Spanish Journal of Agricultural Research 2022-03-24T15:16:49+00:00 SJAR Editorial Office Open Journal Systems <p>SJAR publishes papers reporting research findings on the following topics: agricultural economics; agricultural engineering; agricultural environment and ecology; animal breeding, genetics and reproduction; animal health and welfare; animal production; plant breeding, genetics and genetic resources; plant physiology; plant production (field and horticultural crops); plant protection; soil science; and water management.</p> <table style="width: 100%; border-spacing: 0px; border-collapse: collapse; margin-top: 20px;"> <tbody> <tr> <td style="width: 33%; text-align: left; vertical-align: top;"> <p class="check"><img src="/public/site/images/admin/check31.png"> Open Access</p> <p class="check"><img src="/public/site/images/admin/check31.png"> No Article Proccesing Charges</p> <p class="check"><img src="/public/site/images/admin/check31.png"> Indexed</p> <p class="check"><img src="/public/site/images/admin/check31.png"> Original Content</p> </td> <td style="width: 33%; text-align: left; vertical-align: top;"> <p class="check"><img src="/public/site/images/admin/check31.png"> Peer Review</p> <p class="check"><img src="/public/site/images/admin/check31.png"> Ethical Code</p> <p class="check"><img src="/public/site/images/admin/check31.png"> Digital Identifiers</p> <p class="check"><img src="/public/site/images/admin/check31.png"> Digital Preservation</p> </td> <td style="width: 33%; text-align: left; vertical-align: top;"> <p class="check"><img src="/public/site/images/admin/check31.png"> PDF, HTML, XML</p> <p class="check"><img src="/public/site/images/admin/check31.png"> Online First</p> </td> </tr> </tbody> </table> Tunisian consumer preferences for local forest honey attributes: A market segmentation analysis 2022-03-24T15:16:44+00:00 Samir Ben-Ali Ibtissem Taghouti <p><em>Aim of study: </em>This study focuses on the segmentation of local forest honey market based on consumer preferences for its origin and other sensory attributes.</p> <p><em>Area of study</em>: Tunisia</p> <p><em>Material and methods</em>: The empirical analysis relies on a face-to-face questionnaire survey of 200 respondents, conducted in 2019 among Tunisian consumers. A cluster analysis was used to identify the market segments and multinomial logit analysis was used to determine segment membership characteristics.</p> <p><em>Main results</em>: Three distinct market segments were identified. The first segment of consumers (44% of the sample) prefer eucalyptus and multifloral honey from the Northwest origin; the second segment (39%) is composed of consumers that tend to buy honey mainly produced in the eastern region of the country; in the third (17%), consumers prefer thyme-rosemary' honey.</p> <p><em>Research highlights: </em>Consumer preferences for local forest honey mainly depend on its geographical origin, flower type, flavor and color. Findings suggest that gender, income, and grocery shopping task are the main determinants of the importance of these attributes<em>.</em></p> 2022-02-21T09:21:25+00:00 Copyright (c) 2022 Spanish Journal of Agricultural Research Simulation modelling of mechanical systems for intra-row weeding in a precision farming approach 2022-03-24T15:16:48+00:00 Alberto Assirelli Paolo Liberati <p><em>Aim of study:</em> To test new approaches to perform mechanical weeding inside the row in horticulture and tree fruit fields. The idea is to weed the row by skipping the crop by means of a rotating system instead of a traditional crosswise one.</p> <p><em>Area of study</em>: North of Italy.</p> <p><em>Material and methods</em>: Numerical models have been developed to simulate mechanical weeding over time by generating numerical maps to quantify the different kind of worked areas.</p> <p><em>Main results</em>: Considering the efficiency of weed control on the row, the rotating plant-skipping system with vertical axis (RPSS-VA model) with two working tools gives the best performance index (<em>1.1.RWA%</em> = 95.9%). A similar performance can be obtained by the crosswise displacement plant-skipping system, but with very high crosswise translation velocity (with <em>v</em><em><sub>a</sub></em>/<em>v</em><em><sub>r</sub></em> ratio = 1/5, <em>1.1.RWA%</em> = 94.5%). With regard to the outwards worked area the RPSS-VA models give the best performances (<em>2.2.