Edaphoclimatic Conditions Research Articles

Development of Smart Irrigation Equipment for Soilless Crops Based on the Current Most Representative Water-Demand Sensors.

Due to the edaphoclimatic conditions in southeast Spain, which are expected to worsen due to climate change, more efficient ways of using water must be found to maintain sustainable agriculture. Due to the current high price of irrigation control systems in southern Europe, 60-80% of soilless crops are still irrigated, based on the experience of the grower or advisor. The hypothesis of this work is that the development of a low-cost, high-performance control system will allow small farmers to improve the efficiency of water use by obtaining better control of soilless crops. The objective of the present study was to design and develop a cost-effective control system for the optimization of soilless crop irrigation after evaluating the three most commonly used irrigation control systems to determine the most efficient. Based on the agronomic results comparing these methods, a prototype of a commercial smart gravimetric tray was developed. The device records the irrigation and drainage volumes and drainage pH and EC. It also offers the possibility of determining the temperature, EC, and humidity of the substrate. This new design is scalable thanks to the use of an implemented data acquisition system called SDB and the development of software in the Codesys programming environment based on function blocks and variable structures. The reduced wiring achieved by the Modbus-RTU communication protocols means the system is cost-effective even with multiple control zones. It is also compatible with any type of fertigation controller through external activation. Its design and features solve the problems in similar systems available on the market at an affordable cost. The idea is to allow farmers to increase their productivity without having to make a large outlay. The impact of this work will make it possible for small-scale farmers to have access to affordable, state-of-the-art technology for soilless irrigation management leading to a considerable improvement in productivity.

Multi-site comparison of clonal arrangements for tropical and subtropical hybrids of Eucalyptus

The definition of the ideal eucalyptus clonal arrangement directly affects the forest industrial chain, quality of products, and stand yield. The impact of eucalyptus in mono- versus multiclonal stands on plantation production and sustainability has been frequently discussed by primary stakeholders within the pulp industry, but few studies have examined this topic through direct comparison. In this study, we evaluated the differences in genotype ranking and yield of Eucalyptus spp. and clones displayed in mono- and multiclonal arrangements. In this context, the objectives addressed were: (i) to estimate genetic parameters in multi-environment and site-by-site analyses; (ii) to predict genotypic values of clones and the effects of species in mono- and multiclonal experiments, and (iii) to compare the similarity between the ranks of clones and species in the two types of clonal stands. The study was conducted in 2018 at four different sites of the CMPC Celulose Riograndense company, located in the state of Rio Grande do Sul, Brazil. Mono- and multiclonal arrangements were tested at each site, involving 33 eucalyptus clones belonging to 10 species and hybrids. Multiple-tree-plot (MTP) and single-tree-plot (STP) experiments were used to simulate monoclonal stands and multiclonal or composite stands, respectively. In each experiment, a randomized block design was set with three repetitions, 16 plants per plot for MTP, and 24 repetitions and one plant per plot for STP. Traits monitored were diameter at breast height (DBH), total height (H), tree volume (VOL), mean annual volume increment (MAI), and survival (SUV). Data were analyzed using mixed model approaches, considering a normal distribution for growth traits and a binomial family for survival. There was a strong genotype × site interaction for all traits, indicating that edaphoclimatic conditions must be considered for the successful establishment of clonal composites of differing genotypes. There was high similarity in the classification of clones in both mono- and multiclonal experiments, with genetic correlation values above 0.90. The performance of clones differed in mono- and multiclonal experiments, which correlated with their competition behavior toward each other (aggressive, suppressed, or homeostatic). Thus, clonal composites can be recommended based on clonal competition and genetic heterogeneity to maximize the yield of the stand and safeguard the plantations from biotic and abiotic disturbances. This study allowed us to identify the differences between the two types of commercial stands and provide direction for future research regarding the performance of Eucalyptus spp. in differing clonal arrangements. Novel information about competition categories for different eucalyptus tropical and subtropical species were provided.

