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Sunflower is one of the most important oilseeds in the world, whose achenes are valued in several industrial chains, mainly for the extraction and processing of its oil. Although there is some information in the literature, the nitrogen (N) requirements for sunflower in semiarid conditions under irrigation are not yet clear. The experimental design used randomized blocks, with treatments in subdivided plots with four replications during two agricultural seasons. The N doses (e.g., 0, 30, 60, 90 and 120 kg ha-1) were assigned to the plots, and to the four sunflower cultivars used (e.g., Aguará 06, Altis 99, Multissol and BRS 122), which were planted in the subplots. The N doses for the maximum achene yields for the Multissol and BRS 122 cultivars were 81.8 and 86.6 kg ha-1, respectively, while N doses of 120 kg ha-1 produced the maximum achene yields for the Altis 99 and Aguará 06 cultivars in the 2016 crop season. In 2017, the Multissol and BRS 122 cultivars were given N doses of 100.7 and 92.8 kg ha-1, respectively, and the Altis 99 and Aguará 06 cultivars were each given an N dose of 120 kg ha-1 of N. The fertirrigated doses of maximum economic efficiency of N were 60 and 70 kg ha-1 for the Multissol and BRS 122 cultivars, respectively. For the oil yields, the maximum N doses of 78.0 and 86.7 kg ha-1 for the BRS 122 and Aguará 06 cultivars and for the Multissol and Altis 99 cultivars at an N dose of 120 kg ha-1 were used for the 2016 harvest. In 2017, the BRS 122 and Multissol cultivars received N doses of 88.6 and 99.1 kg ha-1, respectively, and the Altis 99 and Aguará 06 cultivars received N doses of 120 kg ha-1. The use of fertigation allowed greater efficiency for the N doses in the sunflower cultivars in the semiarid region.

The objective of this work was to evaluate the agro-economic performance of sesame (Sesamum indicum) under nitrogen fertigation in the semiarid region of Northeastern Brazil. The experimental design was randomized complete blocks with four replicates, and the treatments were arranged in a split-plot, where the plots were assigned five N rates (0, 30, 60, 90, and 120 kg ha-1) and the sub-plots were represented by four sesame genotypes ('CNPA G2', 'CNPA G3', 'CNPA G4', and 'BRS Seda'). The following variables were evaluated in two agricultural harvests in 2016: gross and net incomes, rate of return, and profit margin. In both harvests, there was a variation in production costs between N rates. In the second harvest, the highest values of net income were achieved with 120 kg ha-1 N fertigation, being: R$7,428.36 ha-1 for 'CNPA G2', R$8,630.74 ha-1 for 'CNPA G3', R$9,828.64 ha-1 for 'CNPA G4', and R$8,354.06 ha-1 for 'BRS Seda'. Increasing N rates provide an increase in the gross income, net income, rate of return, and profit margin for sesame producers. Fertigation with 120 kg ha-1 N provides the maximum agro-economic performance for sesame, whereas the 'CNPA G4' genotype shows the greatest agro-economic efficiency. Resumo: O objetivo deste trabalho foi avaliar o desempenho agroeconômico do gergelim (Sesamum indicum) sob fertirrigação com nitrogênio na região semiárida do Nordeste brasileiro. O delineamento experimental foi em blocos ao acaso, com quatro repetições, e os tratamentos foram dispostos em arranjo de parcelas subdivididas, em que as parcelas receberam cinco doses de N (0, 30, 60, 90 e 120 kg ha-1) e as subparcelas foram representadas por quatro genótipos de gergelim ('CNPA G2', 'CNPA G3', 'CNPA G4' e 'BRS Seda'). As seguintes variáveis foram avaliadas em duas safras agrícolas, em 2016: rendas bruta e líquida, taxa de retorno e margem de lucro. Nas duas safras, houve variação nos custos de produção entre as doses de N. Na segunda safra, os maiores valores de renda líquida foram obtidos com 120 kg ha-1 de fertirrigação com N, a saber: R$ 7.428,36 ha-1 para 'CNPA G2', R$ 8.630,74 ha-1 para 'CNPA G3', R$ 9.828,64 ha-1 para 'CNPA G4' e R$ 8.354,06 ha-1 para 'BRS Seda'. Doses crescentes de N proporcionam aumento na renda bruta, na renda líquida, na taxa de retorno e no índice de lucratividade para produtores de gergelim. A fertirrigação com 120 kg ha-1 de N proporciona o máximo desempenho agroeconômico para o gergelim, enquanto o genótipo 'CNPA G4' apresenta a maior eficiência agroeconômica.

