Optimization of Nitrogen in Durum Wheat in the Mediterranean Climate: The Agronomical Aspect and Greenhouse Gas (GHG) Emissions

Durum wheat (Triticum turgidum L. subsp. durum) is the most cultivated cereal crop in the Mediterranean basin, traditionally grown under rainfed conditions using conventional tillage. Agronomical practices, soil type and climate variables are known to influence crop productivity. Their interaction effect is very complex and the time in which they occur strongly affects yield and quality. The nitrogen supply, in combination with climatic conditions, is the main constraint determining the physiological performance, grain yield and quality response of wheat. In addition, the N formulation, fertilizer management, crop sequence, seasonal trends, and the supply of residual and mineralized N influence the response of wheat to N fertilizer. N fertilizer management must be optimized to prevent N deficiency in the critical crop growth period, to avoid yield and quality losses and also prevent the excessive application of N fertilizer, thus reducing the environmental impact. The split application of N fertilizer is a promising strategy that satisfies plant needs and reduces N losses through improved nitrogen use efficiency (NUE). Such a strategy can result in a remarkable reduction in greenhouse gas (GHG) emissions and the carbon footprint of Italian durum wheat, considering that the highest proportion of the total emissions deriving from N fertilizer production and its application

Climate Variability Impact on Wheat Production in Europe: Adaptation and Mitigation Strategies

Increased carbon dioxide concentration, rise in temperature and drought stress are important key factors causing frequent occurrence of climate events. Important adaptation strategy such as modification of phenological pattern to avoid stressful period during plant development will be key feature in crop plants. In addition, comprehensive understanding of plants response to elevated CO2 concentration, temperature and drought stress alone or in combination will be needed to acclimatize crop plant to these changes. Study of climate variability impact on wheat production concerning mitigation strategies is need of time in order to reduce the risk of climate change on crop yield and growth. Similarly, information about the time in which climate variable(s) occurred in the field is important as the severity of its effect/their combined effect can vary largely. Agronomic practices such as cultivar choice, water and nitrogen supply, nutrients availability and growing conditions should be taken into account to design adaptation options. The failure of agriculture to adapt to climatic variability will impact global food, especially wheat production. A holistic approach will be paramount to sustaining agriculture and the vitality of the world in the face of climate change

Optimization of the environmental performance of rainfed durum wheat by adjusting the management practices

Altering agricultural practices to meet the sustainability criteria can be a promising solution for reducing environmental burdens related to intensive agricultural management practices. In this study, different wheat management practices are proposed and evaluated for their environmental performances from a life cycle prospective. Information on crop yield response to nitrogen (N) fertilizer rates and soil disturbance was collected from field experiments conducted during the growing season (2010e2012) at Pantanelli experimental farm in southern Italy. Environmental impacts are organized in impact categories, which are estimated under the proposed scenarios using different methodology. All impacts are linked to the production of 1 kg of durum wheat using farm gate as a system boundary. Results showed that for all the examined scenarios, largest burdens are related to the production of farm inputs, while the lowest to cultivation face, except for no nitrogen supply scenarios. Impact assessment results at midpoint level indicate that most impact categories have a direct correlation between impact assessment values, which are very much linked to grain productivity, and management intensity with some exceptions. In most cases, T1 performed better than other scenarios whereas T8 reported the highest impact. At damage category, however, most of the impacts on human health came from Climate change (49.4%) and Particulate matter formation (49.5%). For the damage to ecosystems, minor differences between the different production scenarios were calculated with best option was for the lowest input scenario (T1). Only two impact categories contributed in a clear manner to the total impact on ecosystem. Climate change and Agricultural land occupation represent the majority of the total impacts on ecosystem with 50.5% and 46.3%, respectively. Impact assessment for the damage category "Resources" show that the majority of the impacts came from the depletion of fossil fuel. The use of diesel fuel in tractors for the various agricultural steps was a significant process that was responsible for the impact on the proposed scenarios. Comparative analysis for the proposed management scenarios give the possibility for the optimization of farming systems, which resulted in increasing productivity with minimum input. This has led to the reduction of impacts resulted from the production of 1 kg of product. It was found that the contribution of conservation agriculture technique (NT with low input of N fertilizer) to the impact categories and GWP index was small compared to that of CT and RT. Data obtained from this study could help farmers as well as the industry to focus on the most emission-intensive stages of durum wheat production in order to reduce impacts by improving productivity

The Effect of Tillage on Faba Bean (<i>Vicia faba</i> L.) Nitrogen Fixation in Durum Wheat ((<i>Triticum turgidum</i> L. subsp. <i>Durum</i> (Desf))-Based Rotation under a Mediterranean Climate

