The soil moisture content can vary the behavior of biochemical activity and its incidence on herbicides. The objective of this manuscript was to assess, under controlled laboratory conditions, whether a prolonged 75-day drought can affect the behavior of 4-chloro-2-methylphenoxyacetic acid (MCPA) herbicide and biochemical properties in three agricultural soils (Typic Xerofluvent, SA, Typic Haploxeralf, SB, and Vertic Chromoxert, SC). During the 75 experimental days, two irrigation levels were maintained: (1) watered soils during this experimental period, and (2) non-watered soils, where no water was supplied during the experimental period. The evolution of the herbicide and the biochemical properties were different depending on the soil moisture status. In the SA, the biochemical properties decreased until day 35 after initiating the experiment, whereas in the SB and SC, the biochemical parameters decreased until days 25 and 45, respectively. The application of herbicide to the non-watered soil increased the inhibition of biochemical properties. In non-watered SA, MCPA degradation occurred at day 45 after initiating the experiment, whereas in SB and SC, MCPA degradation occurred at days 35 and 60 after starting the incubation process, respectively. These results suggest that the soil persistence of MCPA under drought conditions increases, and consequently increases soil contamination.

Carbon sequestration in agricultural soils has been defined as a positive strategy in the mitigation of global warming. The selection of the appropriate soil management system to achieve this goal is fundamental. In this study the effect of two tillage treatments, conventional tillage (CT) and no tillage with bare soil (NT) was analyzed in the complete soil profile (by horizons) in a rainfed olive grove under Mediterranean conditions. The objective was to determine the influence of treatments on soil aggregation and organic carbon (OC) distribution within aggregate fractions both in the surface horizon (0-32.7 cm in CT and 0-21 cm in NT) and in depth (32.7-119.7 cm in CT and 21.7-110 cm in NT) (Bw, BC and C horizons). Soil samples from all horizons were separated into four aggregate-size fractions: large macroaggregates (> 2000 mu m), small macroaggregates (250-2000 mu m), microaggregates (53-250 mu m), and silt + clay (< 53 mu m) by wet-sieving method. Aggregate stability results showed that mean weight diameter of aggregates (MWD) increased in depth in both treatments and the A horizon contained 47.6% (CT) and 55.8 (NT) more percentage of microaggregates. NT obtained greater MWD values (0.76 vs. 0.61 mm) and more proportion of water stable large macroaggregates (15.9% vs. 6.6%) than CT only in the A horizon. Conversely, CT achieved higher MWD values than NT in the depth and more proportion of macroaggregates (large macroaggregates + small macroaggregates) were found in CT in all depths. In addition, CT had larger contribution to SOC stock within aggregate fractions (24.9 Mg ha(-1)) than NT (22.4 Mg ha(-1)). This study indicates that the adoption of NT with bare soil did not increase the OC pool in aggregate fractions and therefore it is not always the best option management change to increase SOC in Mediterranean areas.

The knowledge about land management effects on soil capacity to store carbon is necessary to planning effective strategies by managers and decision-makers. In this study we analyzed the land use change (LUC) effects on soil organic carbon stocks (SOC-S) for long term in the Sardinia region - Italy (Mediterranean area). Throughout the 20th century, the studied area has undergone different LUC. The first LUC was in 1938, from forest to agricultural land under three different uses: vineyards, hay crop and pasture, later (1966) some of this agricultural land were abandoned to seminatural ecosystem (second LUC). The different LUC affected to SOC-S causing decarbonization, carbonization and recarbonization processes along the soil profile. The different land uses studied chronologically were: i) natural forest - cork oak forest (Cof), ii) filled vineyard (Tv), iii) no filled grassed vineyard (Ntgv), iv) hay crop (Hc), v) pasture - silvopastoral and silvoarable practices (P), and vi) former vineyard - vineyards abandoned and naturally revegetated (Fv). The first LUC (Cof to Tv, Ntgv, Hc and P) caused 5.1% and 37.5% reduction on SOC-S for Tv and Ntgv (soil decarbonization), however, the SOC-S increased 47.1% and 51.3% for Hc and P respectively (soil carbonization). The second LUC (Tv and Ntgv to Fv) increased the SOC-S on average 66.3% (soil recarbonization). In general, these effects were observed principally in depth. This study shows the importance of land use and LUC with respect to SOC-S, and that the human action can degrade and/or regenerate the soil, affecting to soil functions. Consequently, is necessity to promote good environmental practices to improve the soil functions and to reduce the greenhouse gases (ecosystem services). On the presumption that the SOC sequestration through of agricultural management can reduced the atmospheric CO2 concentration (4p1000 target in the XXI Conference of the Parties - Paris, 2015). Therefore, the soils regeneration via carbonization and/or recarbonization is an opportunity to prevent the climate change.