Knowledge on nitrogen (N) utilization efficiency in colored cotton enables the correct management of N fertilizers, optimizing yield and minimizing environmental degradation.The objective of this study was to evaluate the N utilization efficiency and to determine the accumulation of dry matter and N by naturally colored cotton cultivars subjected to N fertilization in the Brazilian semi-arid region.The experiment was carried out under field conditions, at the Farm of the Federal Rural University of the Semi-Arid, in 2016 and 2017. The experimental design was in randomized blocks with split plots and four replicates, randomizing five N doses (0; 50; 100; 150 and 200 kg ha-1) in the main plot and four colored cotton cultivars (BRS Safira, BRS Rubi, BRS Topázio and BRS Verde) in the subplots. Dry matter and N accumulations, agronomic, recovery, agrophysiological and physiological efficiencies in N utilization, and harvest index were evaluated. Cotton accumulates around 130 kg ha-1 of N along its cycle and directs 56.3% to seeds, 29% to leaves, 10.6% to stem and 3.8% to fibers. Nitrogen agronomic efficiency and recovery efficiency decrease with increased N doses. The cultivar BRS Topázio is the most responsive to N fertilization and the cultivar BRS Verde is the least responsive.

Sunflower is one of the most important oilseeds in the world. However, cultivation in semi-arid regions requires analysis of production costs and profitability, ensuring effective decision-making, focused on farming procedures and techniques. In two agricultural crops, 2016 and 2017, experiments were conducted to evaluate the economic indicators of sunflower cultivars (‘Aguará 06’, ‘Altis 99’, ‘Multissol’ and ‘BRS 122’) submitted to nitrogen (N) doses (0; 30; 60; 90 and 120 kg ha-1) via fertirrigation under semi-arid conditions. The net margin corresponded to the increase of N doses, reaching a maximum net margin in the 2016 harvest of R$ 366.89 ha-1 at the dose of 81 kg ha-1 of N for ‘BRS 122’; R$ 577.41 ha-1 with 118 kg ha-1 of N for ‘Multissol’; and for ‘Aguará 06’ (R$ 2,124.00 ha-1) and ‘Altis 99’ (R$ 976.66 ha-1) at the dose of 120 kg ha-1 of N. In the 2017 harvest, ‘BRS 122’ obtained R$ 190.90 ha-1 in the dose of 83 kg ha-1 of N and ‘Multissol’ reached R$ 657.50 in the dose of 85 kg ha-1 of N; the cultivars ‘Aguará 06’ (R$ 1,078.00 ha-1) and ‘Altis 99’ (R$ 957.14 ha-1) in the dose of 120 kg ha-1 of N. The rate of return and the profitability index were positive for all cultivars in both crops. O girassol é uma das mais importantes oleaginosas do mundo. No entanto, o cultivo em regiões semiáridas requer análise dos custos de produção e rentabilidade, garantindo tomadas de decisão eficazes, focadas em procedimentos e técnicas agrícolas. Em duas safras agrícolas, 2016 e 2017, foram conduzidos experimentos para avaliar os indicadores econômicos de cultivares de girassol ('Aguará 06', 'Altis 99', 'Multissol' e 'BRS 122') submetidos a doses de nitrogênio (N) (0; 30; 60; 90 e 120 kg ha-1) via fertirrigação em condições semiáridas. A margem líquida correspondeu ao aumento das doses de N, atingindo uma margem líquida máxima na safra 2016 de R$ 366,89 ha-1 na dose de 81 kg ha-1 de N para 'BRS 122'; R$ 577,41 ha-1 com 118 kg ha-1 de N para 'Multissol'; e para 'Aguará 06' (R$ 2.124,00 ha-1) e 'Altis 99' (R$ 976,66 ha-1) na dose de 120 kg ha-1 de N. Na safra de 2017, 'BRS 122' obteve R$ 190,90 ha-1 na dose de 83 kg ha-1 de N e 'Multissol' alcançaram R$ 657,50 na dose de 85 kg ha-1 de N; as cultivares 'Aguará 06' (R$ 1.078,00 ha-1) e 'Altis 99' (R$ 957,14 ha-1) na dose de 120 kg ha-1 de N. A taxa de retorno e o índice de lucratividade foram positivos para todas as cultivares em ambas as culturas.