Biological nitrogen fixation (BNF) is a sustainable approach to improving soil fertility that not only provides nitrogen to subsequent crops but also reduces the impacts of synthetic fertilizers. Here, a field experiment was established within the faba bean (Vicia faba L.), cv Prothabat 69-durum wheat (Triticum turgidum L. subsp. Durum (Desf)), cv Iride rotation framework of a long-term experiment in southern Italy to quantify BNF over two consecutive years (2012/13–2013/14). The effect of tillage systems (reduced, conventional, and no tillage) on faba bean N2 fixation was estimated at the flowering and maturity stages via the natural abundance technique, using wheat as a reference crop. The effect of tillage on the percentage of nitrogen fixation from the atmosphere (Ndfa) and the amount of N2 fixed (kg ha−1) were higher under a no-tillage system in both years and at both growth stages, with values of 66.5% at flowering and 81.7% at maturity. The same trend was reported for the amount of N2 fixed (kg N ha−1) at both faba bean growth stages. The N balance was positive in both years, with a mean value of 40.4 kg N ha−1, across all tillage systems; this value was greater in the no-tillage systems (45.7 kg N ha−1) with respect to the others. The values for the organic matter content and stability index were higher under the no-tillage system, which provided favourable conditions that improved N2 fixation by faba beans. The overall results indicate that no-tillage soil management represents a sustainable strategy for improving soil quality and fertility, therefore reducing the dependency of agriculture on synthetic fertilizers

Effect of different crop management systems on rainfed durum wheat greenhouse gas emissions and carbon footprint under Mediterranean conditions

The impact of management practices and input intensities on the greenhouse gas (GHG) emissions and carbon footprint (CF) of Italian durum wheat is not well documented. A field experiment was established in 2009 to gain insight into the effects of different crop management systems on total GHG emissions of faba bean–wheat rotations per unit area over five years. The aim was to estimate the emission intensity generated from the production of 1 kg of durum wheat in a typical wheat cultivation area of southern Italy. We proposed different crop management systems to reduce GHG emissions and enhance crop productivity. The proposed management practices consisted of three levels of soil disturbance – conventional (CT), reduced (RT) and no-tillage (NT) – and different nitrogen (N) fertilizer rates. These were applied and tested in order to validate their workability in the area. Results showed relatively higher emissions resulting from the pre-farm phase, whereas the cultivation phase was responsible for 49%, most of which was due to soil emissions (37.4%). In average, our wheat system was responsible for the emission of 1481.1 kg CO2eq ha−1 and 0.295 kg CO2eq Kg−1 of grain, which varied significantly between the proposed management systems. The tillage system had a significant impact on the total emissions. In general, NT and RT resulted in lower emissions than CT, although there were some exceptions in terms of GHG emissions per kilogram of grain due to the lower productivity of RT compared to CT and NT. On a hectare basis, NT reduced the emissions by 22% and by 35% on a kilogram basis compared to the highest emissions in CT in RT, respectively. N fertilizer, however, had both strong direct and indirect effects on total emissions resulted in increase by 60% when the highest N rate was applied. This positive correlation was reflected in CF data where a minimum of 0.155 kg CO2eq kg−1 of grain was obtained when the lowest N fertilizer rate was applied with a reduction of 65%. This was very much linked to the grain yield, thus, a low grain yield together with a high N fertilizer rate led to higher emissions and, therefore, a higher carbon footprint. The effect of the cropping system was clear, as the grain yield increased compared to the base year, with a consequent 31% reduction in CF at the end of the study period. This is the first study in Italy to focus on the emission intensities associated with the production of durum wheat using different input intensities. Our findings indicate that achieving synchrony between minimum input requirements and crop demand without excess or deficiency is the key for optimizing a trade-off between yield and environmental protection

Nitrogen management strategy for optimizing agronomic and environmental performance of rainfed durum wheat under Mediterranean climate

Efficient nitrogen (N) fertilizer management is critical for wheat production and the long-term protection of the environment. Given the importance of durum wheat for the Italian economy, its environmental implications need to be investigated for designing sustainable production system. Three concurrent experiments were carried out in Gravina in Puglia (Apulia, southern Italy) to investigate the agronomic and environmental response of rainfed durum wheat (Triticum turgidum L., var. durum) to different N rates, N source and application time over three years (2010â2012). In the three experiments, the following parameters were analyzed: grain yield, yield components (i.e. harvest index, spikes mâ2), quality traits (i.e. hectoliter weight, protein content), energy input/output analysis including the calculation of energy indexes and greenhouse gas (GHG) emissions. The N rate experiment included rates of 45, 90 and 135 kg N haâ1. Each rate was split in various proportions between sowing, tillering and stem elongation. For the experiment on N timing and splitting, a single dose of 90 kg N haâ1was split between sowing, tillering and stem elongation at different fractions (0-90-0; 40-50-0; 10-40-40). The N fertilizer source experiment tested the effect of the application of 90 kg N haâ1of urea split at sowing and tillering (12-78-0) on the investigated parameters, and compared to Entec®26 and Sulfammo 23 with the same does and application time. Nitrogen agronomic efficiency (NAE) was also calculated to assess the potential yield increase in response to different N fertilizer rates and types. The results showed that N rate, N source and the application time had a significant impact on grain yield, grain protein content, energy output and GHG emissions under normal weather conditions. Considering the site-specific condition, the overall results revealed that the split application of 90 kg N haâ1during three growth stages gave favorable results in terms of grain yield and quality, and optimizes NAE with less environmental impact. The effectiveness and efficiency of this strategy was more pronounced when two-third of the full N dose was applied at later stages (tillering and stem elongation). This strategy found to be more effective in improving wheat yield and quality than the increase in the N rate, which could offer the potential to decrease N fertilization rate in wheat production. This study provides useful information for farmers on how to manage the N fertilization of wheat for sustainable production system