%OWAR</em> index from 127.2% up to 282.3%). To reduce the worked area outside the row, the FBTS models give lower index (<em>2.1.OWAR%</em>), while the RPSS-HA works only on the row, but with the lower <em>1.1.RWA%</em> index among all tested models (55.8%).</p> <p><em>Research highlights:</em> Rotating systems resulted more efficient than traditional ones, and provide considerations on the use of electric drive power instead of hydraulic one. This study highlights also the need of new approaches in designing lighter working tools. Lastly, the proposed classification of the worked areas could be used as reference standard.</p> 2022-01-10T00:00:00+00:00 Copyright (c) 2022 Spanish Journal of Agricultural Research Effect of potato contact parameters on seed metering performance using discrete element method 2022-03-24T15:16:47+00:00 Linrong Shi Xiaoping Yang Wuyun Zhao Bugong Sun Guanping Wang Wei Sun <p><em>Aim of study: </em>To study the effect of potato surface with or without sandy loam soil on seed metering performance, we investigated the motion behaviour of the potato seed particles during the seed metering process using a self-designed across-bridge metering device by discrete element method (DEM).</p> <p><em>Area of study</em>: Tonganyi Town, Dingxi, Gansu, China</p> <p><em>Material and methods</em>: First, the contact characteristics of potatoes were measured using some novel devices. Second, simulations were performed under the same experimental conditions to verify the reliability of the contact parameters. Finally, the velocity and angular velocity of the seed in the seed box and the number of seeds taken by the large spoon during the taking and clearing process were analysed using ANOVA.</p> <p><em>Main results</em>: The coefficients of static friction (SF) and rolling friction (RF) of seed particles with soil were smaller than those without soil and had the highest values between particles and plastic, followed by between particles and steel, and between particles. Further, the rates of metering single seed particle in simulation and experiment were 98.17% and 97.57%, respectively. The rate of missing seed particles was 1.83% and 2.43%, respectively; it was found to significantly decrease as RF increased from 0.01 to 0.06 to 0.12, and the resultant angular velocity and velocity also significantly decreased as SF increased from 0.1 to 0.5 to 1.0. In addition, the number of seeds taken by the large spoon also reduced.</p> <p><em>Research highlights: </em>Therefore, potato seed particles surface with or without soil can significantly affect the seeding performance and highlight the need for surface treatment using mechanised metering.</p> 2022-01-20T00:00:00+00:00 Copyright (c) 2022 Spanish Journal of Agricultural Research Assessment of consumer-grade camera-derived vegetation indices for monitoring nitrogen and leaf relative water content of maize 2022-03-24T15:16:46+00:00 Fatemeh Mousabeygi Samira Akhavan Yousef Rezaei <p><em>Aim of study:</em> To develop non-destructive and rapid monitoring of water and nitrogen status in maize crops.</p> <p><em>Area of study:</em> Bu-ali Sina University, Hamedan province, Iran.</p> <p><em>Material and methods:</em> We used a low-cost modified consumer-grade camera to extract 40 vegetation indices for monitoring leaf N concentrations, SPAD values and relative water content (RWC). In this regard, 528 images taken by the low-cost camera in two consecutive years (2017 and 2018) from maize plants cultivated in a greenhouse under different irrigation and N treatments were evaluated.</p> <p><em>Main results:</em> Results showed that the best performance outcomes regarding the studied vegetation indices were MCARI, CTVI and CR for SPAD values; MCARI, HUE and CTVI for leaf N concentrations; and TRVI, NDVI and DVI for RWC. In order to increase accuracy of estimated measured data, multiple linear regression equations with combinations of the MCARI, TRVI, NDVI and EVI indices were used. As observed, R<sup>2</sup> value was 0.91, 0.60 and 0.90 for SPAD, leaf N concentration and RWC estimation, respectively.</p> <p><em>Research highlights:</em> The combination of MCARI, TRVI, NDVI and EVI indices provided more accuracy to most of the previous single variable regression models.