The main objective of this work was to study the effect of three organic wastes (municipal solid waste, MSW, sheep manure, SM, and green forage vermicomposts, GFV) applied during five consecutive years to a calcaric Cambisol soil located near Cordoba (Spain). The effects of these amendments on soil biochemical properties (enzymatic activities and humus-enzymatic complexes) and olive yield were determined. At the end of the experimental period, soil enzymatic activities were highest in soils amended with GFV, followed by SM and MSW, whereas the humus-enzyme complexes were highest in soils amended with MSW, followed by SM and GFV. The application of organic matter to soil increased the levels of macro- and micronutrients in leaf. At the end of the experiment, the leaf N concentration was 49.6%, 43% and 34.1% higher in GFV, SM and MSW treatments, when compared with non-organic amended soil. Similarly, and compared with the non-organic amended soil, leaf P, K, Ca and Mg contents increased in GFV, SM and MSW-amended soils. Compared to the non-organic amended soil and at the end of the experimental period, olive yield increased 26.8% in soils amended with SM and 35.5% in soils amended with GFV. Also, the olive oil content in fruits showed only significant differences with the GFV treatment. These results suggested that the organic matter quality influenced the olive yield, suggesting that this parameter increased in soils amended with organic matter with higher fulvic acid and higher protein content and low molecular weight contents, readily degradable by soil microorganisms and assimilated by the olive tree.

We studied the flazasulfuron behavior in a soil amended with three organic wastes (municipal solid waste, MSW, poultry manure, PM, and cow manure, CM) and their influence both on its mobility and on the soil's biochemical properties (soil humus-enzymatic complexes, soil microbial biomass-C and soil ATP). The organic wastes were applied to soil on February 2nd 2014. On June 6th 2014, flazasulfuron was applied. Adsorption and leaching experiments were also performed in soils with herbicide and without and whit organic wastes. Flazasulfuron did not cause changes in soil biochemical properties. Soil biochemical properties were highest in MSW-amended soil, followed by PM and CM. With the MSW amendment, flazasulfuron sorption increased by a factor of 6.7 while for PM and CM, the factor increased 5.8 and 5, respectively. The application of organic matter decreased the soil's herbicide concentration, possibly due to flazasulfuron sorption by organic matter. The maximum concentration of flazasulfuron in leachates was reduced from 8.94 mu M for the unamended soil, to 3.5, 5.4, 6.9 mu M for the MSW, PM and CM-amended soils, respectively. Therefore, because decrease the flazasulfuron concentration in leachates, the application to the soil of organic matter with higher humic acid contents is a good environmental practice.

