Effects of fresh and field-aged holm-oak biochar on As, Cd and Pb bioaccumulation in different rice growing environments.

Arsenic, Cd, and Pb environmental fate is influenced when the traditional permanent flooding rice production systems are replaced by water-saving and soil conservation practices, urging for additional strategies that avoid their bioaccumulation in rice grain. The aim of this two-years field study was to evaluate the effects of fresh and field-aged biochar on As, Cd, and Pb bioaccumulation, and on As speciation, in rice grain produced in different growing environments (flooding versus sprinkler and conventional tillage versus direct seeding). Biochar produced from holm-oak pruning residues (pyrolysis at 550 °C, 48 h), in a single application (28 Mg ha-1), reduced As bioaccumulation in rice grain in the permanent flooding system to non-quantifiable concentrations (e.g., from 0.178 mg kg-1 to <0.04 mg kg-1, for inorganic-As, respectively), an effect which remained under field-aging conditions, increasing rice commercial value. When adopting sprinkler irrigation, the undesirable increase in Cd bioaccumulation in rice, relatively to the anaerobic system, was counteracted by biochar application, reducing its bioaccumulation in kernels between 32 and 80 %, allowing a simultaneous control of metals and metalloids bioaccumulation in rice. The bioaccumulation of Pb was also prevented with biochar application, with a reduction in its concentration four- to 13-times, in all the management systems, relatively to the non-amended plots, under fresh biochar effects. However, Pb immobilization decreased with biochar field-aging, indicating that the biochar application may have to be repeated to maintain the same beneficial effect. Therefore, the present study shows that the implementation of sprinkler irrigation with holm-oak biochar could reduce the risk of heavy metals(loids) bioaccumulation in rice grains and, thereby, ensuring food safety aspects, particularly under fresh biochar effects.

Medium-Term Effects of Sprinkler Irrigation Combined with a Single Compost Application on Water and Rice Productivity and Food Safety.

Traditional rice (Oryza sativa L.) management (tillage and flooding) is unsustainable due to soil degradation and the large amount of irrigation water used, an issue which is exacerbated in the Mediterranean region. Therefore, there is a need to explore rice management strategies in order to improve water-use efficiency and ensure its sustainability. Thus, field experiments were conducted to determine the medium-term effects of different irrigation and tillage methods combined with a single compost application on water and rice productivity, as well as food safety in a semiarid Mediterranean region. The management systems evaluated were: sprinkler irrigation in combination with no-tillage (SNT), sprinkler irrigation in combination with conventional tillage (ST), which were implemented in 2015, and flooding irrigation in combination with conventional tillage (FT), and their homologues (SNT-C, ST-C, and FT-C) with single compost application in 2015. In reference to rice grain yield, the highest values were observed under ST treatment with 10 307 and 11 625 kg ha-1 in 2018 and 2019 respectively; whereas between FT and SNT there were no significant differences, with 8 140 kg ha-1 as mean value through the study. Nevertheless, sprinkler irrigation allowed saving 55% of the total amount of water applied in reference to flooding irrigation. Furthermore, the highest arsenic concentration in grains was found under FT but it decreased with compost application (FT-C) and especially with sprinkler irrigation, regardless of tillage management systems. However, sprinkler irrigation favors the cadmium uptake by plants, although this process was reduced under SNT in reference to ST, and especially under amended compost treatments. Therefore, our results suggested that a combination of sprinkler irrigation and compost application, regardless of the tillage system, could be an excellent strategy for rice management for the Mediterranean environment in terms of water and crop productivity as well as food safety.

Combined use of biochar and alternative management systems for imazamox induced pollution control in rice growing environments.