Wheat Response to No-Tillage and Nitrogen Fertilization in a Long-Term Faba Bean-Based Rotation

A field experiment was conducted in Southern Italy to study the response of durum wheat (Triticum turgidum L. var. durum) grain yield and quality traits to a no-tillage (NT) system and different nitrogen N fertilizer rates (30, 60, and 90 kg N ha&minus;1). The NT system was evaluated and compared to conventional (CT) and reduced (RT) tillage within continuous wheat (WW) and faba bean&ndash;wheat (FW) crop sequences over 3-years (2010&ndash;2012). The results showed a promising grain yield increase (30%) in the last year. The effect of the N rate on protein content was significant, while productive parameters were not significantly influenced due to both weather conditions and the previous crop. Tillage effect was significantly (p &le; 0.05) positive on grain yield, yield components and quality parameters, especially in NT system, and was more pronounced when accompanied with faba bean in the rotation system. Despite producing a lower grain protein content (13%) compared to other systems, NT produced good semolina quality (with higher hectoliter weight and lower percentage of broken and shriveled grains). This study provides useful information for farmers on how to produce a satisfactory yield and good grain quality with minimum inputs, helping to design sustainable strategies for durum wheat cultivation in the dry regions

Land Suitability Analysis of Six Fruit Tree Species Immune/Resistant to <i>Xylella fastidiosa</i> as Alternative Crops in Infected Olive-Growing Areas

Olive agro-ecosystems in southern Italy have been heavily damaged due to Xylella fastidiosa subsp. pauca (Xfp). Replacing the Xfp-infected olive-growing areas with economically viable fruit tree species is thought to be a practical control measure. A land suitability analysis can provide an appropriate evaluation of a crop’s suitability in these areas. We evaluate the suitability of almond (Prunus dulcis B.), fig (Ficus carica L.), hazelnut (Corylus avellana L.), kiwifruit (Actinidia chinensis P.), pistachio (Pistacia vera L.), and pomegranate (Punica granatum L.) as fruit tree species immune/resistant to Xfp to be planted within the Xfp-infected olive-growing areas in the Apulia region to compensate for economic and environmental losses. Climate and soil data were used to carry out the land suitability analysis. We combined information for each parameter to obtain the overall suitability maps for the six proposed fruit tree crops using GIS (Geographic Information System). The analysis showed that the Xfp-infected olive-growing areas are suitable for the plantation of most of the proposed fruit tree crops, with different suitability levels as the climate and soil conditions vary among the study areas. In particular, large olive-growing areas are suitable for the cultivation of pomegranate (268,886 ha), fig (103,975 ha), and almond (70,537 ha), followed by kiwifruit (43,018 ha) and pistachio (40,583 ha). Hazelnut, with just 2744 ha of suitable land, was the species with fewer suitable areas in these semi-arid environments. This is the first study to provide practical containment measures against the diffusion of Xfp in southern Italy. Our results can help in the selection of the right immune/resistant tree species for replanting in Xfp-infected zones, therefore providing guidelines within the decision-making process to encourage the planting of some underrepresented fruit tree crops with viable economic values as well

Different Suitability of Olive Cultivars Resistant to <i>Xylella fastidiosa</i> to the Super-Intensive Planting System

Until today, only Leccino and Fs-17 (=Favolosa®) olive cultivars proved resistant to Xylella fastidiosa subsp. pauca (Xfp) due to a low presence of bacteria in the xylem. Integrated disease management in olive growing areas threatened by the spread of Xfp is crucial to overcoming the environmental, economic and social crisis. Since the EU Decision allows for the plantation of resistant olive cultivars in infected areas, there is a need to define a suitable plantation system for these cultivars. The adoption of new planting systems, such as intensive and super-intensive (SHD), could compensate for the economic losses and restore the olive agroecosystem. The aim is to ascertain the suitability of the available Xfp-resistant cultivars to SHD planting systems that demonstrate the best economic and environmental sustainability. Hence, a five-year study was established in an experimental SHD olive orchard (Southern Italy) in order to analyse the main vegetative and productive traits of Leccino and Fs-17, together with four other Italian cultivars (Cipressino, Coratina, Frantoio and Urano), compared with the well-adapted cultivars to SHD orchards (Arbequina and Arbosana), by means of the von Bertalanffy function. The results indicated that cv. Fs-17 showed sufficient suitability for SHD planting systems, giving the best-accumulated yield despite some canopy growth limitations, whereas cv. Leccino did not show satisfactory results in terms of both vegetative and yield parameters, confirming its suitability for intensive planting systems. These results are useful for optimizing integrated resistance management in Xfp-infected areas by planting resistant host plants