Root length density (RLD) of oil palm (Elaeis guineensis Jacq) in a haplic Luvisol in Chiapas, Mexico

The tight relationship between root architecture and uptake capacity of soil water and minerals, is well established. Support roots, generally long-lived, perform support functions such as transportation and food storage. Absorbing roots, thin and short-lived, absorb nutrients and regulate plant metabolism. Roots distribution in the soil profile is crucial for plant development. It optimizes resource usage and ensures a prompt response to seasonal changes. This work aimed to study the vertical distribution of the root system of nine-year-old oil palms in a haplic Luvisol, low fertility, moderately acidic, with Nitrogen (N) and Potassium (K) deficiency, average content of Phosphorous (P), and medium to low Cation Exchange Capacity (CEC). Using the cylinder method, soil samples were collected every 10 cm and down to 150 cm of soil depth, from each cardinal side of three soil profiles. The results showed that oil palms had good root development. Most roots (73%) were found in the first 30 cm of soil, with a predominance of fine roots (78%). At 50 cm in depth, fine roots represented 88%, thin roots, 67% and medium roots, 94%. Further study should assess root length density at 15, 20, 25, and 30 years. Highlights - Haplic luvisols are optimal soils for oil palm cultivation due to their depth (> 150cm), over 50% base saturation, and pH of 5.5-6.6. - Root length density (RLD) decreased as soil depth increased. Although most oil palm roots are found in surface horizons, roots can still be found at depths of up to 1.5-5 m. - The highest number of oil palm roots (73%) was found in the first 30 cm, with 78% of fine roots. - Fine roots were distributed throughout the entire soil profile, evidencing  high nutrient-absorption and metabolic activities.The tight relationship between root architecture and uptake capacity of soil water and minerals, is well established. Support roots, generally long-lived, perform support functions such as transportation and food storage. Absorbing roots, thin and short-lived, absorb nutrients and regulate plant metabolism. Roots distribution in the soil profile is crucial for plant development. It optimizes resource usage and ensures a prompt response to seasonal changes. This work aimed to study the vertical distribution of the root system of nine-year-old oil palms in a haplic Luvisol, low fertility, moderately acidic, with Nitrogen (N) and Potassium (K) deficiency, average content of Phosphorous (P), and medium to low Cation Exchange Capacity (CEC). Using the cylinder method, soil samples were collected every 10 cm and down to 150 cm of soil depth, from each cardinal side of three soil profiles. The results showed that oil palms had good root development. Most roots (73%) were found in the first 30 cm of soil, with a predominance of fine roots (78%). At 50 cm in depth, fine roots represented 88%, thin roots, 67% and medium roots, 94%. Further study should assess root length density at 15, 20, 25, and 30 years. Highlights - Haplic luvisols are optimal soils for oil palm cultivation due to their depth (> 150cm), over 50% base saturation, and pH of 5.5-6.6. - Root length density (RLD) decreased as soil depth increased. Although most oil palm roots are found in surface horizons, roots can still be found at depths of up to 1.5-5 m. - The highest number of oil palm roots (73%) was found in the first 30 cm, with 78% of fine roots. - fine roots were distributed throughout the entire soil profile, evidencing  high nutrient-absorption and metabolic activities

Evaluación de la fertilización convencional y de liberación controlada, sobre la calidad de plantas de jagua (Genipa americana L.) en vivero