Imazamox (IMZX) is a persistent herbicide having probable risks for non-target organisms in the environment and water contamination. Alternatives to conventional flooding rice production, including biochar amendment, may induce changes in soil properties which can greatly modify the environmental fate of IMZX. This two-year study is the first to evaluate how tillage and irrigation practices, with or without fresh or aged biochar (Bc), that are alternatives to conventional rice production impact IMZX's environmental fate. The treatments were: conventional tillage and flooding irrigation (CTFI), conventional tillage and sprinkler irrigation (CTSI), no-tillage and sprinkler irrigation (NTSI), and the corresponding Bc-amendment treatments (CTFI-Bc, CTSI-Bc, and NTSI-Bc). Fresh and aged Bc amendment decreased IMZX's sorption onto the soil in tillage treatments, with Kf values decreasing 3.7 and 4.2-fold (fresh case) and 1.5 and 2.6-fold (aged case) for CTSI-Bc and CTFI-Bc, respectively. The transition to sprinkler irrigation reduced IMZX persistence. Overall, Bc amendment also reduced chemical persistence with half-life values decreasing 1.6 and 1.5-fold for CTFI and CTSI (fresh year) and 1.1, 1.1, and 1.3-fold for CTFI, CTSI, and NTSI (aged year), respectively. Sprinkler irrigation reduced IMZX leaching by up to a factor of 2.2. The use of Bc as amendment led to a significant decrease in IMZX leaching only under tillage conditions, but notable in particular for the CTFI case where leaching losses were reduced in the fresh year from 80% to 34% and, in the aged year, from 74% to 50%. Hence the change in irrigation from flooding to sprinkler either alone or in combination with the use of Bc (fresh or aged) amendment could be considered an effective way to sharply mitigate IMZX contamination of water in environments where rice is grown, particularly in those managed with tillage.

Effects of Combined Use of Olive Mill Waste Compost and Sprinkler Irrigation on GHG Emissions and Net Ecosystem Carbon Budget under Different Tillage Systems.

Traditional rice (Oryza sativa L.) production by flooding is a source of greenhouse gases (GHG), especially methane. The high consumption of water, as well as the chemical and physical degradation caused by these traditional practices in rice soils, is promoting a decrease in rice production in the Mediterranean area. The aim of this study was to monitor GHG emissions and the net ecosystem carbon balance (NECB) from rice produced with sprinkler irrigation techniques and also assess the impact of olive mill waste compost (C-OW) application and tillage on GHG emissions and the NECB. A field experiment for irrigated rice production was implemented by considering four different treatments: (1) tillage (T); (2) no tillage-direct seeding techniques (DS); (3) application of C-OW followed by tillage (TC); and (4) application of C-OW followed by direct seeding (DSC). The C-OW was only applied in the first year at a dose of 80 Mg ha-1. GHG emissions were monitored over three years in these four treatments in order to estimate the direct (first year) and residual (third year) effects of such practices. The application of C-OW caused an increase of 1.85 times the emission of CO2-C in the TC-DSC compared to the T-DS in the first year. It is noteworthy that the TC treatment was the only one that maintained an emission of CO2-C that was 42% higher than T in the third year. Regardless of the treatments and year of the study, negative values for the cumulative CH4 were found, suggesting that under sprinkler irrigation, CH4 oxidation was the dominant process. A decrease in N2O emissions was observed under direct seeding relative to the tillage treatments, although without significant differences. Tillage resulted in an increase in the global warming potential (GWP) of up to 31% with respect to direct seeding management in the third year, as a consequence of the greater carbon oxidation caused by intensive tillage. DS presented a positive NECB in the accumulation of C in the soil; therefore, it provided a greater ecological benefit to the environment. Thus, under Mediterranean conditions, rice production through a sprinkler irrigation system in combination with direct seeding techniques may be a sustainable alternative for rice crops, reducing their GWP and resulting in a lower carbon footprint. However, the use of C-OW as an organic amendment could increase the GHG emissions from rice fields irrigated by sprinklers, especially under tillage conditions.

Environmental fate and efficiency of bispyribac­sodium in rice soils under conventional and alternative production systems affected by fresh and aged biochar amendment.

