Scientific Journals of INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria)
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Effect of different substrates for organic agriculture in seedling development of traditional species of Solanaceae
Sowing of seedlings is one of the most critical processes on the establishment of a crop, since the future development of the plant depends largely on its health when is planted on the field. Moreover, organic agriculture has to deal with the low application of fertilizers and pesticides, which hinder the growth of seedlings. In this work, we studied the big influence of different mixtures of substrates suitable for organic agriculture based on peat, coconut husk and vermicompost in traditional varieties of tomato, pepper and eggplant. Our results indicate that the use of coconut husk based substrates in organic agriculture can reduce the growth of seedlings between 20 and 30% compared with peat-based substrates. Moreover, the plants growth in this substrate showed lower levels of chlorophyll and lower weight, but the results are strongly dependent on the species tested. Comparison between traditional plants demonstrates that traditional varieties are strongly influenced by the substrate, whereas the growth of a commercial variety of tomato barely differs when different substrates are used. The election of the substrate in organic agriculture is critical to the correct development of the plant, especially when traditional plant varieties are used
Short communication: Biochemically active humic substances in contrasting agricultural managements
Because their crucial role in several soil biochemical cycles and their fast response to changes in soil management, extracellular enzymes activities are widely used as sensitive indicators of ecological change and soil quality. The aim of this work was to determine the effects of soil management on the stable pool of soil carbon cycling enzymes as indicators of essential functions. For this, extracellular β-glucosidase enzymes bounded by humic acids (C higher than 104 Da) were used to compare four long-term contrasting agricultural managements in a rainfed olive orchard representative of semi-arid Mediterranean habitats. The study was conducted for 30 years by designing a random-block of four treatments (nude vs. covered soils) and four replicates. Maintaining cover crops through fall, winter and early spring provoked a more stable and active pool of extracellular β-glucosidase in soils only if spontaneous vegetation was managed with mechanical methods. When herbicides were used during 30 years, the pattern of the molecular composition and activity of humus β-glucosidase complexes were similar in covered and nude soils, although higher activity was retrieved in the former. Tillage management increased carbon mineralization and the level of humic substances and the activity of β-glucosidase humic-bound were quite lower than in the rest of treatments. Given the ecological role of extracellular soil carbon cycling enzymes, the characterization of humus β-glucosidase complexes could be an adequate indicator of sustainability of agricultural management systems
Comparative analysis of traditional and modern apricot breeding programs: A case of study with Spanish and Tunisian apricot breeding germplasm
Traditional plant breeding is based on the observation of variation and the selection of the best phenotypes, whereas modern breeding is characterised by the use of controlled mating and the selection of descendants using molecular markers. In this work, a comparative analysis of genetic diversity in a traditional (Tunisian) and a modern (Spanish) apricot breeding programme was performed at the phenotypic and molecular level using simple sequence repeat (SSR) markers. Seven phenotypic traits were evaluated in 42 Tunisian apricot accessions and 30 genotypes from the Spanish apricot programme. In addition, 20 SSR markers previously described as linked to specific phenotypic traits were assayed. Results showed that modern breeding using controlled crosses increases the size of the fruit. The fruit weight average observed in the Tunisian cultivars was of 20.15 g. In the case of traditional Spanish cultivars the average weight was 47.12 g, whereas the average weight of the other progenitors from France, USA and South Africa was 72.85 g. Finally, in the new releases from the CEBAS-CSIC breeding programme, the average weight was 72.82 g. In addition, modern bred cultivars incorporate desirable traits such as self-compatibility and firmness. Cluster and structural analysis based on SSR data clearly differentiates the genotypes according to their geographic origin and pedigree. Finally, results showed an association between some alleles of PaCITA7 and UDP96003 SSR markers with apricot fruit weight, one allele of UDAp407 marker with fruit firmness and one allele of UDP98406 marker with fruit ripening