The objective of this work was to evaluate the response of sunflower cultivars submitted to increasing levels of phosphate fertilization in two crops. The experimental design was a randomized complete block design with four replicates in subdivided plots, where five doses of simple superphosphate (0, 50, 100, 150, and 200 kg ha-1 P2O5) were allocated to the plots and three sunflower cultivars (Aguará 06, Altis 99, and Embrapa 122-V2000) were assigned to the subplots. The variables evaluated were the P content in the diagnostic leaf, number of achenes per capitulum, achene yield (kg ha-1), oil content (%) and oil yield. The phosphorus doses increased the components of production. The dose that provided the best sunflower performance varied for the different cultivars. Among the doses studied, fertilization with 100 kg ha-1 P2O5 in the 2016 agricultural crop and 150 kg ha-1 P2O5 in the 2017 agricultural crop provided the best conditions for sunflower cultivation. The cultivar Aguará 06 produced more achenes and oil than the other cultivars analyzed in the agricultural crops. The objective of this work was to evaluate the response of sunflower cultivars submitted to increasing levels of phosphate fertilization in two crops. The experimental design was a randomized complete block design with four replicates in subdivided plots, where five doses of simple superphosphate (0, 50, 100, 150, and 200 kg ha-1 P2O5) were allocated to the plots and three sunflower cultivars (Aguará 06, Altis 99, and Embrapa 122-V2000) were assigned to the subplots. The variables evaluated were the P content in the diagnostic leaf, number of achenes per capitulum, achene yield (kg ha-1), oil content (%) and oil yield. The phosphorus doses increased the components of production. The dose that provided the best sunflower performance varied for the different cultivars. Among the doses studied, fertilization with 100 kg ha-1 P2O5 in the 2016 agricultural crop and 150 kg ha-1 P2O5 in the 2017 agricultural crop provided the best conditions for sunflower cultivation. The cultivar Aguará 06 produced more achenes and oil than the other cultivars analyzed in the agricultural crops.

Sesame is an oleaginous plant that requires suitable management in the field to achieve satisfactory production; however, to better understand the requirements of the culture, it is necessary to obtain more information on the behavior of sesame cultivars, in relation to the nutrition and edaphoclimatic factors that can interfere with its response. Therefore, the aim of this work was to evaluate the production components of fertirrigated sesame cultivars, in the northeastern semi-arid region of Brazil, as a function of nitrogen (N) fertilization in two crops. The experiments were conducted at the Rafael Fernandes Experimental Farm, which belongs to the Universidade Federal Rural do Semi-Arido (UFERSA), from February to May (first crop) and July to October (second crop), in the year 2016. The experimental design was of a randomized complete blocks type with four replications, with the treatments arranged in a split plots scheme, where in the plots were assigned five rates of N (0, 30, 60, 90, and 120 kg ha−1) and in the subplots four sesame cultivars (CNPA G2, CNPA G3, CNPA G4, and BRS Seda). The evaluated variables were N content in the diagnostic leaf (NCDL), number of capsules per plant (NC), plant dry mass (PDM), seed yield (SY), oil content (OC), and protein content (PC). The maximum values of the variables studied were obtained at a rate of 120 kg ha−1 of N. The cultivar CNPA G4 presented the highest productive performance in comparison to the other cultivars, and the cultivar BRS Seda had the highest oil content in the seed. The second crop (July to October) obtained the best agronomic performance for the sesame. Regarding the protein content, the cultivars CNPA G3 and CNPA G4 obtained the highest at a rate of 120 kg ha−1 of N. The second harvest also provided higher levels of protein in the seed, independent of the cultivar evaluated.

This study aimed to evaluate the emergence, growth, biomass accumulation and tolerance of peanut genotypes under salt stress. The experiment was conducted in a protected environment (greenhouse), evaluating six peanut genotypes (Tatuí, L7151, Caiapó, IAC8112, IAC881 and Havana), which were subjected to two levels of irrigation water salinity (0.5 [control] and 3.5 dS m-1), arranged in a 6 x 2 factorial scheme, in a randomized block design, with five repetitions, with two plants per plot. Plants were cultivated for 30 days after sowing in lysimeters with capacity for 0.5 dm3, filled with a mixture of non-saline, non-sodic soil and commercial substrate in 1:1 proportion on volume basis. During this period, plants were evaluated for emergence, growth, biomass accumulation, tolerance to salinity and dissimilarity. The genotypes Tatuí and L7151 are the most sensitive to salt stress in the emergence stage. Irrigation with high-salinity water reduced the growth and biomass accumulation of the peanut genotypes, and Caiapó and IAC8112 were the least affected. The classification of salinity tolerance had the following sequence: Caiapó > IAC8112 > Havana > Tatuí > IAC881 > L7151. RESUMO Objetivou-se avaliar a emergência, o crescimento, o acúmulo de biomassa e a tolerância de genótipos de amendoim sob estresse salino. O experimento foi desenvolvido em ambiente protegido (casa de vegetação), avaliando seis genótipos de amendoim (Tatuí, L7151, Caiapó, IAC8112, IAC881 e Havana) submetidos a dois níveis de salinidade da água de irrigação (0,5 (controle) e 3,5 dS m-1), arranjados em esquema fatorial 6 x 2, em delineamento experimental de blocos casualizado, com cinco repetições, com duas plantas por parcela. As plantas foram cultivadas durante 30 dias após a semeadura, em lisímetros com capacidade para 0,5 dm3, preenchidos com uma mistura de solo não salino e não sódico, com substrato comercial na proporção de 1:1 base em volume. Durante esse período as plantas foram avaliadas quanto à emergência, crescimento, acúmulo de biomassa e tolerância à salinidade e dissimilaridade. Os genótipos Tatuí e L7151 são os mais sensíveis ao estresse salino na fase de emergência. A irrigação com água de alta salinidade reduziu o crescimento, o acúmulo de biomassa dos genótipos de amendoim, sendo os genótipos Caiapó e IAC8112 os menos afetados. A classificação de tolerância à salinidade teve a seguinte sequência: Caiapó > IAC8112 > Havana > Tatuí > IAC881 > L7151.