</p> 2022-01-28T13:17:12+00:00 Copyright (c) 2022 Spanish Journal of Agricultural Research Genomic evaluation of binary traits in dairy cattle by considering genotype × environment interactions 2022-03-24T15:16:44+00:00 Bahareh Eteqadi Seyed A. Rafat Sadegh Alijani Sven König Mehdi Bohlouli <p><em>Aim of study: </em>To assess genotype by environment (G×E) interaction via single- and multi-trait animal models for binary traits in dairy cattle.&nbsp;</p> <p><em>Area of study</em>: University of Tabriz, Tabriz, Iran.</p> <p><em>Material and methods</em>: Phenotypic and genomic data were simulated considering a binary trait in four environments as different correlated traits. Heritabilities of 0.05, 0.10, 0.15, and 0.20 were considered to mimic the genetic variation of the binary trait in different environments. Eight scenarios resulted from combining the number of QTLs (60 or 300), LD level (high or low), and incidence of the binary trait (10% or 30%) were simulated to compare the accuracy of predictions. For all scenarios, 1667 markers per chromosome (depicting a 50K SNP chip) were randomly spaced over 30 chromosomes. Multi-trait animal models were applied to take account of G×E interaction and to predict the genomic breeding value in different environments. Prediction accuracies obtained from the single- and multi-trait animal models were compared.</p> <p><em>Main results</em>: In the models with G×E interaction, the largest accuracy of 0.401 was obtained in high LD scenario with 60 QTLs, and incidence of 30% for the fourth environment. The lowest accuracy of 0.190 was achieved in low LD scenario with 300 QTLs and incidence of 10% for the first environment.</p> <p><em>Research highlights:</em> Genomic selection with high prediction accuracy can be possible by considering the G×E interaction during the genetic improvement programs in dairy cattle.</p> 2022-02-18T13:37:47+00:00 Copyright (c) 2022 Spanish Journal of Agricultural Research Prevalence and risk factors of lameness in dairy cattle in Alexandria, Egypt 2022-03-24T15:16:48+00:00 Amr M. A. Rashad Ahmed A. Kohla Mahmoud A. Aziz Dalia K. A. EL-Hedainy <p><em>&nbsp;&nbsp;Aim of study:</em> Providing further information on the prevalence of lameness in four dairy cattle herds and gain insights into the risk factors associated with the frequency of lameness incidence including farm, frequency of mastitis, and number of lactations.</p> <p><em>&nbsp;&nbsp;</em><em>Area of study</em>: Alexandria, Egypt.</p> <p><em>&nbsp;&nbsp;Material and methods</em>: Four dairy Holstein cattle farms near Alexandria Governorate in Egypt were involved in a retrospective investigation of lameness episodes between the years 1987 and 2011. The association between the frequency of lameness injury and the explanatory variables was tested by the maximum likelihood analysis of variance, adopting a loglinear model. The explanatory variables included in the model were farm, frequency of mastitis injury and number of lactations as well as their one-way interactions.</p> <p><em>&nbsp;&nbsp;</em><em>Main results</em>: The prevalence of lameness ranged between zero and 19% in the four farms and the frequency of lameness events (from 0 to 4 times) increased with lactation number and mastitis incidence with correlation coefficients of 0.15 and 0.12, respectively.</p> <p><em>&nbsp;&nbsp;Research highlights: </em>Lameness is present in Egyptian dairy cow herds with highly variable prevalence and the risk increases with lactation number and mastitis.</p> 2022-01-17T15:08:50+00:00 Copyright (c) 2022 CSIC Pathogenesis of domestic pigs submitted to mycobacterial sensitizations previous to experimental infection with Mycobacterium bovis 2022-03-24T15:16:47+00:00 María X. Cuerda María A. Colombatti María J. Gravisaco María J. Marfil Soledad Barandiaran Iker A. Sevilla Joseba M Garrido Roberto D. Moyano Martin José Zumarraga María I. Romano Ramón A. Juste María de la Paz Santangelo <p><em>Aim of study: </em>To demonstrate the virulence of a <em>Mycobacterium bovis</em> local pig isolate in order to contribute to a better understanding of the pathological and immunological consequences of <em>M. bovis</em> infection in previous sensitized animals.