A adoção de práticas de manejo do solo nas áreas de produção de cana-de-açúcar deve assegurar à sustentabilidade econômica e ambiental. Este estudo avaliou os efeitos de diferentes sistemas de manejo (preparo convencional – SPC, preparo reduzido – SPR e plantio direto – SPD) e escarificação de soqueiras de cana sobre os indicadores de qualidade física de solo. O experimento foi conduzido em delineamento experimental de blocos casualizados, com parcelas subdivididas e três repetições. As parcelas consistiram nos sistemas de manejo e as subparcelas corresponderam aos tratamentos sem e com escarificação (SE e CE, respectivamente). Na quarta soqueira (05 anos após o plantio) avaliou-se os seguintes atributos físicos do solo nas camadas de 0,00-0,10 m, 0,10-0,20 m e 0,20-0,30 m: densidade, macro e microporosidade, porosidade total, resistência do solo à penetração. Os dados foram submetidos à análise fatorial multivariada, com extração de fatores pelo método de componentes principais. Os resultados indicaram que o preparo convencional do solo (CT) foi eficaz na manutenção da qualidade física do solo (com valores de densidade variando de 1,56 ± 0,05 a 1,64 ± 0,03 Mg m-3), mantendo abaixo do limite crítico na camada de 0,00–0,30 m (1,70 Mg m-3) após cinco anos de cultivo de cana-de-açúcar. A escarificação mecânica mostrou-se benéfica em áreas sob SPD, reduzindo a resistência à penetração em solos arenosos, mas não apresentou efeitos significativos nos sistemas SPC e SPR. Dentre os atributos avaliados, a resistência à penetração foi o mais sensível às variações nos métodos de escarificação mecânica para os sistemas de manejo. A escarificação é recomendada em SPD, enquanto o SPC mostrou maior eficácia na preservação da qualidade física do solo em longo prazo.
A alface (Lactuca sativa) é uma hortaliça folhosa amplamente consumida devido ao seu elevado valor nutricional. A intensidade luminosa desempenha um papel crucial no crescimento e na produtividade da alface. No entanto, as informações sobre a intensidade de luz ideal para o cultivo de alface, especialmente em ambientes urbanos, ainda são limitadas. Este estudo teve como objetivo avaliar o crescimento morfológico e fisiológico, bem como a produtividade, de três variedades de alface cultivadas sob diferentes intensidades de luz solar e luz artificial. O experimento foi conduzido em delineamento de parcelas subdivididas com três repetições. As parcelas principais consistiram em três condições de luz: 55% de sombreamento (S55% + SL), 80% de sombreamento (S80% + SL) e 100% de sombreamento suplementado com luz artificial proveniente de lâmpadas LED (S100% + LED), representando condições de baixa luminosidade. As subparcelas compreenderam três variedades de alface: Romana (Lactuca sativa L. var. longifolia) (V1), Grand Rapids (Lactuca sativa L. var. New Grand Rapids) (V2) e Siomak (Lactuca sativa L. var. Augustuna) (V3). Os resultados indicaram que 80% de sombreamento (S80% + SL) e 100% de sombreamento com suplementação de LED (S100% + LED) inibiram significativamente parâmetros de crescimento, incluindo o desenvolvimento de folhas e raízes. Além disso, esses tratamentos reduziram fatores microclimáticos, como temperatura do ar e intensidade luminosa. Em conclusão, as três variedades de alface não apresentaram crescimento ideal em condições de baixa luminosidade, e o sombreamento de 100% com suplementação de LED mostrou-se inadequado para promover crescimento e produtividade ótimos.