The objective of this work was to evaluate the profitability of sweet potato cultivars, harvested at different ages and cultivated in different periods (rainy and dry) in the municipality of Mossoró, semi-arid region of Rio Grande do Norte. The experimental design was a randomized complete block design with four replications and treatments arranged in split plots scheme. The plots were composed of three sweet potato cultivars (ESAM 1, Paraná and Mother of Family) and the subplots for five harvest ages (90 , 105, 120, 135 and 150 days after transplanting - DAT). Productivity of commercial roots and production costs was evaluated, as well as the economic indicators: gross income, net income, rate of return and profit margin. Independently of the growing periods, the productivity of commercial roots increased with the later harvest of the crop and differentiated the cultivars. Production costs averaged R$ 6,087.97 ha-1 in the rainy season and R$ 6,181.42 ha-1 in the dry period. Labor expenditures were the most impacting of total expenditures. The cultivars ESAM 1 and Paraná presented higher productivities of commercial roots and profitability when cultivated in the rainy season, while Paraná cultivar was superior to the other cultivars in the crop in the dry season. In both growing periods, the harvest age of 150 DAT promoted higher productivities of commercial roots and profitability to sweet potato production. Este trabalho teve como objetivo avaliar a rentabilidade de cultivares de batata-doce, colhidas em diferentes idades e cultivadas em períodos distintos (chuvoso e seco) no município de Mossoró, semiárido do Rio Grande do Norte. O delineamento experimental foi em blocos ao acaso, com quatro repetições e tratamentos arranjados em parcelas subdivididas, sendo as parcelas formadas por três cultivares de batata-doce (ESAM 1, Paraná e Mãe de Família) e as subparcelas por cinco idades de colheita (90, 105, 120, 135 e 150 dias após o transplantio – DAT). Avaliaram-se produtividade de raízes comerciais e custos de produção, assim como os indicadores econômicos: renda bruta, renda líquida, taxa de retorno e índice de lucratividade. Independentemente dos períodos de cultivo, a produtividade de raízes comerciais aumentou com a colheita mais tardia da cultura e diferenciou as cultivares. Os custos de produção foram em média da ordem de R$ 6.087,97 ha-1 no período chuvoso e R$ 6.181,42 ha-1 no período seco. As despesas com mão de obra foram as mais impactantes nas despesas totais. As cultivares ESAM 1 e Paraná apresentaram maiores produtividades de raízes comerciais e lucratividades quando cultivadas no período chuvoso, enquanto a Paraná foi superior as demais cultivares no cultivo na época seca. Em ambas as épocas de cultivo, a idade de colheita de 150 DAT promoveu maiores produtividades de raízes comerciais e rentabilidade à produção de batata-doce.

