Efficiency in the use of phosphorus by cowpea genotypes

Cowpea (Vigna unguiculata (L.) Walp.) is an edible legume with good ability to fix nitrogen and not demanding soil fertility. However, some genotypes may have a greater ability to utilize the nutrients available in the soil for their growth. Thus, the objective of this work was to evaluate the efficiency of phosphorus (P) use in genotypes of cowpea. The experiment was conducted in the field and the experimental design was a randomized complete block design with four replicates arranged in a 2 x 5 factorial scheme. The treatments consisted of two P doses (0 and 60 kg ha-1 of P2O5) and five bean genotypes (Paulistinha, BRS Xiquexique, Pingo de Ouro, Corujinha, and Costela de Vaca). Each plot was formed by four plant rows, measuring 3.0 m in length, spaced 1.0 x 0.3 m, and with two plants per hole. The genotypes responded significantly to the increase in P levels in the soil, with increases in the number of seeds per pod, number of pods per plant, productivity, dry mass, and plant P accumulation. "BRS Xiquexique" was efficient and responsive, and it could be indicated as the most appropriate for cultivation in the region. "Corujinha" is the most suitable cultivar for production in high levels of P among the creole genotypes evaluated. "Costela de Vaca" and "Paulistinha" can be indicated for low P production in the soil. low P production

Effects of planting dates on growth and nutrient accumulation of carrots in the brazilian semi-arid

Fertilization plays an important role on carrot’s yield, root quality, storage, plant growth and on the environment. It was aimed to evaluate the plant growth and macronutrients accumulation of carrot cultivars as a function of two planting dates, under high temperatures in the Brazilian semi-arid. The experiments were carried out in randomized blocks design, with ten treatments and four repetitions. Treatments consisted of ten carrot cultivars sowed in two Planting dates. The characteristics that were evaluated were: plant growth (plant height, number of leaves, plant dry matter accumulation, mean fresh mass of the root) and macronutrient accumulation (N, P, K, Ca and Mg) in plant, leaves and root. Plant’s mean height ranged from 42.53 cm (Melinda) to 49.25 cm (Nativa); the highest plant dry matter was obtained by BRS Planalto (12.36 g) and Kuronan (12.18 g); the mean number of leaves was the lowest in Melinda and Nativa: 8.64 and 7.64 leaves plant-1. The root’s fresh weight had a significant decrease among the planting dates for the Brasília, Francine and Suprema cultivars. The nutrient accumulation varied accordingly to the planting date and cultivar

Eficiência do oxyfluorfen no controle de plantas daninhas na cultura da cebola transplantada irrigada por gotejamento.

Objetivou-se com este trabalho avaliar a seletividade e a eficiência do herbicida oxyfluorfen em aplicação sequencial na cultura da cebola transplantada irrigada por gotejamento. O experimento foi conduzido em Mossoró-RN, na horta didática da Universidade Federal Rural do Semi-Árido(UFERSA). O delineamento experimental foi o de blocos casualizados em esquema de parcelas subdivididas. Nas parcelas foram avaliados os seguintes tratamentos: 120 g ha-1 de oxyflorfen aplicado aos 7 dias após o transplantio (DAT); 60 + 60 g ha-1 de oxyflorfen aplicado aos 7 e 21 DAT; 120 + 120 g ha-1 de oxyflorfen aplicado aos 7 e 21 DAT; 240 g ha-1 de oxyflorfen aplicado aos 7 DAT e uma testemunha sem herbicida. Nas subparcelas foram avaliados dois tratamentos: um mantido no limpo todo o ciclo da cultura com capinas, e outro sem capinas, com o intuito de determinar a seletividade e a eficácia do herbicida, respectivamente. O oxyfluorfen foi seletivo para a cultura da cebola em todas as doses utilizadas independentemente da forma sequencial de aplicação, com controle satisfatório das espécies Amaranthus spinosus, Trianthema portulacastrum e Commelina benghalensis até 28 DAT, e insatisfatório de Digitaria bicornis. Posteriormente, houve reinfestação em todas as doses avaliadas, mesmo nas aplicações sequenciais, o que resultou em queda na produtividade de até 100% de bulbos comerciais nos tratamentos sem capinas

