated by the presence of GC in the soil and by the first application of mesotrione. The second application of mesotrione and pethoxamid positively affected soil DHA, but this did not occur for triasulfuron. The repeated applications of herbicides and soil organic amendments have different effects on herbicide dissipation, adsorption, and soil DHA, and they should be taken into account when assessing soil quality and other potential environmental implications of pesticide use.

Biosolids could potentially be used for reforestation of degraded soils in New Zealand with native vegetation. Many native plant species of New Zealand thrive in low-fertility soils, and there is scant knowledge about their nutrient requirements. Therefore, it is unclear whether they will respond positively to the addition of biosolids. We used a pot trial to determine the responses of 11 native plant species to biosolids addition (10% w/w, ~90 Mg hm-2) on two distinct degraded soils, Lismore stony silt loam and a Kaikoura sand. We also intended to prove that the soil microbial activity improves with the addition of biosolids, depending on the plant species. All species grew better in Lismore stony silt loam than the Kaikoura sand. All species in the Lismore stony silt loam responded positively to biosolids. The response to biosolids addition in the Kaikoura sand was variable, with four species showing no improvement in growth when biosolids were added. The nutrient status (N, P, S, Cu, and Zn) of all species improved when the two soils were amended with biosolids. However, some plant species, especially Pittosporum tenuifolium Sol. ex Gaertn. and Coprosma robusta Raoul, showed concerning concentrations of Cd (up to 2.4 mg kg-1). Dehydrogenase activity of soils (indicator of soil microbial activity) increased in biosolidsamended soils, with a strong species effect. Future work should involve field trials to determine the effect of biosolids addition on the establishment of native plant communities.

La quema de la paja de arroz en Valencia, tercera ciudad española, está causando severos problemas. Diversas prácticas de manejo como la retirada, la incorporación al suelo o el compostaje de la misma están siendo ensayadas como alternativas a la quema. Para el estudio de los cambios que estas prácticas generan en algunas propiedades biológicas de los suelos se han realizado dos ensayos en parcelas experimentales. El primer ensayo compara la retirada, quema e incorporación de la paja, como distintas formas de manejo de la misma, y el segundo ensayo evalua el efecto de la aplicación de un compost de paja de arroz en el suelo del arrozal. No se encontraron diferencias estadísticamente significativas en las medidas de actividad biológica en ninguno de los dos ensayos, indicando que la modalidad de manejo de la paja tan solo induce pequeños cambios en el suelo. Sorprendentemente, la quema no afectó a las actividades enzimáticas ni a la biomasa microbiana del suelo, ya que no se observaron diferencias entre tratamientos, o puede que se recuperaran los niveles usuales en pocos meses. Asimismo, en el ensayo de la aplicación del compost de la paja de arroz, se observó una ligera variación en la actividad deshidrogenasa, pero aparentemente no le afectaron ni la dosis de compost aplicada ni la combinación conjunta de fertilización mineral y fertilización orgánica. Sin embargo, la actividad fosfomonoesterasa pareció incrementar de forma paralela con las dosis aplicación de compost/fertilización mineral., Severe problems are caused by site burning of rice straw in Valencia, the third largest Spanish city. Removal, incorporation or composting are being tested as alternatives to burning, and the changes they produce in selected soil biological properties have been studied in two field trials. One compares removal, burning and incorporation the straw, and a second evaluates the application of straw-derived compost for rice production. No statistically-significant effects on the measured indicators of biological activity were found in either experiment, indicating that management-induced changes are small. Unexpectedly, burning did not affect negatively enzyme activities or microbial biomass contents since there were no differences between treatments, or usual levels were recovered in a few months. The changes induced by straw removal or incorporation were also not statistically significant. When straw-derived compost applications were assayed, dehydrogenase activity was slightly variable and apparently unaffected by N and compost rates or compost/mineral N combinations, but phosphomonosterase activity seems to increase parallel to compost to mineral N ratio