Irrigation and tillage practice alternatives to conventional flooding production, with or without organic amendments, are attracting great interest to adapt rice cultivation to climate change. However, they can alter the behaviour of pesticides and their efficiency against weeds. A two-year field experiment was conducted to investigate how the environmental fate and the weed control efficiency (WCE) of bispyribac­sodium (BS) were influenced by biochar produced from holm oak prunings (BHO) testing both the fresh and the aged effects. The treatments were: flooding irrigation and tillage (FT), sprinkler irrigation and tillage (ST), sprinkler irrigation and no-tillage (SNT), and the corresponding homologues with BHO addition (FT-BHO, ST-BHO, and SNT-BHO, respectively). Fresh BHO amendment decreased the sorption of BS onto the soil in all treatments, while, after aging, it also decreased sorption in FT-BHO (1.3-fold) but increased it in SNT-BHO and ST-BHO (1.1-fold). BHO addition reduced BS persistence under non-flooding and flooding incubation conditions, except for FT under the former condition for which t1/2 increased ≈1.5-fold in both years. The addition of BHO led to a decrease in BS leaching from 58.3 % and 44.6 % and from 70.4 % and 58.1 % in ST and FT to 50.1 % and 38.3 % and 63.6 % and 50.3 % in the homologue amended soils for the fresh and aged years, respectively. While fresh BHO addition decreased the WCE of BS in SNT-BHO, ST-BHO, and FT-BHO on average by a factor of 1.5, with aged BHO there was only such a decrease (by a factor of 1.4) in FT-BHO. The use of BHO could be effective for reducing water contamination by BS in flooding or sprinkler irrigation rice farming as long as conventional tillage is used. But it may also contribute to greatly reducing the herbicide's efficiency, although with time to allow aging, this reduction would only persist under conventional flooding production.

Combined use of olive mill waste compost and sprinkler irrigation to decrease the risk of As and Cd accumulation in rice grain.

Sprinkler irrigation has been successfully introduced in rice production as an alternative to the traditional flooding system, allowing water savings and the reduction of As accumulation in the grain. However, the same conditions can increase Cd mobility and grain accumulation, an effect that needs to be countered. A 3-year field experiment was set-up in a Mediterranean region (Extremadura, Spain), to evaluate how the application of compost from olive mill waste (single application, 80 t ha-1), influences the accumulation of As and Cd in the grain under different irrigation regimes. Accumulation of As in the grain was always lower in the sprinkler irrigation when compared with the flooding irrigation, reaching a 5-fold difference in the third year. Compost application did not evidence a clear effect on the As accumulation in the rice grain, but highly significant negative correlations (p < 0.001) were obtained between As content in the grain (total, inorganic, and organic) and the humification parameters in the soil, evidencing the importance of using a mature and stable organic amendment to avoid As accumulation in the grain. Cadmium accumulation in the rice grain decreased in each treatment where compost was applied, relatively to the non-treated counterpart (e.g., from 0.080 to <0.010 mg kg-1, in direct seeding with sprinkler irrigation, in the third year). There were no significant differences in the total inorganic As between treatments with or without compost application, but it was possible to observe an increase in the predominance of the organic As over the more toxic inorganic As, when compost was applied, allowing a decrease in the risk associated to As accumulation. Therefore, the aerobic cultivation of rice, with the simultaneous application of an adequate source of organic matter, can be considered a good solution to cope with the risk of accumulation of As and Cd in the rice grain.

Olive mill sludge may reduce water contamination by 4-chloro-2-methylphenoxyacetic acid (MCPA) in non-flooding but enhance it in flooding rice cropping agroecosystems.