Maize production plays an essential role in global food security. In order to maintain both high quality and maize production, there is a great demand for fertilizers. The main objective of this work was to study, over two experimental seasons, the effect of a biofertilizer obtained from sewage sludge (SS) on the yield and on the quality of maize crops (Zea mays L.). The biofertilizer was applied in two ways: (i) to soil, at rates of 0, 10 and 20 Mg ha(-1) before sowing, and (ii) via foliar fertilization, applying 0, 3.6 and 7.21ha(-1) three times during each growing season accounting for a total rate of 0, 10.81ha(-1) and 21.61ha(-1). This study is novel because there are no previous studies of the effect of this biofertilizer on any agricultural crops. The results obtained show that, when the SS was applied directly to the soil, the macro- and micronutrients analyzed in both soil and leaves showed no significant differences between either of the fertilizer treatments. Foliar application of SS, however, increased the leaf concentrations of macro- and micronutrients. When the SS rate was 7.21ha(-1), grain protein concentration increased significantly by about 30% and the yield increased significantly by about 17% compared with the control treatment (SS not applied). These results suggested that, in order to improve agricultural maize yields, quality and nutritional, this SS should be applied as a foliar fertilizer instead of applying it to soil. (C) 2016 Elsevier B.V. All rights reserved.

As vermicomposts promote germination, growth, and improved plant yield, they have been promoted as a viable alternative to peat as container media components for the horticultural industry. The aim of this article was to compare the effects of two vermicomposts of animal origin, VCD, and of vegetable origin, VGF, as well as a cotton gin compost (CC), on a commercial peat-based (P) substrate on the growth of tomato seedlings (Lycopersicum esculentum cv. Momotaro) under greenhouse conditions. The results showed that the VCD treatment had the highest values of tomato seedling height, stem diameter, number of leaves per seedling, and total dry matter, followed by VGF, CC, and P treatments. These results support previous studies showing that both vermicomposts and compost can be used with very good results as alternative growth media to peat-based substrates. Nevertheless, the greatest plant growth values were obtained when applying the VCD and VGF vermicomposts followed by CC and P, possibly due to the higher mineral element contents of VCD, followed by VGF, CC, and P, respectively.

In this paper we studied in the laboratory the bioremediation effects of an oxyfluorfen herbicide-polluted soil with and without three earthworms (Eisenia fetida, Lumbricus terrestris and Allolobophora molleri) and its influence on soil biochemical properties over 90 days. Glutathione-S-transferase activity (GST) and weight in earthworms were measured at four different incubation times (3, 15, 60 and 90 days). Cocoon numbers, average weight per cocoon and hatchlings per cocoon were measured 30 days after the oxyfluorfen exposure. Herbicide in soils and the earthworms was determined during the incubation period. To observe the effects of bioremediation of the contaminated soil, ATP, and urease, phosphatase and arylsulphatase activities were measured. Although the bioaccumulation factor of oxyfluorfen was 1.4- and 3.5-fold higher in A. molleri than for E. fetida and L. terrestris, respectively, compared to the unpolluted soils, the GST activity of A. molleri significantly decreased by 19% in soils polluted with oxyfluorfen, whereas for E. fetida and L. terrestris the GST activity significantly decreased by 23.3% and 34.2%, respectively. Furthermore, the earthworms' weight, cocoon numbers, average weight per cocoon and hatchlings per cocoon showed a pronounced decrease among L. terrestris, E. fetida and A. molleri, respectively, in polluted soils. When the concentration of herbicide decreased, so did enzyme activity. This decrease inhibition was more pronounced in soils with A. molleri than E. fetida and L. terrestris. Of the three species tested, A. molleri appears to the best suited for bioremediation of oxyfluorfen-contaminated soil. (C) 2015 Elsevier B.V. All rights reserved.

