Estudos químico-agrícolas sôbre o enxofre

1. Analyses of soluble sulphates in 2 N ammonium chloride extracts of 24 samples of soils of the state of São Paulo, Brazil, S. A., showed a sulphur content varying from 0,0013 g per 100 g (found in the b layer of a genuine "terra roxa") to 0,007 g per 100 g of soil (b layer of a soil of depression without definite characteristics). (The results are expressed as elemental sulphur). Determinations of total sulphur in 56 samples of soils of the same state using the method of fusion with sodium carbonate and sodium nitrate revealed 0.007 g of elemental S per 100 g of soil as the lowest value (found in several soil types) and 0.096 g as the highest one (found in the b layer of an ar-quean soil). Apparently soluble sulphates accumulate in the upper layers and total sulphur does the opposite. It was found a strong correlation between total S and carbon content. 2. Under laboratory conditions, in a compost of fresh soil, powdered sulphur and apatite, it was verified after a three months period of incubation that the pH value lowered from 6.30 to 3.23; the citric acid solubility of apatite increased to 271.1 per cent of the original one. Lupinus sp. grown in soil manured with sulphur and apatite has showed fresh and dry weights higher than the plants in control pots; the results are significant at 5% level of probability; phosphorus content is also higher in the manured plants. It was observed a net influence of the apatite plus sulphur treatment on the weight of root nodosities that was four times greater than in the control plants. 3. Nearly five hundred determinations of S, N and P were carried out in 35 species of plants cultivated in the state of São Paulo. A great variation in the amounts of these elements was observed. As a general rule, the leaves contain more sulphur than the stems and roots show the lowest percentages. The conjunct roots and stem of guar (Cyamopsis psoraloides) revealed only 0.019 per cent sulphur; the leaves of kale showed the highest sulphur content, i. e., 2.114%. Apparently there is no correlation between the amounts of S, N and P. The ratio S/N increases from 0.006 (guar) to 0.485 (kale). The ratio S/P, always higher than the corresponding S/N, increases from 0.082 (guar) to 6.381 (older leaves of tomato plants). It is interesting to mention that several among the most important crops in the state of São Paulo namely, cotton, rice, coffee and sugar cane contain more sulphur than phosphorus. 4. Tomato plants cultivated in nutrient solution lacking sulphur showed the following visual symptons of deficiency : chlorosis first in the younger leaves and afterwards in all the leaves; anthocyanin pigments in the petioles and stems; absence of fruits; primary roots stunted and secondary ones longer than in the control plants; stems slender, hard, woody. The histological study of petioles suffering from sulphur deficiency revealed anthocyanin in the parenchyme layer instead of clo-rophyll pigments observed in normal petioles; in the chlorotic leaves the large chloroplasts present only the stroma but the small ones have a little amount of green pigments. Chemical analysis revealed in the abnormal plants : less sulphur and an increased proportion of phosphorus; older leaves contain more sulphur and less phosphorus than the younger ones probably due to physiological difficulties in translocation of sulphur bearing material; increased amount of total N attributed to accumulation of nitrates; marked decrease in ash, sugars and starch; increased proportion of crude fiber and dry material. In the plants suffering from sulphur deficiency photosyntetic rate decreased 34 per cent. 5. Tomato plants were succesfully cultivated in nutrient solution in absence of mineral sulphur but in presence of cysteine. The plants absorbed sulphur, under that form and were able to grow up quite well; the fruiting was normal. In this way rested cleary demonstrated the possibility of absorption of organic sulphur without previous mineralization and its utilization in the building up of protein molecules

Dinâmica da matéria orgânica e da biomassa microbiana em solo submetido a diferentes sistemas de manejo na Amazônia Ocidental

