Effect of fertilization on the contents of macronutrients and chlorine in tobacco leaves cv. flue-cured (Nicotiana tabacum L.) in two municipalities in Huila, Colombia

In Colombia, there is little information on tobacco crops and the effect of fertilization on the nutrient content of leaves. The aim of this study was to determine the contents of mineral nutrients in tobacco (Nicotiana tabacum L. cv. flue-cured) plants subjected to different fertilizer rates and sources in two municipalities in the Huila Province (Colombia). Six foliar analyses, with three measurements from vegetative growth to f lowering and three measurements during harvest, were carried out. Seven treatments, including six fertilization alternatives (three doses and two alternative sources of application) and a commercial control, were evaluated. The contents of the macronutrients N, P, K, Ca, Mg, S, and chlorine in the leaves were evaluated. The leaf analyses performed from vegetative growth to f lowering showed differences in the foliar contents of nitrogen, calcium, magnesium, and chlorine between the two municipalities and over time, with contents that increased. During this stage, the elements with higher accumulations in the plants included N, K, and Ca. At harvest, the contents of potassium, magnesium, and calcium decreased over time. For nitrogen, sulfur and chlorine, differences were found in the time-municipality interaction

Evaluation of seed yield and oil contents in four materials of ricinus communis l.

Four castor materials were evaluated in 2009 in the middle region of Valle del Sinu, Colombia. The variables were phonological development, plant height, seed production and oil yield, in order to determine the best material for commercial purposes. All materials reported high yields of oil seeds and highlighting the commercial genotype Nordestina BRS149, 2.2 t ha-1 seed and 47% oil content. Planting distances were 1.5 x 1.5 m and 2.0 x 2.0 m, with densities of 6,666 and 3,906 plants ha-1, respectively. The plant height, seed productivity and oil yield showed significant differences for the interaction density × material; while comparing each material density, seed production only showed differences. These variables were significantly different between population densities, which shows that the higher the plant height, lower productivity. The planting distance of 2.0 x 2.0 m, provides higher productivity per plant values but seed oil yields were not different between densities. The oil quality parameters were assessed using free fatty acid value, iodine, acidity index, saponification, refraction and specific gravity, found that planting distance does not affect the quality of oil

Algunos aspectos de la biología y manejo de digitaria sanguinalis (l). scop. en asociación con el cultivo del arroz y otras especies adventicias