ABSTRACTAgriculture soils in the Mediterranean need restoration and rehabilitation after 10 millenia of use and abuse. Maize straw residues crushed at three sizes [<1 (C1), 1–10 (C2) and >10 cm (C3)] at 5 Mg ha−1 y−1 and with and without urea (150 kg N ha−1) were applied during a period of 3 years for the purpose of restoration of a Typic Xerofluvent located near Córdoba (Spain). The effect on the vegetal cover and biological properties (microbial biomass, soil respiration and enzymatic activities) were determined. The size of the crushed maize residues (particle size <1 cm) and N supply influenced in the evolution of soil biological properties and vegetal cover. The stimulation of microbial biomass, soil respiration, dehydrogenase, urease, β‐glucosidase, phosphatase and arylsulphatase activities was higher in C1 + N‐amended soils for 14·9%, 16·3%, 8·8%, 24·3%, 13·5%, 7·1% and 10·3%, respectively, compared with C2 + N and for 25·8%, 26·9%, 18·3%, 38·5%, 28·2%, 19·1% and 18·3%, respectively, compared with C3 + N. Vegetal cover from the C1 + N treatment was 11·4%, 17·8%, 29·4%, 37·6%, 44·9% and 75·1% greater than that in C2 + N, C3 + N, C1, C2, C3 and control soil. These results suggested that under dry climatic conditions, the application of crushed maize straw finely crushed + N fertilizers improved the soil biological properties and also favour the appearance of spontaneous vegetation, which will protect the soil and will contribute to its restoration. Consequently, the addition of the crushed maize straw finely crushed + N fertilizers may be considered a good environmental strategy for recovery of degraded soils. Copyright © 2014 John Wiley & Sons, Ltd.

The objective of the present study was to study the effect of two vermicomposts [animal (VCD) and vegetal origin (VGF)] and a cotton gin compost (C) at rates of 1780 and 3560 kg fresh organic matter ha−1 for 3 years on an Typic Xerofluvent located near Seville (Spain) on soil biological properties, nutrition (leaf N, P and K concentration, pigments and soluble carbohydrate concentrations) and yield parameters of maize (Zea mays cv. Tundra) crop. All organic waste materials had a positive effect on the soil biological properties, plant nutrition and crop yield parameters, although at the end of the experimental period and at the high organic matter rate, the soil microbial biomass and dehydrogenase, urease, β-glucosidase, phosphatase and arylsulfatase activities increased more significantly in the VCD-amended soils (86.4, 85.8, 94.5, 99.3, 70.1 and 63.8%, respectively) respect to the control soil, followed by VGF-amended soils (84.8, 80.6, 92.7, 99.1, 68.3 and 61.6%, respectively) and CC-amended soils (80.5, 75.9, 89.7, 99, 65.7 and 59.9%, respectively). Leaf N, P and K contents and pigments and soluble carbohydrate contents were highest in VCD-amended soils, followed by VGF and CC treatments. Compared with the control soil, the application of VCD in soils at high doses increased the crop yield parameters, followed by VGF and CC treatments. This may have been due to a greater labile fraction of organic matter in the VCD than the VGF and CC, respectively.

Four biostimulants (BS): WCDSs, wheat condensed distiller solubles: PA-HE, hydrolyzed poultry feathers; CGHE, carob germ enzymatic extract: and RB, rice bran extract were applied annually at 4.7 t organic matter (OM) ha(-1) for a 3-year period to a Xerollic Calciorthid soil to evaluate their efficiency in soil restoration. Their effects on the plant cover, soil enzymatic activities and the structure of the soil microbial community by analysing phospholipid fatty acids (PLFAs) were determined. Application of BS that contain higher amounts of protein and higher percentage of peptides under 3 kDa had a greater effect on the soil biological properties, possibly due to the low molecular weight protein content can be easily assimilated by soil microorganisms. Following 3 years of successive soil amendment, the dehydrogenase activity was 4.6, 9.6, and 17.6% higher in PA-HE-amended soils than in the RB, CGHE and WCDS-amended soils, respectively. The urease activity was 5.3, 14.5, and 28.8% higher in PA-HE-amended soils than in the RB, CGHE and WCDS-amended soils, respectively. The phosphatase activity was 8, 15.3, and 20.2% higher in PA-HE-amended soils than in the RB, CGHE and WCDS-amended soils, respectively. The arylsulfatase activity was 16, 21.1, and 27.2% higher in PA-HE-amended soils than in the RB, CGHE and WCDS-amended soils, respectively. Total soil phospholipid fatty acid (PLEA) concentration was significantly (p < 0.05) higher in BS-amended soil than control soil. Principal component analysis discriminated between the BS-amended soils, mainly based on content of lower molecular weight peptides. Thus. PA-HE and RB were grouped and differentiated from CGHE and WCDS, respectively. After 3 years of treatment, vegetal cover was 11.4, 17.7, 24.1, and 85.8% higher in PA-HE-amended soils than in the RB, CGHE, WCDS treatments and control soil. These results suggested that under semiarid climatic conditions the application of BS with higher amounts of protein (> 50%) and a higher percentage of peptides under 0.3 kDa (> 60%) notably increased the soil enzymatic activities, induced changes in microbial community because the protein with lower molecular weight can be more easily absorbed by soil microorganisms, and also favoured the establishment of vegetation, which will protect the soil against erosion and will contribute to its restoration. (C) 2011 Elsevier B.V. All rights reserved.