The objective of this work was to evaluate the alterations of the microbial biomass activity as an indicator of C and N dynamics in a soil submitted to the succession of plant cover and management in the Western Amazon. The work was carried out in two chronosequences: CA – a succession from primary forest to a three years old cupuaçu (Theobroma grandiflorum) plot – and CB – a succession from primary forest to an eight years old Brachiaria humidicola pasture and a three years old cupuaçu plot. The succession primary forest-pasture-cupuaçu affects negatively the stock of the soil carbon, with significant decrease of organic matter and C of the soil microbial biomass. The primary forest presents lower metabolic quotient and higher C/N ratio of the biomass, which results in less carbon loss. The N of the microbial biomass found in the 0–10 cm layerir respective of the management adopted, increases significantly in the cupuaçu plot and the total N decreases. Ammonium concentration decreases according to soil depth, but this does not occur with nitrate.O objetivo deste trabalho foi avaliar as alterações na atividade da biomassa microbiana como um indicador da dinâmica de C e N em solo submetido à sucessão de cobertura vegetal e de manejo na Amazônia Ocidental. Os trabalhos foram realizados em duas cronosseqüências: CA – sucessão floresta primária e cupuaçuzal (Theobroma grandiflorum) de três anos – e CB – sucessão floresta primária, pastagem de Brachiaria humidicola de oito anos e cupuaçuzal de três anos. A sucessão floresta primária-pastagem-cupuaçuzal afeta negativamente o estoque de C do solo, com diminuição significativa da matéria orgânica e do C da biomassa microbiana do solo, ao passo que na sucessão floresta primária-cupuaçuzal ocorre diminuição apenas do C da biomassa microbiana. A floresta primária apresenta menor quociente metabólico e maior relação C/N da biomassa, o que resulta em menor perda de carbono. O N da biomassa microbiana na camada de 0–10 cm, independentemente do manejo adotado, aumenta significativamente na área de cupuaçuzal, ao passo que o N total diminui. A concentração de amônio no solo diminui com a profundidade, de modo oposto ao verificado com o nitrato

Sources, rates and extractants of phosphorus on alfalfa and centrosema

O objetivo deste trabalho foi estudar o efeito de quatro fontes e quatro doses de fósforo na produção de matéria seca e nos teores de P em alfafa e centrosema, cultivadas em vasos com Latossolo Vermelho-Amarelo distrófico, e avaliar a disponibilidade de fósforo no solo, por três extratores. O delineamento experimental foi o inteiramente casualizado, em esquema fatorial 4 x 4 x 6: quatro doses de P (0, 50, 100 e 200 mg kg-1), quatro fontes de P (superfosfato triplo - SFT, termofosfato Yoorin - TY, fosfato natural da Carolina do Norte - FNCN e fosfato natural de Arad - FNA) e seis épocas de corte das plantas com intervalos de 30 dias, com três repetições. As doses de P aumentaram a produção de matéria seca total (MS) e o teor de P na MS, sendo que a alfafa apresentou maior resposta. O termofosfato Yoorin proporcionou a maior produção de MS: em seis cortes foram obtidos 50,17 e 70,89 gramas, respectivamente, com a alfafa e centrosema na dose de 200 mg kg-1. Os extratores Mehlich 1, Mehlich 3 e resina apresentaram alta correlação entre si na avaliação do P disponível. Considerando a média das três doses aplicadas e de todos os cortes, a quantidade total de P absorvido obedeceu a seguinte ordem: TY > SFT > FNCN > FNA.The objective of this work was to study the effect of four rates and four sources of P on dry matter production, and of phosphorus content in alfalfa and centrosema grown in pots containing a Red-Yellow Latosol (Oxisol), and to evaluate soil phosphorus by three extractants. The treatments were completely randomized in a 4 x 4 x 6 factorial design, with three replicates. Four sources of P were used at the rates of 0, 50, 100 and 200 mg kg-1, supplied as triple superphosphate (TSP), Arad rock phosphate (ARP), North Caroline rock phosphate (NCRP) and Yoorin magnesium thermophosphate (YTP), and six monthly harvests were made. The various rates of phosphorus applied increased both dry matter and P content in dry matter, alfalfa being more responsive. YTP ranked first in the total dry mater production: in six cuttings 50.17 g and 70.89 g were obtained, respectively with alfalfa and centrosema when 200 mg kg-1 was used. The extractants Mehlich 1 and 3 and resin presented each other a high correlation in the evaluation of the available phosphorus. Considering the average of the three rates of application and all cuttings, total P taken up obeyed the following decreasing order: YTP > TSP > NCRP > ARP

Localização do adubo em relação à semente (I)