Physicochemical Quality and Fatty Acid Profile in the Meat of Goats Fed Forage Cactus as a Substitute for Tifton 85 Hay

Low rainfall in Northeast Brazil is a limiting factor for animal production. Forages that present crassulacean acid metabolism, such as forage cactus, are adapted to the edaphoclimatic conditions of this region, as they lose little water through the stomata. Thus, the objective was to evaluate the physical and chemical quality, fatty acid profile and sensory acceptance of the meat from goats fed forage cactus as a substitute for Tifton 85 hay. Twenty-one uncastrated mixed-breed goats with a mean body weight of 18 ± 0.86 kg and 7 ± 1 months of age were used. A completely randomized design with three treatments and seven replications per treatment was performed. The inclusion of 0 (control), 25 and 55% of forage cactus in substitution of Tifton 85 hay in the diet of the goats was evaluated. The lipid content in the meat of animals fed 25 and 55% of forage cactus was 1.33% and 1.26%, respectively, and was lower (p < 0.05) in relation to the meat of animals that received the control diet (1.56%). The inclusion of 55% of forage cactus provided an increase (p < 0.05) in the content of monounsaturated fatty acids in the meat (52.71%) in relation to the control meat (37.75%). Sensory analysis differed (p < 0.05) between treatments. We recommend replacing Tifton 85 hay with 55% forage cactus, as it presents greater sensory acceptance, and provides lower lipid content and higher content of monounsaturated fatty acids in goat meat.

Effect of edapho-climatic conditions on fruit productivity, yield and olive oil quality in olive orchards (Olea europaea L.): case of a semi-arid region

The objective of the present work is to evaluate the relationship between the edapho-climatic conditions of the cultivation environment and the variability of olive productivity, yield, and quality of olive oil in orchards of the Moroccan Picholine (PM) population variety (Olea europaea L.). This work was carried out on different agricultural territorial units (agroecosystems) of the Beni Mellal-Khenifra region with a semi-arid climate during four agricultural seasons (2016/2017 to 2019/2020). For this purpose, the relevant agronomic and agro-biochemical parameters were studied, namely the stage of maturity, fruit and olive oil yields and quality indices. The data treatments of the results were performed according to descriptive and affiliated statistics by analysis of variance (ANOVA). We have found significant correlations (according to Pearson's R) between agroecosystems, particularly for weight of crude olives produced per hectare and temperature (R= 0.803), olive yield and humidity (R= 0.654), olive oil yield and temperature (R= 0.837), olive oil richness and humidity (R= -0.622), as well as the qualitative characteristics of the extracted oils, through the levels of free acidity and peroxide value (R = 0.467). These results confirm that in the studied semi-arid environments, the properties of the biotope of the cultivated olive groves, combined with the interannual agroclimatic variability, effectively influence the productivity of the olive trees, the oil production and the chemical and organoleptic quality of the extracted olive oil

Use of brown sugar adhesive adhesive agents based on, palm and alobe extracts in the coating of crean bean seeds with rock dust

Beans are extremely important for the Brazilian economy, are part of the diet, are very nutritious and have great commercial value, with high production due to their ability to adapt to different edaphoclimatic conditions. Traditional peoples produce seeds of local varieties, called creole seeds. They are resistant because they retain relevant characteristics left as an inheritance from their ancestors, who, free of charge, provided an environmental service for the preservation and perpetuation of this genetic heritage. Based on this, the objective of this work was to evaluate the effect of the adherent agents palm extract, aloe vera extract and sugar syrup in the pelleting of creole bean seeds (Minguita) with rock dust. The work was carried out in the Laboratory of Phytotechnics belonging to the Campus of Engineering and Agricultural Sciences of the Federal University of Alagoas. As adherent agents were used: water, palm extract, aloe vera extract and sugar solution. Rock dust (MB-4) was used for the coating. The evaluated parameters were: water content, weight of a thousand seeds, first germination count, germination, germination speed index, average germination time, germination uncertainty, length of root and aerial part and dry mass of seedlings. Palm is the most efficient adherent agent in the pelleting of bean seeds with rock dust, and can therefore be recommended for sustainable pelleting.

