Spanish Journal of Agricultural Research
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The role of abiotic factors modulating the plant-microbe-soil interactions: toward sustainable agriculture. A review
No full textMicrobial soil communities are active players in the biogeochemical cycles, impacting soil fertility and interacting with aboveground organisms. Although soil microbial diversity has been studied in good detail, the factors that modulate its structure are still relatively unclear, especially the environmental factors. Several abiotic elements may play a key role in modulating the diversity of soil microbes, including those inhabiting the rhizosphere (known as the rhizosphere microbiome). This review summarizes relevant and recent studies that have investigated the abiotic factors at different scales, such as pH, temperature, soil type, and geographic and climatic conditions, that modulate the bulk soil and rhizosphere microbiome, as well as their indirect effects on plant health and development. The plant–microbiome interactions and potential benefits of plant growth-promoting rhizobacteria are also discussed. In the last part of this review, we highlight the impact of climate change on soil microorganisms via global temperature changes and increases in ultraviolet radiation and CO2 production. Finally, we propose the need to understand the function of soil and rhizospheric ecosystems in greater detail, in order to effectively manipulate or engineer the rhizosphere microbiome to improve plant growth in agricultural production
Genotype × environment interaction for fertility and milk yield traits in Canadian, Mexican and US Holstein cattle
No full textThe objective of this study was to evaluate genotype × environment interaction (G×E) between Canada, the United States and Mexico for fertility and milk yield traits using genetic correlations between countries estimated from genetic evaluations of sires. Genetic correlation between Mexican and Canadian Holsteins for age at first calving was ≤ 0.48 and lower than the simulated value obtained accounting for data structure and selection effects. For calving interval, genetic correlation between Mexico and Canada ranged from 0.48 to 0.69. Genetic correlation between calving interval in Mexico (multiplied by -1) and daughter pregnancy rate in the United States ranged from 0.64 to 0.73, and was lower than simulated and actual Canada-United States values. Genetic correlations between Mexico and Canada and the United States for milk yield traits were ≥ 0.83, similar to simulated genetic correlations, but lower than Canada-United States values (≥ 0.93). Heritability estimates for age at first calving, calving interval, milk yield, fat yield, protein yield, fat content, and protein content for the Mexican Holstein population were 0.06, 0.03, 0.18, 0.20, 0.19, 0.46, and 0.49, respectively. G×E interaction effects between Canada and Mexico for age at first calving were high, whereas G×E interaction effects between Canada and Mexico for calving interval and between daughter pregnancy rate in the United States and calving interval in Mexico were moderate. G×E interaction effects for milk yield traits between Canada or the United States with Mexico in registered Holsteins were low
Whole-plant mineral partitioning during the reproductive development of rice (Oryza sativa L.)
No full textMinimal information exists on whole-plant dynamics of mineral flow. Understanding these phenomena in a model plant such as rice could help in the development of nutritionally enhanced cultivars. A whole-plant mineral accumulation study was performed in rice (cv. Kitaake), using sequential harvests during reproductive development panicle exertion, grain filling, and full maturity stages in order to characterize mineral accumulation in roots, non-flag leaves, flag leaves, stems/sheaths, and panicles. Partition quotient analysis showed that Fe, Zn, Cu and Ni are preferentially accumulated in roots; Mn and Mg are accumulated in leaves; Mo, Ca, and S in roots and leaves; and K in roots, leaves and stems/sheaths. Correlation analysis indicated that changes in the concentrations of mineral pairs Fe-Mn, K-S, Fe-Ni, Cu-Mg, Mn-Ni, S-Mo, Mn-Ca, and Mn-Mg throughout the reproductive development of rice were positively correlated in all four of the above ground organs evaluated, with Fe-Mn and K-S being positively correlated also in roots, which suggest that root-to-shoot transfer is not driven simply by concentrations in roots. These analyses will serve as a starting point for a more detailed examination of mineral transport and accumulation in rice plants
Nitrogen replenishment using variable rate application technique in a small hand-harvested pear orchard
No full textPrecision agriculture is a management approach for sustainable agriculture. It can be applied even in small fields. It aims to optimize inputs, improve profits, and reduce adverse environmental impacts. In this study, a series of measurements were conducted over three growing seasons to assess variability in a 0.55 ha pear orchard located in central Greece. Soil ECa was measured using EM38 sensor, while soil samples were taken from a grid 17 × 8 m and analysed for texture, pH, P, K, Mg, CaCO3, and organic matter content. Data analysis indicated that most of the nutrients were at sufficient levels. Soil and yield maps showed considerable variability while fruit quality presented small variations across the orchard. Yield fluctuations were observed, possibly due to climatic conditions. Prescription maps were developed for nitrogen variable rate application (VRA) for two years based on the replacement of the nutrients removed by the crop. VRA application resulted in 56% and 50% reduction of N fertiliser compared to uniform application
Autopolyploids in fodder grass breeding: induction and field performance
No full textDoubling of chromosome set directly affects plant performance through increase of organ size, higher feeding value and increased resistance to adverse environmental factors. Therefore efficient methods of polyploid induction are needed in order to develop new varieties of naturally diploid fodder grass species. The efficiency of antimitotic agents as colchicine, amiprophos-methyl, trifluralin and oryzalin was compared in a series of tetraploid induction experiments in Lolium multiflorum, L. perenne and Festuca pratensis, while newly developed tetraploid plants were compared to standard tetraploid varieties in the field trials. Colchicine treatment proved to be the most efficient method for in vitro cultured embryos in comparison with the other agents. Induced tetraploids of F. pratensis produced higher dry matter and seed yield and could be used for the development of new varieties. Induced tetraploid plants of Lolium spp. were equal to the standard varieties in field trials, therefore they could be used as parental genotypes in crosses. Induced tetraploids of F. pratensis produced higher dry matter and seed yield and could be used for development of new variety
