Effect of biochar amendment on nitrate retention in a silty clay loam soil

Biochar incorporation into agricultural soils has been proposed as a strategy to decrease nutrient leaching. The present study was designed to assess the effect of biochar on nitrate retention in a silty clay loam soil. Biochar obtained from the pyrogasification of fir wood chips was applied to soil and tested in a range of laboratory sorption experiments. Four soil treatments were considered: soil only (control), soil with 2, 4 and 8% of biochar by mass. The Freundlich sorption isotherm model was used to fit the adsorbed amount of nitrate in the soil-biochar mixtures. The model performed very well in interpreting the experimental data according to a general linear regression (ANCOVA) statistical approach. Nitrate retention in the soil-biochar mixtures was always higher than control, regardless the NO3- concentration in the range of 0-400 mg l-1. Different sorption capacities and intensities were detected depending on the biochar application rate. The highest adsorption capacity was observed in the soils added with 2 and 4% of biochar, respectively. From the results obtained is possible to infer that nitrate retention is higher at lower biochar addition rate to soil (2 and 4%) and at lower nitrate concentration in the soil water solution. These preliminary laboratory results suggest that biochar addition to a typical Mediterranean agricultural soil could be an effective management option to mitigate nitrate leaching

WP 6: MODELLING STAKEHOLDER INTERPLAY AND POLICY SCENARIOS FOR BIOREFINERY AND BIODIESEL PRODUCTION. D 6.6: Detailed specification of the questionnaire to be delivered to various stakeholders

In this deliverable we first present a technical note on how to identify the key agro-energy stakeholders involved (or potentially involved) in the production of biodiesel in the province of Foggia (Capitanata). Subsequently, we present the questionnaire which will be distributed to these stakeholders.

Grasses and legumes in mixture: an energy intercropping system intended for anaerobic digestion

Batch testing of biomethanization was conducted on organic matrices from a mixture of grasses (triticale and barley) and legumes (field bean - Vicia faba L. var . minor ). These tests were performed in mesophylic conditions (35°C) on previously chopped and ensiled biomass. The three crops have been cultivated in Southern Italy (Puglia region), both as single-crops and intercropping between triticale or barley and field bean, in different mixture combinations, during the season 2009-2010. Emphasis was placed on the determination of the chemical composition of feedstock from the three single species and their different intercropping ratios, mowed at two subsequent stages (milk and dough development of grasses), also assessing their consequent biogas and methane potential yields after silage. Seven overall treatments have been compared: the three species in monoculture (triticale, barley and field bean, respectively); two mixtures between triticale and field bean (with triticale at 70 and 50%, respectively); two mixtures between barley and field bean (again with barley at 70 and 50%, respectively). Immediately after cutting and for the next 90 days, biomass samples were closed into plastic mini-silos, each having a 5-L capacity, in order to simulate the silage process. Thereafter, the batch testing was performed and biogas and methane production have been determined, with respect to the main chemical characteristics of the chopped and ensiled biomass samples, able to affect biogas and methane yield. Considering the single-crop treatments the highest biogas per hectare production has been found with respect to triticale (8737.1 nm 3 ha -1 ) and barley (8837.6 nm 3 ha -1 ), at the first and second harvesting stage, respectively. Concerning grass-legume intercropping, the highest biogas yield (8635.0 nm 3 ha -1 ) was observed with reference to the 70:30 mixing ratio, specifically on barley mowed at the milk development stage. The methane content in the biogas ranged from 61.1% (on a 50:50 mixing ratio of barley at the milk stage) to 53.7% (on a barley monoculture at the dough stage)

Irrigation management in Mediterranean salt affected agriculture: how leaching operates

In the frame of a crop rotation currently applied in a farm of the Apulian Tavoliere (Southern Italy), this paper reports the effect of brackish water irrigation on soil, outlines the corresponding salinity balance, formulates quantitative relations to model salt outflow below the soil root-layer and defines operational criteria to optimize irrigation management at farm level in order to control soil salinity through leaching. The general aim is to contribute to a sustainable use of the available water resources and a proper soil fertility conservation. A three-year trial (2007-2010) was carried out on a farm located close to the coast of the Manfredonia gulf (Mediterranean - Adriatic sea), where irrigation with brackish water is frequently practiced due to seawater intrusion into the groundwater. An especially designed experimental field-unit was set-up: the bottom of three hydraulically insulated plots was covered with a plastic sheet to intercept the percolating water and collect it into tanks by means of drain tubes. Each year a double crop cycle was applied to the soil; a spring-summer crop (tomato, zucchini and pepper, respectively) was followed by a fall-winter crop (spinach, broccoli and wheat). Short "fallow" periods (completely bare soil) were inserted between two crop cycles. Irrigation or rain completely restored crop water consumptions (with the exception of wheat, considered a rainfed crop) and leaching was performed both unintentionally (by rainfalls) or intentionally (supplying higher irrigation volumes whenever the soil electrical conductivity exceeded a fixed threshold). The soil electrical conductivity was periodically measured together with volume and electrical conductivity of irrigation and drainage water. All these measures allowed to draw-up the salt-balance of the soil, respectively at the beginning and the end of each crop cycle. Absolute and relative variations in soil salt content were interpreted with respect to absolute and relative drainage volumes according to a three steps procedure of covariance analysis. A simple, general and comprehensive leaching model is thus presented. Results showed that salt build up into the soil can be very rapid, generally occurring within a single irrigated summer crop cycle. Rainfalls of the autumn-winter period had a crucial role in the removal of salts brought into the soil by summer irrigation. This paper strongly emphasises that additional fresh water supply is of great importance to establish acceptable soil conditions. Two suitable periods for intentional leaching were identified