The authors discuss in the introduction the literature about the distribution and placemement of fertilizers in agricultural experiments in U.S.A. in such crops as cotton, corn, potato, beans and some vegetables. An experiment was carried out with corn in a randomized block with 7 treatments, and 4 repetitions. The plots were 11,2m wide by 10m long. The 7 treatments were the following: one broadcast, 3 applications of fertilizer in hills and 3 in rows. In the latter six treatments application in rows or hills was combined with applications in three different depths: below the seeds without mixing the soil, below the seeds but with mixing of the soil, and above the seeds without mixing the soil. The variation between treatments was significant, and the best treatment was the application of fertilizer in hill, below the seeds and with mixing of the soil. The most unfavorable was application in rows above the seed without mixing of the soil. The second best treatment was the application by broadcasting the fertilizer, with mixing the fertilizer and soil by hoeing. New experiments will be carried out, applying the fertilizer in two rows, parallel on each side to the seed row, at three depths: above, below and level with seeds planted. In their discussion the authors stress the need for more experimentation on the methods of applying fertilizers not only to corn plants, but with respect to all main crops and diferent types of soils

Pesquisas sôbre a análise estatística de experiências de adubação com o auxílio da lei de Mitscherlich

Statistical analyses of an experiment on wheat were carried out with the aid of Mitscherlich's law. The experiment was made in Ponta Grossa, Paraná, by the Ministry of Agriculture of Brasil. Lime, in the form of Ca(OH)2, was applied at the levels of 0, 2, 4, 6 and 8 metric tons per hectare. A 5 x 5 Latin square was used. Lime was applied in 1940 and wheat was cultivated in the same plots for several years. The following fertilizers were annually used for all plots: NaNO3 100 kilograms per hectare, Superphosphate 350 kilograms per hectare, K2S04 80 kilograms per hectare. The statistical analysis of the data collected in 1941, 1942, 1943, 1947 and 1948, carried out in accordance with the methods previously introduced by Pimentel Gomes and Malavolta (1949 a, 1949 b) and Pimentel Gomes (1950), proved: I. That Mitscherlich's law could be correctly applied to the data. II. That there was a statistically significant effect of lime on wheat yield. III. That the optimum amount of lime to be applied to the soil lies between 5 and 15 hundred kilograms of Ca(OH)2 per hectare. IV. That there is a migration of calcium from some plots to others, in such a way that the data obtained in 1947 and 1948 are not representative of the amounts of lime applied in 1940. V. That the analysis of variance can be used, as the Bartlett test shows that the variances at the distinct levele of lime application are not statistically different. It must be noted that, with improved variety and fertilization, the yield was rised to about 2500 kilograms per hectare in 1947, and 1600 in 1948, being only of about 100 kilograms per hectare in 1940

Crescimento vegetativo de sorgo granífero em resposta à nutrição fosfatada

Morphological variables such as phytomass, plant height, leaf area, number of leaves, have been used to express the influence of mineral nutrients on plant growth patterns, since the vegetative development responds, in general, favorably to fertilizer applications. This work evaluates the effect of P on both, some morphological characteristics and total [P] in the shoot of eight grain sorghum (Sorghum bicolor L. Moench) genotypes. Genetic materials were grown in nutrient solution under three concentrations of P (0; 0.5 and 1.0 mmol L-1). Plants were harvested 41 days after sowing, and leaf area per plant (LA), number of leaves (NL) per plant, root volume (RV), plant height (PH), root dry matter (RDM), shoot dry matter (SDM), total dry matter (TDM), RDM/SDM ratio, and total P concentration in shoot were determined. RDM/SDM was high for treatment P(0) and diminished about twice when P was added. Lack of applied P decreased the final NL and LA. Shoot [P] was positively correlated with solution [P], but the increase in P concentration in the nutrient solution from 0.5 to 1.0 mmol L-1 had a negative effect on growth. Both under deficiency and sufficiency conditions of P, Himeca-101 showed the best behavior in terms of RDM, SDM, TDM, RV, LA and NL. LA and PH were identified as the best indicators to predict dry matter yield of sorghum plants under P supply conditions.Peso da matéria (fresca e/ou seca), altura de planta, área foliar e número de folhas por planta são variáveis usadas para estudar o efeito dos nutrientes minerais sobre o crescimento das plantas ou de alguns de seus órgãos. Assim, é indicado que o crescimento vegetativo responde favoravelmente a aplicações de P. Avaliou-se o efeito do P em oito genótipos de sorgo granífero (Sorghum bicolor L. Moench). Os materiais genéticos foram crescidos em solução nutritiva sob condições de casa de vegetação, com três concentrações de P (0, 0,5 e 1,0 mmol L-1). Plantas foram colhidas 41 dias após a semeadura e o número de folhas por planta (NL), área foliar por planta (LA), volume de raízes (RV), altura de planta (PH), matéria seca de raízes (RDM), matéria seca da parte aérea (SDM), matéria seca total (TDM), razão raiz/parte aérea (RDM/SDM) e o teor de P total na parte aérea foram usados para avaliar o crescimento vegetativo. RDM/SDM foi alta no tratamento deficiente em P e diminuiu perto de duas vezes nos tratamentos que receberam o nutriente. [P] na parte aérea foi positivamente correlacionada à [P] na solução nutritiva. Observou-se diminuição do crescimento quando os genotipos passaram de 0,5 a 1,0 mmol L-1. Sob condições de carência e suprimento de P, Himeca-101 mostrou o melhor comportamento em termos de RDM, SDM, TDM, RV, LA e NL. LA e PH foram os melhores indicadores para predizer o rendimento da matéria seca sob condições de suprimento de P