Severe problems are caused by site burning of rice straw in Valencia, the third largest Spanish city. Removal, incorporation or composting are being tested as alternatives to burning, and the changes they produce in selected soil biological properties have been studied in two field trials. One compares removal, burning and incorporation the straw, and a second evaluates the application of straw-derived compost for rice production. No statistically-significant effects on the measured indicators of biological activity were found in either experiment, indicating that management-induced changes are small. Unexpectedly, burning did not affect negatively enzyme activities or microbial biomass contents since there were no differences between treatments, or usual levels were recovered in a few months. The changes induced by straw removal or incorporation were also not statistically significant. When straw-derived compost applications were assayed, dehydrogenase activity was slightly variable and apparently unaffected by N and compost rates or compost/mineral N combinations, but phosphomonosterase activity seems to increase parallel to compost to mineral N ratio, La quema de la paja de arroz en Valencia, tercera ciudad española, está causando severos problemas. Diversas prácticas de manejo como la retirada, la incorporación al suelo o el compostaje de la misma están siendo ensayadas como alternativas a la quema. Para el estudio de los cambios que estas prácticas generan en algunas propiedades biológicas de los suelos se han realizado dos ensayos en parcelas experimentales. El primer ensayo compara la retirada, quema e incorporación de la paja, como distintas formas de manejo de la misma, y el segundo ensayo evalua el efecto de la aplicación de un compost de paja de arroz en el suelo del arrozal. No se encontraron diferencias estadísticamente significativas en las medidas de actividad biológica en ninguno de los dos ensayos, indicando que la modalidad de manejo de la paja tan solo induce pequeños cambios en el suelo. Sorprendentemente, la quema no afectó a las actividades enzimáticas ni a la biomasa microbiana del suelo, ya que no se observaron diferencias entre tratamientos, o puede que se recuperaran los niveles usuales en pocos meses. Asimismo, en el ensayo de la aplicación del compost de la paja de arroz, se observó una ligera variación en la actividad deshidrogenasa, pero aparentemente no le afectaron ni la dosis de compost aplicada ni la combinación conjunta de fertilización mineral y fertilización orgánica. Sin embargo, la actividad fosfomonoesterasa pareció incrementar de forma paralela con las dosis aplicación de compost/fertilización mineral

The ionic liquids (ILs) are often denominated as “green fluids”, because they are considered as innocuous due to their negligible volatility. Due to this apparent innocuousness, the ILs are attracted a great attention as an alternative to traditional organic solvents, highly contaminant. However, the problem of contamination is not limited to the atmosphere, since also aquatic and terrestrial environments can be affected. Therefore, and because the toxic effects of ILs on the environment are largely unknown, research studies are needed to deepen this aspect before to assign them the appellation of “green fluids”. Nevertheless, and despite the increased number in the last few years of studies on different aspects of ILs, the toxicity of these compounds to the environment in general, and to the soils in particular, only rarely is investigated. One of the most used ILs in different applications is 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4). Among all the soil properties, those determining the edaphic metabolism, and especially the enzymatic activities, are highly sensitive to ascertain the disturbance caused by any external agent. Given the lack of studies investigating the effect of ILs on the edaphic environment, before the use of enzymatic activities as indicators of the toxicity for soils of any given IL, it is necessary to test if classical methods to determine the soil enzymatic activities are adequate for their use in soils spiked with that given IL. In this study we investigated the suitability of dehydrogenase method to determine the activity of this enzyme in soils with spiked BMIMBF4, modifying the method according to the problems identified

