What is the optimal fertigation start time and frequency in lettuce seedlings?

Although lettuce is one of the most important vegetable crops cultivated in Brazil, producers conduct seedling production empirically, as there are no published reports on the optimal start time and management strategy for seedling fertigation. The present aimed to assess the influence of fertigation management on the growth, physiological aspects and nutritional status of lettuce seedlings and to determine the optimal fertigation start time and frequency. Two experiments were conducted, each with a randomized block design and six repetitions. The first consisted of six treatments, namely six fertigation start times at 0, 3, 6, 9, 12, and 15 d after emergence (DAE), and the second consisted of five treatments, representing different application frequencies at 3, 4, 5, 6, and 7 d intervals. The assessment of nutrient accumulation levels and biometric and physiological characteristics of the seedlings were performed after transplanting. Fertigation start times significantly affected 14 of the 18 variables assessed, particularly the number of leaves, shoot dry weight, leaf area, initial chlorophyll fluorescence, and P, K, Ca, Mg, and S accumulation. The best results for ten variables were obtained when fertigation began at emergence, with values 17.77 - 35.63% higher than those at fertigation onset at 15 DAE. Application frequency only influenced chlorophyll content and N, P, K, and S accumulation, with optimal results obtained at 3 - 6 d intervals. Beginning fertigation at plant emergence favors dry weight production, nutrition and photosynthesis and shortens the production time of lettuce seedlings. The optimal start time for lettuce seedling fertigation is at emergence, with application performed every 6 d.

The effects on the root and plant development of soybean of organic fertilizer applications

Organic fertilizers increase soil aeration, water and nutrient holding capacity, improve seed germination and encourage the production of thicker roots, increase the yield and quality of the crop. This study was aimed to determine the effects of organic fertilizer (vermicompost, sheep manure, cattle manure, poultry manure and inorganic fertilizer as control) applications on the root and plant development of soybean during two growth stages, namely third trifoliate stage (V3) and beginning of flowering of the plants (R1) in the pot condition. The experiment was established with a two-factorial randomized plot design with four replications. The fertilizer applications had a significant effect (p<0.01) on the V3 and R1 growth stages of soybean. The highest plant height (36.78 cm) and root length (41.18 cm) were achieved with vermicompost, and the lowest plant height (21.73 cm) was recorded with inorganic fertilizer. The number of nodules was highest for vermicompost and cattle manure applications (17.16 plant-1 and 16.76 plant-1, respectively), and lowest for poultry manure (0.22 plant-1). In the R1 growth stage, poultry manure produced the highest biological fresh and dry weights, root dry weight at 25.08 g plant-1 and 5.67 g plant-1, 3.99 g plant-1 respectively. As a result, it was demonstrated that vermicompost and poultry manure applications promote strong root and plant development due to high organic matter and phosphorus and can be used successfully without inorganic fertilize application in soybean farming.

Challenges of organic agriculture for the production of composts and vermicompost for the production of medicinal plants: a socioeconomic demand / Desafios da agricultura orgânica na produção de composto e vermicomposto na produção de plantas medicinais: uma demanda socioeconômica

Although the demand for organic fertilizers in agriculture is growing, it remains incipient in some production sectors, such as medicinal plant production, which does not possess specific technology for its development. Solid residues are highly contaminant to water sources, soil, populations and biodiversity but can potentially be used to produce organic composts and vermicompost, such production not only enables nutrient recycling but also acts on soil conditioning, increasing soil organic matter and improving its physical, chemical and biological characteristics, as well as strengthening organic production with an emphasis on medicinal plant production. In this context, recommendations for and applications of organic fertilizers available in the market were reviewed; in addition, the imminent socioeconomic demand for organic compost and vermicompost production was contextualized based on residues from coffee and sugarcane production and cattle farming for application to the medicinal plant production chain. It is concluded that although these sectors produce a considerable amount of residues, they are not being reused in formulation of organic composts and vermicompost, and commercial organic fertilizers recommended for medicinal plant production were not found. Thus, the formulation of vermicomposting and composting from the reuse of agricultural residues, are potential social, economic technologies and tools to be valued and disseminated to traditional and family farmers. (AU)

