Resumo -A aplicação do medidor indireto de clorofila SPAD-502 tem sido estudada para diversas culturas e com resultados satisfatórios, para predição do estado nutricional de nitrogênio. O objetivo deste trabalho foi avaliar o emprego do SPAD-502 na avaliação dos teores foliares de clorofila, N, S, Fe e Mn, em algodão herbáceo, cultivado em casa de vegetação. Foram instalados quatro experimentos, e foram estudadas doses de N (1,5, 7,5, 15 e 22,5 mM L -1 ), S (0,2, 1, 2 e 3 mM L -1 ), Fe (10, 50, 100 e 150 µmol L -1 ) e Mn (10, 50, 100 e 150 µmol L -1 ), equivalentes em todos os casos a 0,1, 0,5, 1,0 e 1,5 vez a concentração normal da solução Hoagland & Arnon, respectivamente. A clorofila a se relaciona mais fortemente com as leituras SPAD do que as clorofilas b. As leituras SPAD correlacionaram-se, positivamente, com os teores foliares de N e negativamente com os de S. Os teores foliares de Fe e Mn não apresentaram correlação com as leituras SPAD.Termos para indexação: clorofilômetro, medida indireta de clorofila, solução nutritiva. Use of SPAD-502 in the evaluation of chlorophyll contents and nutritional status of herbaceous cotton to nitrogen, sulphur, iron and manganeseAbstract -The application of indirect meter of chlorophyll SPAD-502 has been studied for several cultures and with satisfactory results in evaluation of the nutritional state of nitrogen. This work aimed at evaluating the employment of SPAD-502 in the leaf content analysis of chlorophyll, N, S, Fe and Mn in herbaceous cotton under greenhouse conditions. Four experiments were installed to study doses of N (1.5, 7.5, 15 and 22.5 mM L -1 ), S (0.2, 1, 2 and 3 mM L -1 ), Fe (10, 50, 100 and 150 µmol L -1 ) and Mn (10, 50, 100 and 150 µmol L -1 ), equivalent in all cases to 0.1, 0.5, 1.0 and 1.5 times the normal concentration of the solution Hoagland & Arnon, respectively. The SPAD index had a better correlation with chlorophyll a than with clorophyll b. The SPAD indexes were positively correlated to N leaf content and negatively correlated to S. Leaf contents of Fe and Mn did not correlate to SPAD index.Index terms: chlorophyll meter, chlorophyll indirect measure, nutrient solution.A cultura do algodoeiro herbáceo (Gossypium hirsutum L. r. latifolium Hutch) é responsável por empregar, no campo, aproximadamente 150 mil pessoas, e ocupar 1,71% das propriedades agrícolas do país. No Brasil, a área plantada com algodão vem diminuindo desde 1985, passando de 2,25 milhões de hectares para 0,81 milhão em 2001. Contudo, a produção aumentou em 99,41% nesse mesmo período, e tal efeito foi o reflexo do maior nível de tecnologia utilizado na produção dessa cultura, com o maior uso de adubos e corretivos de acidez dos solos (Embrapa, 2001). Na avaliação do estado nutricional das plantas, diversos métodos podem ser empregados, entretanto, há de se considerar a rapidez e segurança dos mesmos. O uso de medidas indiretas, para determinar a necessidade de um determinado elemento, como o teor de clorofila na avaliação do estado nutricional de N das plantas, tem sido m...

Pineapple is one of the most important fruits, with large production in tropical and subtropical regions and great appreciation by consumers all over the world. The pineapple plant has many specific morphological, anatomical and physiological characteristics that determine crucial aspects of pineapple crop management, such as flower induction, water use and vegetative methods of propagation. The use of sexual reproduction of pineapple is restricted to breeding purposes carried out by research institutes looking for new hybrids with improved agronomic characteristics. Seeds are only produced if cross pollination among varieties occurs. Commercially pineapple has to be propagated by vegetative material, an asexual reproduction, without new combinations of genes. Some types of propagules are naturally produced by the plants and called conventional planting material. Its availability and quality depend on many factors, especially cultivar and environment. Management techniques of this material have been continuously developed and will be addressed. In addition to the conventional planting material, which in many situations is not sufficient to assure expansion or at least maintenance of the cultivated area, several other methods of vegetative propagation of pineapple have been studied and made available along the last decades and will also be discussed, involving techniques of stem sectioning, apical growing point gouging and chemical treatment for transformation of flowers into plantlets. Stem sectioning has been especially interesting, as it is mostly done using plant residues available at low cost, and is a rather simple method suited for multiplication and production of disease-free planting material in nurseries. Gouging and chemical treatment are less practiced, but can be applied in ratoon crops, thereby avoiding the loss of the first cycle fruit. Chemical treatment usually results in rather small plantlets, that must be further grown in nurseries before planting them in the field. And finally micropropagation will also be focused, as in vitro production of plantlets is a very important method of multiplication of new pineapple varieties, but this method yet has not been transformed into a common commercial way of pineapple propagation due to the final high cost and to the still high risks of incidence of somaclonal variations among the plantlets produced.