La quema de la paja de arroz en Valencia, tercera ciudad española, está causando severos problemas. Diversas prácticas de manejo como la retirada, la incorporación al suelo o el compostaje de la misma están siendo ensayadas como alternativas a la quema. Para el estudio de los cambios que estas prácticas generan en algunas propiedades biológicas de los suelos se han realizado dos ensayos en parcelas experimentales. El primer ensayo compara la retirada, quema e incorporación de la paja, como distintas formas de manejo de la misma, y el segundo ensayo evalua el efecto de la aplicación de un compost de paja de arroz en el suelo del arrozal. No se encontraron diferencias estadísticamente significativas en las medidas de actividad biológica en ninguno de los dos ensayos, indicando que la modalidad de manejo de la paja tan solo induce pequeños cambios en el suelo. Sorprendentemente, la quema no afectó a las actividades enzimáticas ni a la biomasa microbiana del suelo, ya que no se observaron diferencias entre tratamientos, o puede que se recuperaran los niveles usuales en pocos meses. Asimismo, en el ensayo de la aplicación del compost de la paja de arroz, se observó una ligera variación en la actividad deshidrogenasa, pero aparentemente no le afectaron ni la dosis de compost aplicada ni la combinación conjunta de fertilización mineral y fertilización orgánica. Sin embargo, la actividad fosfomonoesterasa pareció incrementar de forma paralela con las dosis aplicación de compost/fertilización mineral., Severe problems are caused by site burning of rice straw in Valencia, the third largest Spanish city. Removal, incorporation or composting are being tested as alternatives to burning, and the changes they produce in selected soil biological properties have been studied in two field trials. One compares removal, burning and incorporation the straw, and a second evaluates the application of straw-derived compost for rice production. No statistically-significant effects on the measured indicators of biological activity were found in either experiment, indicating that management-induced changes are small. Unexpectedly, burning did not affect negatively enzyme activities or microbial biomass contents since there were no differences between treatments, or usual levels were recovered in a few months. The changes induced by straw removal or incorporation were also not statistically significant. When straw-derived compost applications were assayed, dehydrogenase activity was slightly variable and apparently unaffected by N and compost rates or compost/mineral N combinations, but phosphomonosterase activity seems to increase parallel to compost to mineral N ratio

The objective of this study was to compare the effects of conventional and organic production system on microbial activity in the soil cultivated with bean and maize crops. The trial in Đurđevo was set up according to the conventional farming system, while organic farming system was used in Futog. Two maize hybrids and two bean cultivars were used in the trial. Soil samples were collected in two periods during 2014 (before sowing, at flowering stage of bean crops, and at 9-11 leaf stage of maize) at two depths, at both locations. The following microbiological parameters were tested: the total number of micro­organisms, number of ammonifiers, Azotobacter sp., free nitrogen fixing bacteria, fungi, actinomycetes, and activity of dehydrogenase enzyme. The results showed that the total number of microorganisms, number of free N-fixers and dehydrogenase activity were high­er within organic production, while Azotobacter sp. was more abundant in conventional production. Variations in the number of ammonifiers, fungi and actinomycetes in relation to the type of production were not obtained. Significant differences in microbial activity were also obtained between period and depths of sampling., Cilj ovih istraživanja bio je da se uporede efekti konvencionalnog i organskog sistema gajenja na mikrobiološku aktivnost u zemljištu koje je pod pasuljem i kukuruzom kao usevima. Ogled u Đurđevu postavljen je u sistemu konvencionalne poljoprivredne proizvodnje, a ogled u Futogu u sistemu organske proizvodnje. U ogledima su korišćena dva hibrida kukuruza i dve sorte pasulja Instituta za ratarstvo i povrtarstvo u Novom Sadu. Uzorci zemljišta za mikrobiološke analize uzeti su tokom 2014. godine (pre setve i u fazi cvetanja pasulja, kao i u fazi 9-11 listova kukuruza), sa dve dubine, na oba lokaliteta. Mikrobiološka aktivnost praćena je na osnovu zastupljenosti ukupnog broja mikroorganizama, amonifikatora, Azotobacter sp., slobodnih azotofiksatora, gljiva, aktinomiceta i aktivnosti enzima dehidrogenaze. Rezultati su pokazali da su ukupan broj mikroorganizama, broj slobodnih azotofiksatora i dehidrogenazna aktiv­nost bili veći u sistemu organske proizvodnje, dok su vrste iz roda Azotobacter sp. bile zastupljenije u sistemu konvencionalne proizvodnje. Nisu zabeležene razlike u brojnosti amonifikatora, gljiva i aktinomiceta u zavisnosti od sistema gajenja. Takođe, značajne razlike u mikrobiološkoj aktivnosti utvrđene su između perioda i dubine uzorkovanja.