</p> <p><em>Area of study</em>: Buenos Aires, Argentina</p> <p><em>Material and methods</em>: One group of ten pigs received two oral doses of killed <em>M. bovis</em> suspension and a comparative intradermal tuberculin test (CIT) (multiple sensitized) and then was infected with the <em>M. bovis </em>strain. Another group only received the CIT (single sensitized) and the infective dose. Humoral immune response was followed monthly, and gross pathology, histopathological and bacteriological analysis were performed at necropsy 100 days after infection.</p> <p><em>Main results</em>: <em>M. bovis</em> oral infection induced lesions and allowed bacterial growth in most of the animals. Previous sensitization with killed <em>M. bovis</em> suspension slightly raised the intensity of the response, as the multiple sensitized group showed higher lesion scores and humoral response.</p> <p><em>Research highlights:</em> Although the differences in lesion scores were not statistically significant, oral route infection after sensitization can modify the course of infections towards a fast development of lesions with a higher fibrotic component suggestive of increased resistance to infection in the right conditions.</p> 2022-01-26T16:27:44+00:00 Copyright (c) Evaluation of the anti-coccidial effect of aqueous Sacoglottis gabonensis (Magnoliophyta, Humiriaceae) stem bark extract in broilers experimentally infected with mixed Eimeria species 2022-03-24T15:16:46+00:00 Chukwuma P. Eze Chukwunonso F. Obi Idika K. Idika Chukwunyere O. Nwosu <p><em>Aim of the study:</em> The aqueous <em>Sacoglottis gabonensis </em>stem bark extract (SGSBE) was evaluated for its anti-coccidial effects and toxicity in broiler chickens</p> <p><em>Area of the study:</em> Nsukka, Nigeria</p> <p><em>Materials and methods</em><strong>:</strong> A hundred and nineteen, four-week old, broiler birds were used for this study. The toxicity of SGSBE was evaluated by administering graded doses of the extract once and for 21 days. The anticoccidial effect of SGSBE was determined using 25 birds arbitrarily divided into five groups (A-E) of five birds each. Groups A-D were orally infected with 200,000 sporulated mixed <em>Eimeria </em>oocysts while group E served as the uninfected control. Groups A and B birds were treated orally with SGSBE (200 mg/kg) once and daily for five consecutive days respectively while group C birds were treated with amprolium daily for five days. Birds in group D remained infected-untreated. The birds were observed for clinical signs, body weight changes, oocyst output, and some haemato-biochemical parameters.</p> <p><em>Main results:</em> Mild signs of toxicity were detected with mortality only in the group that received the highest dose of SGSBE following toxicity tests. Clinical signs of coccidiosis were observed following infection of the birds. Oocyst output, clinical signs and lesions were significantly reduced (<em>p</em>&lt;0.05) while body weight, survivability and haemato-biochemical indices of the birds were significantly improved (<em>p</em>&lt;0.05) in SGSBE treated groups. Moreover, five days consecutive treatment with SGSBE yielded better results.</p> <p><em>Research highlights:</em> The aqueous <em>S. gabonensis </em>stem bark extract is relatively safe and possesses anti-coccidial efficacy against mixed <em>Eimeria</em> infections in broiler chickens.</p> 2022-02-02T00:00:00+00:00 Copyright (c) 2022 Spanish Journal of Agricultural Research Replacement of inorganic trace minerals by chelated minerals in pullet diets (12 to 20 weeks of age) 2022-03-24T15:16:45+00:00 Bruno M. Santos Fernanda V. Castejon Eduardo M. Oliveira Fabyola B. Carvalho Heloisa H. C. Mello Marcos B. Café José H. Stringhini <p><em>Aim of study: </em>An experiment was carried out aimed to evaluate the effects of different levels and sources of trace mineral to laying pullets with two initial body weights (BWs).</p> <p><em>Area of study</em>: The experiment was carried out in Federal University of Goiás, Goiânia, Goiás, Brazil</p> <p><em>Material and methods</em>: Two hundred and eighty eight Bovans White pullets aged 12 weeks old were allotted in a completely randomized design and a 2×3 factorial arrangement, wherein the main effects included initial BW (light-weight and heavy-weight) and three dietary trace mineral sources and levels (100% inorganic, 100% chelated and low-dose corresponding to 50% chelated), totalizing six treatments with eight replicates of six birds. The performance, the metabolizability coefficient of nutrients, and the onset of lay were evaluated at rearing phase (12 to 20 weeks). At 17th and 20th weeks of age, the relative weight of reproductive and digestive organs, abdominal fat, and tibia quality were assessed. A residual effect was evaluated at production phase on productive performance and egg quality.