The bioremediation effects of three biostimulants (BS): WCDS, wheat condensed distillers soluble; PANE, hydrolyzed poultry feathers; and RB, rice bran extract in a soil polluted with two rates of benzo(a)pyrene (BaP) (50 or 100 mg kg(-1) soil, respectively) over 90 days were studied. Their effects on the soil biochemical properties (ATP and urease and phosphatase activities) and ergosterol were determined. Also, extractable BaP in soils was determined during the incubation period. An non-polluted and non-organic-amended soil was used as control. The results indicated that at the end of the incubation period and compared with the control soil, the ATP, ergosterol, urease and phosphatase activities decreased 29.4%, 24.8%, 44.7% and 42.9%, respectively in the non-organic amended soil polluted with polluted 100 mg BaP kg(-1) soil. The application of biostimulants to unpolluted soil increased the biochemical parameters. However, this stimulation was higher in the soil amended with PAHE, followed by RB and WCDS. The application of BaP in organic-amended soils decreased the biochemical properties. However, this decrease was lower than for the non-amended BaP polluted soil. Possibly the low molecular weight protein content easily assimilated by soil microorganisms is responsible for less inhibition of these soil biochemical parameters. (C) 2011 Elsevier B.V. All rights reserved.

A study was undertaken to investigate the influence of protein concentration and the addition of different doses of endopeptidase (Alcalase) and exopeptidase (Flavourzyme) on the sequential enzymatic hydrolysis of a protein concentrate obtained from defatted sunflower wholemeal. The results show that the greatest degree of hydrolysis (37.8%) is achieved by hydrolyzing an aqueous substrate with a 5% protein concentrate, and using a 0.02 g Alcalase/g of protein concentrate of the substrate. The aminograms performed reveal that the free amino acid found in the highest proportion in the hydrolysate was aspartic acid, which accounted for over 50% of the free amino acids present, regardless of the substrate concentration and the enzyme dosage used. Finally, the hydrolysate obtained from a substrate containing a 5% protein concentrate and a 0.02 g Alcalase/g of protein concentrate displayed characteristics that indicate its suitability for use as a vegetable-origin plant growth regulator.

This paper describes an experiment performed in order to study the possibility of using zeolite in organic olive groves. Soil and leaf analysis was performed and an increase in soil N levels was observed. Furthermore, higher levels of K in the soil and the trees point to the improved nutritional potential of these soils in terms of K, as a result of adding zeolite. The results obtained under experimental conditions can be extrapolated for real plantations in the area and will also lead to significant water savings, greater efficiency, decreased use of fertilizers and less contamination of underground water supplies, which can then be used elsewhere.

The process that permits the ability to obtain a protein extract from defatted sunflower flour also produces a solution very rich in phosphorus (P) and potassium (K), which also contains small concentrations of humic substances. The aim of this study has been to determine the possible agricultural use of this extract. Therefore the phosphorus–potassium solution (experimental solution) was analyzed to determinate its pH and its content of nitrogen, proteins, organic carbon, humic substances potassium and phosphorous. The experimental solution was applied on rye-grass (Lolium multiflorum Lam.) and afterwards the results were analyzed we calculated the germination percentage and the fresh and dry weights that were obtained after each cut throughout the duration of the experiment. In addition the different pigment types (chlorophyll a, chlorophyll b and carotenoids) were quantified. The conclusions of the study examine how this time-stable experimental solution improves the long-term effects and also the level of pigments, especially carotenoids, of the plants that have been treated.