Salt leaching due to rain in Mediterranean climate: is it enough?

The increasing limitation of available water resources for agriculture raises the issue of an appropriate use of low quality water (particularly brackish or saline water) for agricultural productivity without jeopardizing the quality of soil and its productive capacity. Referring to typical Mediterranean climate conditions and assuming a systematic irrigation use of brackish groundwater, this paper analyzes the capability of yearly rainfall, particularly in fall-winter period, to leach the salts accumulated in the soil during the previous spring-summer irrigation season. The leaching capability of water supplies exceeding the soil water holding capacity has undergone direct evaluation through a particular experimental arrangement: under a rain shelter, soil columns (inside special cylindrical containers), previously salinized and bare at the surface, were treated with repeated irrigations. Fresh water was used for this purpose, in order to simulate rainwater. The amounts and proportions of salt removed from the soil as well as the relative quantity of salt left in the soil were monitored. An appropriate statistical data analysis led to the interpretation of the observed process by developing a leaching curve able to predict the fraction of salts remaining along the soil profile according to the height of leaching water added to the soil, expressed as a fraction of the depth of the soil layer considered. According to the experimentally determined "leaching curve" (related to a silt-loam textured soil, basically unstructured and compacted as a result of a prolonged salinization), the following rule of thumb can be taken: the application of a defined height of leaching fresh water reduces by 70% (i.e. reduces to 30%) the salt content of a soil layer of equal depth. The elaboration of this conveniently parameterized "leaching curve" prompted an attempt to extend what had been experimentally observed to a larger time and spatial scale. Therefore, different scenarios were elaborated, regarding soil salinity in relation to particular hypotheses of irrigation management and crop rotation aimed, respectively, at promoting salt leaching and minimize salt load into the soil. This has been done on the basis of historical rain-gauge series reported by the Foggia weather observatory, with reference to the years 1951-2000. Very critical scenarios follow from the performed simulations. If only brackish groundwater is used for irrigation, the annual cultivation of a spring-summer irrigated crop without any additional leaching (apart from rain) leads to a saline buildup. This compromises agricultural soil quality. Therefore, a recommended technical choice is the cultivation of irrigated summer crops not more than once every two years. At the same time, a limited (100-200 mm) but influential fresh water applications for leaching purposes could be usefully associated

Role of the irrigation charges to induce the adoption of water saving innovation in semi-arid regions

The paper investigates about the effectiveness of water charges in inducing farmers to adopt the technical innovation aimed at water saving. It is claimed that by increasing water charge, the signal of the scarcity of the water resource is directly and effectively conveyed to farmers, who are supposed to promptly react by adopting a water saving technology. The analysis is referred to two types of innovation: an agronomic innovation, consisting on a crop mulching practice, and a management innovation, based on a voluntarily water pricing scheme with tariffs differentiated according to a peak and off-peak season. A theoretical model based on farms’ profit maximization is proposed, to evaluate the trigger conditions for the innovation. The model is applied to a case study referred to a semi-arid region, located in the South of Italy, according to which there is no clear evidence that a generalized increase may induce farmers to adopt the innovatio

