Examinando por Autor "Ottos Díaz, Elvis"

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Spatial analysis of soil acidity and available phosphorus in coffee-growing areas of Pichanaqui: Implications for liming and site-specific fertilization
(MDPI, 2025-07-28) Quispe Matos, Kenyi Rolando; Hermoza Ayme, Nilton Alexander; Mejia Maita, Sharon Yahaira; Romero Chávez, Lorena Estefani; Ottos Díaz, Elvis; Arce, Andrés; Solórzano Acosta, Richard
Soil acidity is one of the main limiting factors for coffee production in Peruvian rainforests. The objective of this study is to predict the spatial acidity variability for recommending site-specific liming and phosphorus fertilization treatments. We analyzed thirty-six edaphoclimatic variables, eight methods for estimating liming doses, and three geospatial variables from 552 soil samples in the Pichanaqui district of Peru. Multivariate statistics, nonparametric comparison, and geostatistical analysis with Ordinary Kriging interpolation were used for data analysis. The results showed low coffee yields (0.70 ± 0.16 t ha⁻¹) due to soil acidification. The interquartile ranges (IQR) were found to be 3.80–5.10 for pH, 0.21–0.87 cmol Kg⁻¹ for Al⁺³, and 2.55–6.53 mg Kg⁻¹ for available P, which are limiting soil conditions for coffee plantations. Moreover, pH, Al⁺³, Ca⁺², and organic matter (OM) were the variables with the highest accuracy and quality in the spatial prediction of soil acidity (R² between 0.77 and 0.85). The estimation method of liming requirements, MPM (integration of pH and organic material method), obtained the highest correlation with soil acidity-modulating variables and had a high spatial predictability (R² = 0.79), estimating doses between 1.50 and 3.01 t ha⁻¹ in soils with organic matter (OM) > 4.00%. The MAC (potential acidity method) method (R² = 0.59) estimated liming doses between 0.51 and 0.88 t ha⁻¹ in soils with OM < 4.00% and potential acidity greater than 0.71 cmol Kg⁻¹. Regarding phosphorus fertilization (DAP), the results showed high requirements (median = 137.21 kg ha⁻¹, IQR = 8.28 kg ha⁻¹), with high spatial predictability (R² = 0.74). However, coffee plantations on Ferralsols, with Paleogene parental material, mainly in dry forests, had the lowest predicted fertilization requirements (between 6.92 and 77.55 kg ha⁻¹ of DAP). This research shows a moderate spatial variation of acidity, the need to optimize phosphorus fertilization, and an optimal prediction of liming requirements using the MPM and MAC methods, which indicate high requirements in the southwest of the Pichanaqui district.
Weed Species Associated with Cacao Cultivation Exhibiting Phytoremediation Potential for Cadmium and Lead: A Study Based on Bioconcentration and Translocation Factors
(Tech Science Press, 2026-06-29) Romero Chávez, Lorena Estefani; Calero Rios, Emilee Nahomi; Aldava Pardave, Uriel; Ottos Díaz, Elvis; Salgado Veramendi, Noelito; Huerto Pajuelo, Eldhy Sianina; Ibarra Porras, Carolina del Carmen; Solórzano Acosta, Richard Andi
The exploration and identification of spontaneous weed species in heavy metal–contaminated soils represent a relevant approach for understanding the role and their potential application in phytoremediation. In cacao cultivation, cadmium contamination poses a significant risk due to the restrictions established for soils and cacao-derived products, thereby threatening productive sustainability and export viability. The objective of this study was to identify weed species associated with cacao cultivation exhibiting accumulation patterns and phytoremediation potential for Cd and Pb, through the assessment of biomass production and the bioconcentration factor (BCF) and translocation factor (TF), in natural conditions. Soil samples were collected from seven cacao-growing zones, and the site with the highest Cd concentration (1.65 mg kg−1) was selected, where ten dominant weed species were identified and evaluated. Significant interspecific differences were observed in biomass production and in Cd and Pb concentrations (p < 0.05). Talinum paniculatum exhibited the highest total biomass (6.15 g) and the highest TF for Cd, whereas Cyperus aggregatus showed the greatest total Cd accumulation (2.68 mg kg−1). BCF and TF values enabled the identification of species with accumulation patterns consistent with Cd phytoextraction (T. paniculatum, C. aggregatus, Pseudelephantopus spiralis, Bidens riparia, Euphorbia heterophylla, and Malvastrum coromandelianum) and with phytostabilization (Ocimum campechianum). For Pb the observed patterns were consistent with potential phytoextractive behavior in B. riparia, P. spiralis, E. heterophylla, Hilleria latifolia, and Acalypha stachyura. Although these results do not constitute functional evidence of remediation, they describe heavy metal accumulation and translocation patterns in native weed species, providing a technical basis for the design of future experimental trials aimed at the sustainable remediation of contaminated soils.