Enhancement of physical and hydrological properties of a sandy loam soil via application of different biochar particle sizes during incubation period
In spite of many studies that have been carried out, there is a knowledge-gap as to how different sizes of biochars alter soil properties. Therefore, the main objective of this study was to investigate the effects of different sizes of biochars on soil properties. The biochars were produced at two pyrolysis temperatures (350 and 550°C) from two feedstocks (rice husk and apple wood chips). Produced biochars were prepared at two diameters (1-2 mm and <1 mm) and mixed with soil at a rate of 2% (w/w). Multiple effects of type, temperature and size of biochars were significant, so as the mixture of soil and finer woodchip biochars produced at 550°C had significant effects on all soil properties. Soil aggregation and stabilization of macro-aggregates, values of mean weight diameter and water stable aggregates were improved due to increased soil organic matter as binding agents and microbial biomass. In addition, plant available water capacity, air capacity, S-index, meso-pores and water retention content were significantly increased compared to control. But, saturated hydraulic conductivity (Ks) was reduced due to blockage of pores by biochar particles, reduction of pore throat size and available space for flow and also, high field capacity of biochars. So, application of biochar to soil, especially the finest particles of high-tempered woody biochars, can improve physical and hydrological properties of coarse-textured soils and reduce their water drainage by modification of Ks
Short communication: Effects of summer rainfall variations on sheep body state and farming sustainability in sub-Mediterranean pastoral systems
In sub-Mediterranean climate the grassland aboveground phytomass production peaks in late spring and drops in summer, when the decrease of the pasture feed value may lead to the worsening of the animal welfare. Our goal was to define the summer rainfall values leading to a decrease of semi-extensive farming system sustainability in sub-Mediterranean regions. Summer rainfall variations reflect in the aboveground phytomass production and on the sheep body state. Differences of body condition score (BCS) among years were significant in late summer, which is the mating period for sheep. In the driest year the BCS of end August drops down to 2.1, largely below the value considered sufficient to ensure the animal breeding/milking performances (2.5). Reduction of summer rainfall greater than 15–20% compared to the normal average value (thus less than expected by the scenario of climate change) might be detrimental for semi-extensive rearing sustainability in sub-Mediterranean climate
Optimization of Land Use Pattern Reduces Surface Runoff and Sediment Loss in a Hilly-Gully Watershed at the Loess Plateau, China
Aim of study: The aim is to find a way increasing gain yield and lessen area of farmland, and then increasing vegetation cover, improving environment and alleviating soil erosion.Area of study: The Hilly-Gully region at the loess plateau of China.Material and methods: In this study, an adjusted and optimized land use pattern was developed in Luoyugou watershed in the Yellow River valley based on the gradient distribution of land use types, and its effect on water and sediment transport was simulated using the SWAT model and GIS, with remote sensing images, land use maps and hydrologic data.Main results: The results indicate: average simulated runoff and sediment for the period 1986-2000 under conditions of the three land use pattern (2011, 2008 and optimized land use) reduced by 0.002-0.013 m3/s (2.7-17.6%) and 0.66 million tons, respectively. The runoff and sediment data obtained were compared with observed data from 2008, which showed that runoff and sediment production would be reduced by 467625 m3 and 22754 tons, respectively.Research highlights: The adjustment of the land use pattern in comprehensive consideration of vegetation and geography have a positive effect on water and sediment transport which will be important for decision making and water resources management, and provides a reference for future environmental management and ecological construction in the loess plateau Hilly-Gully region.