Diamide seed treatment may protect early soybean growth stages against Helicoverpa armigera

In intensive soybean cropping systems, early-season pest insects such as lepidopteran larvae can seriously compromise crop establishment. Using a polyphagous global pest ̶̶ the Old World bollworm Helicoverpa armigera (Lepidoptera: Noctuidae), we determined the potential of seed treatments with diamide or neonicotinoid-carbamate mixture for systemic plant protection and residual efficacy against noctuid larvae. In controlled edaphoclimatic conditions, we infested differently aged soybean plants and recorded plant damage and insect mortality, growth, development, and fecundity to assess lethal and sublethal post-exposure effects. The seed treatments reduced plant damage by 50% during 1–7 days after plant emergence. The lowest damage (<25% defoliation) occurred on plants treated with chlorantraniliprole or cyantraniliprole. These diamides caused larval mortality >80% until 14 days after soybean emergence, which was the window of residual control efficacy. Carbofuran or thiodicarb + imidacloprid caused less than 50% larval mortality and minor plant protection against the larvae. There were sublethal effects on the growth, development, and fecundity of the insects surviving on plants of the insecticide seed treatments. The diamide seed treatments reduced the overall insect fitness for a longer time after plant emergence than did the other treatments. Therefore, soybean seed treatment with chlorantraniliprole or cyantraniliprole is potentially efficacious against noctuid larvae in the VE–V1 soybean growth stages (emergence until the first trifoliate), causing lethal and sublethal effects on the insects. Judicious use and effective resistance management for these systemic compounds are relevant as they are helpful for seed treatment and foliar applications against diverse targets.

Agronomic efficiency of an inoculant based on Bacillus amyloliquefaciens FZB45 for corn and soybean crops

The use of plant growth-promoting bacteria to replace or reduce the application of chemical fertilizers has been consolidated in recent decades. However, most of studies have been carried out under controlled conditions and tests under field conditions are necessary to validate this technology. The objective of this work was to evaluate the agronomic efficiency of the Phosbac-45 product based on Bacillus amyloliquefaciens FZB45 in promoting the growth and yield of corn and soybean crops. Tests were conducted in Brazilian territory under two different edaphoclimatic conditions for two consecutive harvests (2018-2019 and 2019-2020). The design used was randomized blocks in a 3 × 2 factorial scheme (inoculation treatments × levels of phosphate fertilization) and two additional treatments, with five replications of each treatment. It was verified that the use of Phosbac-45 product increased the variables shoot dry mass, root dry mass and grain yield, showing a positive correlation with P uptake by corn and soybean under the conditions evaluated. Thus, the Phosbac-45 product emerges as a promising technology for agricultural use.

Adhering Agents in Maize Seed Pelletizing

The maize very important role in the Brazilian economy because it has a high commercial value, having great production due to its ability to adapt to different edaphoclimatic conditions. Family farming produces seeds from local varieties, called creole seeds. This type of seed is resistant because it keeps relevant characteristics left as an inheritance from its ancestors, who, free of charge, performed an environmental service for the preservation and perpetuation of this genetic heritage. Therefore, the work had to evaluate the effect of the adherent agents palm extract, aloe vera extract and sugar solution in the pelleting of creole corn seeds with rock dust. The work was carried out in the Plant Propagation Laboratory belonging to the Campus of Engineering and Agricultural Sciences of the Federal University of Alagoas. As adherent agents were used: water, palm extract, aloe vera extract and sugar solution. Rock dust (MB-4) was used for the coating. The evaluated parameters were: water content, weight of a thousand seeds, first germination count, germination, germination speed index, average germination time, germination uncertainty, length and dry mass of the root and aerial part. Palm extract is the most efficient adherent agent for pelletizing corn seeds with rock dust.