</p> <p><em>Main results</em>: The mineral source did not affect the performance of pullets. Birds fed 50% chelated mineral produced the lowest eggshell. The heavy-weight birds showed higher egg weight and eggshell quality. The lighter birds showed lower abdominal fat weight and lower tibia robustness index.</p> <p><em>Research highlights:</em> The replacement of 100% of inorganic mineral for chelated mineral do not result in decrease of bird performance at rearing and at production phase, but a minimum amount should be provided to ensure growth and nutrient metabolizability.</p> 2022-02-07T19:30:03+00:00 Copyright (c) 2022 Spanish Journal of Agricultural Research Short communication: Sodium chloride levels in pacu (Piaractus mesopotamicus) fingerling feeds free of fish meal 2022-03-24T15:16:49+00:00 Natalia C. Aguiar Izabel V. Zadinelo Patrícia S. Dias Marlise T. Mauerwerk Robie A. Bombardelli Fábio Meurer <p><em>Aim of study: </em>To evaluate the effects of increasing NaCl levels on the zootechnical performance of pacu fingerling.</p> <p><em>Area of study</em>: The experiments were conducted at the Aquatic Organism Production and Reproduction Systems Laboratory belonging to the Federal University of Paraná (UFPR), in the Palotina Sector, Paraná Estate, Brazil.</p> <p><em>Material and methods</em>: Seven hundred and fifty fingerlings with an average weight of 3.41 ± 0.09 g were distributed in circular boxes, in a completely randomized design consisting of six treatments and five replications. Treatments comprised soybean- and maize-based diets containing increasing levels of NaCl (0.00, 0.25, 0.50, 0.75, 1.00 and 1.25%). The experiments were conducted for 50 days. At the end of the experimental period the fish were fasted for 24 hours, anesthetized, weighed and measured to calculate zootechnical performances. Performance data were subjected to an analysis of variance followed by Tukey’s test when significant differences were found between the means (<em>p</em>&lt;0.05).</p> <p><em>Main results</em>: The influence (<em>p</em>&lt;0.05) of dietary NaCl levels on final weight, feed intake, apparent feed conversion, specific growth rate, average weight gain, clean trunk production, head carcass yield, headless carcass yield, feed intake and survival was assessed. The results indicate that non-salt treated fingerlings along with the 0.25% salt inclusion treatment led to better feed use, as evidenced by apparent feed conversions of 1.64 and 2.02, respectively.</p> <p><em>Research highlights:</em> The inclusion of NaCl in pacu fingerling soybean and maize-based diets is not recommended.</p> 2021-12-21T00:00:00+00:00 Copyright (c) 2022 Spanish Journal of Agricultural Research Effectiveness of the entropy weight method to evaluate abiotic stress tolerance in citrus rootstocks 2022-03-24T15:16:44+00:00 Shashi Pathania Harminder Singh Manpreet S. Mavi Om P. Choudhary Sanjula Sharma <p><em>Aim of study</em>: The entropy weight method (EWM) is considered one of the most reliable and scientific approaches when decision making is influenced by multiple factors. However, there are no reports on the application of EWM in the evaluation of abiotic and biotic stress tolerance in crops. In this study, abiotic stress via saline water irrigations was imposed on different citrus rootstocks. The relative stress tolerance levels of rootstocks were ascertained using EWM and compared with standard fuzzy membership approach and the factor analysis.</p> <p><em>Area of study:</em> Punjab Agricultural University Regional Research Station Abohar, India, 2017-2019.</p> <p><em>Material and methods:</em> In a pot culture study, about 1½ yr-old rootstock seedlings were exposed to saline water irrigations with 4 and 6 dS m<sup>-1</sup> electrical conductivity (EC) for 60 days. Saline water response index for mineral composition of plant parts, physiological and biochemical attributes of rootstocks were calculated for each salinity level over 2 dS m<sup>-1</sup> conductivity water, considered as control and subjected to further analysis.