Recently, many efforts have been made to efficiently impregnate different textile materials with metal and metal oxide nanoparticles in order to provide antimicrobial, UV protective or self-cleaning properties. Evidence of their environmental risks is limited at this point. The aim of this study was to explore the influence of Ag and TiO2 nanoparticles on biodegradation of cotton fabrics. Biodegradation behavior of cotton fabrics impregnated with Ag and TiO2 NPs from colloidal solutions of different concentrations was assessed according to standard test method ASTM 5988-03 and soil burial test. Degradation of cotton fabrics was also evaluated by enzymatic hydrolysis with cellulase. The morphology of fibers affected by biodegradation was analyzed by scanning electron microscopy (SEM). In order to get better insight into biodegradation process, dehydrogenase activity of soil has been determined. Ag and particularly TiO2 nanoparticles suppressed the biodegradation of cotton fabrics. The dehydrogenase activity of soil with cotton fabrics impregnated with TiO2 nanoparticles was the weakest. Severe damage of cotton fibers during the biodegradation process was confirmed by SEM.

Recently, many efforts have been made to efficiently impregnate different textile materials with metal and metal oxide nanoparticles in order to provide antimicrobial, UV protective or self-cleaning properties. Evidence of their environmental risks is limited at this point. The aim of this study was to explore the influence of Ag and TiO2 nanoparticles on biodegradation of cotton fabrics. Biodegradation behavior of cotton fabrics impregnated with Ag and TiO2 NPs from colloidal solutions of different concentrations was assessed according to standard test method ASTM 5988-03 and soil burial test. Degradation of cotton fabrics was also evaluated by enzymatic hydrolysis with cellulase. The morphology of fibers affected by biodegradation was analyzed by scanning electron microscopy (SEM). In order to get better insight into biodegradation process, dehydrogenase activity of soil has been determined. Ag and particularly TiO2 nanoparticles suppressed the biodegradation of cotton fabrics. The dehydrogenase activity of soil with cotton fabrics impregnated with TiO2 nanoparticles was the weakest. Severe damage of cotton fibers during the biodegradation process was confirmed by SEM.

Recently, many efforts have been made to efficiently impregnate different textile materials with metal and metal oxide nanoparticles in order to provide antimicrobial, UV protective or self-cleaning properties. Evidence of their environmental risks is limited at this point. The aim of this study was to explore the influence of Ag and TiO2 nanoparticles on biodegradation of cotton fabrics. Biodegradation behavior of cotton fabrics impregnated with Ag and TiO2 NPs from colloidal solutions of different concentrations was assessed according to standard test method ASTM 5988-03 and soil burial test. Degradation of cotton fabrics was also evaluated by enzymatic hydrolysis with cellulase. The morphology of fibers affected by biodegradation was analyzed by scanning electron microscopy (SEM). In order to get better insight into biodegradation process, dehydrogenase activity of soil has been determined. Ag and particularly TiO2 nanoparticles suppressed the biodegradation of cotton fabrics. The dehydrogenase activity of soil with cotton fabrics impregnated with TiO2 nanoparticles was the weakest. Severe damage of cotton fibers during the biodegradation process was confirmed by SEM.