Evaluating the environmental sustainability of energy crops: A life cycle assessment of Spanish rapeseed and Argentinean soybean cultivation
No full textRapeseed oil is expected to be increasingly used in Spain as raw material to produce biodiesel to the detriment of extra-EU imports of biodiesel mainly based on soybean oil from Argentina. Therefore, the environmental impacts produced throughout the life cycle of energy crops used to produce biodiesel which is consumed in Spain could be radically affected. In this context, the environmental impacts of rapeseed cultivation in Spain and soybean cultivation in Argentina, were compared under certain growing conditions using Life Cycle Assessment (LCA). Two methods of calculation for Life Cycle Impact Assessment (LCIA) and two functional units (FUs) were used to test potential biases. The results showed that the cultivation of soybean in Argentina had, in general, fewer environmental impacts than rapeseed cultivation in Spain when the FU was the area of cultivation, but these findings are inverted when the analysis is conducted according to the energy content of the biodiesel obtained from these crops. Soybean in fact has very low oil content, meaning that larger areas of land are required to obtain the same amount of biodiesel and that consequently it has a higher environmental impact by energy content. Fertilization was, in general, the process that generated the greatest environmental burdens, and is an area in which improvement is necessary in order to increase sustainability, particularly with regard to Spanish rapeseed
Is the increase of scale in the tropics a pathway to smallholders? Dimension and ecological zone effect on the mixed crop-livestock farms
No full textMixed crop-livestock farms are widely spread in different tropical regions in the world; they contribute to food security, rural development, sustainability and poverty alleviation. The effect of scale on performance of dual purpose (DP) cattle farms was evaluated in two Mexican ecological zones: dry (DT) and wet tropics (WT). In 2011, a questionnaire of 184 items distributed into technical and social characteristics was applied to a representative sample of 3,285 farms with 50 or less cows (0.97%). The farms were classified into three groups according to their dimension: very small (1-9 cows), small (10-19 cows) and medium (20-50 cows). A general linear model (GLM) with two factors and their interactions was applied. Significant effects in dimension and ecological zone were found as well as seven interactions between both factors (p<0.05). Native pastures were used in all farms for grazing. However, small farms’ herds frequently grazed on cultivated pastures and on crop residues (p<0.05). Medium farms showed the highest grazing surface, but in the WT silage and green fodder were used while in the DT dry fodders were used (p<0.001). The interactions between factors showed a bigger specialization in milk production in DT farms, whereas WT farms were more specialized in meat production. The mixed crop-livestock system in tropic region requires an increase in herd size according to farm’s own productive structure, which is strongly influenced by the ecological zone. The systems would improve with the active participation of smallholders to identify and achieve best practices, higher technological adoption level and with an effective support from public and private Institutions
Germination success under different treatments and pod sowing depths in six legume species present in olive groves
No full textThis study analysed the germination success of pods of six annual native legumes species: Astragalus hamosus, Medicago minima, Medicago orbicularis, Medicago polymorpha, Medicago rigidula and Scorpiurus muricatus. The use of these species has been proposed as a means of generating and improving herbaceous cover in olive groves. Germination success was studied in terms of the variability in the number of seeds germinated per pod after 18 months at two different sowing depths, on the surface (S) and buried 10 mm (B). Pods were subject to five different pre-germination treatments: chemical scarification, consisting of immersion in sulphuric acid for 15 min (S_15) and 20 min (S_20), immersion in water for 48 h (W_48), pod precooled to -18ºC for one month (P_18º) and untreated pods (Con). The results showed that the effectiveness of the different treatments and sowing depths depended on the species, and that there were no problems of ‘sibling-competition’ in any of the treatments or at any of the sowing depths. Species with larger, non-spiralled pods, such as A. hamosus or S. muricatus, or with very loosely spiralled pods such as M. orbicularis, had greater germination rates when buried, mainly in the case of untreated pods and pods that were immersed in sulphuric acid for 20 minutes
In vitro effects of copper nanoparticles on plant pathogens, beneficial microbes and crop plants
No full textCopper-based chemicals are effectively used as antimicrobials in agriculture. However, with respect to its nanoparticulate form there has been limited number of studies. In this investigation, in vitro tests on effect of copper nanoparticles (CuNPs) against plant pathogenic fungi, oomycete, bacteria, beneficial microbes Trichoderma harzianum and Rhizobium spp., and wheat seeds were conducted. Integration of CuNPs with non-nano copper like copper oxychloride (CoC) at 50 mg/L concentration each recorded 76% growth inhibition of the oomycete Phytophthora cinnamomi in vitro compared to the control. CuNPs also showed synergistic inhibitory effect with CoC on mycelial growth and sporulation of A. alternata. Pseudomonas syringae was inhibited at 200 mg/L of CuNPs. CuNPs were not significantly biocidal against Rhizobium spp. and Trichoderma harzianum compared to CoC. Evaluation of the effect of CuNP on wheat revealed that rate of germination of wheat seeds was higher in presence of CuNPs and CoC compared to control. Germination vigor index, root length, shoot dry weight and seed metabolic efficiency of wheat were negatively affected. At low concentration, CuNPs promoted the growth of the plant pathogenic fungi Botrytis fabae, Fusarium oxysporum f.sp. ciceris, F.oxysporum f.sp. melonis, Alternaria alternate and P. syringae, and sporulation of T. harzianum. Synergistic effect of CuNPs and CoC in inhibiting P. cinnamomi offers a possibility of developing new fungicide formulation for better control of the oomycetes. Non-biocidal effect of CuNPs against beneficial microbes indicates its potential use in the agri-ecosystem