Objective: Select the type and dose of fertilizer suitable for the best quality, highest accumulation of dry biomass and photosynthetic rate in plants of G. americana L. during the nursery stage. Design/methodology/approach: A completely randomized experimental design with four repetitions was used. The plants were evaluated for a period of three months in nursery, for which at 20 days of age they were transplanted in 310 cm3 polyethylene tubes using a substrate composed of vermiculite, perlite and peat, which was mixed with Conventional fertilizer (CF) Triple 17 (17N-17P-17K) in doses of 3.3 (low), 6.6 (medium) and 10 kg * m-3 (high), and Osmocote® controlled release fertilizer (CRF) (15N-9P -12K), in doses of 10 (low), 20 (medium) and 30 kg * m-3 (high), plus a control without fertilization. The variables were measured: neck diameter, height, root length, aerial and radical biomass, robustness index (IR), biometric proportionality index (IPB), Dickson quality index (ICD) and photosynthetic rate. The averages were compared by the Tukey test at a 5% confidence level. Results: The plants of G. americana L. fertilized with Osmocote® in its three doses (high, medium and low) showed the highest growth in all morphological variables; in IR the Osmocote® generated plants of better quality than the control, the IPB only the high dose of Osmocote® was different from the control although it is considered of lower quality; and in the ICD the low and medium doses were better than the control since they are considered of better quality; the photosynthetic rate was better with the application of Osmocote® fertilizer in all its doses than Triple 17 and the control. Limitations on study/implications: The low dose (10 kg * m-3) of the Osmocote® fertilizer presents a good option to generate plants of G. americana L. since it did not show differences with the high dose, however nutritional deficiencies will be noticed after three months after of the transplant. Findings/conclusions: With the application of the Osmocote® controlled-release fertilizer in its three doses, plants of G. americana L. are obtained with better morphological attributes, greater biomass accumulation and photosynthetic rate than with the application of the conventional Triple 17 fertilizer.Objetivo: Seleccionar el tipo y dosis de fertilizante adecuado para obtener la mejor calidad, mayor acumulación de biomasa seca y tasa fotosintética en plantas de G. americana L. durante la etapa de vivero. Diseño/metodología/aproximación: Se empleó un diseño experimental completamente al azar con cuatro repeticiones. Las plantas fueron evaluadas por un periodo de tres meses en vivero, para los cual a los 20 días de edad fueron trasplantadas en tubetes de polietileno de 310 cm3 de capacidad utilizando un sustrato compuesto de vermiculita, perlita y turba, el cual se mezcló con fertilizante convencional (FC) Triple 17 (17N-17P-17K) en dosis de 3.3 (baja), 6.6 (media) y 10 kg*m-3 (alta), y fertilizante de liberación controlada (FLC) Osmocote® (15N-9P-12K), en dosis de 10 (baja), 20 (media) y 30 kg*m-3 (alta), más un testigo sin fertilización. Se midieron las variables: diámetro del cuello, altura, longitud de raíces, biomasa aérea y radical, índice de robustez (IR), índice de proporcionalidad biométrica (IPB), índice de calidad de Dickson (ICD) y tasa fotosintética. Las medias fueron comparadas por la prueba de Tukey a un nivel del 5% de confianza. Resultados: Las plantas de G. americana L. fertilizadas con Osmocote® en sus tres dosis (alta, media y baja) presentaron el mejor desempeño en todas las variables morfológicas; en IR el Osmocote® generó plantas de mejor calidad que el testigo, en el IPB la dosis alta de Osmocote® fue de menor calidad que le testigo; y en el ICD las dosis baja y media resultaron ser mejores en calidad que el testigo; la tasa fotosintética fue mejor con la aplicación del fertilizante Osmocote® en todas sus dosis , respecto al fertilizante Triple 17 y al testigo. Limitaciones del estudio/implicaciones: La dosis baja (10 kg*m-3) del fertilizante Osmocote® presenta una buena opción para generar plantas de G. americana L. ya que no presentó diferencias con la dosis alta, sin embargo se notar deficiencias nutrimentales a partir de los tres meses después del trasplante. Hallazgos/conclusiones: Con la aplicación del fertilizante de liberación controlada Osmocote®, en sus tres dosis, se lograron obtener plantas de G. americana L. con mejores atributos morfológicos, mayor acumulación de biomasa y tasa fotosintética, respecto a la aplicación del fertilizante convencional Triple 17

Efecto de Arachis pintoi sobre las arvenses asociadas al plátano macho (Musa AAB ), Cárdenas, Tabasco, México.