Para el cultivo del arroz en Colombia se reportan más de 70 especies de malezas que, por orden de competitividad biológica y económica, las malezas gramíneas son las de mayor afección al cultivo. Por su nocividad, las más importantes son: Echinochloa colonum (L.) Link, Oryza sativa L. (arroz rojo), Cyperus rotundus L., Rottboellia cochinchinensis U., Fimbristylis annua (Alt.) Riets, Murdania nudiflora (L.) Brenan, y Digitaria sanguinalis (L.) Scop. La ausencia de trabajos realizados sobre Digitaria sanguinalis (L) Scop., dirigidos al conocimiento de sus aspectos biológicos, el aumento en la incidencia y agresividad de la especie en los cultivos de arroz y sorgo en la zona norte del Tolima, justificó la elaboración del presente estudio, para el cual se propusieron los siguientes objetivos: identificar aspectos dela biología y fenología, evaluar el banco de semillas y medir el efecto de la competencia de diferentes densidades de población de Digitaria sanguina lis (L.) Scop. en los cultivos de arroz en Lérida, (Tolima). Los momentos de mayor suceptibilidad a la presencia de malezas en el cultivo del arroz fueron: a) Germinación: D. sanguinalis completó esta fase en los tres primeros días después de humedecer el terreno, a diferencia de las semillas de arroz que requirieron dos días más. b) Macollamiento: D. sanguinalis inició esta fase a los 20 días, a diferencia de las plantas de arroz que iniciaron a los 28 días. e) Formación de Panícula: D. sanguina lis, la inició a los 65 días, a diferencia del arroz que inició a los 70 días. d) Maduración de semillas: Las semillas de D. sanguinalis necesitaron 110 días para completar esta fase, las semillas de las plantas de arroz necesitaron 10 días más. D sanguinalis comenzó a liberar semillas a los 100 días aproximadamente. Mediante la emergencia de plántulas selogró estimar la composición del Banco de Semilla, obteniendo los mayores porcentajes de emergencia en Murdania nudiflora, con 42,5 %, y el grupo de las dicotiledóneas, con 39 %. Para las especies gramíneas, D.sanguina lis, 12,5 % y Echinochloa sp., 6 %. Las variables de mayor sensibilidad a la competencia interespecífica cultivo maleza fueron número promedio de macollas viables, con reducción del 25 %, a una densidad de una planta/m2; altura de planta, con reducción del 8,7; 21; y 23,5 %, a densidades de una, cinco y veinte plantas/m" de D. sanguinalis respectivamente. Los diferentes componentes de rendimiento del arroz se vieron afectados con densidades superiores a una planta por m2. Los resultados obtenidos, al estudiar los aspectos de la biología de Digitaria sanguinalis, tales como la cantidad de semillas en el banco de suelo, la sincronía de su ciclo biológico con el ciclo biológico de las plantas de cultivo y alta capacidad de competencia, señala, para su manejo, laplaneación e implementación de tratamientos especílicos en los ciclos del cultivo de arroz.In the rice crop in Colombia there are 70 species of weed. The gramineae species are the plants in direct biological and economical competition with the crop. Echinochloa cotonum (L.) Link, Oryza sativa L. (red rice) Cyperus rotundus L. ,Rottboellia cochinchinensis U., Fimbristylis annua (Alt.) Riets , Murdania nudiflora (L.) Brenan and Digitaría sanguinalis (L.) Scop., are the most common weeds in the rice crop. This work was necessary tor two reasons: there is nowork presenting the biological aspects of D. sanguinalis, and also there is an increasing population of weed in sorghum and rice crops in Lerida in the region Tolima. The objectives were: to know Phenology development, to evaluate the seed bank and to know the competitive ellects of three densities (one, live and twenty ptantslrn-) of Digitaria sanguinalis in the rice crop. Four stages were affected considerably in the rice plants by the presence of D. sanguinalis. Germination: D. sanguinalis needed three days of growth after the wetting of the land, however the rice seeds required two days more; Tillering: D. sanguinalis began this phase in 20 days asopposed to rice plants that began in 28 days. Booting: D. sanguinalis began this state in the 65 days compared with the rice plants, that took 70 days. Ripening: The seeds of D. sanguinalis needed 110 days to complete this phase with the seeds, needing 10 days more. D. sanguinalis began to free seeds at 100 days approximately. The method to evaluate the composition of the seed bank, was the emergence of seedlings obtaining the greater percentages M. nudiflora with 42,6 %, the second level the group frorn the broad lealwith 39 %, D. sanguinalis with 12,5 % and Echinochloa sp., with 6 %. The results of the plant competition were: reduction in the tillering number by 25 %, to a density of a plant/m2 ; plant height, with reduction of the 8,7, 21 and 23,5 r to density of one, live and twenty plantslrn of D. sanguinalis respectively. The different yield components of the rice were affected by densities superior to a plant by m2. The results obtained upon studying the aspects of the biology of Digitaria sanguinalis, such as, the quantity of seeds in the soil bank, the similar development of their biological cycles of the competition weed and cultivated plants it is necessary to a plan a specilic treatments for implementation in the cycles of the rice crop

Effect of fertilization on the contents of macronutrients and chlorine in tobacco leaves cv. flue-cured (<i>Nicotiana tabacum</i> L.) in two municipalities in Huila, Colombia

In Colombia, there is little information on tobacco crops and the effect of fertilization on the nutrient content of leaves. The aim of this study was to determine the contents of mineral nutrients in tobacco (Nicotiana tabacum L. cv. flue-cured) plants subjected to different fertilizer rates and sources in two municipalities in the Huila Province (Colombia). Six foliar analyses, with three measurements from vegetative growth to f lowering and three measurements during harvest, were carried out. Seven treatments, including six fertilization alternatives (three doses and two alternative sources of application) and a commercial control, were evaluated. The contents of the macronutrients N, P, K, Ca, Mg, S, and chlorine in the leaves were evaluated. The leaf analyses performed from vegetative growth to f lowering showed differences in the foliar contents of nitrogen, calcium, magnesium, and chlorine between the two municipalities and over time, with contents that increased. During this stage, the elements with higher accumulations in the plants included N, K, and Ca. At harvest, the contents of potassium, magnesium, and calcium decreased over time. For nitrogen, sulfur and chlorine, differences were found in the time-municipality interaction

Phytosociology of weeds associated with rice crops in the department of Tolima, Colombia