</p> <p><em>Main results:</em> At 4 EC, the entropy weight and membership function value of the rootstocks ranged 0.758-0.998 and 0.682-0.731, respectively. The corresponding values at 6 EC ranged between 0.759-0.991 and 0.391-0.728, respectively. Following EWM, the rootstocks were rated for their relative tolerance levels as: Rangpur Lime&gt;Cleopatra&gt;Volkamer Lemon=Rough Lemon&gt;Carrizo at 4 EC salinity level. At 6 EC, the order was: Cleopatra&gt;Rangpur Lime&gt;Volkamer Lemon&gt;Rough Lemon&gt;Carrizo. The results were consistent between EWM and standard principle component analysis approaches.</p> <p><em>Research highlights:</em> The study suggests that the comprehensive evaluation of crop genotypes for abiotic stress tolerance is also feasible with the EWM.</p> 2022-02-15T19:16:50+00:00 Copyright (c) 2022 Spanish Journal of Agricultural Research Short communication: Organic fertilization for the improvement of production and quality of ripe figs 2022-03-24T15:16:46+00:00 Mauro B. D. Tofanelli Gabriel L. de Jesus Ricardo S. A. Silva <p><em>Aim of study</em>: The use of natural inputs in farming practices and the consumption of <em>in natura</em> products have been on the rise. Natural crop fertilizing sources gains force when the intent lies in crop by way of an ecologically correct agricultural system. To this end, this paper targeted assessing the use of cattle (CM) and bird manure (BM) in organic fertilization of fig culture in organic handling, and its effect on the production of ripe figs.</p> <p><em>Area of study</em>: Federal University of Paraná, Curitiba, Paraná, Brazil.</p> <p><em>Material and methods</em>: In 2011, an experimental fig orchard was established using the ‘Roxo de Valinhos’ cultivar. The experimental outline adopted was in randomized blocks, with 3 repetitions and 7 treatments comprised of: the control and 6 types of fertilization using CM and/or BM. Harvests were performed in 2016 and 2017. The characteristics evaluated were mean weight, length and diameter of individual fruits, mean weight and number of fruits per tree, total soluble solids content, total titratable acidity and pH.</p> <p><em>Main results</em>: Organic fertilization with 5 L of CM per fig tree promoted the best results in all biometric variables as compared to the plants that were not fertilized. Considering quality, only 5 L of CM or 1.25 L of BM provided equal total titratable acidity in comparison with control. Plants fertilized with 2.5 L of CM produced figs with higher maturation index against plants fertilized with 5 L of CM or 1.25 L of BM.</p> <p><em>Research highlights</em>: Considering the fig tree productivity and quality of ripe figs, organic fertilization with CM and BM promoted good characteristics.</p> 2022-02-07T00:00:00+00:00 Copyright (c) 2022 Spanish Journal of Agricultural Research Short communication: Virulence of barley leaf rust in the South of Russia in 2017-2019 2022-03-24T15:16:49+00:00 Anastasiya V. Danilova Galina V. Volkova <p><em>Aim of study:</em> To analyze the structure of <em>Puccinia hordei</em> populations by virulence in southern Russia during 2017-2019.</p> <p><em>Area of study</em><em>:</em> South of Russia, the leading Russian region for barley production where barley leaf rust is an important foliar disease.</p> <p><em>Material and methods:</em> Uredinial samples of <em>P. hordei</em> were collected at the production sites of winter barley in the south of Russia. Single uredinial isolates (total 95) were tested for virulence with 17 differentials with <em>Rph</em> resistance genes.</p> <p><em>Main results:</em> No isolates were found virulent to the host line with the <em>Rph13</em> gene. There was a decrease in the number of fungal isolates virulent to the host lines with <em>Rph5</em> and <em>Rph7</em> genes. In 2017 and 2019, isolates containing a large number of virulence alleles (from 11 to 15) prevailed. In 2018, isolates with low (1-5) and medium (6-10) frequency of virulent alleles prevailed, as well as avirulent isolates. The values of the Nei index via diversity showed high similarity of the pathogen populations in 2017-2018 (N = 0.05) and minor differences in 2017-2019 and 2018-2019 (N = 0.13 and 0.16, respectively). The greatest frequency of virulence alleles in accordance with the Nei (Hs) index was noted for the 2018 population (Hs = 0.36). For the 2017 and 2019 populations, this indicator was on average Hs = 0.29 and 0.20, respectively.