Increased Production of Tara (Caesalpinia spinosa) by Edaphoclimatic Variation in the Altitudinal Gradient of the Peruvian Andes

Tara production occurs mainly in the altitude gradient, where the edaphoclimatic conditions that affect the production of pods still need to be understood. The goal was to determine the altitudinal and edaphoclimatic effect on the production of tara pods in agroforestry and natural remnants in Cajamarca, Peru. Data analyses performed were the following: principal component analysis (PCA), regression analysis, the bootstrap method, and Pearson correlation analysis. For each 1 °C increase in temperature, the length and width of the pod decreased by 2.1 and 0.62 mm, and of the seed by 0.17 and 0.12 mm in the agroforestry environment; likewise, pod, valve, seed and gum weights were reduced by 23.9, 10.9, 13 and 2.3 g in the agroforestry environment, and 22.3, 13, 9.3 and 2.1 g in the natural environment. Activities such as association with annual crops and perennial pasture possibly favor the length and width of the pod and seed and the weight of the pod, valve, seed and gum in the agroforestry environment when compared to the natural environment. Larger pod and seed dimensions and higher pod, valve, seed and gum weights are related to higher soil CaCO3 contents in the natural environment and higher soil P and B contents in the agroforestry environment at higher altitudes. Higher Fe contents in the soil suggest an improvement in tara’s tannin weight (valve) in the natural and agroforestry environment. The effective response of tara, reflected in its weight and size of pods, was higher in an agroforestry environment than in a natural environment. Further studies on the production of tara pods are necessary for a better understanding of the interaction between altitude and soil fertility to expand the revenue and employment of Peruvian tara farmers.

Tropical grass silages with spineless cactus in diets of Holstein × Zebu heifers in the semiarid region of Brazil.

One of the factors that limit ruminant production in the semiarid region is the lack of roughage in the dry season. The management of forage plants adapted to edaphoclimatic conditions is a strategy to improve animal production. This study was conducted to examine the effects of biomass sorghum silage (BSS; Sorghum bicolor (L.) Moench) and BRS capiaçu grass silage (CGS; Pennisetum purpureum Schum) with or without spineless cactus (Opuntia spp.) in crossbred Holstein × Zebu heifers' diets on the intake, apparent digestibility of the nutrients and animal performance (e.g., final weight, daily weight gain) (experiment 1). Also, to evaluate the ruminal kinetics of dry matter (DM) and neutral detergent fiber (NDF) of roughages used in diets using two animals cannulated in the rumen (experiment 2). In experiment 1, ten heifers with an initial body weight of 200 ± 2.74kg (mean ± standard deviation) and a mean age of 10months were used. The animals were distributed in an experimental design in two simultaneous 5 × 5 Latin squares. Five experimental diets were used: diet 1, Volumax sorghum silage (VSS); diet 2, biomass sorghum silage (BSS); diet 3, BRS capiaçu silage (CGS); diet 4, biomass sorghum silage (60%) with spineless cactus (40%) (BSS + SC); and diet 5, BRS capiaçu grass silage (60%) with spineless cactus (40%) (CGS + SC). The diets were formulated with sorghum silage or BRS capiaçu grass silage with or without spineless cactus (roughage) and a maize- and soybean-based concentrate (75:25 roughage-to-concentrate ratio) on DM basis. The experiment lasted 105days, divided into five periods of 21days (17days for the adaptation of the animals to the diets and management and 4 for data collection and samples). The diets containing CGS and CGS + SC resulted in lower dry matter intake (DMI; 5.61kgday-1; P < 0.01), which was 19.4% lower than the diets with VSS, BSS, and BSS + SC (7.00kgday-1). The BSS + SC and CGS + SC diets showed higher crude protein digestibility (P < 0.01) at 21.9% than the other treatments (Volumax, BSS, CGS). The different diets did not change the final weight or the daily weight gain of the heifers. The BRS 716 biomass sorghum silage and BRS capiaçu grass combined with spineless cactus increased (P < 0.05) the intake of nonfibrous carbohydrates and did not interfere (P > 0.05) with the final weight or average daily gain of the crossbred Holstein × Zebu heifers. The standardized potentially degradable fraction (Bp) of the NDF was 13.91% higher (P < 0.01) for BSS and BSS + SC (61.6%) compared to the others (53.0%). A diet based on BSS + SC is recommended for feeding crossbred heifers in the growing phase.