Producers in the northeastern semiarid region of Brazil have been cultivating irrigated corn. The commercialized product comprises mainly green ears and silage. However, the irrigation of crops for dry grain has been questioned regarding costs and price competitiveness in relation to the same non-irrigated product cultivated in other regions. In recent years, the use of drip tapes and fertigation has spread among corn producers in the region. The aim of this study was to determine the N dose, via fertigation, which provides the maximum economic production of corn for dry grain, in two crop seasons (summer and winter), in the semiarid region of Brazil. The experimental design was performed in randomized blocks, with four replications. In both crops, the treatments consisted of four doses of N (0, 80, 160, and 240 kg ha-1) applied in the form of urea. In the hybrid corn (Bt Feroz), the N content was evaluated in terms of leaves, grain yield, gross and net incomes, the rate of return, and the profitability index. Independent of the crop season, the yield of dry grain (5,441.03 kg ha-1) was highest when the corn was fertigated with a dose of 104.05 kg ha-1 N. The highest net incomes of the dry grain were obtained with 80 kg ha-1 N in summer (R$ 1,190.78 ha-1) and 160 kg ha-1 N in winter (R$ 2,757.54 ha-1). The winter crop was more favorable to the economic production of dry grain. Producers in the northeastern semiarid region of Brazil have been cultivating irrigated corn. The commercialized product comprises mainly green ears and silage. However, the irrigation of crops for dry grain has been questioned regarding costs and price competitiveness in relation to the same non-irrigated product cultivated in other regions. In recent years, the use of drip tapes and fertigation has spread among corn producers in the region. The aim of this study was to determine the N dose, via fertigation, which provides the maximum economic production of corn for dry grain, in two crop seasons (summer and winter), in the semiarid region of Brazil. The experimental design was performed in randomized blocks, with four replications. In both crops, the treatments consisted of four doses of N (0, 80, 160, and 240 kg ha-1) applied in the form of urea. In the hybrid corn (Bt Feroz), the N content was evaluated in terms of leaves, grain yield, gross and net incomes, the rate of return, and the profitability index. Independent of the crop season, the yield of dry grain (5,441.03 kg ha-1) was highest when the corn was fertigated with a dose of 104.05 kg ha-1 N. The highest net incomes of the dry grain were obtained with 80 kg ha-1 N in summer (R$ 1,190.78 ha-1) and 160 kg ha-1 N in winter (R$ 2,757.54 ha-1). The winter crop was more favorable to the economic production of dry grain.

Because vegetables have a fast production cycle, they require fertilization in quantities and at ideal times to obtain maximum productivity, and green manure is an alternative practice to the use of mineral fertilizers. This study was conducted to evaluate the effects of different amounts of roostertree [Calotropis procera (Ait.) R. Br.] biomass and its incorporation times in two growing seasons, in the agronomic performance of carrots. The experiment was conducted on an experimental farm at the Universidade Federal Rural de Pernambuco (UFRPE) in the autumn-winter period (March-July 2012) and the spring-summer period (September-December 2012). The experimental design was a randomized block design with three replications. The treatments were arranged in a factorial 4 x 4 design; the first factor consists of four amounts of roostertree biomass (5.4, 8.8, 12.2 and 15.6 t ha-1 on a dry basis), and the second factor consists of four times of incorporation of this manure into the soil (0, 10, 20 and 30 days before sowing the carrots). The carrot cultivar used was Brasília. The following traits were evaluated: plant height, number of leaves per plant, root dry mass, total and commercial yield of roots. The best agronomic performance of carrot cultivar Brasília was found with the amount of roostertree biomass of 15.6 t ha-1, in the time of incorporation into the soil of 10 days before seeding. The cultivation in the autumn-winter showed higher total and commercial productivities of carrot roots fertilized with roostertree. As hortaliças, por possuírem ciclo rápido de produção, demandam adubações em quantidades e momentos ideais para a obtenção da máxima produtividade, sendo a adubação verde uma prática alternativa ao uso de fertilizantes minerais. O presente estudo foi realizado com o objetivo de avaliar os efeitos de diferentes quantidades de biomassa de flor-de-seda [Calotropis procera (Ait.) R. Br.] e seus tempos de incorporação, em duas épocas de cultivo, no desempenho agronômico da cenoura. O experimento foi conduzido em campo experimental pertencente à Universidade Federal Rural de Pernambuco (UFRPE), nos períodos outono-inverno (março a julho de 2012) e primavera-verão (setembro a dezembro de 2012). O delineamento experimental utilizado foi em blocos casualizados, com três repetições. Os tratamentos foram arranjados em esquema fatorial 4 x 4, com o primeiro fator constituído por quatro quantidades de biomassa de flor-de-seda (5,4; 8,8; 12,2 e 15,6 t ha-1 em base seca), e o segundo fator, por quatro tempos de incorporação ao solo deste adubo (0, 10, 20 e 30 dias antes da semeadura da cenoura - DAS). A cultivar de cenoura utilizada foi a Brasília. Foram avaliados a altura de plantas, número de folhas por planta, massa seca de raízes, produtividades total e comercial de raízes. O melhor desempenho agronômico da cenoura cv. Brasília foi obtido com a quantidade de flor-deseda de 15,6 t ha-1, no tempo de incorporação ao solo de 10 dias antes da semeadura. O cultivo no outono-inverno promoveu maiores produtividades total e comercial às raízes de cenoura adubada com flor-de-seda.

