Multiple benefits of legumes for agriculture sustainability: an overview

Food security, lowering the risk of climate change and meeting the increasing demand for energy will increasingly be critical challenges in the years to come. Producing sustainably is therefore becoming central in agriculture and food systems. Legume crops could play an important role in this context by delivering multiple services in line with sustainability principles. In addition to serving as fundamental, worldwide source of high-quality food and feed, legumes contribute to reduce the emission of greenhouse gases, as they release 5–7 times less GHG per unit area compared with other crops; allow the sequestration of carbon in soils with values estimated from 7.21 g kg−1 DM, 23.6 versus 21.8 g C kg−1 year; and induce a saving of fossil energy inputs in the system thanks to N fertilizer reduction, corresponding to 277 kg ha−1 of CO2 per year. Legumes could also be competitive crops and, due to their environmental and socioeconomic benefits, could be introduced in modern cropping systems to increase crop diversity and reduce use of external inputs. They also perform well in conservation systems, intercropping systems, which are very important in developing countries as well as in low-input and low-yield farming systems. Legumes fix the atmospheric nitrogen, release in the soil high-quality organic matter and facilitate soil nutrients' circulation and water retention. Based on these multiple functions, legume crops have high potential for conservation agriculture, being functional either as growing crop or as crop residue. Open image in new window Graphical abstract

Effect of Soil Tillage and Crop Sequence on Grain Yield and Quality of Durum Wheat in Mediterranean Areas

Abstract: Conservation agriculture (CA) can be very strategic in degradation prone soils of Mediterranean environments to recover soil fertility and consequently improve crop productivity as well as the quality traits of the most widespread crop, durum wheat, with reference to protein accumulation and composition. The results shown by two years of data in a medium long-term experiment (7-year experiment; split-plot design) that combined two tillage practices (conventional tillage (CT) and zero tillage (ZT)) with two crop sequences (wheat monocropping(WW)and wheat-faba bean (WF)) are presented. The combination ZT + WF (CA approach) induced the highest grain yields (617 and 370 g m-2 in 2016 and 2017, respectively), principally due to an increased number of ears m-2; on the other hand, the lowest grain yield was recorded under CT + WW(550 and 280 g m-2 in 2016 and 2017, respectively). CA also demonstrated significant influences on grain quality because the inclusion of faba bean in the rotation favored higher N-remobilization to the grains (79.5% and 77.7% in 2017). Under ZT and WF, all gluten fractions (gliadins (Glia), high molecular-weight glutenins (GS), and low molecular-weight GS) as well as the GS/Glia ratio increased. In durum wheat-based farming systems in Mediterranean areas, the adoption of CA seems to be an optimal choice to combine high quality yields with improved soil fertility

Desfolha e nutrição do S no rabanete: crescimento, polifenóis e atividade antiradical

ABSTRACT Experiments were carried out to study patterns of artificial defoliation in radish in combination with sulphur (S) fertilization, to evaluate the contribution of younger and older leaves on plant growth and phenolics accumulation in storage roots. Biomass accumulation and partitioning were related to leaf age, magnitude and timing of the clipping treatments. Older leaves increased biomass production and translocation into the storage organ; besides, they induced higher accumulation of phenolic compounds compared to the younger leaves. The highest S fertilization rate (120 kg ha-1) significantly enhanced the polyphenols accumulation, as well as the antiradical activity. The modulation of S inputs in combination with slightly induced stress from defoliation could effectively enhance the concentration of some important phytochemicals, providing higher nutritionally improved vegetables, without affecting yield

Precision Agriculture Digital Technologies for Sustainable Fungal Disease Management of Ornamental Plants

Ornamental plant production constitutes an important sector of the horticultural industry worldwide and fungal infections, that dramatically affect the aesthetic quality of plants, can cause serious economic and crop losses. The need to reduce the use of pesticides for controlling fungal outbreaks requires the development of new sustainable strategies for pathogen control. In particular, early and accurate large-scale detection of occurring symptoms is critical to face the ambitious challenge of an effective, energy-saving, and precise disease management. Here, the new trends in digital-based detection and available tools to treat fungal infections are presented in comparison with conventional practices. Recent advances in molecular biology tools, spectroscopic and imaging technologies and fungal risk models based on microclimate trends are examined. The revised spectroscopic and imaging technologies were tested through a case study on rose plants showing important fungal diseases (i.e., spot spectroscopy, hyperspectral, multispectral, and thermal imaging, fluorescence sensors). The final aim was the examination of conventional practices and current e-tools to gain the early detection of plant diseases, the identification of timing and spacing for their proper management, reduction in crop losses through environmentally friendly and sustainable production systems. Moreover, future perspectives for enhancing the integration of all these approaches are discussed