Recently, many efforts have been made to efficiently impregnate different textile materials with metal and metal oxide nanoparticles in order to provide antimicrobial, UV protective or self-cleaning properties. Evidence of their environmental risks is limited at this point. The aim of this study was to explore the influence of Ag and TiO2 nanoparticles on biodegradation of cotton fabrics. Biodegradation behavior of cotton fabrics impregnated with Ag and TiO2 NPs from colloidal solutions of different concentrations was assessed according to standard test method ASTM 5988-03 and soil burial test. Degradation of cotton fabrics was also evaluated by enzymatic hydrolysis with cellulase. The morphology of fibers affected by biodegradation was analyzed by scanning electron microscopy (SEM). In order to get better insight into biodegradation process, dehydrogenase activity of soil has been determined. Ag and particularly TiO2 nanoparticles suppressed the biodegradation of cotton fabrics. The dehydrogenase activity of soil with cotton fabrics impregnated with TiO2 nanoparticles was the weakest. Severe damage of cotton fibers during the biodegradation process was confirmed by SEM.

Pesticide metsulfuron-methyl (chemical name: methyl 2-(4-methoxy-6-methyl-1,3,5-triazin-2-ylcarbamoylsulfamoyl) benzoate) is a post-emergence sulfonylurea herbicide which controls most annual grass broadleaf weeds in cereals, and it has been used for a long time. The effect of metsulfuron-methyl on microbiological activity in soil was investigated. Trials were set up in laboratory on chernozem soil (pH 7.0, organic matter 3.5%, sand 26%, silt 45%, clay 29%) at Surcin, Serbia. Metsulfuron-methyl was added at rates 1, 5, 25 i 50 mg/kg soil. Untreated soil served as control. Samples were collected for analysis 5, 20, 40 and 60 days after metsulfuron-methyl application. The effects were assessed on dehydrogenase activity, bacteria abundance and fungi abundance. Metsulfuron-methyl was found to cause different effects on the soil microbial activity in soil and its influence depended on the rate of application and duration of activity. Metsulfuron-methyl applied at 1 and 5 mg/kg soil did not have any effect on microbial parameters. The higher herbicide doses (25 and 50 mg/kg) induced increasing activity from the 5th to 40th day. These experimental data indicated that metsulfuron-methylon affected soil microbial activity, but the effects were only detected at higher doses and they were slight and transitory.

The strong relationships between plant and soil microbial communities suggest that post-fire vegetation may be a critical driver of the post-fire recovery of the structure and functioning of the soil microbial community. In this study, we conducted an experimental burning and evaluated the effect of the post-fire persistence traits of the vegetation (resprouter and seeder) on the medium-term (3 years after fire) post-fire response of the soil microbial activity in Mediterranean shrublands. The experiment was carried out in a Mediterranean shrubland (Eastern Spain), where four main types of microsites were selected: Bare-soil inter-patch (BS); Resprouter patch (R), Seeder patch (S), and Mixed patch (R+S). For each microsite, we analyzed soil basal respiration, water-soluble carbon, microbial biomass carbon, total organic carbon, and dehydrogenase activity at 0-5 cm soil depth. We also assessed plant cover dynamics. Our results suggest that, in general, fire impacts on soil microbial activity are not long-lasting, with most assessed soil variables being similar between burned and unburned areas three years after the fire. However, while the unburned microsites showed a trend in microbial biomass and activity from lower values in bare soils to higher values in R+S patches, these differences disappeared in the burned area, due to both a slight increase in microbial activity and biomass in bare soils, and the opposite response for soils under R+S patches. Our results highlight the role of the plant persistence trait in the microbial post-fire response of Mediterranean soils.