The consumption of arugula is low compared to lettuce and coriander. However, it has been increasing, and there is a lack of information on fertilization and culture times. Growth and development characteristics of arugula were assessed. It was fertilized with different amounts of rooster tree biomass, at different times in the soil. It was cultured at two planting times (spring-summer and fall), in the municipality of Serra Talhada, PE, Brazil. The experimental design was randomized block, with treatments arranged on a 4 × 4 factorial, with three replications. The first factor is the amounts of rooster tree biomass (5.4, 8.8, 12.2 and 15.6 Mg ha-1 on a dry base), and the second one is times of incorporating in the soil (0, 10, 20 and 30 days before the planting of arugula). The characteristics of arugula assessed were: Plant height, number of leafs per plant, yield of green and dry mass of the above-ground part. The maximum yield of arugula was obtained at a dose of 15.6 Mg ha-1 of green fertilizer. Some synchronicity between the supply of nutrients (green fertilizer) and the period of maximum demand by the arugula plants was observed when they were incorporated 20 days before planting. The culture increased the cycle of arugula during the fall, offering greater green and dry mass yields to the culture. Key words: Calotropis procera (Ait.) R. Br., Eruca sativa L., green fertilizer, meteorological conditions, organic fertilization.

Sweet potato constitutes a source of energy and nutrient which is very important economically, especially, for the poorest people in the world, supplies calories, vitamins and minerals in the diet. The determination of the harvest age has great influence on vegetative production, quality, productivity and root biomass. The planting season is determined by climatic elements, which have influence on the growth, development and crop productivity. The objective of this paper was to evaluate the agronomic performance of sweet potato cultivars, as a function of the age of harvest in two growing seasons. Two experiments were conducted, the first in the rainy season and the second in the dry season in semiarid Brazil. In both experiments, the experimental design was a randomized block with split plots with four replications, being the plot formed by three cultivars (ESAM 1, Parana and Mae de Familia), and the subplot by 5 harvest times (90, 105, 120, 135 and 150 days after planting). The length and diameter of commercial roots, dry mass of roots and shoots, and fitomass production were determined. The diameter, total dry mass of roots, commercial and total productivities of roots showed increasing responses with increasing harvest age in both crop growing seasons. The Parana cultivar showed the best productive performance among cultivars. The harvest age of 150 days after planting was more productive. The best time of cultivation was in the dry season. Considering the importance of sweet potatoes, further studies are recommended in order to solve some problems related to adaptability and cultural reproduction in other regions to elucidate the effects of harvesting ages and growing seasons at longer intervals. Key words: Ipomoea batatas, productivity, roots, tuberous.

Nitrogen (N) is an essential macronutrient for plant growth and rate applications can influence the performance of sesame, and when applied in excess can cause nitrogen loss in the environment, and consequently make the cost of production more costly to the producer. Therefore, the objective of this work was to evaluate the efficiency of nitrogen use by different cultivars of irrigated sesame seeds under the edaphoclimatic conditions of the northeastern semi-arid region in two harvests. The experiments were carried out from February to May (1st harvest) and from July to October (2nd harvest) in 2016. The treatments were arranged in a split plot scheme, in which the plots were the five nitrogen doses (0, 30, 60, 90 and 120 kg ha-1), and in the subplots, the four sesame genotypes (CNPA G2, CNPA G3, CNPA G4 and BRS Seda), the design was in randomized complete blocks with four replications. The nitrogen use efficiency assessments evaluated were: agronomic efficiency (AE), physiological efficiency (PE), agrophysiological efficiency (APE), recovery efficiency (RE) and efficiency of use (EU). The rate that provided the greatest efficiency of use was 30 kg ha-1 of N applied. The cultivar BRS Seda had greater efficiency of use in relation to the other cultivars studied. The crop that had better efficiency of use was the 2nd agricultural harvest. O nitrogênio (N) é um macronutriente essencial para o crescimento das plantas e aplicações de doses podem influenciar o desempenho do gergelim, e quando aplicado em excesso pode ocasionar perda de nitrogênio no meio ambiente, e consequentemente tornado o custo de produção mais oneroso ao produtor. Diante disso, o objetivo deste trabalho foi avaliar a eficiência de uso do nitrogênio por diferentes cultivares de gergelim irrigado nas condições edafoclimáticas do semiárido nordestino em duas safras agrícolas. Os experimentos foram conduzidos na Fazenda Experimental Rafael Fernandes pertencente à Universidade Federal Rural do Semiárido (UFERSA), no período de fevereiro a maio (1ª safra agrícola) e julho a outubro (2ª safra agrícola), no ano de 2016. O delineamento experimental foi em blocos completos casualizados com quatro repetições em parcelas subdivididas, onde nas parcelas, foram alocadas cincos doses de nitrogênio (0, 30, 60, 90 e 120 kg ha-1), e nas subparcelas os quatro genótipos de gergelim (CNPA G2, CNPA G3, CNPA G4 e BRS Seda). As variáveis avaliadas de eficiência de uso do nitrogênio foram: eficiência agronômica (EA), eficiência fisiológica (EF), eficiência agrofisiológica (EAF), eficiência de recuperação (ER) e eficiência de utilização (EU). A dose que propocionou maior eficiência de utilização foi a de 30 kg ha-1 de N aplicado. A cultivar BRS Seda teve maior eficiência de utilização em relação às outras cultivares estudas. A safra que teve melhor eficiência de utilização foi a 2ª safra agrícola.