Cereal straw management: a trade-off between energy and agronomic fate

Climate change mitigation is the most important driving force for bioenergy development. Consequently, the environmental design of bioenergy value chains should address the actual savings of both primary energy demand and greenhouse gases (GHG) emissions. According to the EU Renewable Energy Directive (2009/28/EC), no direct impacts and no GHG emissions should be attributed to crop residues (like cereal straws) when they are removed from agricultural land for the purpose of bioenergy utilisation. The carbon neutral assumption applied to crop residues is, however, a rough simplification. Crop residues, indeed, should not be viewed simply as a waste to be disposed, because they play a critical role in sustaining soil organic matter and therefore have an inherent C-capturing value. Moreover, considering straws as an energy feedstock, its status of co-product is clearly recognised and its availability could be obtained according to different cropping systems, corresponding to different primary energy costs and GHG emissions. This paper highlights some hidden features in the assessment of agricultural energy and carbon balance, still very difficult to be detected and accounted for. Although they are frequently disregarded, these features (such as long term dynamic trend of soil organic carbon and annual nitrous oxide emissions from the soil) should be carefully considered in assembling the energy and emission balance. By using a crop simulation model, the long-term soil organic matter and annual N2O soil emissions were estimated. Consequently, a comprehensive energy and GHG balance was determined in accordance with the life cycle assessment methodology. Contrasting methods of straw management and wheat cultivation were compared: straw retention vs removal from the soil; conventional vs conservation tillage; wheat cropping system as a single-crop or in rotation. The resulting carbon footprint of straws has different magnitudes with respect to the several experimental conditions. By selecting the best agricultural practices, energy from straw can be optimally coupled with grain productions, without detrimental effects on soil fertility. An improved and specifically tailored cropping system is designed to obtain an optimal trade-off

Irrigation pricing policy aimed at the enhancement of water saving innovation at farm level. A case study

In this study we analyze the price inducement effect of a generalized water tariff increase in the adoption of water saving innovation at farm level. We apply a linear programming decision making model to analyze the determinants affecting the adoption of two types of innovation: a process innovation, consisting on a crop mulching practice, and a management innovation, based on a voluntary water seasonal pricing scheme, differentiated according to a peak and off-peak periods. According to our results, the mulching practice is not affected by the tariffs that are still lower than the water marginal productivity, while they exert a negative effect when they become higher. On the contrary, the adoption of the voluntary water seasonal pricing scheme is affected by the tariffs increase only if the latter induce an excessive concentration of water demand during the peakDans cette étude nous présentons une recherche relative à la possibilité que l augmentation de tarif de l eau est capable d induire l agriculteur de adopter une innovation adressée à l épargne de l eau. Notre modèle de programmation linéaire nous a permis de analyser le procès de décision de l agriculteur et d entendre les causes déterminantes de l adoption de deux typologies d innovation: une innovation de procès, relative à une technique de paillis, et une innovation de management, relative à l introduction d un plan volontaire, avec des tarifs différentes entre les periodes de intense et de normale utilisation de l eau. Nos résultats montre que l augmentation de tarif de l eau n est pas une mesure sufficiente pour stimuler les agriculteurs à adopter la technique de paillis, lorsque le tarif de l eau est inférieur à sa productivité marginale. Ou contraire, quand le tarif est plus grand que la productivité marginale de l eau, l augmentation de tarif freine l adoption de l innovation. L introduction des tarifs différentes entre les periodes de intense ed de normale utilisation de l eau est encouragée par l augmentation de tarif seulement quand la demande de l eau est plus concentrée dans la la periode de intense utilisation de l ea

A modified sentinel node and occult lesion localization (SNOLL) technique in non-palpable breast cancer. A pilot study

Background: The spread of mammographic screening programs has allowed an increasing amount of early breast cancer diagnosis. A modern approach to non-palpable breast lesions requires an accurate intraoperative localization, in order to achieve a complete surgical resection. In addiction, the assessment of lymph node status is mandatory as it represents a major prognostic factor in these patients. The aim of this study is to evaluate the reliability of a modified technical approach using a single nanocolloidal radiotracer to localize both sentinel node and breast occult lesion. Methods: Twenty-five patients with a single non-palpable breast lesions and clinically negative axilla were enrolled. In the same day of surgery, patients underwent intratumoral and peritumoral administration of 99mTc-labeled nanocolloid tracer under sonographic guidance. A lymphoscintigraphy was performed to localize the sentinel lymph node and its cutaneous projection was marked on the skin in order to guide the surgeon to an optimal incision. During surgery an hand-held gamma-detection probe was used to select the best surgical access route and to guide localization of both occult breast lesion and sentinel lymph node. After specimen excision, the surgical field was checked with the gamma-probe to verify the absence of residual sources of significant radioactivity, thereby ensuring a radical treatment in a single surgical session and minimizing normal tissue excision. Results: Both targeted breast lesion and sentinel lymph node were localized and removed at the first attempt in every patients and histopathological diagnosis of malignancy was confirmed in 25/26 samples. Non-palpable lesions were included within the surgical margins in all patients and in all samples surgical margins were free from neoplastic infiltration thus avoiding any further reintervention. Only two patients showed metastatic involvement of sentinel lymph node. Conclusions: The modified sentinel node and occult lesion localization (SNOLL) technique performed with a single injection of nanocolloidal radiotracer has shown an excellent intraoperative identification rate of both non-palpable lesion and sentinel lymph node. This procedure offers, as opposed to standard techniques, an accurate, simple and reliable approach to the management of non-palpable breast cancer