Use of 32P, in aluminum sensibility tests with bean

Foram conduzidos quatro ensaios em casa de vegetação visando verificar a viabilidade de utilização de 32P nos testes de tolerância ao alumínio pelo feijoeiro (Phaseolus vulgaris L.). As cultivares foram classificadas previamente, de acordo com os dados de produção de matéria seca, através de análises de regressão como tolerantes (C20 - Mulatinho Paulista, C26 - Ricobaio 1014 e C33 – Roxo 750) e sensíveis ao alumínio (C13 - Jamapa, C28 - Rio Tibagi e C34 - Tambó). Raízes provenientes de plantas cultivadas em soluções nutritivas completas durante trinta dias e submersas em outra solução contendo alumínio mostrou ser um indicador confiável da eficiência de absorção de 32P das cultivares tolerantes e sensíveis ao alumínio. A taxa de absorção de 32P foi maior nas cultivares tolerantes que nas sensíveis. Esses resultados mostram que as cultivares tolerantes ao alumínio podem absorver fósforo com maior eficiência que as sensíveis. A concentração iônica externa (NaH2PO4) aumentou a absorção de 32P na presença de 48 ppm de alumínio.Four greenhouse experiments were conducted to study the possibility of using 32P, in aluminum tolerance tests of bean (Phaseolus vulgaris L.) The cultivars were previously classified according to dry matter yield date by regression analysis as aluminum tolerant (C20 - Mulatinho Paulista; C26 - Ricobaio 1014; and C33 - Roxo 750) and aluminum sensitive (C17, - Jamapa; C28 - Rio Tibagi; and C34. Tambó). Chopped roots from plant grown in a complete nutrient solution during thirty days and submerged in another solution containing aluminum showed to be a reliable indicator of 32P absorption efficiency to aluminum tolerant and sensitive cultivars. Rate of 32P uptake was more in aluminum tolerant cultivars than sensitive ones. These results are showing that aluminum tolerant cultivars can absorb phophorus more efficiently than sensitive ones. External ionic concentration (NaH2PO4) increased 32P absorption in presence of 48 ppm of aluminum

