Closing the yield gap of soybean (Glycine max (L.) Merril) in Southern Africa: a case of Malawi, Zambia, and Mozambique

Siyabusa Mkuhlani Isaiah Nyagumbo (2023, [Artículo])

Introduction: Smallholder farmers in Sub-Saharan Africa (SSA) are increasingly producing soybean for food, feed, cash, and soil fertility improvement. Yet, the difference between the smallholder farmers’ yield and either the attainable in research fields or the potential from crop models is wide. Reasons for the yield gap include low to nonapplication of appropriate fertilizers and inoculants, late planting, low plant populations, recycling seeds, etc. Methods: Here, we reviewed the literature on the yield gap and the technologies for narrowing it and modelled yields through the right sowing dates and suitable high-yielding varieties in APSIM. Results and Discussion: Results highlighted that between 2010 and 2020 in SSA, soybean production increased; however, it was through an expansion in the cropped area rather than a yield increase per hectare. Also, the actual smallholder farmers’ yield was 3.8, 2.2, and 2.3 times lower than the attainable yield in Malawi, Zambia, and Mozambique, respectively. Through inoculants, soybean yield increased by 23.8%. Coupling this with either 40 kg ha−1 of P or 60 kg ha−1 of K boosted the yields by 89.1% and 26.0%, respectively. Overall, application of 21–30 kg ha-1 of P to soybean in SSA could increase yields by about 48.2%. Furthermore, sowing at the right time increased soybean yield by 300%. Although these technologies enhance soybean yields, they are not fully embraced by smallholder farmers. Hence, refining and bundling them in a digital advisory tool will enhance the availability of the correct information to smallholder farmers at the right time and improve soybean yields per unit area.

Decision Support Tools Digital Tools Site-Specific Recommendations CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA DECISION SUPPORT SYSTEMS LEGUMES YIELDS SOYBEANS

DINÁMICA DE ACUMULACIÓN DE ARSÉNICO EN RELACIÓN A OTROS ELEMENTOS TRAZA Y POLISACÁRIDOS DE LA PARED CELULAR DE Sargassum spp. DE ARRIBAZONES

Paulina Annette Ortega Flores (2023, [Tesis de doctorado])

"La frecuencia e intensidad del fenómeno de arribazón de macroalgas marinas ha ido en aumento a nivel mundial. En el Caribe Mexicano, se ha identificado a especies pelágicas de algas pardas del género Sargassum como dominantes en estos arribazones. La gran cantidad de material que arriba a la costa ha resaltado la necesidad de generar información sobre la biología y composición química de las especies presentes en este fenómeno, la cual pueda ser incorporada en futuras estrategias sustentables de aprovechamiento de la biomasa arribada. En el presente estudio se determinaron las concentraciones totales de arsénico (As), cadmio (Cd), plomo (Pb), cobre (Cu), hierro (Fe) y zinc (Zn) en S. fluitans, S. natans I, S. natans VIII, recolectadas mensualmente durante un año, en Puerto Morelos, Quintana Roo, México mediante Espectrofotometría de Absorción Atómica (EAA). Para As, se determinó el contenido de su especie química inorgánica (iAs) en los tres morfotipos mediante voltametría. Adicionalmente, en S. fluitans se determinó el contenido de alginato, fucoidano, ácidos urónicos y sulfatos y se identificaron las variables de contribución significativa en la acumulación de As a partir de un Modelo Lineal Generalizado (GLM). La presencia de As se detectó en el 100% de las muestras; seguido de Fe (98%), Zn (90%), Cu (78%), Pb (71%) y Cd (65%). Las concentraciones máximas obtenidas en las especies pelágicas de Sargassum fueron de 255.20 mg kg-1 para As, 3.75 mg kg-1 para Cd, 17.39 mg kg-1 para Pb, 6.44 mg kg-1 para Cu, 78.27 mg kg-1 para Fe y 33.25 mg kg-1 para Zn. En general, las concentraciones promedio de los elementos analizados se encuentran en rangos previamente reportados para algas pardas. Los elementos As, Cu, Fe y Pb presentaron diferencias estadísticamente significativas entre morfotipos, mientras que los elementos Cd y Zn no. El morfotipo S. natans VIII presentó las concentraciones más elevadas de As respecto a las especies S. fluitans y S. natans I, siendo la temporada de lluvias (julio a octubre) cuando se presentaron las concentraciones más elevadas de este elemento. En cuanto al iAs, este representó del 14.15% al 81.70 % del As total (TotAs), lo que corresponde a 12.69 mg kg-1 a 62. 93 mg kg-1..."