This study aimed to analyze the effects of applying to analyze the effects of applying the biostimulants Stimulate® and Fertiactyl® and varying plant population densities on canopy closure, yield components, and grain yield in soybean crops. The experiment was conducted during the 2014/2015 growing season at the State University of Mato Grosso do Sul – Aquidauana University Unit. A randomized block design in a 3 x 3 factorial scheme was used. The soybean cultivars SYN 9070 RR and AS 3610 IPRO were used, with treatments including seed treatment with Fertiactyl® and Stimulate®, and a control without biostimulant application, combined with plant populations of 100,000, 300,000, and 500,000 plants ha-1. Canopy closure was assessed at the V3 and V6 growth stages. At the R8 stage, the yield components: fertile branches, number of pods, number of grains, and yield were measured. No significant difference was observed between the analyzed variables for yield components and yield across cultivars when growth stimulants were applied. However, plant population density significantly affected the yield components. This was especially true for the cultivar AS 3610 IPRO, which showed increased number of pods, number of grains, and yield at a population density of 300,000 plants ha-1. The absence of bioestimulant effects on the cultivars is attributed to the favorable climatic conditions - temperature, precipitation distribution, and adequate soil fertility - which provided good plant development and may have masked the potential biostimulant responses.
A soja (Glycine max) é uma cultura estratégica para as economias brasileira e mundial. A plantabilidade é determinante no estabelecimento da lavoura e na eficiência produtiva, pois condições adequadas de velocidade e profundidade de deposição de sementes favorecem maiores rendimentos. Portanto, objetivou-se avaliar a plantabilidade durante a semeadura de soja, especificamente considerando o efeito da velocidade e profundidade de deposição de sementes no desempenho produtivo da cultura. O experimento foi conduzido em uma área comercial de produção de soja no município de Três Marias - MG. Os tratamentos incluíram duas profundidades de deposição (3 e 5 cm) e quatro velocidades operacionais (5, 7, 9 e 12 km h-1), em um delineamento experimental em faixas aleatorizadas. Foram avaliados o coeficiente de variação de semeadura (CV%), índices de espaçamentos múltiplos, falhos e aceitáveis, além da produtividade final. Os resultados mostraram que a velocidade influenciou diretamente os espaçamentos aceitáveis, com melhores índices a 5 km h-1. Os espaçamentos falhos foram mais frequentes na profundidade de 3 cm, enquanto os múltiplos aumentaram em velocidades superiores a 7 km h-1 e com semeadura à 5 cm. O CV% apresentou crescimento linear com a velocidade. A produtividade diminuiu com o aumento da velocidade e com menor profundidade de semeadura. A semeadura à 5 km h-1 na profundidade de 5 cm foi a que promoveu o melhor equilíbrio entre espaçamentos adequados e produtividade.
O espaçamento entre linhas influencia diretamente a produtividade e a longevidade dos canaviais. O objetivo deste estudo foi identificar, em três safras consecutivas, o espaçamento de plantio que proporcione maior rendimento agrícola e maior estabilidade produtiva da cana-de-açúcar. O experimento foi conduzido ao longo de três safras consecutivas (2021/22, 2022/23 e 2023/24) no Centro de Desenvolvimento e Transferência de Tecnologia (CDTT/UFLA), Minas Gerais, Brasil, abrangendo os ciclos de cultivo de cana-planta, primeira cana-soca e segunda cana-soca. O delineamento experimental foi em blocos casualizados completos (DBC) com quatro tratamentos (espaçamento entre linhas) e três colheitas, com quatro repetições. Os espaçamentos avaliados foram: simples 0,9 m, simples 1,5 m, duplo (0,9 × 1,5 m) e triplo (0,75 × 0,75 × 1,5 m). As características analisadas incluíram altura da planta (AP), diâmetro do colmo (DP), número de colmos por metro (NSM), teor de sólidos solúveis totais (TSS, °Brix) e rendimento do colmo (t ha-1). A altura média da planta, considerando a média dos quatro espaçamentos avaliados, aumentou de 2,56 m na cana-planta para 3,23 m na segunda soqueira, enquanto o diâmetro do colmo, também expresso como média dos quatro espaçamentos, atingiu o pico na primeira soqueira (28,78 mm). O espaçamento simples de 1,5 m apresentou a maior densidade de colmos (14–17 colmos m-1), e o TSS manteve-se em média em 18 °Brix. A produtividade foi consistentemente alta (>130 t ha-1) nesse espaçamento, enquanto os espaçamentos simples de 0,9 m e duplo variaram de 97 a 120 t ha-1, e o triplo atingiu 142 t ha-1 na segunda soqueira. Os resultados indicam que o espaçamento simples de 1,5 m garante maior estabilidade do número de colmos por metro e rendimento de colmos.