Este experimento se realizó en Cárdenas, Tabasco, Méxicoen un suelo con textura franca, pH moderadamente ácido, contenido de materia orgánica y nitrógeno total bajo, cultivado con plátano macho, con el objetivo de determinar el control de arvenses con A. pintoi en una plantación de plátano macho. Se utilizó un arreglo factoria l alojado en un diseño de bloques completos al azar, con sombreado y tip o de cobertura vegetal asocia da al plátano como factores, con tres repeticiones (octubre 2008-agosto 2009). Tanto el factor sombreado como el factor cobertura tuvieron dos niveles de porcentaje: 45 (s= ±11,1) y 50 (s= ± 13,2)% de sombra, para suelos con arvenses y, con A. pintoi, respectivamente. Se utilizaron los índices de Shannon-Wiever (H´) y similitud de Sörensen (S) para determinar la riqueza de especies. A los once meses despuésde establecido el experimento los valores de H´ no mostraron diferencias significativas entre los tratamientos, S= 0,8 entre los dos niveles de sombra. Las especie s arvenses dominantes fueron: T. triangulare, S. podophylum, P. paniculatum y C.diffusa. Entre los tratamie ntos probados, el de suelo con arvensesa nivel de 50% de sombra fue el que presentó (p=0,05) mayor producción MS (375,3 ± 83,3 g/m2). La MS producida por A. pintoi fue mayor (p=0,05) con 45% (s= ± 11,1) desombra (198 g/m2) que la producida a 50% (s= ± 13,2) sombra(150,4 g/m2). Se encontró que el nivel de efectividad de A.pintoi para controlar arvenses fue de 52,3% (con 45 ± 11,1%de sombra) y 70,5% (con 50 ± 13,2% sombra)

Cultivo e incorporación de Crotalaria juncea L. en un suelo cañero de la Chontalpa, Tabasco, México

Objetive: to analyze in a sugarcane soil, the yield in aerial biomass of sunn hemp (Crotalaria juncea L.) (Fabaceae) with and without nitrogen fertilization in two periods of cut (40 and 60 d), and to evaluate the changes in its fertility in two dates subsequent to its incorporation Design/methodology/approach: two fertilization treatments NPK 00-60-60 and 120-60-60 and a control were tested. At the beginning of the experiment, 15 and 30 days after the harvest and incorporation of the sunn hemp, compound samples of soil were taken (0-30 cm) to analyze them chemically. Results: in total dry weight (PS) and the aerial components (stem and leaves) of the legume there were no significant differences between treatments, their average yield was 7.08 and 7.16 t ha-1 for the 40 and 60 day cuts, respectively. The N did not show significant differences between doses or cutting season; their average accumulation was 151.61 and 176.37 kg ha-1 for the respective cuts. The P showed higher values and significant differences in the fertilized treatments. Soil analysis before planting showed optimal properties, except for the low OM content. Study limitations/implications: the sensitivity of some of its components may make it difficult to detect changes in OM; the OSC is an alternative and easily measurable parameter, although it is also advisable to follow up in the long term. Findings/Conclusions: the incorporation of sunn hemp to the soil is a viable and promising alternative to restore the N used and incorporate the environment, in addition, OM improves its physical, chemical and biological fertility.Objetivo: analizar en un suelo cañero, el rendimiento en biomasa aérea de crotalaria (Crotalaria juncea L.) (Fabaceae) con y sin fertilización nitrogenada en dos épocas de corte (40 y 60 d), y evaluar los cambios en su fertilidad en dos fechas posteriores a su incorporación. Diseño/metodología/aproximación: se probaron dos tratamientos de fertilización NPK 00-60-60 y 120-60-60 y un testigo. Al inicio del experimento, 15 y 30 d después de la cosecha e incorporación de la crotalaria, se tomaron muestras compuestas de suelo (0-30 cm) para analizarlas químicamente. Resultados: en peso seco (PS) total y de los componentes aéreos (tallo y hojas) de la crotalaria no hubo diferencias significativas entre tratamientos, su rendimiento promedio fue 7.08 y 7.16 t ha-1 para los cortes de 40 y 60 d respectivamente. El N tampoco mostró diferencias significativas entre dosis ni época de corte; su acumulación promedio fue de 151.61 y 176.37 kg ha-1 para los cortes respectivos. El P mostró valores más altos y diferencias significativas en los tratamientos fertilizados. El análisis del suelo antes de la siembra mostró propiedades óptimas, excepto por el bajo contenido de MO. Limitaciones del estudio/implicaciones: la sensibilidad de algunos de sus componentes puede dificultar la detección de cambios en la MO; siendo el COS un parámetro alternativo y fácilmente medible, aunque también es recomendable hacer un seguimiento a largo plazo. Hallazgos/conclusiones: la incorporación de crotalaria al suelo es una alternativa viable y promisoria para restituir el N utilizado e incorporar el del ambiente, además, la MO mejora su fertilidad física, química y biológica