A field experiment covering three years was conducted to evaluate how composted olive mill sludge (OS) influenced MCPA's environmental fate in rice soils under six combinations of tillage and irrigation cultivation techniques: tillage and sprinkler irrigation without (TS) or with (TSOS) the addition of OS (80 Mg ha-1), no-tillage and sprinkler irrigation without (NTS) or with (NTSOS) OS, and tillage and continuous flooding without (TF) or with (TFOS) OS. The measurements made in the first and third years after OS application were taken to constitute the "direct" and "residual" effects, respectively. After OS amendment, Kd (partition coefficients) values in the direct year were lower by factors of 1.1, 1.3, and 1.9 in TSOS, NTSOS, and TFOS, respectively, relative to the corresponding unamended soils, and in the residual year by factors of 1.1 and 1.5 in TSOS and NTOS, but greater by a factor of 1.5 in TFOS, than in the corresponding unamended soils, respectively. The dissipation of MCPA was very fast under both anaerobic (t1/2 = 1.80-5.29 d) and aerobic (t1/2 = 2.23-9.42 d) incubation conditions. The field application of OS led to a decrease in MCPA persistence under both incubation conditions, especially in the TF case. However, while under aerobic conditions the half-life (t1/2) decreased after OS addition in the direct and residual years, under anaerobic condition it only decreased in the direct year. While the application of OS in TS and NTS led to less leaching of MCPA, in TF it led to 1.4 and 1.2 times more leaching losses of the herbicide for the direct and residual years, respectively. Therefore, the use of OS in rice production could be considered an effective strategy for reducing water contamination by MCPA in at least the short- and medium-terms after its application, but only under non-flooding crop management regimes irrespective of the tillage practice implemented.

How the environmental fate of clomazone in rice fields is influenced by amendment with olive-mill waste under different regimes of irrigation and tillage.

BACKGROUND: Irrigation and tillage systems alone or in combination with organic amendments can strongly influence soil properties, which in turn may also modify the environmental fate of any pesticides applied. This study was aimed at determining how amendment with composted olive-mill waste (W) influenced leaching, sorption, and persistence of the herbicide clomazone in rice field soils under different tillage and irrigation management practices. The field trial conducted covered 3 years in succession, with six treatments: irrigation by sprinkler and conventional tillage without (ST) or with W application (80 Mg ha-1 ) (STW), irrigation by sprinkler but no tillage (SNT), irrigation by sprinkler but no tillage with W application (SNTW), and continuous flooding irrigation and tillage without (FT) and with W application (FTW). RESULTS: Application of W significantly increased the adsorption of clomazone to soil in the first and third years. In the first year, the persistence of clomazone under aerobic (t1/2  = 33.1-36.3 days) and anaerobic incubation conditions (t1/2  = 3.43-10.8 days) decreased after W application to t1/2 values in the ranges 18.1-29.7 and 3.06-5.44 days, respectively. However, in the third year, although clomazone persistence increased significantly in SNT and ST when W was applied under both incubation conditions, it decreased significantly in FT management under anaerobic incubation conditions. The addition of W led to less leaching of clomazone, particularly for the FT case where the herbicide leaching losses were 2.8 and 2.6 times lower in the first and third years after W addition, respectively. CONCLUSIONS: Using W as an organic amendment could be regarded as an invaluable strategy to reduce water contamination by clomazone in rice production, especially under traditional tillage and flooding management. © 2019 Society of Chemical Industry.

Environmental fate of bensulfuron-methyl and MCPA in aerobic and anaerobic rice-cropping systems.

Bensulfuron-methyl (BM) and 4-chloro-2-methylphenoxyacetic acid (MCPA) are herbicides widely used in rice agroecosystems, and are commonly found in their environments, especially in water resources. The objective of this study was to evaluate the sorption-desorption, leaching, and dissipation of BM and MCPA under aerobic and anaerobic rice cropping conditions. For this purpose, a three-year field experiment was conducted in SW Spain using four management systems: aerobic with sprinkler irrigation and tillage (ST), sprinkler irrigation and no-tillage (SNT), long-term sprinkler irrigation and no-tillage (SNTLT), and anaerobic with flooding and tillage (FT). At the end of the experiment, the partition coefficients (Kd-values) in ST were (2.7, 3.1, and 3.9) and (1.2, 1.5, and 1.9) times significantly lower than the values in {SNT, SNTLT, and FT} for BM and MCPA, respectively. Greater sorption was related to lower values of soil pH for both herbicides and to higher contents in humic acids for BM and fulvic acids for MCPA. The persistence was much longer for BM (t1/2 = 26.9-52.1 days) than for MCPA (t1/2 = 1.54-21.1 days) in all management systems, and both herbicides' dissipation rates were generally greater under aerobic than under anaerobic conditions. The mobility of MCPA was much greater than that of BM. Compared with SNT and SNTLT, leaching losses of the applied BM were greater by 51% for ST, and of the applied MCPA by 55% and 99% for ST and FT, respectively. Therefore, only aerobic rice production with no-tillage in the short- or long-terms could be considered as alternative management strategies with which to reduce water contamination by BM and MCPA in rice-growing environments.