Nutrient uptake in sesame cultivars under cultivation in semiarid conditions

Sesame is considered the oldest oleaginous seed in use by mankind. It is a culture of high morphophysiological complexity with great variability in growth habit. The accumulation of nutrients in the sesame crop is, in relative terms, proportional to its average productivity. It is a crop that requires the availability of sufficient amounts of nitrogen, phosphorus and potassium to obtain a desired yield. Thus, the aim of this study was to assess the uptake of nutrients for sesame cultivars in two growing seasons conditions semiarid. The experiments were performed in Horta Didatics of Universidade Federal Rural do Semi-Ãrido, in Brazil, from November 2014 to February 2015 (Growing Season I); and from April to July 2015 (Growing Season II). The experimental design was a randomized complete block design with four replications. Treatments were arranged in a split plot where cultivars (CNPA G2, CNPA G3, and CNPA G4) were placed on the following plots with harvesting dates 21, 35, 49, 63, 77, 91, and 105 days after sowing (DAS) of subplots. The vegetative part of the sesame crop had greater uptake of potassium in Growing Season I (the period from November 2014 to February 2015) and of nitrogen in Growing Season II (the period from April to July 2015) for all the cultivars, whereas in the fruits the greatest uptake was that of nitrogen, independent of growing season. As for the total uptake of nutrients at the end of the cycle, it followed the descending order N > K > P in both growing seasons. The period of greatest demand for nutrients occurred between 77 and 105 DAS. In relation to the cultivars, the CNPA G3 obtained larger uptakes in Growing Season I (the period from November 2014 to February 2015), while the CNPA G4 did so in Growing Season II (the period from November 2014 to February 2015)

Crescimento de pimentão em diferentes arranjos espaciais

The objective of this work was to evaluate the growth of green pepper cv. Atlantis under different spatial arrangements. Three spacing arrangements between double and simple planting rows (1.5x0.5 m, 1.6x0.4 m and 1.7x0.3 m) and four spacing distances between plants in the rows (0.2, 0.3, 0.4 and 0.5 m) combined in factorial scheme were evaluated. A randomized block design in split-plots divided in time with three replicates was used. The growth assessment was done in nine occasions, 14 days apart, and the first one was performed 14 days after transplanting (DAT). Leaf area (LA), leaf area index (LAI), dry masses of leaves (LDM), stem (SDM), fruit (FrDM) and total shoot (TDM); absolute growth rate (AGR), rates of net assimilation (NAR) and relative growth (RGR); and leaf area (LAR) and leaf mass (LWR) ratios were evaluated until 126 DAT. The changes in LA, RGR, LWR and LAR did not depend on row spacing, but spacing influenced LDM, SDM, FrDM and TDM, LAI and AGR. The increase in spacing reduces LAI and LAR, and increases LA, LDM, SDM, FrDM, TDM, AGR and NAR, but does not influence RGR and LWR.O objetivo deste trabalho foi avaliar o crescimento do pimentão cv. Atlantis sob diferentes arranjos espaciais. Foram avaliados três arranjos de espaçamentos entre fileiras duplas e fileiras simples de plantio (1,5x0,5, 1,6x0,4 e 1,7x0,3 m), e quatro espaçamentos entre plantas nas fileiras (0,2, 0,3, 0,4 e 0,5 m), combinados em esquema fatorial. Utilizou-se o delineamento de blocos ao acaso, com três repetições e parcelas subdivididas no tempo. A avaliação de crescimento foi realizada em nove épocas espaçadas em 14 dias, com a primeira avaliação realizada 14 dias após o transplantio (DAT). Até os 126 DAT, foram avaliados: área foliar (AF); índice de área foliar (IAF); massas secas de folhas (MSF), do caule (MSC), de frutos (MSFr) e do total da parte aérea (MST); taxa de crescimento absoluto (TCA), assimilatória líquida (TAL) e de crescimento relativo (TCR); e as razões de área foliar (RAF) e de massa foliar (RMF). As alterações em AF, TCR, RMF e RAF foram independentes do espaçamento entre fileiras que, no entanto, influenciou MSF, MSC, MSFr e MST, IAF e TCA. O aumento do espaçamento entre plantas reduz o IAF e a RAF e aumenta a AF, MSF, MSC, MSFr, MST, TCA e TAL, mas não influencia a TCR e RMF