Resiliencia de la cobertura vegetal en el Suroeste de México ante los efectos del cambio climático

The scenarios modeling of climate changes using geographic information systems to estimate the vegetation cover resilience is a useful tool to project future impacts and implement conservation or management strategies. We associate spatially the biodiversity of the vegetation cover of Southwest Mexico with its ability to adapt to the effects of climate change. We analysis this association estimating species richness and diversity indices, and its relationship with scenarios of future climate. Geographical records of the National Forest and Soil Inventory were obtained for eight plant communities (arboreal, shrubby, herbaceous, palm, cactus, vines, ferns, and xerophyte) distributed in Guerrero, Oaxaca, and Chiapas. The climatic projection was to 2050, with global circulation A2 models (CCCMA, HADCM3 and CSIRO average), 19 bioclimatic variables and a resolution of 2.5 minutes. Climate change scenarios were modelled with the MaxEnt algorithm and species richness, diversity index, and spatial regressions with Diva-GIS v7.5 software. The spatial regression models estimated that higher richness and species diversity, the greater resilience that the ecosystem would show. The cactus, palm, and xerophytic plant communities presented greater vulnerability to climate change. Variations in temperature seasonality turned out to be the factor that would condition its future distribution. Therefore, in conservation or management strategies, diversity should be considered as an agent of the ecosystem that cushions the negative effects of future climate.El modelado de escenarios de cambios climáticos utilizando sistemas de información geográfica para estimar la resiliencia de la cobertura vegetal es una herramienta útil para proyectar impactos futuros e implementar estrategias de conservación o manejo. En el presente trabajo asociamos espacialmente la biodiversidad de la cobertura vegetal del Suroeste de México con su capacidad para adaptarse a los efectos del cambio climático. Para analizar esta asociación se estimaron índices de riqueza y diversidad de especies, y su relación con escenarios de clima futuro. Se utilizaron los registros geográficos del Inventario Nacional Forestal y de Suelos para ocho comunidades vegetales (arbórea, arbustiva, herbácea, palma, cactus, bejucos, helechos y xerófita) distribuidas entre Guerrero, Oaxaca y Chiapas. La proyección climática fue al 2050, con modelos de circulación global A2 (promedio CCCMA, HADCM3 y CSIRO), 19 variables bioclimáticas y una resolución de 2.5 minutos. Los escenarios de cambio climático se modelaron con el algoritmo MaxEnt y la riqueza de especies, índice de diversidad y regresiones espaciales con el software Diva-GIS v7.5. Los modelos de regresión espacial estimaron que a mayor riqueza y diversidad de especies mayor seria la resiliencia que mostraría el ecosistema. Las comunidades vegetales cactus, palma y xerófita mostraron mayor vulnerabilidad al cambio climático. Las variaciones en la estacionalidad de la temperatura resultó ser el factor que condicionaría su distribución futura. Por lo que, las estrategias de conservación o manejo deberían considerar a la diversidad como un agente del ecosistema que amortiguaría a los efectos negativos del clima futuro

Distribución vertical de raíces en seis agroecosistemas en un acrisol de la sabana de Huimanguillo, Tabasco, México