HLA analysis of Mexican candidates for bone marrow transplantation and probability of finding compatible related donors.

INTRODUCTION: Oncohematological disorders are the main cause of morbidity in the Mexican population from 1 to 19 years old, where megakaryoblastic and promyelocitic leukemias are more frequent. Considering that the success of a transplant is multifactorial, the criterion of compatibility in the HLA system is crucial and even more so when the source of HSC is bone marrow. OBJECTIVE: To determine the frequency of the HLA genotype in Mexican candidates who require a bone marrow transplant from related donors and the probability to find donors. MATERIALS AND METHODS: One hundred twenty-six candidates for bone marrow transplant and related donors were tested for HLA class I (-A*, -B* alleles) and class II (-DRB1* allele) in intermediate-resolution, as the first phase in the choice of the possible donor. The criteria to identify donors were determined by antigen-matched in each HLA haplotype as follows: 4/6, 5/6 and 6/6 at the HLA-A*, HLA-B*, and HLA-DRB1* alleles. RESULTS: Of all the candidates analyzed, 57.93%, at least one bone marrow donor was identified; in 53 cases, no donor was found. The average size of the families was 4.79 ±â€¯1.06 members. A higher percentage of compatibility with grade 6/6 (31.6%) was identified with brothers, followed by sisters in 25.3%. The probability to find at least one compatible potential donor was 1.51 ±â€¯0.92 donors. CONCLUSION: In the first phase to select donors, Mexican patients studied in this work, have a compatible donor, however the grade of resolution test influenced in the probability identified.

Behaviour of bentazon as influenced by water and tillage management in rice-growing conditions.

Bentazon is a widely used herbicide in rice agroecosystems that has commonly been found in water resources. To assess how tillage and water regimes affect sorption/desorption, dissipation and leaching of bentazon in Mediterranean rice-growing conditions, field experiments were carried out using tillage and flooding (TF), tillage and sprinkler irrigation (TS), no-tillage and sprinkler irrigation (NTS) and long-term no-tillage and sprinkler irrigation (NTS7). After 3 years, the Kd values in TS were 2.3, 1.6 and 1.7 times lower than the values in NTS7, NTS and TF respectively. Greater sorption of bentazon was related to higher contents in total organic carbon and, although to a lesser extent, in humic acids and dissolved organic carbon. The persistence of bentazon was significantly greater under anaerobic (half-life DT50 = 94.1-135 days) than under aerobic (DT50 = 42.4-91.3 days) incubation conditions for all management regimes. Leaching losses of bentazon were reduced from 78 and 74% in TS and TF to 61 and 62% in NTS7 and NTS respectively. The mid- and long-term implementation of sprinkler irrigation in combination with no-tillage could be considered a management system that is effective at reducing water contamination by bentazon in Mediterranean rice-growing agroecosystems. © 2017 Society of Chemical Industry.

De-oiled two-phase olive mill waste may reduce water contamination by metribuzin.