No abstract

RESUMOO algodoeiro (Gossipium hirsuntum L.) é muito sensível à toxidez de alumínio, sendo exigente em correção de solo. O manejo da calagem em plantios direto e semi-direto, na presença de palha na superfície, tem sido pouco estudado para essa cultura. Nesta pesquisa, avaliaram-se o estado nutricional e a matéria seca do algodoeiro em função da calagem em latossolo sob diferentes coberturas vegetais (mata, eucalipto, pinus e pastagem). O experimento foi conduzido em casa de vegetação, durante 45 dias e os tratamentos estudados consistiram da combinação de quatro métodos de manejo da calagem (testemunha, sem calagem, SC; carbonato de cálcio aplicado em superfície, CS; carbonato de cálcio incorporado na camada de 0-10 cm, C10; e carbonato de cálcio incorporado na camada de 0-20 cm, C20) com as coberturas vegetais do latossolo estudado. Foram avaliados os teores de N, P, K, Ca, Mg, S, B, Cu, Fe, Mn e Zn na parte aérea e a matéria seca da parte aérea e de raiz. A correção da acidez do solo em superfície ou a incorporação do calcário a 10 cm de profundidade causaram uma supercalagem na camada de solo de 0-5 cm. A calagem propiciou maior acúmulo da maioria dos nutrientes analisados, aumentou a produção de matéria seca de raízes e da parte aérea do algodoeiro em todos os sistemas de cobertura vegetal dos solos avaliados. As maiores produções de matéria seca foram observadas nas áreas onde o corretivo de acidez foi incorporado ao solo. Em áreas já cultivadas (pastagem), a aplicação do corretivo em superfície do solo propicia produção de biomassa similar à obtida com a correção da camada arável.Termos para indexação: acidez do solo, extração de nutrientes, calagem superficial, Gossipium hirsuntum L. ABSTRACTCotton tree (Gossipium hirsuntum L.) is very susceptible to aluminum toxicity, demanding the soil acidity correction. The management of liming in no tillage and minimum tillage systems, with the presence of straw in the soil surface, is little studied for this crop. The nutritional status and the cotton dry matter production were evaluated in function of liming methods in a latosol (Oxisol) under different previous vegetable covers (forest, eucalyptus, pine and pasture). The experiment was carried out in greenhouse conditions during 45 days, and the treatments evaluated consisted of the combination of four liming methods (wihout lime -WL; surface liming -SL; liming at 0-10 cm soil depth -L10; liming at 0-20 cm soil depth -L20) with four latosol vegetable covers. The contents of N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, Zn were evaluated in the cotton plants and root and aerial part dry matter of this crop. Surface liming and the incorporation of liming at 0-10 cm soil layer caused an overliming in the 0-5 cm soil depth. The use of liming increased the extraction of most of nutrients analyzed and the production of cotton root and aerial part dry matter. The highest dry matter production was observed when lime was incorporated to the soil. The biggest productions of dry matter were observed in the areas where the lime was inco...

The objective of this work was to evaluate two irrigation systems, by drip and diffuser microjets, two types of fertigation, by spraying at the base of the plant and in the soil, and two types of root enhancers in the development and production of the pineapple ‘BRS Imperial’. The drip system promoted greater root development than the diffuser microjet system. Much of the root system was concentrated in the stalk and soil up to 0.1 m depth, where the drip system promoted a higher relative percentage of root growth in the stalk compared to the microjet. The root enhancers promoted greater root growth in the stalk than in the soil. The use of the root enhancers based on humic and fulvic acids was not significant, while the use of the root enhancers based on phosphoric acid and amines was significant for root growth only in the microjet system. Application of fertilizers by spraying at the base of the plant promoted root growth and increased yield compared to the use of fertigation. The drip system showed higher efficiency of crop and irrigation water productivity for ‘BRS Imperial’ pineapple.