Francisco S. O. Rodrigues Filho

Uso de misturas de adubos contendo ou não enxofre na adubação do cultivar IAC 16 de algodoeiro

Durante quatro anos agricolas, foi conduzido com o algodoeiro - cultivar IAC 16, ensaio de carater permanente, de competicao de misturas de adubos contendo ou nao enxofre, em Latossolo Roxo, acido, de baixa fertilidade, anteriormente ocupado com pastagem nao adubada, no municipio de Guaira (SP). A combinacao de produtos comerciais, como sulfato de amonio, salitre-do-chile, nitrato de amonio, superfosfatos simples e triplo, e cloreto de potassio, permitiu ceder as plantas N e K em doses constantes e P e S em doses variaveis. No primeiro e no ultimo ano agricola, foram aplicadas pequenas quantidades de calcario dolomitico. A produtividade das plantas no primeiro ano agricola foi muito baixa, mesmo nos niveis altos de adubacao, o que confirma o risco de insucesso que se corre cultivando o algodoeiro em inicio de correcao de solo acido. O efeito do fosforo sobre a producao das plantas praticamente inexistiu nesse ano e foi de natureza quadratica apos sucessivos acumulos de adubos. A acao do enxofre se fez sentir desde o primeiro ano, aumentando com o tempo e com a efetivacao do efeito das calagens. O superfosfato simples comportou-se como adubo misto, tendo proporcionado aumentos no teor de Ca trocavel do solo e na concentracao de Ca e S na folha do algodoeiro, apos aplicacoes sucessivas. Atraves dos anos, proporcionou produtividades sistematicamente superiores as devidas ao superfosfato triplo. As maiores producoes, entretanto, foram obtidas com a inclusao do sulfato de amonio em cobertura. Nao se observou correlacao satisfatoria entre concentracao de nutrientes na planta e niveis de produtividade, uma vez que K, S, N e P se acumularam nas folhas das plantas que nao receberam PeSna adubacao, devido provavelmente a pouca carga de capulhos formada nesse caso.

Germinação de sementes de algodoeiro deslintadas por diferentes métodos

Sementes de algodao do cultivar IAC 13-1 foram deslintadas por quatro diferentes metodos, a saber: mecanicamente, por acido sulfurico, por gas cloridrico e por flambagem. Apos selecao em mesa de gravidade, cada porcao relativa a um determinado metodo de deslintamento foi dividida em duas, sendo uma delas tratada com fungicida PCNB 75%, nas dosagens recomendadas pelos fabricantes. Apos o teste inicial de germinacao, as sementes foram armazenadas em ambiente de laboratorio e novos testes de germinacao foram feitos aos 3, 6 e 12 meses. Em todos os periodos de armazenamento as porcentagens de germinacao das sementes deslintadas por acido sulfurico e gas cloridrico foram superiores as das sementes deslintadas mecanicamente ou por flambagem que, por sua vez, foram iguais entre si ou com a flambagem ocupando posicao intermediaria. Em todos os periodos as porcentagens de germinacao das sementes tratadas com fungicida foram superiores as das sementes sem esse tratamento.

Efeitos da aplicação de nitrogênio e potássio, na qualidade da fibra do algodoeiro cultivado em latossolos roxos do estado de São Paulo

Effects of N and K applications on cotton fiber quality obtained in field tests conducted in latosolic soils of the State of Sao Paulo are related. Nitrogen fertilization increased fiber length and length uniformity, in soil with medium K content, and fiber strength in soil with high K content. The fiber characteristics were not affected by N application in soils with Potash ceficiency. Potassium fertilization increased length uniformity, Micronaire and maturity index, without changing the fiber length, in soil with low K content. The fiber characteristics were not affected by K application in soil with h:gh K content.

