DG-Artículos
URI permanente para esta colecciónhttps://hdl.handle.net/10953/214
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Examinando DG-Artículos por Materia "63 Agricultura."
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Ítem Correlation of banana productivity levels and soil morphological properties using regularized optimal scaling regression(Elsevier, 2022-06) Olivares, Barlin O.; Calero, Julio; Rey, Juan C.; Lobo, Deyanira; Landa, Blanca B.Soil morphological properties described in the field, such as texture, consistence or structure, provide a valuable tool for the evaluation of soil productivity potential. In this study, we developed a regression model between the soil morphological variables of banana plantations and a crop Productivity Index (PI) previously developed for the same areas in Venezuela. For this, we implemented categorical regression, an optimal scaling procedure in which the morphological variables are transformed into a numerical scale, and can thus be entered in a multiple regression analysis. The model was developed from data from six plantations growing “Gran Nain” bananas, each with two productivity levels (high and low), in two 4-ha experimental plots, one for each productivity level. Sixty-three A horizons in thirty-six soils were described using 15 field morphological variables on a nominal scale for structure type, texture and hue, and an ordinal scale for the rest (structure grade, structure size, wet and dry consistence, stickiness, plasticity, moist value, chroma, root abundance, root size, biological activity and reaction to HCl). The optimum model selected included biological activity, texture, dry consistence, reaction to HCl and structure type variables. These variables explained the PI with an R2 of 0.599, an expected prediction error (EPE) of 0.645 and a standard error (SE) of 0.135 using bootstrapping, and EPE of 0.662 with a SE of 0.236 using 10- fold cross validation. Our study showed how soil quality is clearly related to productivity on commercial banana plantations, and developed a way to correlate soil quality indicators to yield by using indicators based on easily measured soil morphological parameters. The methodology used in this study might be further expanded to other banana-producing areas to help identify the soils most suitable for its cultivation, thereby enhancing its environmental sustainability and profitability.Ítem Does olive cultivation sequester carbon? Carbon balance along a C input gradient(Elsevier, 2023-12) Torrús-Castillo, Milagros; Calero, Julio; García-Ruiz, RobertoCurrently, there are some initiatives aimed at transforming agriculture from being a source to a sink of greenhouse gases, mainly by encouraging combination of management practices that drive nature-based climate processes (NbCS) resulting in an increase in the stocks of soil and biomass organic carbon. Olive grove cultivation represents a key socio-economic and environmental asset for Mediterranean rural regions. Being a woody crop planted in an orchard fashion, the potential for organic carbon accumulation in the biomass and the soil is very high. In this study, farm, trees and soil carbon balances were analysed in 12 pairs of olive groves located in Southern Spain with different tree densities, age, varieties and irrigation regimens. One from each pair of the olive groves has applied (> 8 years) a combination of management practices that promote NbCS resulting in an increase in the entry of carbon, whereas the other comparable nearby olive grove has not implemented management practices that promote NbCS or C entries (non-NbCS). C balance at the farm level was mainly neutral or positive and averaged + 1.20 Mg C ha−1 y−1. However, C balance in the NbCS olive groves was 5 times higher than that of the non-NbCS. The mean soil C balances were negative (−0.18 Mg C ha−1 y−1; losing soil organic C) in the non-NbCS and positive (+1.48 Mg C ha−1y−1) in the NbCS olive groves thanks to the increase in the carbon entries due to the management practices which boost NbCS. This study highlights the important contribution of olive farming in mitigating climate change, which in turn would be an economic incentive for olive growers. Nonetheless, there is a high potential for improvement by implementing management practices which enhance nature-based processes such as the cultivation of temporary spontaneous cover crops and the application of shredded tree pruning and composted olive mill pomace and/or manure to the soil.Ítem Does spontaneous cover crop increase the stocks of soil organic carbon and nitrogen in commercial olive orchard?