</p> <p><em>Research highlights: </em>Analysis of genetics of the <em>P. hordei</em> population is important for the strategy of varietal distribution in the region and development of rust-resistant cultivars.</p> 2021-12-22T18:33:51+00:00 Copyright (c) Soil properties modulate the effect of different carbon amendments on growth and phosphorus uptake by cucumber plant 2022-03-24T15:16:48+00:00 Ana M. García-López Ramiro Recena Antonio Delgado <p><em>Aim of study:</em> Phosphorus (P) is a non-renewable, limited and strategic resource, inefficiently used in agriculture. Organic carbon (C) supply to soil can stimulate microbial activity increasing the mobilization of soil P thus improving its uptake by crops. This work aimed at investigating the effect of different C amendments on P uptake and how may differ depending on soil properties and P fertilization.</p> <p><em>Area of study</em>: Soils used in this study were collected in SW Spain.</p> <p><em>Material and methods: </em>An experiment with cucumber was performed involving three factors: (i) C amendment (cellulose, glucose, citric acid and control without amendment), (ii) soil type (Vertisol and Alfisol), and (iii) P supply (unfertilized, and mineral phosphate in form of KH<sub>2</sub>PO<sub>4</sub>).</p> <p><em>Main results:</em> Cellulose or glucose provided the highest P uptake by plants in soils independently of the treatment. Cellulose and glucose addition was effective increasing dry matter (DM) in the Alfisol. Citric acid application decreased the development of aerial parts and roots, and P uptake in soils compared with other sources. In the Alfisol, increased P uptake with cellulose was associated to an increased concentration of low molecular weight organic acids, which seemed to be related to microbial activity.</p> <p><em>Research highlights:</em> Organic amendments affect microbial activity, and P mobilization mechanisms are associated to microorganisms. This explain the improvement of P supply to plants with amendments; these effects, however, are modulated by soil properties and consequently vary depending on soil type.</p> 2022-01-20T00:00:00+00:00 Copyright (c) 2022 Spanish Journal of Agricultural Research Use of two relative depths of the soil apparent electrical conductivity to define experimental blocks with spatial regression models 2022-03-24T15:16:45+00:00 Edwin F. Grisales Aquiles E. Darghan Carlos A. Rivera <p><em>Aim of study:</em> Our main objective was to take advantage of the ECa information that the EM38-MK2 sensor records simultaneously at two relative depths for modeling using spatial regression and the subsequent blocking of the conductivity estimate values, incorporating elevation.</p> <p><em>Area of study</em>: A 23.1-ha field located in the municipality of Puerto López (Meta, Colombia).</p> <p><em>Material and methods</em>: A series of georeferenced data (15438) was collected from the EM38-MK2 sensor, through which the ECa was obtained at two depths, a spatial aggregation was performed using a grid of 40 m ´ 40 m (167 grid cells), to provide data in Lattice form, the centroid of the cells was determined as the new representative spatial coordinates, to adjust a Spatial Autoregression Model (SAC), and then define the blocks from the predictions of the adjusted model.</p> <p><em>Main results</em>: The adjusted model has a comparative purpose with the usual proposals for delimiting management zones separately, so it was convenient to incorporate in the model a 3D weighting matrix relating the two relative depths recorded by the EM38MK2 sensor. By mapping the surface layer with the predictions of the SAC model, two distinguishable blocks were delimited in its ECa and management zone analyst (MZA), which can be suitable for experimentation or agricultural management.</p> <p><em>Research highlights: </em>These results can be adopted to define the shape and dimension of the blocks in the context of experimental design so that with adequate blocking, the effect of spatial dependence associated with the physicochemical properties of soils related to ECa can be mitigated or suppressed.</p> 2022-02-07T11:49:52+00:00 Copyright (c) 2022 Spanish Journal of Agricultural Research Editorial Board 2022-03-04T13:53:27+00:00 Journal Editorial Office 2022-03-04T13:31:01+00:00 Copyright (c)