Shading and nitrogen management affect quality, safety and yield of greenhouse-grown leaf lettuce

Two growing factors (light and nitrogen) supplied at optimal and sub-optimal levels were studied with the aim of evaluating their effects on greenhouse-grown lettuce' biomass and quality performances. According to a split-plot design with three replications, greenhouse lettuce was subjected to sixteen experimental treatments consisting of four photosynthetically active radiation (PAR) availability levels (0, 50, 65 and 85% PAR reduction) and four nitrogen fertilization rates (0, 75, 150 and 300kgNha-1).Response surface methodology (RSM) allowed to predict the highest achievable dry biomass (10.54gplant-1) at 0.9% PAR reduction and 185.4kgNha-1. This optimal light/N combination induced a nitrate concentration of 1176 and 1826mgkg-1 fresh weight (FW) in the inner and outer leaves, respectively. Shading decreased both the total phenolic content (TPC) and antioxidant activity. High N rates lowered both TPC in fully light condition and antioxidant activity in shading environment. The highest chlorophyll (Chl) concentrations were obtained with the combination shading/high N availability (at 85% PAR reduction and 300kgNha-1) with values of 1.938 and 1.716mgg-1 FW for Chla and Chlb, respectively.In general, the results highlighted the potential for sustainable lettuce production, considering both economic and nutritional yields, i.e. providing high nutritionally dense products, slightly affecting the harvested biomass

Drought stress effects on crop quality

Water is among the factors affecting plant growth and development. Despite the fact the negative influence of water stress on crop production is well documented, its effect on crop quality has been less investigated. Drought leads to the activation of plant defense systems with several physiological stress reactions resulting in a significant change in metabolite production, altering the nutritional and health values of the harvested products. The impact of drought on crop quality has been demonstrated for five classes of quality traits: carbohydrates, protein, lipids, and secondary metabolites. All these traits are significantly influenced by water stress determining both positive and negative alterations in chemical and organoleptic characteristics of the harvested crops. The chapter highlights the crop responses to water stress, or deficit irrigation strategies, clarifying the physiological mechanisms involved in the drought-induced modifications of crop chemical composition. This information could represent useful tools for both agronomists and crop breeders in order to develop strategies to obtain higher quality crops and adapted genotypes in water stress conditions, slightly affecting yield

Leaf traits as indicators of limiting growing conditions for lettuce (Lactuca sativa)

Lettuce growth under unstressed conditions was compared to growth under four limiting conditions, i.e. no phosphorus fertilization (0_P), no nitrogen fertilization (0_N), low light (LR) and water stress (WR) over two different growing periods. We investigated the adaptive changes in terms of the morphological and physiological leaf traits, identifying stress-specific and ‘stable’ indicators suitable for use in breeding programmes. The plants subjected to the WR treatments had lower leaf expansion and specific leaf area (SLA), as well as lower soil–plant analysis development (SPAD) values, stomatal conductance (POR), water index (WI) and leaf temperature (TIR) compared with plants in the unstressed CONTROL. Low light increased the leaf area (LA), SLA and leaf mass ratio (LMR). The 0_N treatment induced a general reduction in the normalised difference vegetation index (NDVI) values, as well as strong changes in LMR and SLA. In general, 0_P induced less pronounced effects than the other treatments. Principal component analysis indicated that the stable and suitable selection indicators of adaptive changes for low nitrogen and low light conditions were LA, SLA, leaf area per unit total plant mass (LAR), LMR, SPAD and POR, while SPAD, POR, TIR and WI were suitable indicators for drought

Sustainable agricultural practices for water quality protection

The marked shift in conventional agriculture has brought detrimental effects on natural resources leading to environmental degradation. Indeed, agricultural practices can be considered as both widespread and punctual sources of pollution, heavily affecting surface and groundwater quality, principally through erosion, run-off and leaching. Many contaminants (i.e. sediments, nutrients, heavy metals and agrochemicals) are conveyed by agriculture to the aquatic systems of surface and groundwater. Ecologically sound practices should be adopted to ensure a reduced impact on water resources. Among these, (i) rational rates, timing, type and technology of placement of fertilizers can contribute to obtain economic and environmental benefits; (ii) minimum cultivation systems can mitigate soil erosion and preserve from dispersed pollution losses; (iii) Conservation Agriculture, among the sustainable cropping systems, can reduce surface runoff and can assist in preserving water in the top soil stratum and increase rain infiltration; (iv) Controlled Traffic Farming, through the reduction of the trafficked compacted area, can decrease usage of fertilizers, due to lower losses of nutrients and (v) vegetative buffer strips can prevent runoff and the transport of sediments, organic materials, nutrients and chemicals