Selenium (Se) can be supplemented in the human diet through the consumption of foods rich in this element. However, these foods are often inaccessible to low-income populations. In this context, the enrichment of staple food crops can increase the nutritional quality of the product and contribute to efforts to reduce malnutrition. Thus, during in vitro culture, the culture medium can be enriched with elements such as Se to biofortify the plantlets. The objective of this study was to evaluate the production of Se-biofortified micropropagated banana plantlets. 'Prata Anã' Gorutuba banana plants were cultured in vitro and subsequently acclimatized. The experiment was conducted in a completely randomized design, and the treatments consisted of the addition of sodium selenate at Se concentrations of 0, 10, 20, 30, 40, and 50 µmol L-¹, with five replicates and six culture tubes per replicate. Growth parameters, photosynthetic pigment contents, biochemical parameters, and Se accumulation were evaluated in each treatment at 30 days of in vitro cultivation. The number of leaves, shoot length, and stem base diameter were evaluated at 90 days of greenhouse acclimatization. The intermediate concentration of 20 μmol L-¹ Se was the most suitable for obtaining plants with greater Se accumulation without adversely affecting phytotechnical traits and resulted in greater photosynthetic activity. Higher Se concentrations increased Se accumulation but negatively affected plant growth, indicating a dose-dependent toxic effect at elevated concentrations. During acclimatization, intermediate Se concentrations maintained a better balance between biofortification efficiency and plantlet quality. Photosynthetic pigments responded positively to lower Se concentrations, whereas antioxidant enzyme activity was not significantly affected. Overall, Se biofortification through micropropagation is feasible when appropriate concentrations are used to maintain plant quality and physiological stability.
Common bean (Phaseolus vulgaris L.), native to the Americas and belonging to the family Fabaceae, is widely consumed as a staple food in Brazil. Harvesting at the appropriate time is essential to obtain seeds with higher physiological quality and to minimize yield losses. This study aimed to evaluate the effects of harvest timing on yield, physiological quality, and storage potential of seeds from three common bean cultivars. To this end, seed production fields were established with the cultivars BRSMG Madrep & eacute;rola, BRS Esteio, and BRSMG Marte. Treatments consisted of six harvest times (70, 77, 84, 91, 98, and 105 days after emergence-DAE) and five storage periods (0, 3, 6, 9, and 12 months). Plants were harvested and threshed manually. After seed processing, the yield of each plot was determined, and seed physiological quality was evaluated through germination, accelerated aging, and electrical conductivity tests. Seed quality was also assessed after 3, 6, 9, and 12 months of storage. Maximum yields (1,930; 2,325; and 2,515 kg ha-1) were estimated by regression at 88, 88, and 86 DAE for the cultivars BRSMG Marte, Esteio, and Madrep & eacute;rola, respectively. No immediate or latent effects of harvest timing were observed on seed germination or vigor. Harvesting between 84 and 91 DAE is recommended to achieve higher yields.
Este estudo teve como objetivo avaliar o efeito da aplicação diluída de Bokashi na germinação de sementes e no desenvolvimento de mudas de tomateiro (Solanum lycopersicum) e pepino (Cucumis sativus). O experimento foi conduzido em duas etapas: a primeira, em laboratório, analisou a germinação com dois tratamentos: T1 (controle), irrigado com água, e T2 (Bokashi), com solução diluída (10 mL L-¹ de água). A germinação foi monitorada em incubadora B.O.D. (Biochemical Oxygen Demand) a 25 °C, com fotoperíodo de 12 horas, durante 9 dias. Os resultados mostraram que o Bokashi reduziu em 17% a germinação do tomateiro, mas não afetou o pepino, que manteve 100% de germinação. Na segunda etapa, em casa de vegetação, as mudas foram transplantadas para vasos com argissolo e acompanhadas por 33 dias, recebendo 150 mL de água diariamente. Parâmetros como altura, número de folhas, área foliar e diâmetro do colo foram avaliados semanalmente, sem diferenças significativas ao final. Também não houve alterações nos parâmetros fisiológicos (teor de clorofila, condutância estomática, fluorescência da clorofila a e teor de pigmentos), indicando que o Bokashi não afetou essas variáveis. Assim, os resultados indicam que o uso do Bokashi não promoveu melhorias no desempenho germinativo nem no desenvolvimento das mudas.
