503 research outputs found
Combined effects of potassium and wastewater application on the yield and quality of Bermuda grass (Cynodon dactylon) in the Mediterranean regions
The reuse of treated wastewater is considered as an alternative disposable to potable water in the mediterranean agriculture and landscape, namely in golf courses. Bermuda grass (Cynodon dactylon, Peers) is used very often on the fairways, roughs and tees of golf courses of the Mediterranean Basin due to its tolerance to drought, salinity, high temperatures and damages. The objective of this work is to study the response of this cultivar to the combined effects of municipal wastewater and two levels of potassium fertilization, during Spring and Summer. The experimental design known as sprinkle point source was used to simulate the various levels of wastewater application, expressed by the crop coefficient kc. This procedure is characterized by the assumption that a point creates a linear irrigation gradient from the water point source, producing a gradual change in water application, and a high degree of irrigation uniformity must be obtained in parallel isohyets. Chemical analysis of wastewater irrigation water was monitored through all the experimental period (from April to September). Climatic data was also recorded. Yield (aboveground biomass) and the good visual appearance (GVA) of the lawn were assessed in two sampling dates, May and July. Municipal wastewater can be used to irrigate Bermuda grass, without an apparent decrease on grass quality. As concluding remarks, it may be seen that the irrigation water amount is the most pronounced limiting production factor of bermuda grass (Cynodon dactilon, Peers), when compared with potassium fertilization, but it is possible that there is a positive interaction between water and irrigation. This response is modulated by evaporative air conditions since lower yields were obtained in summer. On the other hand, if the potassium fertilization is increased, two situations may occur: 1) with high amounts of water application, leaching problems may occur, mainly on sandy soils, and production may decrease; 2) if potassium fertilization increases, and irrigation water decreases, yield decreases due to the increase of salinity (potassium fertilizers are salts), mainly on salt affected soils
A semente do algodoeiro I. Uso in natura na alimentação animal.
bitstream/CNPA-2009-09/14471/1/COMTEC120.pd
Calibracao de pulverizadores terrestres e algumas informacoes sobre equipamentos para aplicacoes de defensivos no algodoeiro.
Cuidados, manutencao e principais componentes dos pulverizadores; Pulverizadores especiais, modernos, munidos de bicos centrifugos.bitstream/item/33304/1/CNPA-DOCUMENTOS-13-CALIBRACAO-DE-PULVERIZADORES-TERRESTRES-E-ALGUMAS-INFORMACOES-SOBRE-EQUIPAMENT.pdf2.ed
Consórcio algodão herbáceo + gergelim: fatores, época relativa de plantio e configurações, efeitos no gergelim.
bitstream/item/61259/1/BOLETIM49.pd
Avaliação do comportamento agronómico de porta-enxertos tolerantes à tristeza dos citrinos
A detecção no nosso paÃs de alguns núcleos de plantas infectadas com o citrus tristeza virus (CTV), impôs a necessidade de desenvolver um plano de prevenção, nomeadamente através do incentivo da substituição progressiva dos porta-enxertos susceptÃveis por porta-enxertos tolerantes. Com a identificação do seu principal vector (Toxoptera citricidus Kirk.) em finais 2003, nas regiões de Entre-Douro e Minho e de
Trás-os-Montes é de prever que a dispersão da doença ocorra mais rapidamente.
As novas plantações utilizam na sua maioria as citranjeiras Troyer e Carrizo, que nem sempre se mostram adequadas às condições edafo-climáticas existentes.
Considerando esta problemática, a Direcção Regional de Agricultura do Algarve, em colaboração com outras entidades (Universidade do Algarve e Centro de Citricultura), tem vindo a desenvolver estudos conducentes à adaptação de novos porta-enxertos, com o objectivo de diversificar as opções existentes relativamente aos condicionalismos da região.
Com este objectivo foi instalado em Tavira, em Maio de 1998, num solo calcário, um ensaio de campo para avaliação do comportamento de 11 clones de porta-enxertos (T. Sunki x P. trifoliata FAO 30590; Citranjeira Troyer B2 FAO 31655; T. Cleopatra x P. trifoliata FAO 30584; T. Cleopatra x C. Carrizo FAO 30575; Laranjeira
Gou Tou B7; Citrandarineira 31443; Laranjeira azeda B6C-T1; Tangerineira Changsa; Tangerineira Sunki; Tangerineira Cleópatra; Citranjeira Troyer 4 AS).
Durante três anos, as plantas foram submetidas a três nÃveis de salinidade da água de rega, expressos pela condutividade eléctrica da água de rega ECw – 1; 3 e 6 dS.m-1, obtidos através de um esquema experimental fonte dupla gota-a-gota. Foram medidos vários parâmetros agro-ambientais, como o desenvolvimento vegetativo das plantas e o aumento da condutividade eléctrica do extracto de saturação do solo (medido no extracto aquoso). Os resultados obtidos mostram que os porta-enxertos com maior tolerância à salinidade foram o clone de laranjeira azeda B6C-T1 e a laranjeira Gou Tou.info:eu-repo/semantics/publishedVersio
Quando suspender o tratamento com inseticidas na cultura algodoeira.
bitstream/CNPA/14460/1/DOC66.pd
Comportamento da cultivar 7MH no Estado do EspÃrito Santo, safra 2000/2001.
bitstream/CNPA/15773/1/COMTEC145.pd
Potencialidades da produção de algodão pela agricultura familiar do Nordeste.
bitstream/CNPA-2009-09/22431/1/DOC202.pd
Contaminação de algodão em caroço, e em especial de sementes de algodão por fungos produtores de aflatoxina e como evitá-la.
Origem dos contaminantes (aflatoxinas e outros) na sementes e no caroço do algodão no campo e no armazenamento; Recomendações para se evitar ou controlar a contaminação e a detectação da aflatoxina; Conclusões;Referencias bibliográficas.bitstream/CNPA-2009-09/14608/1/CIRTEC38.pd
Challenges of nematode control in ruminants : focus on Latin America
AbstractGastrointestinal nematodes (GIN) of ruminants (cattle, sheep and goats) are ubiquitous and can cause severe injuries to infected animals and significant losses in farming revenues. GIN are able to survive severe environmental and host conditions, but mankind has developed a number of ingenious methods for parasite control. The commerce and use of modern anthelmintic drugs with a broad spectrum of activity has been a solid tool for nearly 40 years, however the continuous use of these drugs, has led to the selection of populations of drug-resistant worms worldwide. At present, the ever-growing agricultural systems in Latin America are facing many challenges and cannot rely on the far-reaching objective of parasitic elimination from the host or the environment. The lack of extensive programs for monitoring drug resistance exacerbates the negative consequences of reduced efficacy, which is evident in some areas with the increase in mortality rate even after treatment. Experts agree that new schemes of parasitic control are needed and should be based on the strategy of targeted selective treatment where affected hosts are identified and treated accordingly. In this article, we will focus our discussion on the challenges for the control of GIN in Latin America by 2020 imposed by reduced drug efficacy. We will evaluate phenotypic and molecular markers, methods for single-animal evaluation, and the implementation of schemes for anthelmintic treatment that address parasites in refugia
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