Avaliação de métodos químicos para predizer a disponibilidade do nitrogênio orgânico no solo

A study was conducted to evaluate selected chemical methods for assessing the availability of organic soil nitrogen in Mississippi soils using nitrogen mineralized by aerobic and anaerobic incubation under controlled conditions as standards for comparison. Sixty-two soil samples were collected from agricultural and non-agricultural sites in representative physiographic areas of Mississippi. The soils varied greatly in texture, pH, management practices, and organic matter content. The chemical methods evaluated were: organic matter (M1) ; total nitrogen (M2) ; Ca(OH)2 hydrolysis (M3); initial inorganic nitrogen (M4); exchangeable ammonium (M5), autoclaving and washing with 1 M KCl (M6); autoclaving and washing with 0.01 M CaCl2 (M7) ; autoclaving in 0.01 M CaCl2 and washing with 1 M KCl (M8); Walkley-Black nitrogen (M13) ; alkaline permanganate digestion (M14) ; and ultraviolet absorption (M15). The biological methods, used as standards for evaluation of the chemical methods, were: aerobic mineralization - 1 week (M9); aerobic mineralization - 2 weeks (M10); aerobic mineralization - 1 week plus 2 weeks (M12); and anaerobic mineralization 3 weeks (M11). Except for initial inorganic nitrogen (M4), exchangeable ammonium (M5), and ultraviolet absorption by NaHCO3, soil extracts (M15), all the chemical methods were moderately to highly correlated with each other, and, therefore, may be divided into two groups: the autoclaving methods (M6, M7, M8) and the other methods (M1, M2, M3, M13, M14). The highest correlation obtained with the chemical methods was between total nitrogen (M2) and Ca(OH)2, hydrolysis (M3). Of the chemical methods only initial inorganic nitrogen (M4) and exchangeable ammonium (M5) were not highly statistically correlated with the biological methods. The chemical methods were correlated to a lower degree with aerobic mineralization by M10 than with other biological methods. Based on degree and consistency of correlation, the chemical methods were ranked numerically as to their effectiveness in the following order, from simple correlation analysis: Ca(OH)2 hydrolysis (M3) > total nitrogen (M2) > alkaline permanganate digestion (M14) > Walkley-Black nitrogen (M13) > autoclaving procedures (M6, M7, M8) > organic matter (M1) > ultraviolet absorption by NaHCO3 soil extracts (M15). When the C:N ratio was included with the biological methods in a multiple regression analysis, only the effectiveness of organic matter was increased substantially. Consequently, the order of effectiveness as established by simple correlation analysis was unchanged except that of organic matter (Ml) that was brought among the chemical methods having the highest correlation with the biological methods.

Preservation of cottonseeds delinted by different methods

Effects of four delinting methods on the germination and longevity of cottonseeds of the cultivar IAC 13-1, treated and non-treated with the fungicide PCNB 75% were studied. The seeds were stored in uncontrolled conditions at Campinas, State of Sao Paulo for a period of 21 months. Seeds delinted by gas and treated with fungicide maintained germination rates higher than 80 %, up to 15 months storage. At the end of the storage period, the seeds that presented germination higher than 60% were those delinted by gas or acid and treated with fungicide. Seeds delinted by gas or acid presented higher germination percentages and stored longer than those delinted by mechanical means or by flame. Aside the delinting method, the fungicide treatment was beneficial to the germination of the seeds.

Adubação nitrogenada e potássica do algodoeiro no estado de São Paulo: resultados de produção no período de 1970 a 1973

Sao relatados e discutidos resultados de producao do algodoeiro em vinte e nove ensaios de campo, conduzidos no periodo de 1970 a 1973, onde se estudou o efeito da aplicacao de nitrogenio e de potassio, respectivamente nas doses de 0, 50 e 100 kg/ha de N e 0, 50, 100 e 150 kg/ha K2O, em esquema fatorial com quatro repeticoes. Em cinco ensaios conduzidos com a variedade IAC RM3, em solos podzolizados de Lins e Marilia e latossolo vermelho-escuro-fase arenosa, a resposta do do algodoeiro foi mais frequente para a aplicacao de nitrogenio, sendo influenciada pelos teores de fosforo e potassio do solo e pelas condicoes de cultivo das plantas. A resposta a adubacao potassica se relacionou muito bem como os teores de potassio, calcio e magnesio da analise do solo. Em cinco ensaios conduzidos com a variedade IAC RM3, em solos podzolizados de Lins e Marilia e latossolo vermelho-escuro-fase arenosa, a resposta do algodoeiro foi mais frequente para o nitrogenio. A acao do potassio nao se relacionou claramente com indices de analise quimica dos solos.

Efeito de tratamentos com fungicidas na conservação de sementes de algodoeiro (Gossypium hirsutum L.)