Sorghum is an important crop due to its resilience; however, the presence of weeds in cultivation areas can affect yield. This study aimed to evaluate the efficacy of atrazine for controlling weeds in sorghum (Sorghum bicolor) crops. The experiment was conducted at the State University of Mato Grosso do Sul, in Cassil & acirc;ndia. Three weed species, Synedrellopsis grisebachii, Commelina benghalensis, and Digitaria insularis, were considered to evaluate the effectiveness of atrazine control. The visual method was used to evaluate herbicide control, with scores ranging from 0% to 100% at 7, 14, and 21 days after spraying. At 7 days after application of the products, there was no significant difference for C. benghalensis and S. grisebachii. At 14 DAA, S. grisebachii showed high control, thereby significantly differentiating it from the other species. There was no significant difference in the control of S. grisebachii and C. benghalensis at 21 DAA. The results showed that atrazine is ineffective at controlling D. insularis. According to the vegetation cover treatments, none of the treatments differed significantly from each other. Atrazine provided 83% control of S. grisebachii after 21 days. It was observed that millet straw cover provided greater weed control, leading to better weed management and reduced product leaching. There was no satisfactory control for the other species studied.
Cobalt (Co) and molybdenum (Mo) are essential for biological nitrogen fixation (BNF) in soybean and may be supplied through enriched seed. Nickel (Ni) is also essential to BNF; however, there are no reports of its use in association with Co and Mo for seed enrichment. This study aimed to assess whether soybean seeds can be enriched with Co, Mo, and Ni through foliar application to the parent plant, and to evaluate the effects of this application on both the parent plant and the resulting seeds. A study was carried out in a fully randomized design, with seven foliar-applied treatments at the R5.2 growth stage: control; CoMo at a fixed rate (FR) (40/400 g ha-1 Co/Mo); CoMo in FR + 20 g ha-1 Ni; CoMo in FR + 40 g ha-1 Ni; CoMo in FR + 60 g ha-1 Ni; CoMo in FR + 80 g ha-1 Ni; CoMo in FR + 100 g ha-1 Ni. The following variables were assessed: chlorophyll index, biometric and yield performance of the parent plant, and contents of chemical elements, oil, protein, and fatty acids in the seed. The results obtained in this study suggest that applying Co (40 g ha-1), Mo (400 g ha-1), and Ni (up to 100 g ha-1) in a single application at the R5.2 growth stage tends to enrich the seeds produced with these three elements, without harming the growth and development of the parent plant. Seed enrichment altered the contents of other chemical elements in the seeds produced; however, it did not affect the oil, protein, or fatty acid contents.
The aim of this study was to define soybean gene micropools using genes with non-complex actions and to guide future selection strategies. The study was conducted in the 2022/2023 growing season in Ijuí, Rio Grande do Sul, Brazil, at the experimental area of the Regional University of the Northwest of the State of Rio Grande do Sul (UNIJUÍ). The experimental design used was an augmented block design with interspersed controls, with four blocks distributed across the experiment area of 1500 m2. 25 soybean gene micropools were formed based on agronomic traits and morphological and biochemical genetic descriptors. High genetic variability was associated with genes conferring tolerance to downy mildew (Peronospora manshurica) and frogeye leaf spot (Cercospora sojina). The gene micropool (C3) was identified to obtain early lines and cultivars, lanceolate leaflets and tolerance to target spot (Corynespora cassicola). 42 lines were selected for advancement to the next generation due to the absence of the major foliar diseases, which are intended for environments with reduced agrochemical use and increased sustainability.