The sesame crop (Sesamum indicum L.) is sensitive to competition with weeds because of its low competitiveness that is directly linked to its slow initial growth. The control of weeds in the crop is an essential practice to ensure the high productivity of this oilseed. Therefore, to define the critical period of interference prevention is important to ensure efficiency and low control costs. Factors such as cultivar, environmental conditions, and cultivation system may alter the critical weed interference prevention period (CPWC). Therefore, the objective of this work was to determine the critical weed interference prevention period in two sesame cultivars. The critical weed interference prevention period for sesame cultivars, BRS Seda and CNPA G2, was defined in two years (2016 and 2017). Log-logistic regression of four parameters was used to determine the critical weed interference prevention period. The cultivar CNPA G2 was more competitive compared to the cultivar BRS Seda. The CPWC for BRS Seda was on average 67 and 52 days, whereas for CNPA G2 was 52 and 34 days, considering respectively, a loss of 5 and 10%. Weed control for BRS Seda and CNPA G2 should begin respectively between 12 and 15, and 17 and 20 days, considering a loss of 5 and 10%. RESUMO A cultura do gergelim (Sesamum indicum L.) é sensível a competição com plantas daninhas devido a sua baixa competitividade que está diretamente ligada ao seu crescimento inicial lento. O controle de plantas daninhas na cultura é prática fundamental para assegurar a alta produtividade dessa oleaginosa. Nesse sentido, é importante definir o período crítico de prevenção a interferência para alcançar eficiência e baixo custo no controle. Os fatores como cultivar, condições ambientais e sistema de cultivo podem alterar o período crítico de prevenção à interferência de plantas daninhas (PCPI). Portanto, o objetivo deste trabalho foi determinar o período crítico de prevenção de interferência de plantas daninhas em duas cultivares de gergelim. O período crítico de prevenção de interferência de plantas daninhas para os cultivares de gergelim, BRS Seda e CNPA G2, foi definido em dois anos (2016 e 2017). Regressão log-logística de quatro parâmetros foi usada para determinar o período crítico de prevenção de interferência de plantas daninhas. A cultivar CNPA G2 foi mais competitiva em relação à cultivar BRS Seda. O PCPI para BRS Seda é em média 67 dias e 52 dias, enquanto para o CNPA G2 é de 52 dias e 34 dias, considerando respectivamente, uma perda de 5 e 10%. O controle de plantas daninhas para BRS Seda e CNPA G2 deve iniciar respectivamente entre 12º e 15º dia, e 17º e 20º dia, considerando uma perda de 5 e 10%.

Para obter produtos de qualidade e em quantidade ao longo do ano, e necessario o planejamento do plantio, observando a produtividade esperada, o preco praticado no comercio e os custos relativos aos fatores de producao, como despesas com mao de obra e aquisicao de fertilizantes, os quais ditam o sucesso do investimento. O objetivo deste trabalho foi avaliar a rentabilidade do rabanete cv. Crimson Gigante adubado com diferentes quantidades de biomassa de flor-de-seda, em distintos tempos de incorporacao ao solo e cultivado em duas epocas (outubro-dezembro e abril-julho), no semiarido de Pernambuco. O delineamento experimental utilizado em ambos os experimentos foi o de blocos completos casualizados com os tratamentos arranjados em esquema fatorial 4 × 4, com tres repeticoes, sendo o primeiro fator: as quantidades de flor-de-seda (5,4; 8,8; 12,2 e 15,6 t ha–1 em base seca), e o segundo: os tempos de incorporacao ao solo deste adubo (0, 10, 20 e 30 dias). Alem da produtividade comercial de raizes e dos custos de producao, foram determinados os indicadores economicos: renda bruta, renda liquida, taxa de retorno e indice de lucratividade. As maiores receitas bruta e liquida foram observadas com a quantidade de 15,6 t ha–1 de flor‑de-seda. A incorporacao da flor-de-seda 22 dias antes do plantio do rabanete foi considerada ideal a viabilidade economica do investimento.