Potential of plant species adapted to semi-arid conditions for phytoremediation of contaminated soils

Physical and chemical remediation techniques used in contaminated areas are expensive and damaging to the soil structure. Biological alternatives, such as phytoremediation, are economical and applicable to large areas. The main limitation of phytoremediation is identifying plants that are both capable of stabilizing and/or absorbing metals from soil and adapted to edaphoclimatic conditions of the contaminated areas. The objective of this study is to evaluate the ability of plant species adapted to Brazilian semi-arid conditions to grow in soils contaminated with Pb. A greenhouse experiment was carried out in a 4 × 5 factorial: four plant species (M. oleifera, P. juliflora, A. peregrina, and U. ruziziensis) and five Pb concentrations in soil (0.0; 0.52; 1.05; 2.10, and 4.20 g kg−1). All species grew at all Pb levels, but only P. juliflora and A. peregrina did not exhibit significant reductions in most growth variables. U. ruziziensis, despite showing reductions in growth variables, was the species with the highest dry matter accumulation in both shoots and roots, in addition to accumulating higher amounts of Pb. We conclude that the species P. juliflora, A. peregrina and U. ruziziensis are more suitable for cultivation in soils containing high levels of Pb.

Estimation of soluble solids content and fruit temperature in 'Rocha' pear using Vis-NIR spectroscopy and the SpectraNet–32 deep learning architecture

Spectra-based methods are becoming increasingly important in Precision Agriculture as they offer non-destructive, quick tools for measuring the quality of produce. This study introduces a novel approach for estimating the soluble solids content (SSC) of ‘Rocha’ pears using the SpectraNet–32 deep learning architecture, which operates on 1D fruit spectra in the visible to near-infrared region (Vis-NIRS). This method was also able to estimate fruit temperatures, which improved the SSC prediction performance. The dataset consisted of 3300 spectra from 1650 ‘Rocha’ pears collected from local markets over several weeks during the 2010 and 2011 seasons, which had varying edaphoclimatic conditions. Two types of partial least squares (PLS) feature selection methods, under various configurations, were applied to the input spectra to identify the most significant wavelengths for training SpectraNet–32. The model’s robustness was also compared to a similar state-of-the-art deep learning architecture, DeepSpectra, as well as four other classical machine learning algorithms: PLS, multiple linear regression (MLR), support vector machine (SVM), and multi-layer perceptron (MLP). In total, 23 different experimental method configurations were assessed, with 150 neural networks each. SpectraNet–32 consistently outperformed other methods in several metrics. On average, it was 6.1% better than PLS in terms of the root mean square error of prediction (RMSEP, 1.08 vs. 1.15%), 7.7% better in prediction gain (PG, 1.67 vs. 1.55), 3.6% better in the coefficient of determination (R2, 0.58 vs. 0.56) and 5.8% better in the coefficient of variation (CV%, 8.35 vs. 8.86).

Commercial Bioinoculants Increase Root Length Colonization and Improve Petiole Nutrient Concentration of Field-grown Grapevines

