Nelson Paulieri Sabino

Maturidade da fibra de algodão determinada pelo fibrógrafo modelo 430

O metodo de determinar a maturidade da fibra de algodao pelo fibrografo digital Mod. 230-A foi transposto para o novo modelo 430, que apresenta algumas inovacoes tecnicas e opera com um pente unico. A equacao respectiva foi obtida atraves do estudo comparativo das funcoes L = f(p), L2/P = f(L) e M% = f(IM) obtidas para os dois aparelhos, e das relacoes n = p0/p e k = (IM230_A)/IM430, sendo L a leitura inicial em volts, p0 o peso da fibra de dois pentes do Mod. 230-A, p o peso da fibra do pente do Mod. 430, IM o indice de maturidade e M% a maturidade em porcentagem de fibras maduras. A expressao final obtida foi: log M% = 2,4123 - 1,37016.IM430 onde: IM430 = L2/P _ 0,04857.L + 0,3616 Comparando-se os resultados obtidos na analise de ensaios regionais de variedades, pelo emprego dos dois modelos, 230-A e 430, inclusive a equacao de Worley Jr. (in 7) desenvolvida para o segundo modelo, concluiu-se que, entre os tres metodos testados, a expressao apresentada permitiu maior sensibilidade para diferenciar variedades quanto a maturidade.

Efeitos da densidade de plantio e da aplicação de CCC, em algodoeiro

Excessive growth of the cotton plants Gossypium hirsutum L. in some regions causes laying and deficient luminosity, and a consequent lowering in yield and type of cotton. Such problems are specially serious in the case of mechanical picking where between-row spacing is fixed at about 40 inches. Combined effects of the use of growth limitant chemical CCC (Chlorocholine Chloride) and population density were studied in 1972/73 and 1975/76 in four localities of the State of Sao Paulo. Near Campinas and Sumare, the effects of 4, 8 and 16 plants/meter (respectively 40,000, 80,000 and 160,000 plants/ha) with and without CCC were studied. At Tiete and Piracicaba, 4, 8, 16 and 32 plants/meter were used (respectively 40,000, 80,000, 160,000 and 320,000 plants/ha). Only the treatments of 16 and 32 plants/meter were combined with CCC application. The concentration of CCC used was of 50 g a.i../ha applied from 50 to 70 days after emergence of the plants. The results showed that CCC limited the growth of plants, increased earliness of yield, decreased lint percentage and increased fiber length, boll and seed weight. There was no effect observed on cotton yield, fiber length uniformity, Micronaire, Pressely and fiber maturity. Higher density resulted in higher yield. High density also caused better length of fiber and lower boll weight.

Modo e época de aplicação de fosfatos na produção e outras características do algodoeiro

The traditional mode of phosphate application to cotton was compared with broadcasting application in a long term trial conducted on a DusKy Red Latosol, with a low level of phosphorus. Triple superphosphate was applied annualy (121 kg/ha of P2O5)in furrows at sowing, during six years, or broadcasted and incorporated, through one application (728kg/ha of P2O5) in the first year, or two applications in the first and fourth years (364kg/ha, at each time). A thermal phosphate (18% P2O5) was also tested in two broadcasting applications. All treatments were compared to a control, with constant doses of N and K, but without P. During the six years of phosphate fertilization, higher yields of IAC 18 cotton variety were obtained, with annual application at sowing time, except for the first year due to the low initial disponibility of P. High quantities of broadcasted phosphate led to visual potassium deficiency symptoms, with losses in yield, Micronaire index and maturity of fibers. Therefore, due to the good yield performance obtained with a moderate dose of phosphate, in the years of application, it was suggested that a combination between broadcast and localized application should be studied, in future experiments. Other characteristics of cotton such as boll and seed weight plus fiber length, also increased significantly with P fertilization. The residual effect of the traditional mode of phosphate application, studied during the last three years, with IAC 20 cotton variety, showed significant results only for yield.

Efeito de doses de boro aplicadas no sulco de plantio do algodoeiro, em solo deficiente

The effect of boron application on cotton at planting time was studied in a deficient red-yellow latosol sandy phase soil, located at Leme, State of Sa Paulo, Brazil. Field experiments were conducted during three years namely 1976/77, 1977/78 and l978/79. In the first year, boron was applied at the levels of 0, 0.5, 1.0, 1.5 and 2.0kg/ha of B, as borax (11% of B). In the subsequent years, levels of 0.75 and 1.25kg/ha of B were introduced in the experimental area. A latin square design was used in all the trials. A positive effect on cotton yield resulted from boron fertilization. The response to boron was greater at a higher level of plant productivity. With regards to economical aspects, the optimum rate of boron was 1.23kg/ha of B. The influence of micronutrient on earliness and weight of bolls was statistically significant and of a quadratic form, also. Otherwise, boron decreased fiber maturity. Plants of check plots showed severe boron deficiency symptoms such as abnormalities of flowers, dark rings and pith necrosis in leaf petioles and in stems, and plant with longer vegetative cycle, excessively branched, with enlarged, dark and ruptured nodes.

