RESUMO
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.
Assuntos
Produção Agrícola , Daucus carota , Biomassa , Calotropis , FertilizantesRESUMO
Vegetation properties can be estimated using optical sensors, acquiring data on board of different platforms. For instance, ground-based and Unmanned Aerial Vehicle (UAV)-borne spectrometers can measure reflectance in narrow spectral bands, while different modelling approaches, like regressions fitted to vegetation indices, can relate spectra with crop traits. Although monitoring frameworks using multiple sensors can be more flexible, they may result in higher inaccuracy due to differences related to the sensors characteristics, which can affect information sampling. Also organic production systems can benefit from continuous monitoring focusing on crop management and stress detection, but few studies have evaluated applications with this objective. In this study, ground-based and UAV spectrometers were compared in the context of organic potato cultivation. Relatively accurate estimates were obtained for leaf chlorophyll (RMSE = 6.07 µg·cm-2), leaf area index (RMSE = 0.67 m²·m-2), canopy chlorophyll (RMSE = 0.24 g·m-2) and ground cover (RMSE = 5.5%) using five UAV-based data acquisitions, from 43 to 99 days after planting. These retrievals are slightly better than those derived from ground-based measurements (RMSE = 7.25 µg·cm-2, 0.85 m²·m-2, 0.28 g·m-2 and 6.8%, respectively), for the same period. Excluding observations corresponding to the first acquisition increased retrieval accuracy and made outputs more comparable between sensors, due to relatively low vegetation cover on this date. Intercomparison of vegetation indices indicated that indices based on the contrast between spectral bands in the visible and near-infrared, like OSAVI, MCARI2 and CIg provided, at certain extent, robust outputs that could be transferred between sensors. Information sampling at plot level by both sensing solutions resulted in comparable discriminative potential concerning advanced stages of late blight incidence. These results indicate that optical sensors, and their integration, have great potential for monitoring this specific organic cropping system.
Assuntos
Solanum tuberosum , Clorofila , Folhas de PlantaRESUMO
The selectivity of different insecticides, fungicides and fertilizers used in organic soybean cropping was evaluated according to the protocols proposed by the Pesticides and Beneficial Organisms Working Group of the International Organization for Biological Control (IOBC) concerning adults and pupae of the egg parasitoid Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) under laboratory conditions. Treatments 1) baculovirus anticarsia 140 x 109 cpi; 2) Bacillus thuringiensis 16.8 g; 3) azadirachtin-A, azadirachtin-B, nimbina and salamina 9.6 ppm; 4) rotenoids 4% 4 L; 5) nitrogen 1.3%, phosphorus 3.0% and total organic carbon 8.0% 3 L; 6) sodium silicate 2% 4 L; 7) copper 7% + calcium 3.3% 1.8 L; 8) sulfur 20% + quicklime 10% 1.8 L were in general safe (class 1) to both adults and pupae of T. pretiosum . Differently, chlorpyrifos (control treatment) was harmful to this parasitoid. Therefore, the utilization of the tested natural derived products in the production of organic soybean is viable, without impairing the natural biological control allowed by T. pretiosum . Furthermore, both management techniques can indeed be used together in organic cropping aiming at reaching increasing or complementary control of target pests. Chlorpyrifos use, on the other hand, whenever possible, should be replaced by other products more compatible with biological control preservation.(AU)
A seletividade de diferentes inseticidas, fungicidas e fertilizantes usados no cultivo de soja orgânica foi avaliada de acordo com os protocolos propostos pela Pesticide and Beneficial Organisms Working Group of the International Organization for Biological Control (IOBC) sobre pupas e adultos de Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) em condições de laboratório. Os tratamentos 1) baculovírus anticarsia 140 x 109 cpi; 2) Bacillus thuringiensis 16,8 g; 3) azadirachtin-A, azadirachtin-B, nimbina e salamina 9,6 ppm; 4) rotenoides 4% 4 L; 5) nitrogênio 1,3%, fósforo 3,0% e carbono orgânico total 8,0% 3 L; 6) silicato de sódio 2% 4 L; 7) cobre 7% + cálcio 3,3% 1,8 L; 8) enxofre 20% + cal virgem 10% 1,8 L foram, no geral, inócuos (classe 1) para pupas e adultos de T. pretiosum . Diferentemente, clorpirifós (tratamento controle) foi nocivo para esse parasitoide. A utilização dos produtos de origem natural avaliados é viável na sojicultura orgânica sem impactar o controle biológico promovido por T. pretiosum . Ambas as táticas de manejo podem ser utilizadas conjuntamente na agricultura orgânica objetivando aumentar ou complementar o controle da praga-alvo. O uso do clorpirifós, por outro lado, sempre que possível, deve ser substituído por outros produtos mais compatíveis com a preservação do controle biológico.(AU)