Embora a demanda por fertilizantes orgânicos na agricultura seja crescente, ela ainda é incipiente em alguns setores produtivos, como a produção de plantas medicinais, que não possui tecnologia específica para seu desenvolvimento. Os resíduos sólidos são altamente contaminantes para fontes de água, solo, populações e biodiversidade, mas podem ser potencialmente utilizados para a produção de compostos orgânicos e vermicomposto, tal produção não só possibilita a reciclagem de nutrientes, mas também atua no condicionamento do solo, aumentando a matéria orgânica do solo e melhorando seu aspecto físico, químico e características biológicas, além do fortalecimento da produção orgânica com ênfase na produção de plantas medicinais. Nesse contexto, foram revisadas as recomendações e aplicações dos fertilizantes orgânicos disponíveis no mercado; além disso, a iminente demanda socioeconômica pela produção de composto orgânico e vermicomposto foi contextualizada a partir dos resíduos da produção de café, cana-de-açúcar e pecuária para aplicação na cadeia produtiva de plantas medicinais. Conclui-se que embora esses setores produzam uma quantidade considerável de resíduos, eles não estão sendo reaproveitados na formulação de compostos orgânicos e vermicomposto, e não foram encontrados fertilizantes orgânicos comerciais recomendados para a produção de plantas medicinais. Sendo assim, a formulação de vermicompostagem e compostagem a partir do reaproveitamento de resíduos agropecuários, são potenciais tecnologias sociais, econômicas e ferramentas a serem valorizadas e disseminadas para os agricultores tradicionais e familiares. (AU)

Evaluación ecotoxicológica de dos derivados del Nim en lombriz de tierra y abejas / Ecotoxicological assessment of two Neem derivatives in earthworm and honey bees

La utilización de productos con bajo o nulo impacto en organismos circundantes y el ambiente, constituye parte del nuevo concepto de protección de cultivos. Los productos NeoNim 60 y OleoNim 80, obtenidos del árbol del Nim, están propuestos para su uso como insecticida, nematicida y acaricida. Con el objetivo de realizar la evaluación ecotoxicológica de estos productos, se realizaron los ensayos de toxicidad aguda en lombriz de tierra Eisenia andrei y de toxicidad aguda por contacto en abejas Apis mellifera. Cada ensayo contó con un grupo control y dos tratados. El ensayo en lombrices se realizó durante 14 días utilizando suelo artificial, realizando observaciones clínicas, conteo de animales y estudio del comportamiento de la biomasa. La prueba en abejas se prolongó por 48 horas, realizándose observaciones clínicas y conteo de animales. Se obtuvo un 100% de supervivencia en las lombrices de los grupos tratados, obteniendo en el NeoNim 60 valores de disminución de la biomasa significativamente inferiores al grupo control, mientras que el grupo tratado con OleoNim 80 mostró aumento en la biomasa del inicio al final del ensayo. En el ensayo en abejas, la comparación estadística no mostró diferencias entre grupos en cuanto a la mortalidad. Teniendo en cuenta el conjunto de los resultados obtenidos, se pudo concluir que los derivados del Nim NeoNim 60 y OleoNim 80 no producen efecto tóxico sobre las lombrices de tierra y las abejas (AU)