Estudo de amostragens de capulhos em canteiros experimentais de algodão

Ensaios de campo foram conduzidos por dois anos, com a finalidade de verificar se a amostragem comumente feita (usual) em canteiros experimentais de algodao, retirando-se a amostra do terco medio, e representativa de toda a planta. No presente estudo esta avaliacao foi feita analisando as caracteristicas de comprimento da fibra, indice de finura (Micronaire), uniformidade de comprimento, indice de resistencia (Pressley), porcentagem de fibras e peso de um capulho, sendo os dados obtidos para a amostra usual correlacionados com os dados de amostras marcadas, constituidas por capulhos de mesma idade, provenientes de flores abertas no mesmo dia e, portanto, sujeitas as mesmas condicoes climaticas. Tais capulhos foram colhidos de diferentes partes da planta, isto e, do baixeiro, da parte mediana e do ponteiro. Os resultados revelaram que a media das amostras marcadas apresentou boa correlacao com a amostra da parte mediana da planta, indicando ser o terco medio representativo da planta. A amostra usual apresentou melhor correlacao com a media das amostras marcadas. Observou-se tambem que a amostra usual pode, em determinadas condicoes, fornecer melhores conclusoes que a media das amostras marcadas, sendo pratica e possuindo boa precisao.

Efeitos da aplicação de N e de K sobre características gerais do algodoeiro cultivado em latossolos não deficientes em potássio

Em latossolos do Estado de Sao Paulo, nao deficientes em potassio para a cultura algodoeira, os efeitos de N e de K sobre certas caracteristicas da planta se relacionaram com os resultados da analise quimica do solo. A adubacao potassica diminuiu a precocidade da planta, em particular nos solos medianamente bem supridos em potassio. Tal indice nao foi afetado pela adubacao nitrogenada. A aplicacao de N aumentou os valores medios de peso de 100 sementes, peso de um capulho e indice de fibra, com destaque nos solos mais ricos em K. A adubacao potassica nao influenciou essas caracteristicas. O comprimento e a resistencia da fibra foram melhorados pela adubacao nitrogenada, no grupo de solos mais ricos em K. A aplicacao de K nao alterou significativamente as caracteristicas tecnologicas da fibra.

Determinação dos índices de cristalinidade de fibras celulósicas

The purpose of this work was to develop analytical techniques for structural characterization of cellulosic fibers. To establish a relationship between the two methods that determine crystallinity index, three varieties of cotton (IAC 17, IAC 19, and IAC 20) and fibers of viscose, rami and rami chemical treated were used. Two empirical methods, x-ray diffraction and infrared spectroscopy, were used to evaluate the crystallinity index. Differentiation of IAC cotton varieties was possible with the crystallinity index obtained by infrared spectroscopy; but, not with the x-ray diffraction method. The crystallinity index obtained by these two methods had no correlation with physical properties of cotton fibers. When cellulose fibers with different treatment were assayed, there was a high correlation (r = 0.95) between the two methodologies used for the determination of crystallinity index.

Effect of weed competition on cotton

The effect of weed competition on cotton (Gossypium hirsutum L.) was evaluated in the Centro Experimental de Campinas and the Estacao Experimental de Tiete during the 1970/71, 1971/72 and 1972/73 agricultural seasons. In the first season, competition periods of 10, 20, 30, 40, 60, 90 or 120 days, after emergence were studied, compared to checks always either with or without weeds. In the next seasons, competition was studied during the first 10, 20, 30 or 40 days after emergence, or after these periods, until harvest, maintained previously weed free for these different periods and afterwards competition was allowed until harvest. The experimental plots had four rows of five meters, distributed in randomized blocks with five or six replications. For evaluation of the competition effects the following parameters were considered: number, fresh and dry weights of weeds, after each competition period; fiber percentage, boll and seed weight, cotton yield, fiber length uniformity, Micronaire, Pressley and maturity, at harvest. The results showed a lower yield of cotton when the competition period was longer than 20 days after emergence. When the crop was maintained weed free for the first 30 to 40 days yield was similar to the completely weed free treatment. Competition periods of 90 days or longer determined negative effect on yield. In some cases a negative effect of weed competition was observed on fiber percentage, boll and seed weight, Micronaire, fiber uniformity and Pressley.

Influência da aplicação e do efeito cumulativo de boro nas características agronômicas e propriedades tecnologicas da fibra do algodoeiro

The influence of boron applications on the agronomic characteristics and technological properties of the cotton fiber were studied in a regional group of experiments conducted through the Sao Paulo State cotton belt, during the years of 1979 to 1986. The boron cumulative effect was studied in a long term trial of boron fertilization conducted with cotton, installed in 1983 on a low fertility Dusky Red Latosol, limed and frequently fertilized with NPK. In all experiments, rates of 0, 0.2, 0.4, 0.8, 1.6 and 3.2 kg/ha of B as borax (11% of B), were applied at sowing time, in latin square design experiments. The cultivar IAC 17 was used during four years, followed by the IAC 20. The regional experiments were grouped by previous informations about use of liming and mineral manure, associated to the occurrence of boron deficiency as toxicity symptons. In continuously fertilized soil, where the reaction to boron used to be high in terms of productivity, it was demonstrated that the fertilization with boron improved the length and the boll weight, decreased Micronaire index, and was negligible for another characteristics. The effect of boron accumulation increased the boll weight and seed weight.

Effects of planting density and growth regulator on cotton crop

The effects of population density (4, 8 and 16 plants/meter) and the use of chemical growth limitant chlorocholine chloride (CCC) were studied during four years (from 1976/77 to 1979/80), in three localities of Sao Paulo State, Brazil. The variety was IAC 18 and the inter-row spacing was 1.0 m. The CCC used was 50 g a.i./ha, applied from 60 to 70 days after the emergence of the plants. In the trials where plant height was higher than 140 cm, the yield was lower in the highest population density than in the others, and the growth limitant had positive effect in that treatment, promoting increase in the yield. When plants were shorter than 140 cm, no effects were observed in the yield to growth limitant. The CCC increased earliness of yield, number of bolls located in the plants below 35 cm, weight of 100 seeds, weight of one boll, fiber length, maturity and tenacity. It also decreased number of bolls with abnormal opening and fiber percentage, and had no effect in Micronaire index and uniformity.