Objective: We studied the density of length of thin roots (DLRD), less than 6 cm thick, in six agroecosystems that develop in an acid soil characteristic of the Sabana de Huimanguillo, Tabasco, Mexico, an “acahual” was taken as a reference and characterized floristically, identifying 33 species. Design / methodology / approach: A description of a soil profile was made, taking samples from each horizon to perform physical and chemical analyzes. The DRLD was estimated by the monolith method, considering four depths (0-10, 10-20, 20-30 and 30-40 cm), six samples were taken per agroecosystem. Results: The soil corresponded to a Chromic Acrisol (Loamic, Cutanic, Hyperdystric, Humic). The highest values of DRLD occurred in the first 20 cm, being 67, 69.1, 66.5, 81.4, 82.8 and 77.6% for pineapple, eucalyptus, acacia, rubber, grass and acahual, respectively. It was notorious that from 40 cm of depth the DLRD values decreased considerably in all agroecosystems. 33 plant species were identified Limitations of the study/implications: It is necessary to do more research of the DLRD at greater depth and in other savanna soils to establish clear differences of vertical exploration of the radical biomass. Findings / conclusions: The greatest development of DLRD occurs in the first 20 cm in the six agroecosystems, decreasing considerably according to depth. Grass presented the highest values of DLDR in general there were statistical differences between the first and the rest of the depths. No homogeneity of DLRD was observed in the arboreal agroecosystems in the studied depths.Objetivo: Estudiar la densidad de longitud de raíces delgadas (DLRD), de menos de 6 cm de grosor, en seis agroecosistemas que se desarrollan en un suelo ácido característico de la Sabana de Huimanguillo, Tabasco (México), se tomó como referencia y se caracterizó florísticamente un acahual. Diseño/metodología/aproximación: Se describió un perfil de suelo tomando muestras de cada horizonte para determinar sus características físicas y químicas. La DRLD se estimó mediante el método del monolito, considerando cuatro profundidades (0-10, 10-20, 20- 30 y 30-40 cm), se tomaron seis muestras por agroecosistema. Resultados: El suelo correspondió a un Chromic Acrisol (Loamic, Cutanic, Hyperdystric, Humic). Los valores más altos de DRL se presentaron en los primeros 20 cm, siendo 67, 69.1, 66.5, 81.4, 82.8 y 77.6% para piña, eucalipto, acacia, hule, pasto y acahual, respectivamente. Fue notorio que a partir de 40 cm de profundidad los valores de DLRD disminuyeron considerablemente en todos los agroecosistemas. Se identificaron 33 especies de plantas. Limitaciones del estudio/implicaciones: Es necesario hacer más investigación de la DLRD a mayor profundidad y en otros suelos de sabana para establecer con claridad diferencias de exploración vertical de la biomasa radical. Hallazgos/conclusiones: El mayor desarrollo de DLRD se da en los primeros 20 cm en los seis agroecosistemas, decreciendo considerablemente conforme a la profundidad. Pasto presentó los valores más altos de DLRD y de manera general hubo diferencias estadísticas entre la primera y el resto de las profundidades. No se observó homogeneidad de DLRD en los agroecosistemas arbóreos en las profundidades estudiadas

Evaluación de variedades de caña de azúcar (Saccharum spp.) introducidas al estado de Quintana Roo, México