(Elsevier, 2024-12) Pareja-Sánchez, Evangelina; Calero, Julio; García-Ruiz, RobertoManagement practices in the inter-row area of olive orchards are undergoing significant transformations. Current regulations and recommendations are increasingly advocating the implementation of temporary spontaneous cover crops (TSCV) mainly to reduce erosion. Existing research has predominantly focused on evaluating the effectiveness of TSCV in mitigating soil erosion in olive orchards, with limited attention given to carbon (C) cycling, despite the potential of TSCV for contributing to the removal of atmospheric CO2 and in the reduction of eroded carbon. Moreover, the limited number of studies on the effects of TSCV on C cycling have been confined to a few experimental sites and at the short term. This study aimed to assess the potential of TSCV to enhance carbon sequestration and nitrogen retention in rainfed commercial olive orchards under semi-arid conditions. To achieve this, we evaluated the annual aboveground organic carbon input due to TSCV, as well as the stocks of soil organic (SOC) and inorganic (SIC) carbon and total N (STN) in 24 commercial olive groves with calcareous Regosols and calcium Cambisols as the predominant soil types that have implemented TSCV for at least the last 8 years. These were compared with 24 comparable groves with bare soil (BS). Net aboveground annual carbon and CO2 fixation of the TSCV averaged 125.7 kg C ha-1 y-1 and 460 kg CO2 ha-1 y-1, respectively, which are figures relatively low mainly due to the low area covered by the TSCV. After eight years of implementing TSCV, the SOC stocks increased by an average of 2.03 Mg C ha-1 (in the top 30 cm of soil) compared to BS olive orchards. Moreover, SOC content of unprotected (>250 μm) and physically protected (53–250 μm) fractions were 82 and 38 % higher in the TSCV olive farms. Although there was a tendency of lower SIC content in TSCV olive orchards, differences were not significant. The STN content and the potentially mineralizable nitrogen in TSCV farms were on average 26 % and 77 % higher than in BS olive orchards. These findings underscore the potential of TSCV for organic carbon accumulation and nitrogen retention in the soil, contributing to climate change mitigation and soil fertility enhancement. Increasing vegetation coverage and productivity can enhance their effectiveness.Ítem Lanthanides in granulometric fractions of Mediterranean soils. Can they be used as fingerprints of provenance?(Wiley, 2019-03-01) Martín-García, Juan M.; Molinero-García, Alberto; Calero, Julio; Fernández-González, María V.; Párraga, Jesús; Delgado, RafaelThere is geochemical interest in the lanthanides because they behave like a group that is closely related to the parent materials during surface processes, although they also undergo fractionation as a result of supergene dynamics. We analysed lanthanide concentrations (ICPms) in the granulometric fractions fine sand, clay and free forms of clay (FFclay-CDB and FFclay-Ox: extracted with citrate-dithionite-sodium bicarbonate and with ammonium oxalate, respectively) from a soil chronosequence of Mediterranean soils. There was a relative enrichment of heavy rare earth elements (HREE) in the clay fraction and its free forms with respect to fine sand. The clay free forms behaved as scavengers of lanthanides, and oxidative scavenging of cerium (Ce) in FFclay-CDB was also detected. Lanthanide concentrations (lanthanum to gadolinium in fine sand; terbium to lutetium in clay) varied with soil age, and chronofunctions were established. There was a strong positive collinearity between most of the lanthanide concentrations. Furthermore, the value of the correlation index (Pearson's r) of the concentrations between couples of lanthanides (r(CLC)) decreased significantly with increasing separation between the elements in the periodic table; this has never been described in soils. Several geochemical properties and indices in the fine sand and clay soil fractions and in the geological materials of the Guadalquivir catchment showed, on the one hand, a genetic relation between them all, enabling the lanthanides to be used as fingerprints of provenance; on the other hand, fractionation between fine sand and clay showed these are actively involved in soil lanthanide dynamics.Ítem Nitrogen recycling across a spectrum of fertilization strategies: an assessment in olive groves(Elsevier, 2024-09-15) Domouso, Pablo; Calero, Julio; Ruiz-Cátedra, Gustavo; García-Ruiz, RobertoUnder the Zero pollution action, there is a strong emphasis on promoting management practices that enhance nitrogen (N) cycling to decrease reliance on inorganic N fertilizers and mitigate potential environmental impacts. Olive (Olea europaea L.) groves constitute the dominant landscape of many areas of Southern Mediterranean as Andalusia (Spain). Different farming models coexist in the olive sector, but they had not been studied in the context of N cycle. By integrating field and model data, we analyzed N flows, N balance, levels of N cycling closure, and N footprints in olive groves employing various cultivation models. Farms were categorized on: Org (organic external fertilization, high level of biomass recycling, temporary spontaneous cover crops), Tra (organic external fertilization, low recycling, bare soil), Int (inorganic external fertilization, low recycling, bare soil) and IPr (inorganic or organic external fertilization, low recycling, temporary spontaneous cover crops). Tree N demand, averaging 55 kg ha-1 y-1, correlated with fruit production and canopy area, making them suitable proxies for calculating N demand without exhaustive sampling. The N balance was positive for all farming models, with the Org model showing a more neutral balance (+7.4 kg N ha-1 y-1) and the IPr olive farms showing surpluses (+40.2 kg ha-1 y-1). In Org farms, annual N inputs were the lowest and rely on natural entries like N fixation, while Cycling Index was significantly higher than those of other groups (between 1.45 and 1.81 times). This was attributed to N recirculation mechanisms such as cover crops, shredding tree pruning, and returning harvested N through composted olive mill pomace. Soil erosion, often overlooked, emerged as a major N outflow, especially in Org farms with the highest soil N content, resulting in the highest N losses per liter of oil. Per liter of olive oil, Trad, Ipr, and Int farms use between 1.9 and 2.2 times more anthropogenic N inputs than Org farms. Overall, our results highlight significant potential to enhance internal N cycling, increase self-sufficiency, and extend the lifespan of N in olive farming by implementing scalable management practices that promote nature-based processes.