The use of products with low or null impact in surroundingorganisms and the environment constitutes part of the new concept of crop protection. The products NeoNim 60 and OleoNim 80, obtained from the Neem tree, are proposed for its use as insecticide, nematicide and acaricide. With the objective of perform the ecotoxicological assessment of these products, it were carried out the earthworm acute toxicity and the honey bee acute contact toxicity tests. For each assay two Treated and one Control group were established. The assay in earthworms Eisenia andrei was carried out during 14 days using artificial soil, with daily clinical observations, count of animals and study of the changes of the biomass. The test in honey bees Apis mellifera was prolonged for 48 hours, with daily clinical observations and count of animals. A survival of 100% was obtained in the earthworms of the Treated groups, obtaining in the NeoNim 60 group significative lower values of biomass when compared to the Control, while the group treated with OleoNim 80 showed an increase in the biomass from the beginning to the end of the assay. In the assay in bees, the statistical comparison didn't show differences among groups as for the mortality. Taken into account the obtained results, it could be concluded that the Neem derivatives NeoNim 60 and OleoNim 80 don't produce toxic effect on the earthworms and the honeybees (AU)

Compendio de lombricultura y ecología

La lombricultura como método de transformación de materia biodegradable, en especial la Roja Californiana que debido a su aparato digestivo (un verdadero laboratorio viviente), lo procesa todo y como producto final se obtiene el humus que no es más que el propio estiercol del verme. Se describe como un proceso ecológico natural, muy económico, sin gasto de energía, con gran poder descontaminante que permite cerrar el ciclo productivo de varias industrias que tienen deshechos orgánicos, impidiendo que sean arrojados a ríos, lagos y lagunas

Compendio de lombricultura y ecología

La lombricultura como método de transformación de materia biodegradable, en especial la Roja Californiana que debido a su aparato digestivo (un verdadero laboratorio viviente), lo procesa todo y como producto final se obtiene el humus que no es más que el propio estiercol del verme. Se describe como un proceso ecológico natural, muy económico, sin gasto de energía, con gran poder descontaminante que permite cerrar el ciclo productivo de varias industrias que tienen deshechos orgánicos, impidiendo que sean arrojados a ríos, lagos y lagunas

Physicochemical characterization of humic acid extracted from vermicomposting obtained by animal manure

Humic acid extracted from vermicomposting (VHA), originated by animal manure and treated with Eisenia foetida or Lumbricus rubellus, was chemically characterized concernings its elemental composition, cation exchange capacity, carboxylic and phenolic acidity, molar absorption by UV-Vis spectroscopy, and main functional groups by FTIR spectrometry. Vermicompost is the stabilized product from vermicomposting. The isolated VHA was compared to other humic acid samples extracted from peat and from different soils. VHA presented a high nitrogen content. Due to low cost, large amount of raw material, and favorable climatic condiditons, vermicomposting may become a good alternative to produce fertilizers in Brazil.

Laprida, donde la basura da rédito

Con el objeto de proteger el medio ambiente el municipio de la ciudad de Laprida (Buenos Aires), recicla cinco toneladas diarias de residuos e invierte su producido en la comunidad. Desde hace cuatro años se realiza la selección domiciliaria de residuos y el municipio lleva a cabo su posterior reciclaje. La recolección diferenciada puede constituirse en un hito en la cultura ambiental

Laprida, donde la basura da rédito

Con el objeto de proteger el medio ambiente el municipio de la ciudad de Laprida (Buenos Aires), recicla cinco toneladas diarias de residuos e invierte su producido en la comunidad. Desde hace cuatro años se realiza la selección domiciliaria de residuos y el municipio lleva a cabo su posterior reciclaje. La recolección diferenciada puede constituirse en un hito en la cultura ambiental

Tratamiento de lodos de aguas servidas mediante proceso de lombricultura

En las plantas de tratamiento de aguas servidas, una vez depurada la fase líquida, queda retenido un lodo acuoso, que contiene una gran cantidad de microorganismos patogénicos. Para llegar a un resultado económico e higiénico en la planta CEXAS de la ciudad de Melipilla se implementó el tratamiento de lodos mediante el proceso de lombricultura. El producto obtenido es sanitariamente aceptable y de gran valor agronómico, con costos habituales en plantas que utilizan procesos de tratamiento convencional