Micro-environmental changes induced by shape and size of forest openings: effects on Austrocedrus chilensis and Nothofagus dombeyi seedlings performance in a Pinus contorta plantation of Patagonia, Argentina
Aim of the study: to analyze, within a Pinus contorta plantation, the effects of artificially created small rectangular and small medium circular canopy gaps on: i) photosynthetic active radiation (PAR), and soil temperature and moisture, and ii) survival and growth of planted Austrocedrus chilensis and Nothofagus dombeyi seedlings, species which formerly composed the natural forest of the area.Study area: A 2 ha stand of a Pinus contorta stand in Los Alerces National Park, Argentina (42°43’S, 71°43’W, 490 m.a.s.l.). Material and methods: The Pinus contorta stand was 25 yr old, 22 m height and 26 cm DBH, presenting 1000 trees ha-1 of density and 53 m2 ha-1 of basal area. In 2009, rectangular and circular gaps were created within the stand and then seedlings were planted. During two growing seasons (2010-2011 and 2011-2012), PAR, soil temperature and moisture were measured in gaps and understory (control), and seedling survival and growth in gaps.Main results: During both seasons, soil temperature did not differ among gaps and control, whereas PAR and soil moisture were lower in control than in gaps. Seedling survival was high in all gaps regardless of species and season. Seedlings showed higher diameter growth in rectangular than in circular gaps.Research highlights: Austrocedrus chilensis and N. dombeyi seedlings survival is high and their growth slightly affected, when planted in differently-sized canopy gaps within a Pinus contorta plantation in Patagonia. However, other gap sizes and stand densities should be tested before recommending which one shows better results for reconverting monocultures into former native forests.Keywords: planted seedlings; gap structure; photosynthetic active radiation; soil temperature; soil moisture.Abbreviations used: PAR (Photosynthetic Active Radiation); DBH (Diameter at Breast Height); INTA (Argentinean Institute of Agricultural Technology); IFONA (Argentinean Forest Institute)
Effect of giberellic acid (GA4/7) and girdling on induction of reproductive structures in Pinus patula
Aim of study: Seed production in forest tree species commonly takes a long time due to the length of the juvenile stage. Even though several treatments have been used to induce early flowering in conifer species, experience on their use in subtropical Pinus species is limited. This study aimed to evaluate the effect of GA4/7 dose (0, 1.27 and 2.54 mg cm-2) and application time (July-October), alone or in combination with partial stem girdling, on male and female strobili production in young Pinus patula Schiede ex Schltdl. et Cham. clones. Area of study: Nine clones with different flowering background of high-elevation Pinus patula growing in a six-year old seed orchard established in Central México (Aquixtla, Puebla) at 2,800 m elevation.Material and methods: Two independent flowering trials (FT1 and FT2) were carried out in the seed orchard during the 2009 and 2010 flowering cycles; similar factors were evaluated at both trials but time of application, clones tested, and experimental design used varied for each of them. Partial stem girdling was done at the base of the trunk and the GA4/7 solution was injected into the xylem above the point of girdling. The following spring, the percentage of trees with strobili and the number of strobili per tree were determined for both male and female structures.Main results: Significant differences (p ≤ 0.05) among clones in flowering capacity were found at both trials. None of the treatments applied in FT1 resulted in an increase of strobili formation, most probably because they were applied too late in the growing season. In FT2, however, application of GA4/7 combined with partial stem girdling increased the percentage of trees with strobili and the number of strobili of both sexes, particularly when applied in early July. Partial stem girdling was more effective on promoting male strobili than female ones in gibberellin-treated grafts.Research highlights: Timing of GA4/7 application and stem girdling was important, with a significant interaction with clones tested in FT2 on production of male strobili but not on female strobili. Application of 1.27 mg cm-2 GA4/7 and stem girdling in July promoted the highest percentage of trees with strobili, and increased 25-fold the number of female strobili and 5-fold the number of male strobili per tree as compared to the control treatment. Thus, operational use of this induction treatment would be valuable to increase and accelerate seed production in Pinus patula seed orchards in the region.Keywords: early flowering; gibberellins; juvenile stage; seed orchard; seed production.Abbreviations: GA: Gibberellic acid; GA4: Gibberellic acid 4; GA7: Gibberellic acid 7; GA4/7: Mix of gibberellic acids 4 and 7; FT1: Flowering trial carried out in the 2009 season; FT2: Flowering trial carried out in the 2010 season