Phytosociological studies allow for the characterization and descriptive analysis of weed communities in crops. This study aimed to characterize the weed communities associated with weed crops in the "Centro, Meseta, and Norte" zones of the Tolima Department. The study was conducted in 96 commercial lots, in which a 1 ha area was marked off for the sampling. The development stage, density and cover of the weeds were evaluated. The importance value index, the alpha diversity indices of Shannon-Wiener, Simpson and uniformity as well as the similarity indices of Jaccard, Sorensen and Steinhaus were calculated. For the entire department, 42 weed species were identified, with Echinochloa colona being the principal one in all of the zones. In the Centro zone, 27 species were identified; in the Meseta zone, 31 species were identified; and, in the Norte zone, 38 species were identified. The alpha indices demonstrated that the Meseta zone was the most diverse. The Jaccard and Sorensen indices showed dissimilarity in the weed community for all of the comparisons of the zones. The Steinhaus coefficient registered the highest similarity intensity between the Centro and Norte zones

Comparative analysis of Flue-cured tobacco production costs in Santander and Huila (Colombia)

Santander and Huila are the largest producers of Flue-cured tobacco in Colombia. They differ in their production systems and, consequently, in their production costs. Costs provide valuable information on the efficiency of resource use, a variable that determines the profitability of the crop. The purpose of this study was to determine and analyze the structure of production costs by department, as well as, their differences and possibilities for reduction. Data for the analysis was obtained from the records of Protabaco and surveys of 50 producers (farms) in the municipalities of Campoalegre and Garzon in Huila, and Capitanejo and Enciso in Santander. The results say the costs of the most important factors of production in both departments are: labor, inputs and services. Huila has higher total costs per hectare than Santander, but similar unit costs. Huila has a higher technological level of production, more capital and greater surface area per crop unit than Santander. Production costs can be reduced by increasing the availability of investment capital, and irrigation water, as well as, more efficient management of fertilization, cultural practices and mechanization of land preparatio

Predicting long-term organic carbon dynamics in organically amended soils using the CQESTR model

Peer reviewe

Evaluation of seed yield and oil contents in four materials of Ricinus communis L.

&lt;p class="MsoNormal" style="text-align: justify; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none;"&gt;&lt;span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 9.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US"&gt;Four castor materials were evaluated in 2009 in the middle region of Valle del Sinu, Colombia. The variables were phonological development, plant height, seed production and oil yield, in order to determine the best material for commercial purposes. All materials reported high yields of oil seeds and highlighting the commercial genotype Nordestina BRS149, 2.2 t ha&lt;/span&gt;&lt;span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 5.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US"&gt;-1 &lt;/span&gt;&lt;span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 9.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US"&gt;seed and 47% oil content. Planting distances were 1.5 x 1.5 m and 2.0 x 2.0 m, with densities of 6,666 and 3,906 plants ha&lt;/span&gt;&lt;span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 5.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US"&gt;-1&lt;/span&gt;&lt;span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 9.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US"&gt;, respectively. The plant height, seed productivity and oil yield showed significant differences for the interaction density × material; while comparing each material density, seed production only showed differences. These variables were significantly different between population densities, which shows that the higher the plant height, lower productivity. The planting distance of 2.0 x 2.0 m, provides higher productivity per plant values but seed oil yields were not different between densities. The oil quality parameters were assessed using free fatty acid value, iodine, acidity index, saponification, refraction and specific gravity, found that planting distance does not affect the quality of oil.&lt;/span&gt;&lt;/p&gt

Determinación del impacto de competencia de diferentes cohortes de avena silvestre (avena fatua) sobre los rendimientos en un cultivo comercial de trigo (triticum aestivum)