The impact of de-oiled two-phase olive mill waste (DW) on the behavior of metribuzin in Mediterranean agricultural soils is evaluated, and the effects of the transformation of organic matter from this waste under field conditions are assessed. Four soils were selected and amended in the laboratory with DW at the rates of 2.5% and 5%. One of these soils was also amended in the field with 27 and 54 Mg ha(-1) of DW for 9 years. Significant increases in metribuzin sorption were observed in all the amended soils. In the laboratory, the 5% DW application rate increased the t1/2 values of metribuzin from 22.9, 35.8, 29.1, and 20.0 d for the original soils to 59.2, 51.1, 45.7, and 29.4d, respectively. This was attributable mainly to the inhibitory effect of the amendment on microbial activity. However, the addition of DW transformed naturally under field conditions decreased the persistence down to 3.93 d at the greater application rate. Both amendments (fresh and field-aged DW) significantly reduced the amount of metribuzin leached. This study showed that DW amendment may be an effective and sustainable management practice for controlling groundwater contamination by metribuzin.

Environmental fate of the herbicide MCPA in agricultural soils amended with fresh and aged de-oiled two-phase olive mill waste.

Olive oil agrifood industry generates large amounts of waste whose recycling as organic amendment represents an alternative to their disposal. The impact of de-oiled two-phase olive mill waste (DW) on the fate of 4-chloro-2-methylphenoxyacetic acid (MCPA) in Mediterranean agricultural soils was evaluated. Furthermore, the effect of the transformation of organic matter from this waste under field conditions was assessed. Four Mediterranean agricultural soils were selected and amended in laboratory with fresh DW and field-aged DW (DW and ADW treatments, respectively). Adsorption capacity increased by factors between 1.18 and 3.59, for the DW-amended soils, and by factor of 4.93, for ADW-amended soil, with respect to unamended soils, when 5% amendment was applied. The DW amendment had inhibitory effect on dehydrogenase activity and slowed herbicide dissipation, whereas the opposite effect was observed in ADW treatments. In the field-amended soil, the amount of MCPA leached was significantly reduced from 56.9% for unamended soil to 15.9% at the 5% rate. However, leaching losses of MCPA increased in the laboratory-amended soils, because of their high water-soluble organic carbon values which could enhance MCPA mobility, especially in the acidic soils. Therefore, the application of DW as organic amendment in Mediterranean agricultural soils could be an important management strategy to reduce MCPA leaching, especially if the organic matter had been previously transformed by ageing processes.

Sprinkler irrigation of rice fields reduces grain arsenic but enhances cadmium.

Previous studies have demonstrated that rice cultivated under flooded conditions has higher concentrations of arsenic (As) but lower cadmium (Cd) compared to rice grown in unsaturated soils. To validate such effects over long terms under Mediterranean conditions a field experiment, conducted over 7 successive years was established in SW Spain. The impact of water management on rice production and grain arsenic (As) and cadmium (Cd) was measured, and As speciation was determined to inform toxicity evaluation. Sprinkler irrigation was compared to traditional flooding. Both irrigation techniques resulted in similar grain yields (~3000 kg grain ha(-1)). Successive sprinkler irrigation over 7 years decreased grain total As to one-sixth its initial concentration in the flooded system (0.55 to 0.09 mg As kg(-1)), while one cycle of sprinkler irrigation also reduced grain total As by one-third (0.20 mg kg(-1)). Grain inorganic As concentration increased up to 2 folds under flooded conditions compared to sprinkler irrigated fields while organic As was also lower in sprinkler system treatments, but to a lesser extent. This suggests that methylation is favored under water logging. However, sprinkler irrigation increased Cd transfer to grain by a factor of 10, reaching 0.05 mg Cd kg(-1) in 7 years. Sprinkler systems in paddy fields seem particularly suited for Mediterranean climates and are able to mitigate against excessive As accumulation, but our evidence shows that an increased Cd load in rice grain may result.

Behavior of MCPA in four intensive cropping soils amended with fresh, composted, and aged olive mill waste.