Objective: Find at least one variety of (Saccharum spp.) that exceeds, or at least equals, the local varieties in terms of cane yield in the field and factory sugar. Design/methodology/approach: Ten varieties of sugarcane introduced to the state of Quintana Roo during the template cycle were evaluated, which were compared with two local varieties, NCo310 and CP722086. The experimental design consisted of randomized complete blocks and arrangement of divided plots with three repetitions. , in which the treatments were varieties. Measured variables were the length of the stalk (LTM), stem diameter (DT), number of stems per strain (NTM), sucrose content (SAC), field cane yield (RCC) and sugar yield (RA).  Results: The results obtained indicated that at least three varieties of sugarcane introduced had higher agronomic performance and yield than the varieties of the region (control). Regarding the RCC, the varieties B86326, LAICA96606 and CYZ82154 had 162, 147 and 143 t ha-1, respectively, compared with 123 and 136 t ha-1 of the control varieties NCo310 and CP722086, respectively; in terms of sugar yield, the varieties CP941674, SP835073 and SP811763 stand out, with 15.26, 14.46 and 14.09 t ha-1, compared with the control varieties, 15.39 and 12.28 t ha-1 for CP722086 and NCo310, respectively. Limitations on study/implications: An important limitation for this study is that there was only one culture cycle for the evaluation. Also, the irrigation conditions were not counted. Findings/conclusions: Varieties with outstanding yields field (RCC) and sugar (RA) were: CP941674, SP835073, SP811763 and LAICA9213, so its reproduction and culture is recommended.Objetivo: Encontrar al menos una variedad de caña de azúcar (Saccharum spp.) que supere, o al menos iguale, a las variedades locales en cuanto a rendimiento en campo y de azúcar en fábrica. Diseño/metodología/aproximación: Se evaluaron diez variedades de caña de azúcar introducidas al estado de Quintana Roo, México, durante el ciclo plantilla y se compararon con las variedades locales, NCo310 y CP722086. El diseño experimental constó de bloques completos al azar y arreglo de parcelas divididas con tres repeticiones, en el cual los tratamientos fueron las variedades. Se evaluó la longitud de tallo moledero (LTM), diámetro de tallo (DT), número de tallos molederos por cepa (NTM), contenido de sacarosa (SAC), rendimiento de caña en campo (RCC) y rendimiento de azúcar (RA). Resultados: al menos tres variedades de caña de azúcar introducidas tuvieron comportamiento agronómico y rendimiento superiores, o al menos iguales, que las variedades de la región (control). Respecto al RCC, las variedades B86326, LAICA96606 y CYZ82154 registraron 162, 147 y 143 t ha-1 respectivamente, comparado con 123 y 136 t ha-1 de las variedades control NCo310 y CP722086. En cuanto a rendimiento de azúcar destacaron las variedades CP941674, SP835073 y SP811763, con 15.26, 14.46 y 14.09 t ha-1, comparado con las variedades control que reportaron 15.39 y 12.28 t ha-1 para CP722086 y NCo310, respectivamente. Limitaciones del estudio/implicaciones: Los datos son de un ciclo de cultivo en condiciones de lluvias. Hallazgos/conclusiones: Las variedades introducidas con rendimientos sobresalientes de campo (RCC) y azúcar (RA) fueron: CP941674, SP835073, SP811763 y LAICA9213, por lo que se sugiere su multiplicación para el cultivo

Características socioeconómicas de los productores de chile habanero (Capsicum chinense Jacq), en Campeche, México

A qualitative non-experimental-participatory research-action study was carried out from November 2018 to March 2019, with the main objective of identifying the problematic faced by habanero chili producers in Campeche, Mexico, in order to provide a framework for the decision-making, as well as generating a baseline for further studies. A set of indicators was constructed by applying the MESMIS method for the general characterization of the production system. The critical factors were identified on the basis of a participatory rural diagnosis, by selecting the producers who most explained the resolution of the critical points using indicators. A structured survey was applied to diagnose the technological level and the benefits from the activity. As a result, the producers were divided into four levels according to their productive and technological capacity, and the network of total exchanges which characterizes the production system was built. Despite the good results of the activity, its main limitations are as follows: insufficient management of irrigation water, lack of technology transfer, incidence of diseases and pests, excessive use of agrochemicals, lack of capital, inputs expensive, guaranteed prices non-existent, few commercial varieties, lack of added value, lack of organization among producers and poor marketing channels. If these limits are lifted, growing habanero chilis will be a more profitable and competitive activity.Se realizó un estudio de investigación-acción-participativa cualitativa no experimental de noviembre de 2018 a marzo de 2019 con el objetivo de identificar la problemática que enfrentan los productores de chile habanero en Campeche, proveer un marco de referencia para la toma de decisiones, así como generar una línea de base para estudios posteriores. Se construyeron un conjunto de indicadores aplicando el método MESMIS para la caracterización general del sistema producto. Se identificaron los factores críticos sobre la base de un diagnóstico rural participativo, seleccionando a los productores que más explicaron la resolución de los puntos críticos usando indicadores. Se aplicó una encuesta estructurada para diagnosticar el nivel tecnológico y los beneficios derivados de la actividad. Como resultado se dividió a los productores en cuatro niveles según su capacidad productiva y tecnológica, y se construyó la red de intercambios totales que caracteriza al sistema producto. A pesar de los buenos resultados de la actividad, existen como principales limitantes: deficiente manejo del riego, escasa transferencia tecnológica, incidencia de enfermedades y plagas, uso excesivo de agroquímicos, falta de capital, insumos caros, carencia de precios de garantía, pocas variedades comerciales, falta de valor agregado, ausencia de organización de productores y deficientes canales de comercialización. Si esas limitantes son atendidas el cultivo de chile habanero será una actividad más rentable y competitiva