The strong relationships between plant and soil microbial communities suggest that post-fire vegetation may be a critical driver of the post-fire recovery of the structure and functioning of the soil microbial community. In this study, we conducted an experimental burning and evaluated the effect of the post-fire persistence traits of the vegetation (resprouter and seeder) on the medium-term (3 years after fire) post-fire response of the soil microbial activity in Mediterranean shrublands. The experiment was carried out in a Mediterranean shrubland (Eastern Spain), where four main types of microsites were selected: Bare-soil inter-patch (BS); Resprouter patch (R), Seeder patch (S), and Mixed patch (R+S). For each microsite, we analyzed soil basal respiration, water-soluble carbon, microbial biomass carbon, total organic carbon, and dehydrogenase activity at 0-5 cm soil depth. We also assessed plant cover dynamics. Our results suggest that, in general, fire impacts on soil microbial activity are not long-lasting, with most assessed soil variables being similar between burned and unburned areas three years after the fire. However, while the unburned microsites showed a trend in microbial biomass and activity from lower values in bare soils to higher values in R+S patches, these differences disappeared in the burned area, due to both a slight increase in microbial activity and biomass in bare soils, and the opposite response for soils under R+S patches. Our results highlight the role of the plant persistence trait in the microbial post-fire response of Mediterranean soils.

Two bell pepper (Capsicum annuum L.) varieties, viz., California Wonder and Gangavati Local, were raised under nine completely organic nutrient sources, along with recommended package of practices, and, under completely inorganic nutrient sources. Irrespective of the variety and growing environment, there was substantial increase in total bacterial count (22.97% and 24.98%), population of fungi (20.23% and 20.23%), actinomycetes (36.89% and 36.83%) and mycorrhiza (44.63% and 29.40%) in open-field and shade-house conditions, respectively, in all the nutrient combinations where organic sources were used, compared to the inorganic treatment. All organic nutrient sources used were found to be similar in their effect on soil microbes.

Two bell pepper (Capsicum annuum L.) varieties, viz., California Wonder and Gangavati Local, were raised under nine completely organic nutrient sources, along with recommended package of practices, and, under completely inorganic nutrient sources. Irrespective of the variety and growing environment, there was substantial increase in total bacterial count (22.97% and 24.98%), population of fungi (20.23% and 20.23%), actinomycetes (36.89% and 36.83%) and mycorrhiza (44.63% and 29.40%) in open-field and shade-house conditions, respectively, in all the nutrient combinations where organic sources were used, compared to the inorganic treatment. All organic nutrient sources used were found to be similar in their effect on soil microbes.

The ecology and functional role of biological soil crusts (BSCs) in arid and semi-arid zones have been extremely well studied. However, little is known about the biochemical properties related to the number and activity of the microbiota that form the crusts, even though information about these properties is very important for understanding many of the processes that affect the formations. In this study, several properties related to the activity and number of microorganisms (biomass-C, basal respiration, dehydrogenase activity and nitrogen mineralization potential) were determined at different depths (crusts, 0-0.5 cm; middle, 0.5-3 cm and deep, 3-5 cm layers) in two types of crusts (predominated by cyanobacteria and by lichens) in the Tabernas desert (Almeria, SE Spain). The absolute values of the above-mentioned properties and the values expressed relative to the total organic carbon (TOC) content were both much higher in the crust layers than in the surface horizons of soils under Mediterranean or Atlantic climates. A large part of the TOC in the BSCs was contained in the microbiota and another large part was readily metabolized during incubation of the crusts for 10 days at 25 °C. The net nitrogen mineralization rate was also high, and ammonification predominated in the crust layers, whereas nitrification predominated in the middle and deep layers. In all types of BSCs, the microbiota colonized the deep layers, although with greater intensity in the lichen-dominated BSCs than in the cyanobacterial BSCs. The results also indicate that hydrolytic enzymes are not stabilized on soil colloids and their activity depends only on the active microbiota.