An evaluation was made of the impact of olive mill waste and its organic matter transformation on the sorption, desorption, leaching, and degradation of the herbicide MCPA when the waste was applied to four Mediterranean soils. The soils were amended in the laboratory with fresh, composted, and field-aged olive mill waste (OW, COW, and AOW treatments, respectively). It was found that the greater the amount of OW applied to the soils, but especially the greater its organic matter maturity, the greater the adsorption of MCPA. Compared with unamended soils, at the 5% rate of application the adsorption capacity increased by between 9.8% and 40%, 148% and 224%, and by 258% for the OW, COW, and AOW amended soils, respectively. The hysteresis coefficients were significantly lower in the OW-amended soils than in AOW or COW-amended soils, indicating that the adsorbed MCPA could be easily desorbed in OW-amended soils if the amendment is not aged or composted. While the OW addition greatly extended the persistence of MCPA, the application of COW enhanced MCPA degradation in all the soils, as corresponded to the increased soil microbial activity indicated by the higher levels of soil dehydrogenase activity. Fresh OW amendment significantly increased the amount of MCPA leached (from 13.7% in the most alkaline soil to 36.7% in the most acidic, at the 5% rate of application), favored by the higher levels of water soluble organic carbon content. However, leaching losses of the herbicide were reduced by up to 39.9% and 55.3% in the COW- and AOW-amended soils at the 5% loading rate, respectively. The use of OW with a high degree of organic matter maturity may be regarded as a potentially useful management practice to reduce MCPA leaching in soils with low organic matter content. The application of fresh OW, however, could well increase the risk of groundwater contamination by this herbicide, especially in acidic soils.

Impact of oiled and de-oiled olive mill waste amendments on the sorption, leaching, and persistence of S-metolachlor in a calcareous clay soil.

Agricultural practices based on periodic inputs of organic amendments are strongly recommended for Mediterranean agro-ecosystems. Such amendments can change the soil's properties and transport characteristics, and hence affect the behaviour and fate of pesticides. S-metolachlor is an herbicide commonly used in intensive crops. The aim of this study was to investigate the influence of fresh oiled (OW) and de-oiled two-phase olive mill waste (DW) amendments on the sorption, leaching, and persistence of the herbicide S-metolachlor in a calcareous clay soil. The soil was amended in the laboratory with OW and DW at the rates of 2.5% and 5% (w/w). Significant increases in S-metolachlor sorption were observed in all amended soils. The addition of OW and DW increased the herbicide half-life from 27 d for the original soil to 41 and 47 d at the higher application rate of OW and DW, respectively. There was a significantly greater retention of the herbicide at the higher OW and DW loading rate. However, whereas the amount of S-metolachlor in the leachate was reduced by increasing the amount of OW, it was unaffected by increasing the amount of DW. The results lend support to the potential of OW and DW amendments as an effective management practice to increase S-metolachlor persistence in soils. This increase does not necessarily ensure decreased leaching of the herbicide but it could also increase the risk of surface water contamination at higher application rate.

Sorption, leaching and persistence of metribuzin in Mediterranean soils amended with olive mill waste of different degrees of organic matter maturity.

Metribuzin is a widely used herbicide, and worldwide is one of the most important contaminants in ground and surface waters. The aim of this study was to evaluate the impact amendment with fresh, composted, and field-aged olive mill waste (OW, COW, and AOW, respectively) had on the behaviour of this herbicide in four typical Mediterranean soils. A batch equilibration method was used to determine metribuzin adsorption-desorption. Leaching experiments were studied in hand-packed soil columns. Half-lives were calculated with incubation studies. Soil dehydrogenase activity (DHA) was also monitored. Metribuzin adsorption in the soils increased not only with increasing amounts of amendment, but especially with increasing degree of organic matter humification. Compared to unamended soils, the adsorption capacity increased by between 81% and 216%, 135% and 193%, and by 363% for the OW, COW, and AOW amended soils, respectively, at a 5% rate of application. The addition of COW enhanced metribuzin degradation in all the soils. In contrast, OW addition increased metribuzin persistence, attributable mainly to the inhibitory effect of this amendment on microbial activity, especially in the acidic soils. The AOW-amended soils, which had the smallest labile fraction of soil organic matter and greatest degree of humification, showed the shortest herbicide persistence. The OW and COW amendments significantly reduced the amount of metribuzin leached. This was especially so in the latter case because of the higher sorption capacity and the faster degradation of the pesticide. The use of OW as organic amendment, especially when it has a high degree of organic matter humification, may be a useful management practice for reducing the risk of groundwater contamination by metribuzin in soils with low organic matter content.