Efeitos do alumínio e do manganés no feijoeiro

Thirty eight bean (Phaseolus vulgaris L.) cultivars were grown in nutrient solution under a factorial treatment using 4 levels of Al (0, 6, 12, 18 and 24 ppm) and 4 levels of Mn (0, 30, 60, 90 and 120 ppm) to study their behavior in presence of Al and Mn. By applying regression analysis to dry matter yield data it was possible to classify said varieties to Al effect in a. Tolerant – cultivars whose maximum yield appeared in the presence of the element at 1416 ppm: Jalo, Mulatinho Paulista, Ricobaio 1014 and Roxo 760; b. Moderately sensitive – cultivars whose minimum yield occurred in solutions having between 14 and 15 ppm of Al: Jamapa and Porrillo Sintético; c. Sensitive – cultivars whose yield showed a minimum when the nutrient solution had between 2 and 9 ppm of Al: Carioca, Costa Rica, Costa Rica 1031, Cuva 168 N, Goiano Precoce, Rico Pardo, Rio Tibagi and Tambá. Mn toxicity regression analysis allowed the following classification: a. Moderately sensitive – cultivars showing minimum yield when the nutrient solution contained from 102 to 118 ppm of Mn: Carioca, CR 911, Cuva 168W, Rico Pardo and Rio Tibagi; b. Sensitive - cultivars showing minimum yield when the nutrient solution presented from 72 to 99 ppm of Mn: Costa Rica 1031, Goiano Precoce, Jamapa, Porrilio Sintético and Rosinha. The remaining cultivars could not be classified because the estimated values of Al or Mn levels which would allow for maximum of minimum growth fell outside the experimental concentration (0 > Al > 24 and 0 > Mn > 120). For this reason it was not possible to draw safe conclusions on the data obtained.Trinta e oito cultivares de feijão (Phaseolus vulgaris L.) foram submetidas a tratamentos de 0, 6, 12, 18 e 24 ppm de alumínio e 0, 30, 60, 90 e 120 ppm de manganês, em solução nutritiva em combinação fatorial. Análises de regressão do peso da matéria seca da planta inteira permitiram separar as cultivares em três grupos em relação ao alumínio: a. Tolerantes - cultivares que apresentam máximos de produção de matéria seca na presença de 14 a 16 ppm de alumínio: Jalo, Mulatinho Paulista, Ricobaio 1014, Roxo 760. b. Medianamente sensíveis - cultivares que apresentaram mínimos de produção em solução com 14 a 15 ppm de alumínio: Jamapa e Porrillo Sintético. c. Sensíveis - cultivares que apresentaram mínimos de produção entre 2 a 9 ppm de alumínio: Carioca, Costa Rica, Costa Rica 1031, Cuva 168 N, Goiano Precoce, Rico Pardo, Rio Tibagi e Tambó. Análises de regressão deste mesmo parâmetro permitiram separar as cultivares em dois grupos em relação ao manganês: a. Medianamente sensíveis - cultivares que apresentaram mínimos de produção entre 102 a 118 ppm de manganês: Carioca, CR 911, Cuva 168N, Rico Pardo e Rio Tibagi. b. Sensíveis - cultivares que apresentaram mínimos de produção em solução na presença de 72 a 99 ppm de manganês: Costa Rica 1031, Goiano Precoce, Jamapa, Porrillo Sintético e Rosinha. Algumas cultivares não puderam ser classificadas nos grupos tolerantes e sensíveis, porque as raízes das respectivas equações de regressão apresentaram valores fora do campo experimental (0, > A1 > 24 e 0 > Mn > 120). Por esse motivo, não foi possível concluir seguramente sobre os dados obtidos

Ocorrência da podridão estilar em tomateiros (Lycopersicon esculentum Mill.) sob o efeito de reguladores de crescimento

It was observed that gibberellic acid 100 ppm promotes high incidence of blossom-end rot when a high level of ammonium sulphate was used. Under the same conditions, treatments with succinic acid -2,2-dimcthylhydrazide 4,000 ppm, (2-chloroethyl) trimethylammonium chloride 2,000 ppm and indole-3-acetic acid 100 ppm, caused, low incidence of blossom-end rot. It was proposed a mechanism of blossom-end rot incidence in tomatoes.Estudaram-se em condições de casa de vegetação os efeitos da aplicação de reguladores de crescimento na ocorrência da podridão estilar nos frutos de tomateiro cultivar "Miguel Pereira". Observou-se que ácido giberélico na concentração de 100 ppm promoveu alta incidência da anomalia fisiológica em plantas tratadas com altas dosagens de sulfato de amônio. Sob as mesmas condições, tomateiros pulverizados com ácido succínico -2.2-dimetilhidrazida 4.000 ppm, cloreto de (2-cloroetil) trimetilamônio 2.000 ppm e ácido - 3 - indolacético 100 ppm, apresentaram baixa incidência de podridão estilar. Efetuaram-se determinações dos teores de N, R, K, Ca e Mg nas folhas, hastes e frutos dos tomateiros normais e daqueles mostrando a anomalia fisiológica. Realizaram-se análises químicas dos substratos de plantio e foi proposto um mecanismo da incidência da podridão estilar em tomateiros