The topic of how to decrease environmentally adverse effects of agriculture without losing too much crop yield is an important issue. In this respect, nutrient leaching losses were studied from a soil (land fallowing is not practiced) treated with two types of organomineral fertilizers [organomineral fertilizer (OMF) and organic + inorganic fertilizer mixture (O +IF), respectively]. Inorganic N losses were greatest in the soil treated with the O + IF, followed by those treated with the OMF, the former of which resulted in more gradual losses than the latter. Losses of other elements supplied by the fertilizers, particularly P and K, were greatest for the O + IF, followed by OMF treatment. The high nutrient losses observed in the soil treated with the O + IF make it advisable to use an OMF in soils with an abundant water supply. The highest N/P ratios were produced by the OMF, which suggest a lower eutrophication risk in drainage waters from soils treated with this fertilizer. Wheat (Triticum aestivum L. cv. Cajeme) yield parameters obtained and the alveographic assays showed that the OMF has a great potential of being used, at least on the wheat variety tested and under the pedoclimatic conditions prevailing in the study area. In this respect, application of OMF gave a significant increase in grain gross protein content of 2.9%, an increase in number of grains per spike of 2.2%, a significant increase in number of spikes per square meter of 3.4%, an increase in 1000-grain weight of 3.9%, and a significant yield increase of 2.5% with respect to the O + IF treatment.

The influence of pedological variables (soil type and temperature) in the nitrogen mineralization of an organic fertilizer obtained by composting of pig slurry versus a conventional fertilizer was studied. The net nitrogen mineralization rate and mineralization half-time for the different treatments were determined. The final values suggest that the mineralization was more extensive at 30°C than at 15°C, independent of the treatment fertilizer. Similar observations were made for the losses of N. The results reveal that greater losses of gaseous N takes place when a conventional fertilizer is applied (urea) than when compost is applied, which shows a lower pollution potential with compost. The treatment with compost exhibited the greatest residual N effect. The statistical treatment of changes in the inorganic N content during the incubation period showed that the soil+compost treatment contained two N fractions, one of quick mineralization and another of slower mineralization. In the case of the Luvisol soil, the nitrogen fraction of slower mineralization presents a highest half time of mineralization compared to the nitrogen fraction corresponding to the Rendsina soil. Finally, in relation to the pedological variables considered, the soil type has a larger influence than temperature on N mineralization.

Nitrogen (N) mineralization in soil treated With no fertilizer. (U), conventional fertilizer (C),: organic + conventional fertilizer (OC), and organomineral fertilizer. (OM) was studied. The net N mineralization rate and, mineralization half time for the different treatments, were determined. The final. values suggest that the mineralization was found to be more extensive at 25degreesC than at 15degreesC, independently of the treatment fertilizer effected. Similar comments could be made for the losses of gaseous N. Also the final gaseous N losses were higher slightly with the conventional (C) and organomineral (OM) fertilizers that in the soil treated with no fertilizer (U) and organic + conventional fertilizer (OC). The treatment with organic + conventional fertilizer (OC) exhibited the greatest residual effect. The statistical treatment of changes in the inorganic N content during the incubation period showed the organic + conventional fertilizer (OC) to contain two types of N fractions with a mineralization half time of 1 day (conventional fraction) and 243 days (organic fraction, respectively). On the other hand, the organomineral fertilizer (OM) was found to contain a single N fraction the mineralization half time of which was 3 days. On the other hand, the cumulative C-CO2 evolution was significantly greater for organic matter-amended than for non-organic matter-amended soils. Also, the temperature was markedly influential in the evolution Of C-CO2, highlighting the biggest values to 25degreesC and for the treatment OC, independently of the used temperature, due mainly to the presence of labile organic N presents in the treatment OC. The manufacturing process of the organomineral fertilizer (in a reactor at a high temperature) may favor of the more resistant N. fractions, which are initially integrated in the organic fraction.