An experiment was carried out for two years in a greenhouse to study the effect of fungicides treatment on the germination of seeds of Sao Paulo cotton varieties, IAC 13-1 and IAC 17. Treated seeds were stored in uncontrolled conditions and germination was tested yearly. For each variety, the following treatments were applied: 1) PCNB + thiram, 2) Benomyl, 3) Check (mechanically delinted seed), 4) Acid delinted seed (D.A.), 5) D.A. + PCNB + thiram, 6) Metallic mercury. For treatments 1, 2 and 6 mechanically delinted seeds were used. Germination tests were carried out, in a randomized block design with three replications, by using fifty seeds in each experimental plot. Results were avaliated through an emergence index (%) and a resistance index (%) and showed the following: 1) The fungicide metallic mercury, PCNB + thiram, and Benomyl, had a significant effect on germination seven months after treatment, that persisted after sixteen months, except for Benomyl treatment. 2) The acid delinted seeds showed a decrease in germination at the sixteen months test. However, the negative effect of this treatment was adding PCNB + thiram.

Adubação do algodoeiro com micronutrientes e matéria orgânica em solos de cerrado

The effects of micronutrients (Zn, Cu and Mn) and organic matter (chicken-manure) associated with the basic NPK fertilization, on cotton production, yield properties and fiber properties were studied in field tests conducted during the years of 1973 to 1974, in Ibitiruna and Aguai in the State of Sao Paulo, Brazil. The soils utilized presented medium acidity and low fertility, according to chemical analysis, and the cotton variety tested was IAC 13-1. Complete randomized block designs were used, with four replications. The following conclusions were from the results: a) The application of micronutrients did not show a statistically significant effect on cotton yield, although an increase, up to 35%, on cotton yield was observed. b) The effect of the application of organic matter on cotton yield showed a significant effect, but dependent on the year, with increases in cotton yield from 5 to 44%. c) No significant effects of micronutrients or organic matter were detected on yield properties and fiber technology properties. d) The application of the organic matter alone, without association with the NPK fertilizers, showed the same production of the treatment without any fertilization. e) The low levels of productivity obtained might be an indication of lack of other management practices.

Fungicides treatment and storage of cotton seed (Gossypium hirsutum L.)

An experiment was carried out for two years in a greenhouse to study the effect of fungicides treatment on the germination of seeds of Sao Paulo cotton varieties, IAC 13-1 and IAC 17. Treated seeds were stored in uncontrolled conditions and germination was tested yearly. For each variety, the following treatments were applied: 1) PCNB + thiram, 2) Benomyl, 3) Check (mechanically delinted seed), 4) Acid delinted seed (D.A.), 5) D.A. + PCNB + thiram, 6) Metallic mercury. For treatments 1, 2 and 6 mechanically delinted seeds were used. Germination tests were carried out, in a randomized block design with three replications, by using fifty seeds in each experimental plot. Results were avaliated through an emergence index (%) and a resistance index (%) and showed the following: 1) The fungicide metallic mercury, PCNB + thiram, and Benomyl, had a significant effect on germination seven months after treatment, that persisted after sixteen months, except for Benomyl treatment. 2) The acid delinted seeds showed a decrease in germination at the sixteen months test. However, the negative effect of this treatment was adding PCNB + thiram.

Efeito das falhas e respectiva correção na experimentação de campo com o algodoeiro

The effect of missing plants on yield in field experiments with cotton was investigated through a previous study about the relation between mean production by plant and mean available area by plant of a given plot. This relation was described by a 3rd degree polinomial curve but linearity may be assumed between the limits of 0,100m2 and 0,300m2/plant, that correspond to current spacings used by farmers. Based on the assumption of linearity, the following adjustment of data is proposed: N Y1a = k1Y1 - b(k1A1 - Sk1A1/N) i = l with b = S (k1A1) (k1Y1) - (Sk1A1) (Sk1Y1)/N S (k1A1)2 - (Sk1A1)2/N and A1 = ne(c + 2d) - e(L1 - 2m1d) Y is the actual yield of a plot, N the number of plots in the experiment, k the quotient of perfect stand by actual stand and A is the area considered as really used by the plants obtained by deducting exceeding areas from large skips. Adjustments, made for several experiments, showed that the equation was efficient in most of the cases. However, its validity is questionable when skips are totally or partially linked to treatment effect, and there are cases, when no compensations of the gaps occur, in which the regression of yield on final stand permits better adjustment.