"The frequency and intensity of the seaweed massive influx and arrival phenomenon has been increasing globally. On Mexican shores, has been identified to pelagic species of brown algae of genus Sargassum as dominant in these events. The large amount of material that reaches to the coast, has highlighted the need to generate basic information about the biology and chemical composition of the species present in the arrival phenomenon to be incorporated into future sustainable strategies for the use of Sargassum biomass. In the present study, the total concentrations were determined for arsenic (As), cadmium (Cd), lead (Pb), copper (Cu), iron (Fe) and zinc (Zn) in S. fluitans, S. natans I, S. natans VIII, collected monthly during one year, in Puerto Morelos, Quintana Roo, Mexico. For As, the content of its inorganic chemical species (iAs) was determined. Additionally, in S. fluitans the content of alginate, fucoidan, uronic acids and sulfates was determined and a Generalized Linear Model (GLM) was developed to identify the variables of significant contribution in the accumulation of As. The presence of As was detected in 100% of the samples; followed by Fe (98%), Zn (90%), Cu (78%), Pb (71%) and Cd (65%). The maximum concentrations obtained in the pelagic Sargassum species were 255.20 mg kg-1 for As, 3.75 mg kg-1 for Cd, 17.39 mg kg-1 for Pb, 6.44 mg kg-1 for Cu, 78.27 mg kg-1 for Fe y 33.25 mg kg-1 for Zn. Mean concentrations are in ranges previously reported for brown algae. The elements As, Cu, Fe and Pb showed statistically significant differences between morphotypes, while the elements Cd and Zn did not. The S. natans VIII morphotype presented the highest As concentrations respect to S. fluitans and S. natans I species, being the rainy season (July to October) when the highest concentrations was presented. –Regard to iAs. this represented from 14.15% to 81.70% of the total As (TotAs) which corresponds to 12.69 mg kg-1 to 62. 93 mg kg-1. In S. fluitans, identified the variables: Cu, uronic acids and sulfates from fucoidan, as variables that contribute significantly to the accumulation of As. Monitoring of the diverse components of sargazo is important for the decision making regarding the safe use and exploitation of this resource, as well as, the generation of basic knowledge regarding the process of metal accumulation in Sargassum upwelling."

Mexican Caribbean, Massive influxes, macroalgae, heavy metals Caribe Mexicano, arribazones, macroalgas, metales pesados BIOLOGÍA Y QUÍMICA QUÍMICA QUÍMICA INORGÁNICA METALES METALES

Using Observed Residual Error Structure Yields the Best Estimates of Individual Growth Parameters

Marcelo Vidal Curiel Bernal EUGENIO ALBERTO ARAGON NORIEGA MIGUEL ANGEL CISNEROS MATA LAURA SANCHEZ VELASCO SYLVIA PATRICIA ADELHEID JIMENEZ ROSENBERG ALEJANDRO FRANCISCO PARES SIERRA (2021, [Artículo])

"Obtaining the best possible estimates of individual growth parameters is essential in studies of physiology, fisheries management, and conservation of natural resources since growth is a key component of population dynamics. In the present work, we use data of an endangered fish species to demonstrate the importance of selecting the right data error structure when fitting growth models in multimodel inference. The totoaba (Totoaba macdonaldi) is a fish species endemic to the Gulf of California increasingly studied in recent times due to a perceived threat of extinction. Previous works estimated individual growth using the von Bertalanffy model assuming a constant variance of length-at-age. Here, we reanalyze the same data under five different variance assumptions to fit the von Bertalanffy and Gompertz models. We found consistent significant differences between the constant and nonconstant error structure scenarios and provide an example of the consequences using the growth performance index _0 to show how using the wrong error structure can produce growth parameter values that can lead to biased conclusions. Based on these results, for totoaba and other related species, we recommend using the observed error structure to obtain the individual growth parameters."

multimodel inference, error structure, totoaba, growth performance BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA ANIMAL (ZOOLOGÍA) FISIOLOGÍA ANIMAL FISIOLOGÍA ANIMAL

Growth Promoting Activity of Annona muricata L. Leaf Extracts on Lactobacillus casei

NIMCY NOEMI MEZA GUTIERREZ Paola Magallón Servín ROSENDO BALOIS MORALES IZA FERNANDA PEREZ RAMIREZ GRACIELA GUADALUPE LOPEZ GUZMAN GUILLERMO BERUMEN VARELA Pedro Ulises Bautista Rosales (2022, [Artículo])

"Soursop leaves are a source of phytochemical compounds, such as phenolic acids, flavonoids, hydrolyzable tannins, and acetogenins. These compounds can have several types of biological activities. Lactic acid bacteria can uptake phenolic compounds present in plants or fruits. The aim of the present work was to investigate the in vitro effect of hexane, acetone, methanolic, and aqueous extracts of soursop leaves (Annona muricata L.) on the growth, motility, and biofilm formation of Lactobacillus casei, and to determine compounds related to growth. The minimum concentration promoting growth, motility (swimming, swarming, and twitching), and biofilm-forming capacity (crystal violet) were evaluated. The results showed the growth-promoting capacity of acetone and aqueous extracts at low doses 25–50 mg/L, and an inhibition in the four extracts at higher doses of 100 mg/L. The L. casei growth is related to ellagic acid, quercetin rhamnoside, kaempferol dihexoside, quercetin hexoside, secoisolariciresinol, and kaempferol hexoside-rhamnoside. Hexane extract increased the three types of motility, while aqueous maintained swimming and twitching motility similar to control. The four extracts inhibited the biofilm formation capacity."

prebiotic, Lactobacillus, polyphenol, probiotic, growth promoters, soursop leaves CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CIENCIAS AGRARIAS AGROQUÍMICA REGULADORES DEL CRECIMIENTO DE LAS PLANTAS REGULADORES DEL CRECIMIENTO DE LAS PLANTAS