Transformation of organic wastes in soil: effect on bentazone behaviour.

The aim of this study was to evaluate the impact of two organic wastes from olive oil production on the fate of bentazone in soil, and to assess the influence of the transformation of organic matter from these wastes under field conditions. Results on freshly laboratory-amended soils were compared to those with soils amended in the field for nine consecutive years. Two amendments and two doses were studied. Sorption of bentazone increased upon amendment with Kd values from 0.03 to 1.7. The increase was higher for freshly amended soils than for the field amended soils and for the higher dose. Degradation was correlated with sorption in the case of field amended soils, whereas higher persistence in freshly amended soils may be related to the easier microbial availability of DOC molecules than bentazone molecules. The increase in non-conducting pores in amended soils favours sorption and degradation processes reducing leaching. Important differences revealed in herbicide fate between freshly amended soils and aged field amended soils limit further extrapolation of laboratory studies to field studies.

Sampling optimization for printer characterization by greedy search.

Printer color characterization, e.g., in the form of an ICC output profile or other proprietary mechanism linking printer RGB/CMYK inputs to resulting colorimetry, is fundamental to a printing system delivering output that is acceptable to its recipients. Due to the inherently nonlinear and complex relationship between a printing system's inputs and the resulting color output, color characterization typically requires a large sample of printer inputs (e.g., RGB/CMYK) and corresponding color measurements of printed output. Simple sampling techniques here lead to inefficiency and a low return for increases in sampling density. While effective solutions have been proposed to this problem very recently, they either do not exploit the full possibilities of the 3-D/4-D space being sampled or they make assumptions about the underlying relationship being sampled . The approach presented here does not make assumptions beyond those inherent in the subsequent tessellation and interpolation applied to the resulting samples. Instead, the tradeoff here is the great computational cost of the initial optimization, which, however, only needs to be performed during the printing system's engineering and is transparent to its end users. Results show a significant reduction in the number of samples needed to match a given level of color accuracy.

Cumulative and residual effects of de-oiled two-phase olive mill waste application to soil on diuron sorption, leaching, degradation, and persistence.

Laboratory and field experiments were conducted to evaluate the influence of de-oiled two-phase olive mill waste (DTPOMW) amendments on the sorption-desorption, degradation, leaching, and persistence of the herbicide diuron in a representative olive grove soil. The soil was amended in the laboratory with DTPOMW at the rates of 5% and 10% (w/w), and in the field with 27 and 54 Mg ha(-1) of DTPOMW for 7 years. Cumulative and residual effects were evaluated in the last year and 2 years after the last DTPOMW field application (2005 and 2007, respectively). The results showed that the adsorption of diuron to the soil significantly increased in the presence of DTPOMW in the laboratory and field-amended soils, and that humic acid content was mainly responsible for this increase. The DTPOMW soil application only significantly increased the half-life of diuron in the laboratory-amended soils, ranging from 8.6d for the original soil to 51 d at the greater application rate. The DTPOMW amendments significantly reduced the downward mobility of diuron, and reduced the amount of herbicide leached in the laboratory and field-amended soils, and no residues of diuron were detected in the leacheate of the residual-amended columns. In the field study, DTPOMW addition increased the persistence of diuron in the upper 10 and 5 cm of the soils in the cumulative and residual years, respectively, decreasing the herbicide's vertical movement through the amended soils with increasing DTPOMW rate. This study has shown that in olive grove soils DTPOMW amendment may be an effective management practice for controlling ground water contamination by diuron.