O feijão-caupi (Vigna unguiculata) é uma leguminosa de grande importância socioeconômica no Brasil, especialmente nas regiões Norte e Nordeste, onde responde por cerca de 30% da produção nacional de feijão. Sua relevância está associada à segurança alimentar e à geração de renda para pequenos produtores, sobretudo em ambientes de cultivo adversos, como os da Amazônia. Entretanto, sua produtividade é limitada pelo baixo uso de tecnologias e manejo inadequado. A fixação biológica de nitrogênio (FBN), mediada por bactérias simbióticas como Bradyrhizobium e Rhizobium, constitui uma alternativa sustentável aos fertilizantes químicos. Este estudo teve como objetivo isolar e caracterizar rizóbios oriundos de solos amazônicos distintos (várzea, terra preta de índio e latossolo). As bactérias isoladas foram avaliadas em casa de vegetação quanto à promoção de crescimento do caupi e caracterizadas por sequenciamento do gene 16S rRNA. A massa seca da parte aérea (MSPA) variou de 736,67 a 2.220 mg por planta, e o acúmulo de nitrogênio (N-MSPA), de 17,09 a 66,85 mg por planta. A maioria dos isolados promoveu nodulação, com predominância do gênero Rhizobium, e vários isolados apresentaram desempenho agronômico semelhante, não diferindo estatisticamente da estirpe recomendada SEMIA 6462. Os resultados indicam o potencial desses rizóbios nativos como candidatos para o desenvolvimento de bioinoculantes adaptados às condições amazônicas.
Fruit growing in the S & atilde;o Francisco Valley stands out in Brazilian agriculture, especially for the production of grapevines, such as the cultivar 'BRS Vit & oacute;ria'. The objective of this study was to evaluate dry and fresh matter accumulation and to determine micronutrient accumulation rate for the grapevine variety 'BRS Vit & oacute;ria'. The experiment was carried out in Petrolina, PE, Brazil, in a randomized block design, with eight evaluation periods and four replicates. Plant collections were carried out at 15, 30, 45, 60, 75, 90, 105 and 120 days after pruning (DAP). Accumulations of Fe, Zn, Mn and Cu, dry matter and fresh matter, in branches, leaves, fruits and total throughout the cycle were analyzed. The results showed that dry matter accumulation was significant between 45 and 90 DAP, especially in fruits. Micro-nutrients showed an increasing accumulation up to 90 DAP, with iron being the most required, followed by zinc, manganese and copper. Nutrient export was highest for iron, highlighting the need to replace this nutrient in the soil.
This study aimed to analyze the effects of applying to analyze the effects of applying the biostimulants Stimulate (R) and Fertiactyl (R) and varying plant population densities on canopy closure, yield components, and grain yield in soybean crops. The experiment was conducted during the 2014/2015 growing season at the State University of Mato Grosso do Sul-Aquidauana University Unit. A randomized block design in a 3 x 3 factorial scheme was used. The soybean cultivars SYN 9070 RR and AS 3610 IPRO were used, with treatments including seed treatment with Fertiactyl (R) and Stimulate (R), and a control without biostimulant application, combined with plant populations of 100,000, 300,000, and 500,000 plants ha-1. Canopy closure was assessed at the V3 and V6 growth stages. At the R8 stage, the yield components: fertile branches, number of pods, number of grains, and yield were measured. No significant difference was observed between the analyzed variables for yield components and yield across cultivars when growth stimulants were applied. However, plant population density significantly affected the yield components. This was especially true for the cultivar AS 3610 IPRO, which showed increased number of pods, number of grains, and yield at a population density of 300,000 plants ha-1. The absence of bioestimulant effects on the cultivars is attributed to the favorable climatic conditions-temperature, precipitation distribution, and adequate soil fertility-which provided good plant development and may have masked the potential biostimulant responses.