Na dva tipa zemljišta, u laboratorijskim uslovima, ispitivan je uticaj herbicida rimsulfurona iz grupe sulfonilurea na brojnost i aktivnost zemljišnih mikroorganizama. Rimsulfuron je primenjen u koncentracijama 0,2, 2,0 i 20,0 mg a.s. na kilogram zemljišta. Najmanja ispitivana koncentracija (0,2 mg) odgovarala je količini koja se preporučuje za primenu, a druge dve su deset i sto puta veće od preporučene. Kada je primenjen u preporučenoj količini, rimsulfuron nije imao uticaja na ispitivane mikrobiološke parametre. Smanjenje mikrobiološke biomase ugljenika, dehidrogenazne aktivnosti, brojnosti gljiva i bakterija utvrđene su kod većih koncentracija rimsulfurona. Intenzitet ovih promena je, uglavnom, bio slab i prolaznog karaktera., The effects of rimsulfuron a sulfonylurea herbicide on the growth and activity of soil microorganisms under laboratory conditions was investigated in two soils. The application rates were: 0.2, 2.0 and 20.0 mg a.i kg-1 soil. The lowest concentration tested was the label rate (0.2 mg a.i kg-1), and the other two were ten and hundred times higher. No adverse effects on microbiological processes were observed for the label rate. Decrease in microbial biomass carbon, dehydrogenase activity, fungi and bacteria in comparison with untreated control, were found at higher rates. The magnitude of these effects were generally slight and transitory.

The effect of sulphonamides on activity of activated sludge dehydrogenase was studied. Three sulphonamides, such as sulphacetamide (SCM), sulphanilamide (SA), p-toluenesulphonamide(p-TSA), were selected for investigations and their concentrations ranged from 10 to100 mg/l. Dehydrogenase activity was evaluated with the TTC test. Twelve samples of activated sludge collected from the Gdansk wastewater treatment plant were used. Dehydrogenase activity, its inhibition and degree of toxicity at the presence of sulphonamides have been studied and evaluated. It has been found that the dehydrogenase activity decreases with the increase of a sulphonamidesconcentration, and the effect was the highest for p-TSA. On the other side, the maximal toxicityvalue was the highest in case of SA and the lowest for p-TSA., QC 20120420

Despite their widespread use in household activities and various industries, information on the toxicity of quaternary ammonium compounds (QACs) to microbial activities in soil is scant. This study investigated the effect of three commonly used QACs namely hexadecyltrimethyl ammonium bromide (HDTMA), octadecyltrimethyl ammonium bromide (ODTMA) and Arquad on dehydrogenase and potential nitrification activities in three different soils. The toxicity of QACs on the dehydrogenase activity and potential nitrification in these soils followed the order: HDTMA > ODTMA > Arquad and Arquad > HDTMA > ODTMA, respectively. HDTMA, ODTMA and Arquad exhibited toxicity to dehydrogenase activity at concentration of 50, 100 and 750 mg kg−1 soil, respectively, whereas potential nitrification was inhibited by HDTMA and ODTMA even at 50 mg kg−1 soil. Arquad exhibited toxicity to potential nitrification at comparatively higher concentration of 250 mg kg−1 soil, with the severity of toxicity very intense at higher concentrations. The nature of QACs and soil properties influenced the toxicity. The toxic effect of QACs on soil microbial activities was more influenced by the relative release of sorbed QACs in soils. This study provides valuable information on the toxicological properties of some widely used QACs on important soil microbial activity parameters. To our knowledge, this is the first report.

Conservation management systems such as no tillage may enhance sequestration of soil C. The soil properties that contribute to soil C storage under such systems are still largely unknown, especially in subtropical agroecosystems. We investigated the influence of tillage [mouldboard plough (MP) and no tillage (NT)] on soil organic C, microbial biomass and activity, structural stability and mycorrhizal status of a field cultivated with maize (Zea mays L.) or bean (Phaseolus vulgaris L.) on a Vertisol in Northern Tamaulipas, Mexico. Crop type, tillage system and soil depth had a significant effect on soil organic C, aggregate stability and bulk density. Soil organic C, microbial biomass C and N and dehydrogenase and phosphatase activities were greater with NT than with MP, particularly under bean cultivation. In the 0–5 cm layer, microbial biomass C and N were, on average, about 87 and 51% greater in the soils cultivated with bean and maize, respectively, under NT than under MP. Higher levels of mycorrhizal propagules, glomalin related soil protein (GRSP) and stable aggregates were produced under NT than under MP in both crops. The no-tillage system can be considered an effective management practice for carrying out sustainable agriculture under subtropical conditions, due to its improvement of soil physical and biochemical quality and soil C sequestration.