Agricultural bioinoculants containing arbuscular mycorrhizal fungi represent a potential opportunity to reduce the dependence of grapevines (Vitis) on agrochemicals. This field study assessed the ability of four commercial bioinoculants to colonize grapevine roots and their effects on petiole nutrient concentration, berry composition, and root morphology of ‘Pinot noir’ (Vitis vinifera) grafted onto rootstock ‘Couderc 3309’ (Vitis riparia × Vitis rupestris) and ‘Riesling’ (V. vinifera) grafted onto ‘Couderc 3309’ and Selection Oppenheim four (Vitis berlandieri × V. riparia). Three bioinoculants increased root mycorrhizal colonization; however, regardless of the treatment, mycorrhizal fungal structures were enhanced. Grapevine petiole nutrient concentration was improved by bioinoculants. Root diameter, root length density, and specific root length increased with greater mycorrhizal root colonization. Using bioinoculants to reduce chemical fertilizers may be a good strategy to improve grapevine productivity and health in cool climates; however, the impact of mycorrhizal bioinoculants in the vineyard may differ among scion–rootstocks, edaphoclimatic conditions, and vineyard soil microbiomes.

Geostatistical analysis of fall armyworm damage and edaphoclimatic conditions of a mosaic of agroecosystems predominated by push-pull systems

Some agroecological pest management systems manipulate insect behavior. The push-pull systems are the most functional implemented, reducing the insect-pest density and modifying its distribution. The present work analyzed the spatial distribution of incidence and severity of fall armyworm (FAW) (Spodoptera frugiperda (J.E. Smith), Lepidoptera: Noctuidae), and soil moisture and temperature in maize (Zea mays L.) crops of a mosaic of agroecosystems predominated by push-pull systems established in Yautepec, Morelos, Mexico. Univariate and multivariate spatial estimates were performed by geostatistical analysis applying ordinary kriging and cokriging, respectively. The results indicated that FAW incidence and severity presented an aggregated spatial distribution and soil moisture and temperature, a more continuous distribution. The estimated spatial distributions in the third week indicated that FAW incidence in push-pull systems varied between 10% and 40%, and in maize monocultures, between 35% and 90%. Fall armyworm damage severity ranged between 20% and 70% in monocultures and between 1% and 25% in the push-pull systems.

Legume growth and straw retention in sugarcane fields: Effects on crop yield, C and N storage in the central-south Brazil

Large amounts of straw are remained in the sugarcane fields after the crop to be mechanically harvested. Straw is pointed out as a feedstock to attend high bioenergy production demand. However, either indiscriminate straw removal or high amount of straw kept on the field may impair several soil functions and thereafter decreases plant tillering and crop yield. Better nutrients cycling and soil physical protection due to Leguminosae species grown within the sugarcane renewal period may offset implications of straw managements across the crop cycles. Thus, does Crotalaria sp. grow within the sugarcane renewal period can offset the undesirable implications of unsustainable straw management on soil and crop yield? To address this research question, a two-year experiment was carried out in Quirinópolis, Chapadão do Céu, Iracemápolis and Quatá, first two sites are in Goiás state, while the other sites are in São Paulo state, Brazil. Soil and plant parameters under straw retention rates (i.e., 0%, 50% and 100% of straw retention) were assessed. This management was coupled with fallow (F) and Crotalaria sp. (CR) grown within the sugarcane renewal period. Soil parameters evaluated included, carbon (C) and nitrogen (N) stocks, while stalk yield was plant parameters assessed. The straw retention implications on soil and plant were site-specific. Carbon and N stocks in the upper 0.4 m soil layer were, respectively, 3.5 and 3.1 time higher at the fine-textured soil than the stocks of those elements at the coarse-textured soil. Regardless of Crotalaria sp. grown, stalk yield increased (ranged from 3 to 16 Mg ha−1) under total straw retention rate for most sites, while in the coolest site 50% and 100% straw retention reduced stalk yield in 13 and 14 Mg ha−1, respectively. In addition, Crotalaria sp. grown within the sugarcane renewal period does not seem able to avoid reduction on soil N availability due to straw retention along the ratoon cycles. Overall, straw removal for bioenergy should be judiciously performed, according to local edaphoclimatic conditions.