A busca por substratos alternativos, que possam substituir produtos comerciais na produção de mudas de tomate, é de fundamental importância para a redução dos custos nessa fase inicial da cultura. Objetivou-se, com esta pesquisa, avaliar a qualidade de mudas de tomate industrial IPA 6, produzidas com substratos à base de esterco ovino. O experimento foi conduzido em viveiro da Universidade Federal Rural de Pernambuco, Unidade Acadêmica de Serra Talhada, de 16 de fevereiro a 30 de março de 2012. Utilizou-se o delineamento inteiramente casualizado, com quatro repetições. Os tratamentos avaliados foram: T1 - [substrato comercial]; T2 - [esterco ovino + areia (1:1)]; T3 - [esterco ovino + areia (2:1)]; T4 - [esterco ovino + areia (3:1)]; T5 - [esterco ovino + solo (1:1)]; T6 - [esterco ovino + solo (2:1)]; T7 - [esterco ovino + solo (3:1)]; T8 - [esterco ovino + areia + solo (1:1:1)];T9 - [esterco ovino + areia + solo (2:1:1)]; T10 - [esterco ovino + areia + solo (3:1:1)]. Os indicadores de emergência avaliados foram: percentagem, índice de velocidade e tempo médio de emergência. Analisaram-se as seguintes características de desenvolvimento: número de folhas, altura de plântula, diâmetro de caule, comprimento de raízes, massa da matéria seca da parte aérea e das raízes. O substrato comercial proporcionou melhor vigor de mudas de tomate IPA 6. Por outro lado, o uso do esterco ovino mais solo (2:1), para compor substratos alternativos constituiu-se opção viável para a produção de mudas desse cultivar. The search for alternative substrat that can replace commercial products in the tomato seedlings production is very important to reduce costs at the first stage of such culture. The present study aimed to evaluate the quality of industrial tomato IPA 6 seedlings produced with alternative substrate of sheep manure. The experiment was carried ou at a plant nursery at the Universidade Federal Rural de Pernambuco, in Serra Talhada, Pernambuco State, Brazil, from February 16 to March 30, 2012. The experimental design was a completely randomized design with four replications. The treatments were: T1 - commercial substrate; T2 - sheep manure + sand (1:1); T3 - sheep manure + sand (2:1); T4 - sheep manure + sand (3:1); T5 - sheep manure + soil (1:1); T6 - sheep manure + soil (2:1); T7 - sheep manure + soil (3:1); T8 - sheep manure + sand + soil (1:1:1); T9 - sheep manure + sand + soil (2:1:1); T10 - sheep manure + sand + soil (3:1:1). The emergence indicators were: percentage, speed index and average time of emergence. Regarding the development characteristics of seedlings were analyzed: leaf number, stem diameter, seedling height, root length, shoot dry matter and root dry matter. The commercial substrate provided better vigor of tomato IPA 6 seedlings. Moreover, the use of soil and sheep manure (2:1) to compose alternative substrates consisted of a viable option for seedlings production of this cultivar.

Potassium (K) participates in critical processes in sunflower cultivation, such as osmotic regulation and translocation of photosynthesis. However, the absorption or accumulation of this nutrient occurs differently owing to edaphoclimatic factors or between cultivars. The objective of this study was to evaluate the nutritional efficiency of sunflower cultivars as a function of different dosage K dosages in a semiarid region. To this end, two experiments were conducted in 2016 and 2017. The treatments consisted of five dosages of K at 0, 30, 60, 90, and 120 kg ha-1 K2O and four sunflower cultivars, Aguará 6, Altis 99, Multissol, and BRS 122. The experimental design was a randomized block with four replications and subdivided plots. The characteristics evaluated were agronomic efficiency, physiological efficiency, recovery efficiency, utilization efficiency, and accumulation of total K in the plant. Sunflower cultivars responded to K dosages in the two crops, with variations in efficiency parameters. Crop 2 showed better nutritional efficiency compared to crop 1. Aguará 6 showed greater nutritional efficiency than the other two crops. The use of dosages between 75 and 91 kg ha-1 of K2O provided better efficiency in K usage for the cultivars.

The objective of the present work was to evaluate the influence of the genotype - environment interaction on genetically divergent soybean grown under semiarid conditions. Four experiments were carried out in randomized blocks with four replicates to evaluate twenty-one soybean genotypes. Made available in DSpace on 2022-07-28T10:19:38Z (GMT). No. of bitstreams: 1 InfluenceGenotypeEnvironment-InteractionSoybean.pdf: 928129 bytes, checksum: ec8d539f70cb9ca47e36dda6aeb88e6a (MD5) Previous issue date: 2022