The aim of this paper was to investigate microbiological activity in barley rhizosphere, after the experiment with 17 recultivation treatments of deposols with different organo-mineral materials. The most important agrochemical properties of deposols have been examined. The presence of the microorganisms was determined by the usual microbiological mediums. Dehydrogenase activity was determined by the Cassida et al. method. The deposols were poor in organic matter, nitrogen, phosphorus and potassium. The number of bacteria ranged from 9.3 to 413.3 × 106g-1. The addition of organo-mineral materials into deposols has caused an increase of microbial biomass and dehydrogenase activity, comparing with control.

The aim of this paper was to investigate microbiological activity in barley rhizosphere, after the experiment with 17 recultivation treatments of deposols with different organo-mineral materials. The most important agrochemical properties of deposols have been examined. The presence of the microorganisms was determined by the usual microbiological mediums. Dehydrogenase activity was determined by the Cassida et al. method. The deposols were poor in organic matter, nitrogen, phosphorus and potassium. The number of bacteria ranged from 9.3 to 413.3 × 106g-1. The addition of organo-mineral materials into deposols has caused an increase of microbial biomass and dehydrogenase activity, comparing with control.

We designed a microcosm experiment to assess the influence of inoculation with Eisenia foetida earthworms and the establishment of an Avena sativa cover crop on biological (enzyme activities and labile carbon fractions) soil quality indicators in a soil treated with a composted organic residue, and to determine the contribution of these treatments to carbon dioxide emissions from the soil to the atmosphere of the microcosm. The microcosms were incubated for 53 days under 28 °C/18 °C day/night temperatures. The addition of earthworms and the planting of A. sativa increased dehydrogenase activity of compost amended soil by about 44% after 23 days of incubation. The metabolic potential, calculated as the ratio dehydrogenase activity/water soluble C, was higher in the compost amended soil planted with A. sativa. The highest total amount of CO2–C evolved occurred in the soil treated with composted residue and earthworms (about 40% of the total amount of CO2 evolved came from earthworm activity). The planting of A. sativa increased the decomposition rate constant of organic matter in the amended soil but decreased the potentially mineralizable C pool. In conclusion, the establishment of an A. sativa cover crop and the addition of E. foetida to a degraded agricultural soil treated with composted residue were effective treatments for improving the biological and biochemical quality and the metabolic potential of the soil.

The dehydrogenase activity (DHA) in the upper 10 cm of forest soils was measured in three experimental plots (1 ha) in Los Alcornocales Natural Park (southern Spain). In each plot, a silviculture treatment of thinning and shrub-clearing had been previously carried out in one half, while the other half was left as a forest control. Soil samples were taken during the dry season (July 2000) and after the first autumn rains (October 2000). The DHA of forest soil in autumn [527+/-165 nmol p-iodonitrotetrazolium formazan (INTF) g(-1) h(-1)] was almost double that in summer (289+/-95 nmol INTF g(-1) h(-1)), for one of the studied plots. During the dry season, DHA of forest control soils (324+/-85 nmol INTF g(-1) h(-1)) was higher than in the thinned and shrub-cleared forest (253+/-93 nmol INTF g(-1) h(-1)). During the autumn (wet season), however, the effects of the silvicultural practices on the soil dehydrogenase were negligible. Significant differences in DHA were found between the three sites. Multiple regression analysis identified pH as the best predictor of DHA of these soils. Other soil properties (pH, K, Ca, Mg, and soil moisture) also showed significant correlations with DHA. In addition, clay content appeared to enhance the enzyme activity. Our results suggest that thinning and shrub-clearing in Mediterranean forests seem to affect negatively the soil DHA, and their impact is more marked during the dry season. However, season and site effects are better determinants of DHA than management practices.