Does soil thinning change soil erodibility? An exploration of long-term erosion feedback systems

Abstract. Soil erosion rates on arable land frequently exceed the pace at which new soil is formed. This imbalance leads to soil thinning (i.e. truncation), whereby subsoil horizons and their underlying parent material become progressively closer to the land surface. As soil erosion is a selective process and subsurface horizons often have contrasting properties to the original topsoil, truncation-induced changes to soil properties might affect erosion rates and runoff formation through a soil erosion feedback system. However, the potential interactions between soil erosion and soil truncation are poorly understood due to a lack of empirical data and the neglection of long-term erodibility dynamics in erosion simulation models. Here, we present a novel model-based exploration of the soil erosion feedback system over a period of 500 years using measured soil properties from a diversified database of 265 agricultural soil profiles in the UK. For this, we adapted the Modified Morgan–Morgan–Finney model (MMMF) to perform a modelling experiment in which topography, climate, land cover, and crop management parameters were held constant throughout the simulation period. As selective soil erosion processes removed topsoil layers, the model gradually mixed subsurface soil horizons into a 0.2 m plough layer and updated soil properties using mass-balance mixing models. Further, we estimated the uncertainty in model simulations with a forward error assessment. We found that modelled erosion rates in 99 % of the soil profiles were sensitive to truncation-induced changes in soil properties. The soil losses in all except one of the truncation-sensitive profiles displayed a decelerating trend, which depicted an exponential decay in erosion rates over the simulation period. This was largely explained by decreasing silt contents in the soil surface due to selective removal of this more erodible particle size fraction and the presence of clayey or sandy substrata. Moreover, the soil profiles displayed an increased residual stone cover, which armoured the land surface and reduced soil detachment. Contrastingly, the soils with siltier subsurface horizons continuously replenished the plough layer with readily erodible material, which prevented the decline of soil loss rates over time. Although our results are limited by the edaphoclimatic conditions represented in our data, as by our modelling assumptions, we have demonstrated how modelled soil losses can be sensitive to erosion-induced changes in soil properties. These findings are likely to affect how we calculate soil lifespans and make long-term projections of land degradation.

Biomass characterization of wild and cultivated cardoon accessions and estimation of potential biofuels production

Cardoon is considered an interesting raw material to obtain second-generation biofuels, due to its perennial culture condition and its rare use as food. In addition, cardoon, being a rustic species, requires few inputs and has fast growth and high lignocellulosic biomass production. However, despite its large genetic variability worldwide, both cardoon botanical varieties were subject only to few (cultivated cardoon)/zero (wild cardoon) breeding programs. The aims of this study were (I) to characterize biomass quality and quantity of genotypes of wild and cultivated cardoon in order to produce different types of biofuels and (II) to identify the most promising accessions to be included in breeding programs for bioenergy characteristics or to be incorporated in the local agro-productive system. The performance of twelve Cynara cardunculus L. accessions (six cultivated cardoons and six wild cardoons) was compared through biometric, chemical, and energetic characteristics. Moreover, the potential bioethanol and biomethane yields and the energy potentially generated from direct combustion were calculated for each botanical variety. Significant differences were found between botanical varieties for several biometric traits, but not in chemical traits except for ash content. Results indicate that cardoon biomass, especially cultivated cardoon, has characteristics that make this species a promising candidate to be grown for energy purposes under very low crop inputs in the local edapho-climatic conditions. In addition, our screening identified an accession that stands out based on yield, biomass composition, and potential to produce different types of biofuels/bioenergy.