Characterization of weed flora in a cassava crop in Tabasco

Objective: to evaluate the effect of the incorporation of Crotalaria juncea L. as a green manure on the weed community in cassava crop in Tabasco. Design/methodology/approach: the study was carried out in the Experimental Field of Colegio de Postgraduados, Campus Tabasco (18º01' N and 93º03' W). The samplings were done on four dates: 1) at the planting of crotalaria (12/03/2018); 2) at flowering (31/01/2019); 3) 20 days after incorporation (22/02/2019); 4) at cassava harvest (25/04/2019) using metal squares 50 x 50 cm. Two planting densities, 50 and 80 cm (16,600 and 10,375 plants ha-1), and two doses of NPK fertilization (160-40-80 and 00-40-80+GM) were tested, and a control. The name of the species, number of individuals and coverage (percentage) were recorded to calculate the richness indices (S), Shannon diversity (H'), uniformity (E) and importance value index (IVI). Results: The weed community consisted of 32 species, 28 genera and 16 families, the best represented: Convolvulaceae, Asteraceae, Cyperaceae and Poaceae; the most recorded species: Lindernia crustacea, Ludwigia octovalvis and Ageratum houstonianum. Diversity index reflected a poor community, especially GM treatments. Diversity ranged from low to medium and uniformity from medium to high. The importance of the species was more related to the environmental conditions than to the treatments; Cyperaceae were more important in the rainy season and Asteraceae in dry season; L. crustacea appeared throughout the cycle. Limitations/implications: it is advisable to extend the investigation period. Findings/conclusions: the weed flora consisted of 32 species; Convolvulaceae family and L. crustacea species were the most diverse and the most recorded during the cycle, respectively. Diversity indices reflected a poor community. The importance of families was related to the environmental conditions; Cyperaceae stood out in the rainy season and Asteraceae in the dry seasonObjective: To evaluate the effect of the incorporation of Crotalaria juncea L. as green manure on the weed community in a cassava crop in Tabasco. Design/methodology/approach: The study was carried out in the Experimental Field of Colegio de Postgraduados, Campus Tabasco (18º01' N and 93º03' W). The samplings were made on four dates: 1) at the planting of crotalaria (12/03/2018); 2) at flowering (31/01/2019); 3) 20 days after incorporation (22/02/2019); 4) at cassava harvest (25/04/2019), using metal squares 50 x 50 cm. Two planting densities, 50 and 80 cm (16,600 and 10,375 plants ha-1), two doses of NPK fertilization (160-40-80 and 00-40-80+GM), and a control were tested. The name of the species, number of individuals and coverage (percentage) were recorded to calculate the richness (S), Shannon diversity (H') and uniformity (E) indices, and the importance value index (IVI). Results: The weed community consisted of 32 species, 28 genera and 16 families, of which the best represented are: Convolvulaceae, Asteraceae, Cyperaceae and Poaceae. The most frequently recorded species are Lindernia crustacea, Ludwigia octovalvis, and Ageratum houstonianum. The diversity indices reflected a poor community, especially with GM treatments; diversity ranged from low to medium and uniformity from medium to high. The importance of the families was more related to the environmental conditions than to the treatments; Cyperaceae were more important in the rainy season and Asteraceae in the dry season. L. crustacea appeared throughout the cycle. Limitations/implications: It is advisable to extend the investigation period. Findings/conclusions: The weed flora consisted of 32 species; the Convolvulaceae family was the most diverse and L. crustacea was the most recorded species during the cycle. The diversity indices reflected a poor community. The importance of the families was related to environmental conditions, where Cyperaceae stood out in the rainy season and Asteraceae in the dry seaso