Ítem Pedogenic information from fine sand: A study in Mediterranean soils(Wiley, 2020-07) Martín-García, Juan M.; Molinero-García, Alberto; Calero, Julio; Sánchez-Marañón, Manuel; Fernández-González, María V.; Delgado, RafaelThe fine sand fraction (50–250 μm) of Mediterranean soils from southern Spain provides valuable information on soil genesis and the origin of their parent materials. This study considers the whole fine sand and heavy fine sand (ρ > 2.82 g cm−3) of Luvisols, Calcisols and Fluvisols, which form a chronosequence (ages from 600 to 0.3 ka) of the River Guadalquivir terrace system. Advanced techniques (X-ray diffraction, inductively coupled plasma mass spectrometry, inductively coupled plasma atomic emission spectroscopy, variable pressure scanning electron microscope with an energy dispersive X-ray spectroscopy system and Raman analysis) were employed. Inheritance is the principal pedogenic process. The whole fine sand consisted of carbonates (calcite and dolomite), tectosilicates (quartz, K-feldspar and plagioclases), phyllosilicates (illite/moscovite, biotite, Na-mica, chlorite, kaolinite, interstratified vermiculite-chlorite, vermiculite-illite and smectite-illite) and iron oxides (goethite and haematite). The minor minerals (rutile, anatase, ilmenite, zircon, staurolite, monazite, barite, apatite, andalusite, garnet and titanite) are concentrated, also through inheritance, in the heavy fine sand. However, there is also substantiated evidence for neoformation of rutile in these soils, never reported previously. In addition, we report that (a) the geochemical indices calculated in fine sand (SiO2/CaO, Chemical Index of Weathering (CIW), Weathering Index of Parker (WIP), Weathering Index (WI), Base Depletion Index (BDI), Weathering Ratio (WR) and Sr/Zr) are closely related to soil age, allowing chronofunctions to be established, and (b) geochemical indices provide information on the origin of soils and permit the establishment of a “critical point” corresponding to “time zero;” that is, the start of pedogenic alteration of the parent material.Ítem The role of cover crops in the loss of protected and non-protected soil organic carbon fractions due to water erosion in a Mediterranean olive grove(Elsevier, 2021-09) López-Vicente, Manuel; Gómez, José A.; Guzmán, Gloria; Calero, Julio; García-Ruiz, RobertoSoil erosion plays an important role in C cycling at farm scale, especially in bare soil areas. In Mediterranean woody crops, temporary cover crops (CC) effectively reduce soil erosion and increase total and protected soil organic carbon (SOC) fractions. However, the effects of CC in olive groves on the preferential loss of organic carbon (Corg) fractions remains poorly understood. To address this issue, in four plots with seeded CC and two tilled plots (CT) in a Spanish olive grove, the unprotected and protected Corg fractions were measured in soil and sediments over the course of a hydrological year. The sediment/soil C enrichment ratios (ERSOC) were calculated, and results analysed considering the rainfall regimes of the site: dry (DS), heavy-rainy (HRS) and rainy (RS). Total, unprotected and protected Corg contents in the top 5 cm soil of CC plots were 46 %, 88.4 % and 28.5 %, respectively, higher than those of CT. 79.7 % and 70.3 % of the annual sediment yield (SY) was collected during December in CC and CT plots, respectively. Soil loss in CC plots (x¯ = 9.2 Mg ha–1 yr–1) was significantly lower (−55.6 %) than that in CT plots. Despite that the average eroded Corg was higher in the CT (x¯ = 222 kg C ha–1 yr–1) compared to CC (x¯ = 148 kg C ha–1 yr–1) plots differences were not significant due to the higher Corg concentration in the sediment from CC plots. The highest proportion of eroded Corg (44%–45%) corresponded to the physically protected fraction. The highest ERSOC (1.99 and 2.04 for CC and CT, respectively) was recorded in DS whereas the lowest was in the RS (0.90) and HRS (0.96) seasons. The mean ERSOC were of 1.00 and 0.92 in the CC and CT plots, with no significant difference. The fact that most of the SY was recorded in one month, when CC plants were not fully developed, might explain the ERSOC at 1, and why their presence did not modify it. This study demonstrates that CC favours greater total, unprotected and protected Corg fractions in the topsoil, promoting soil C sequestration. The asynchrony between the periods of full development of the CC plants and those with the highest rainfall erosivity prevented any selectiveness of the eroded Corg. Thus, fast-growing CC plant species with short life-cycles are recommended, as well as adequate management to promote self-seeding avoiding soil disturbance for seeding in erosion prone seasons.