Productivity of pecan nut in the Anta Gorda region in Rio Grande do Sul

The south of Brazil has the largest area cultivated for pecan walnut (Carya illinoinensis). In recent years, the crop has shown considerable potential for planting expansion, increased consumption linked to health benefits, in addition to financial return. This work aimed to study the productivity of pecan trees, in southern Brazil, over six years of production with different varieties, Barton, Pitol 1, Cenci, Pitol 2 and Imperial, planted under free standing, with a spacing of 10 x 10 meters. In order to correlate these varieties with the edaphoclimatic factors of the Anta Gorda region in Rio Grande do Sul. The experimental design in the field was completely randomized blocks, with ten replications, in a bifactorial scheme. Factor A composed of the five pecan tree varieties (Barton, Pitol 1, Cenci, Pitol 2 and Imperial) and factor B composed of the six periods (2012, 2013, 2014, 2015, 2016 and 2017). Barton stood out in five harvests, contrasting with the Pitol 1, Cenci, Pitol 2 and Imperial varieties and within each harvest, with a general average productivity of 24.90 Kg plant-1, standing out in the sixth harvest with an estimated productivity of 4,185 Kg ha-1. Following, the Cenci and Pitol 2 varieties deserve to be highlighted, with average harvest values of 13.12 and 11.8 Kg plant-1, respectively, much higher values than the others. With this study it was observed that Barton, Cenci and Pitol 2 maintained their productivity indexes in the edaphoclimatic conditions of Anta Gorda in Rio Grande do Sul, Brazil.

Cation nutrient reserves decline markedly under intensive cropping of Pampas Mollisols

The availability of exchangeable cationic nutrients in soils, such as calcium (Cae), magnesium (Mge), and potassium (Ke), is vital for crops growth and development. However, the concentration of these nutrients can be diminished by land use and management practices. The objectives of this study were i) to determine the concentration of Cae, Mge, and Ke in uncropped soils or soils under continuous agriculture, ii) to determine the Cae, Mge and Ke decrease rate due to agriculture (dCae, dMge, and dKe, respectively), iii) to evaluate the relative contribution of edaphoclimatic and farming variables on dCae, dMge, and dKe, and iv) to evaluate the spatial variability of Cae, Mge, and Ke. Surface soil samples (0–20 cm layer) were taken in 2011 and 2018 at geo-referenced sampling locations within 507 agricultural production fields (AGR2011 and AGR2018) from the Argentinean Pampas region (PR). Additionally, surface soil samples were taken from areas under gramineous vegetation that had never been cropped at each sampling point. Path analysis explained 58, 42, and 56 % of the variability on dCae, dMge and dKe between 2011 and 2018, respectively. The main factors determining the depletion of these nutrients were the soybean relative harvested area for dCae, magnesium concentration in 2011 for dMge, and rainfall for dKe. The spatial variation of Cae, Mge, and Ke increased with the history of agricultural use of soils, particularly in the case of Ke and Mge. If the depletion of exchangeable cationic nutrients in the PR continues at current rates, their deficiencies for the main crops could become evident in the medium/short term, depending on the area. For this reason, it is necessary to continue surveying the evolution of soil Cae, Mge and Ke over time in the PR and other areas in the world with similar edaphoclimatic conditions.

Variação sazonal do teor de nutrientes em folhas de abacateiros dos genótipos Geada, Fortuna e Quintal

Abstract Avocado is an important fruit for fresh consumption and as raw material for several industries. In order to obtain good productivity and fruit quality, adequate plant nutrition is essential. However, information on the relationship between time of year, phenology and nutritional status of plants of different genotypes is difficult to compare, as most data are obtained from plants of different ages, planted in soils with different fertility levels, different management strategies and most cultivated under edaphoclimatic conditions different from those of Brazil. This study evaluated the seasonal nutrient content variation of avocado leaves, genotypic differences, the relationship with phenological stages and the periods of greater nutrient content stability in ‘Fortuna’, ‘Geada’ and ‘Quintal’ avocado genotypes cultivated in the municipality of Jardinópolis-SP, Brazil. All plants aged 30 years, were randomly planted within the same area and submitted to the same cultural treatments and management. Nutrient contents are more stable during the flowering phase (July to September) and in the final phase of fruit formation (February to March). In most of the cycle, ‘Geada’ plants have lower S, P and Zn levels compared to ‘Fortuna’ and ‘Quintal’ genotypes. ‘Fortuna’ genotype has higher Ca, Mg and Mn levels than the others at the time of fruit harvest (April to June). In the budding phase of the three genotypes (October), increase in N, P, K, S, Cu, Zn contents and decrease in Ca, Mg and Mn contents were observed.