El objetivo de este trabajo fue determinar el comportamiento de la avena silvestre (Avena fatua L.) sobre el cultivo de trigo (Triticum aestívum LO.). Estainvestigaciónfue desarrollada en el Centro Agropecuario , Universidad Nacional de Colombia del municipio de Mosquera, Cundinamarca, principalmente para determinar la variación de las poblaciones de la avena silvestre mediante el establecimiento de 8 cohortes a intervalos de 15 días cada una. Se evaluaron los cambios fenológicos en cada cohorte dos veces por semana. También, fue evaluado el impacto de la competencia a través del peso seco de las plantas. El trabajo se desarrollócon diseño experimental de bloques completos al azar, con cuatro replicas y cada tratamiento se acompañó con dos testigos: una parcela siempre limpia y otra siempre enmalezada. Se realizó la prueba de Duncan para las variables significativas. La emergencia de plantas de avena se presentó durante todo el ciclo del cultivo. Las plantas de las primeras cohortes de avena fueron tan altas como las plantas de cultivo. La densidad de plantas y el peso seco de estas primeras 5 cohortes fueron superiores a los de las3 cohortes finales. Las plantas de las cohortes 6 a, 7 a y e-. presentaron menor número de tallos y menor peso seco por planta. Estas diferencias hacen que las plantas de las primerascohortes presentaran mayor capacidad de competencia.The objective of this study was to determine the behaviour of wild oats (Avena fatua L.) in a wheat crop (Tritícum aestivum LO.). This research was conducted at the Centro Agropecuario "Marengo" , Universidad Nacional de Colombia, near the town of Mosquera, Cundinamarca. In order to determine the variation of Avena fatua populations, 8 succesive cohorts were established with intervals of 15 days. The experimental design used was randomized complete blocks with tour replications. In addition to the the eight treatments (cohorts) there were two check plots, one was kept always clean and the other was kept always weedy. Each cohort was examined for phenological changes twice per week, and the impact of competition was established on the basis of dry weight of each plant. Differences were observed among the oat cohorts. In the tirst five cohorts, oat plants were as tall as wheat plants, and density and dry weight were higher than for the last three cohorts. Plants from cohorts 6 th 7th and 8th had less number of stems and lower dry weight. Thesedifferences among cohorts suggest a stronger competitive impact on crop yield from the earlier oats populations

Determinación del impacto de competencia de diferentes cohortes de avena silvestre (Avena fatua) sobre los rendimientos en un cultivo comercial de trigo (Triticum aestivum) Assessment of competition impact from different cohorts of wild oats (Avena fatua) on the yields of a commercial wheat crop (Triticum aestivum)

El objetivo de este trabajo fue determinar el comportamiento de la avena silvestre (Avena fatua L.) sobre el cultivo de trigo (Triticum aestívum LO.). Estainvestigaciónfue desarrollada en el Centro Agropecuario &lt;Marengo&gt;, Universidad Nacional de Colombia del municipio de Mosquera, Cundinamarca, principalmente para determinar la variación de las poblaciones de la avena silvestre mediante el establecimiento de 8 cohortes a intervalos de 15 días cada una. Se evaluaron los cambios fenológicos en cada cohorte dos veces por semana. También, fue evaluado el impacto de la competencia a través del peso seco de las plantas. El trabajo se desarrolló&lt;br /&gt;con diseño experimental de bloques completos al azar, con cuatro replicas y cada tratamiento se acompañó con dos testigos: una parcela siempre limpia y otra siempre enmalezada. Se realizó la prueba de Duncan para las variables significativas. La emergencia de plantas de avena se presentó durante todo el ciclo del cultivo. Las plantas de las primeras cohortes de avena fueron tan altas como las plantas de cultivo. La densidad de plantas y el peso seco de estas primeras 5 cohortes fueron superiores a los de las&lt;br /&gt;3 cohortes finales. Las plantas de las cohortes 6 a, 7 a y e-. presentaron menor número de tallos y menor peso seco por planta. Estas diferencias hacen que las plantas de las primerascohortes presentaran mayor capacidad de competencia.<br>The objective of this study was to determine the behaviour of wild oats (Avena fatua L.) in a wheat crop (Tritícum aestivum LO.). This research was conducted at the Centro Agropecuario "Marengo" , Universidad Nacional de Colombia, near the town of Mosquera, Cundinamarca. In order to determine the variation of Avena fatua populations, 8 succesive cohorts were established with intervals of 15 days. The experimental design used was randomized complete blocks with tour replications. In addition to the the eight treatments (cohorts) there were two check plots, one was kept always clean and the other was kept always weedy. Each cohort was examined for phenological changes twice per week, and the impact of competition was established on the basis of dry weight of each plant. Differences were observed among the oat cohorts. In the tirst five cohorts, oat plants were as tall as wheat plants, and density and dry weight were higher than for the last three cohorts. Plants from cohorts 6 th 7th and 8th had less number of stems and lower dry weight. These&lt;br /&gt;differences among cohorts suggest a stronger competitive impact on crop yield from the earlier oats populations.&lt;br /&gt