The transition period in tropical riparian wetland areas involves alternating drought and flooding. During this period, the land can be used for vegetable cultivation, such as tomato, but unpredictable rhizosphere water saturation often induces transient anaerobic conditions that limit root function and nutrient uptake. Therefore, this study aims to evaluate the growth of tomato plants in tropical riparian wetland areas using mycorrhizal biofertilizers and bioameliorants at various levels of water-saturated rhizosphere. A factorial design was used with 2 factors, namely levels of water-saturated rhizosphere as well as the doses of mycorrhizal biofertilizers and bio-ameliorants. The results showed that tomato plants exposed to water saturation experienced more favourable growth when treated with 15 g of mycorrhizal biofertilizers per plant, 120 g of goat manure, and 80 g of rice husk charcoal per plant. The impact of the treatment on tomato plant growth was observed for 4 days after stress and 2 weeks after recovery. Increases were observed in plant height (approximately 30-40%), leaf number (60-70%), and root length (30-35%) compared to the control. The effect of a water-saturated rhizosphere was reflected in the reduction in dry matter accumulation of all plant organs. Meanwhile, the application of biofertilizers and bio-ameliorants under water-saturated conditions increased total dry matter relative to untreated plants. The results showed that tomato cultivation in tropical conditions was optimally supported under field capacity, and to a lesser extent in partial waterlogging. This was achieved by the combined application of 15 g plant-1 mycorrhizal biofertilizer and 200 g plant-1 bio-ameliorant, which resulted in the greatest improvements in growth and biomass.
O feijão é uma planta originária das Américas, pertencente à família Fabaceae, sendo utilizada como fonte de alimento pela população brasileira. A realização da colheita no momento adequado é fundamental para garantir sementes de maior qualidade fisiológica e, portanto, maior produtividade. Objetivou-se, neste trabalho, avaliar os efeitos das épocas de colheita sobre a produtividade, a qualidade fisiológica e o potencial de armazenamento das sementes de três cultivares de feijão. Para isso, foram conduzidos campos de produção de sementes das cultivares BRSMG Madrepérola, BRS Esteio e BRSMG Marte. Os tratamentos foram compostos por seis épocas de colheita (70, 77, 84, 91, 98 e 105 dias após a emergência – DAE) e cinco períodos de armazenamento (zero, três, seis, nove e 12 meses). As plantas foram colhidas e debulhadas manualmente. Após o beneficiamento, determinou-se a produtividade de cada parcela e avaliou-se a qualidade fisiológica das sementes por meio dos testes de germinação, envelhecimento acelerado e condutividade elétrica. A qualidade das sementes também foi avaliada após 3, 6, 9 e 12 meses de armazenamento. As produtividades máximas (1.930; 2.325 e 2.515 kg ha-1) foram estimadas por regressão em 88, 88 e 86 DAE, para as cultivares BRSMG Marte, Esteio e Madrepérola, respectivamente. Não houve efeito imediato ou latente das épocas de colheita sobre a germinação e o vigor das sementes. Recomenda-se a colheita na faixa de 84 a 91 DAE visando maiores produtividades.
Amazonian spinach is classified as a non-conventional vegetable species with high agricultural potential and may serve as an alternative to conventional leafy crops. This study aimed to evaluate the yield of Amazonian spinach plants grown from seedlings produced using cuttings of different sizes. The experiment was conducted at the experimental unit of the Federal University of Acre from May to July 2023. A completely randomized design was adopted, with three treatments and ten replications. The treatments consisted of seedlings produced from cuttings with different numbers of nodes: T1 = 1 node; T2 = 2 nodes; and T3 = 3 nodes. After 50 days of cultivation, the following variables were evaluated: height, stem diameter, total number of shoots, total number of leaves, leaf width, leaf length, shoot fresh mass, root fresh mass, shoot dry mass, root dry mass, and yield. Seedling quality significantly affected plant productivity. Plants derived from seedlings produced from 3-node cuttings exhibited the highest yields. Although plants originating from 1- and 2-node cuttings completed their development, they showed lower productivity. The use of 3-node cuttings is therefore recommended to enhance the yield of Amazonian spinach.
Soybean (Glycine max (L.) Merr.) is a strategic crop for Brazilian and global economies. Plantability performance is crucial for crop establishment and production efficiency, as adequate seed placement, speed, and depth can improve yields. This study evaluated the effects of plantability on soybean performance, focusing on operating speed and sowing depth. The experiment was conducted at a commercial soybean production site in Tr & ecirc;s Marias, Minas Gerais, Brazil. Treatments included two seed deposition depths (3 and 5 cm) and four operating speeds (5, 7, 9, and 12 km h-1), in a randomized strip-plot design. The variables evaluated were the coefficient of variation of seed distribution (CV%), multiple spacing, missing spacing index, acceptable spacing index, and grain yield. Results showed that operating speed directly influenced acceptable spacing, with the best indices at 5 km h-1. Missed (failed) spacings were more frequent at the 3-cm sowing depth, whereas multiple spacings increased at operating speeds above 7 km h-1 and at the 5-cm sowing depth. The CV% increased linearly with speed. Crop yield decreased with increasing speed and lower sowing depth. Sowing at 5 km h-1 and a sowing depth of 5 cm provided the best balance between acceptable spacing and soybean yield.
Lettuce (Lactuca sativa) is a leafy vegetable that is widely consumed due to its high nutritional content. The growth and yield of lettuce plants are significantly influenced by light intensity. Despite its potential, information about the intensity required for plants to grow optimally, specifically in urban areas, is still limited. Therefore, this study aims to evaluate the morphological and physiological growth and yield of 3 lettuce varieties under the intensity of sunlight and artificial light. The procedures were carried out using a split-plot design with 3 replications. The main plot comprised 55% shade (S55% + SL), 80% shade (S80% + SL), and 100% shade combined with artificial light from Light Emitting Diode (LED) lights (S100%+LED), which served as low-intensity light. Meanwhile, the subplots were 3 varieties of lettuce, including Romaine Lactuca sativa L. VAR. Longifolia (V1), Grand rapids Lactuca sativa L. VAR. new grand rapids (V2), and siomak Lactuca sativa L. VAR. Augustuna (V3). The results showed that shading intensity of 80% (S80% +SL) and 100% (SD100%+LED) inhibited plant growth, particularly in leaves and roots. Microclimate conditions, such as air temperature and light intensity, were lower due to the influence of shade. In conclusion, 3 lettuce varieties cannot grow optimally under low intensity shade, and 100% shade (SD100%+LED) is not suitable for the specific needs of plant to promote optimal growth and yield of lettuce.
Row spacing directly influences sugarcane productivity and field longevity. This study aimed to identify, over three consecutive harvests, the row spacing that yields the highest and most stable production in sugarcane. The experiment was conducted over three consecutive seasons (2021/22, 2022/23, and 2023/24) at the Technology Development and Transfer Center (CDTT/UFLA), Minas Gerais, Brazil, covering the crop cycles of plant cane, first ratoon, and second ratoon. The experimental design was a randomized complete block (RCBD) with four treatments (row spacings) and three harvests, with four replications. The evaluated spacings were single 0.9 m, single 1.5 m, double (0.9 & times; 1.5 m), and triple (0.75 & times; 0.75 & times; 1.5 m). The analyzed traits included plant height (PH), stalk diameter (SD), number of stalks per meter (NSM), total soluble solids content (TSS, degrees Brix), and stalk yield (t ha(-1)). Mean plant height, averaged across the four row spacings, increased from 2.56 m in the plant cane to 3.23 m in the second ratoon, while stalk diameter, also expressed as the mean of the four spacings, peaked in the first ratoon (28.78 mm). The single 1.5 m spacing showed the highest stalk density (14-17 stalks m(-1)), and TSS remained at an average of 18 degrees Brix. Yield was consistently high (>130 t ha(-1)) at this spacing, whereas the single 0.9 m and double spacings ranged from 97 to 120 t ha(-1), and the triple spacing reached 142 t ha-1 in the second ratoon. The results indicate that the single 1.5 m spacing ensures greater stability in the number of stalks per meter and stalk yield.
