1000 resultados para foliar fertilizers
Resumo:
Due to the great importance of coffee to the Brazilian economy, a good deal of the work carried out in the "Laboratório de Isótopos", E. E. A. "Luiz de Queiroz", Piracicaba, S. Paulo, Brazil, was dedicated to the study of some problems involving that plant. The first one was designed to verify a few aspects of the control of zinc deficiency which is common in many types of soils in Brazil. An experiment conducted in nutrient solution showed that the leaf absorption of the radiozinc was eight times as high as the root uptake; the lower surface of the leaves is particularly suited for this kind of absorption. Among the heavy metal micronutrients, only iron did not affect the absorption of the radiozinc; manganese, copper, and molybdenum brought about a decrease of fifty per cent in total uptake. In another pot experiment in which two soils typical of the coffee growing regions were used, namely, a sandy soil called "arenito de Bauru" and a heavy one, "terra roxa", only O.l and 0.2 per cent of the activity supplied to the roots was recovered", respectively. This indicates that under field conditions the farmer should not attempt to correct zinc deficiency by applying zinc salts to the soil: leaf sprays should be used wherever necessary. In order to find out the most suitable way to supply phosphatic fertilizers to the coffee plant, under normal farm conditions, an experiment with tagged superphosphate was carried out with the following methods of distribution of this material: (1) topdressed in a circular area around the trees; (2) placed in the bottom of a 15 cm deep furrow made around the plant; (3) placed in a semicircular furrow, as in the previous treatment; (4) sprayed directly to the leaves. It was verified that in the first case, circa 10 per cent of the phosphorus in the leaves came from the superphosphate; for the other treatments, the results ware, respectively: 2.4, 1.7, and 38.0 per cent. It is interesting to mention that the first and the last methods of distribution were those less used by the farmers; now they are being introduced in many coffee plantations. In a previous trial it was demonstrated that urea sprays were an adequate way to correct nitrogen deficiency under field conditions. An experiment was then set up in which urea-C14 was used to study the metabolism of this fertilizer in coffee leaves. In was verified that in a 9 hours period circa 95 per cent of the urea supplied to the leaves had been absorbed. The distribution of the nitrogen of the urea was followed by standard chemical procedures. On the other hand the fate of the carbonic moiety was studied with the aid of the radiochromatographic technique. Thus, the incorporation of C14 in aminoacids, sugars and organic acids was ascertained. Data obtained in this work gave a definite support to the idea that in coffee leaves, as in a few other higher plants, a mechanism similar to the urea cycle of animals does exist.
Resumo:
In order to find out the best way to supply phosphorus to coffee plants when growing in "terra roxa misturada", a red soil with a high fixing capacity, tagged superphosphate was applied by the following procedures: (1) topdressed in a circular strip around the trees; (2) placed in the bottom of a circular furrow 15 cm deep; (3) placed in a semicircular furrow also 15 cm deep; (4) sprayed directly to the leaves. In each case 150 gms. of ordinary superphosphate tagged with H3 P32 O4 to give 5 X 10(9) c.p.m. were given to the two and half year old coffee plants. It was found that for the several treatments of the total phosphorus in the leaves the following values, on a per cent basis, came from the applied superphosphates: (1) topdressed 10.2 per cent, (2) circular furrow 2.4 per cent, (3) semicircular furrow 1.7 per cent, (4) sprayed 38.0 per cent; one can see, then, that methods (2) and (3) commonly used by the coffee planters are a very inefficient way to supply phosphorus in this type of soil. The remarkable foliar absorption was checked twice: a water culture experiment was carried out, the radiophosphorus being supplied by brushing it in the upper and lower surfaces of a given leaf; radioactivity was detected all over the plant as a result both of absorption and translocation; on the other hand, leaves collected from the sprayed trees were radioautographed; the radioautographs showed the pattern of distribution of the P32 which indicates true absorption rather than a surface contamination. In another locality, an experiment was caried out with 8 year old plants growing in "arenito de Bauru" which is a sandy soil with much less phosphorus fixing capacity. In this experiment the aim was to compare absorption of tagged superphosphate by trees growin under mulch against plants not receiving this treatment, The uptake of phosphorus was the same for both sets of plants. In both field experiments soil samples down to 15 cm in the profile were collected and its 0.2NHC1 soluble phosphorus was counted; rather significant values were observed mainly in the upper 5 cm layers.
Resumo:
1. A presente contribuição trata do estudo morfológico e anatômico das domácias que ocorrem em 21 variedades e 4 formas da espécie Coffea arabica L. 2. Além da revisão da literatura, que se cingiu unicamente aos trabalhos que focalizam o assunto em aprêço, constam, na introdução, algumas obras que se referem às domácias existentes em outras famílias. 3. A fim de apreciar convenientemente os conceitos que os diferentes autores expediram a respeito das domácias, desde que se tornaram conhecidas, foram registradas, no capítulo correspondente, as funções e as diversas denominações que lhes foram atribuidas. 4. As principais classificações das domácias propostas são de CHEVALIER, LEBRUM e DE WILDEMAN. As domácias das variedades e formas de Coffea arabica L., se enquadram no tipo b, isto é, domácias em fenda, segundo a classificação de CHEVALIER. 5. O material utilizado no presente estudo, constante de ramos com fôlhas de várias idades, proveio do Instituto Agronômico de Campinas e da Secção de Agricultura Especial da E.S.A. "Luiz de Queiroz". As observações morfológicas das domácias foram feitas com o auxílio do microscópio estereoscópico e constam do Quadro I e II. A estrutura anatômica foi apreciada em cortes transversais medianos da domácia, coloridos pelo violeta cristal e eritrosina, com espessura de 18 micra, cujos dados acham-se anotados nos Quadros de n.os III a XI. 6. No capítulo referente à morfologia e à anatomia das domácias, para melhor apreciação do assunto foi introduzida a estrutura anatômica da fôlha adulta da variedade typica. 7. Morfològicamente as domácias foram examinadas nas suas duas faces, isto é, superior e inferior, anotando-se-lhes os aspectos apresentados, bem como a sua localização no limbo, isto é, na axila formada pelas nervuras principal e secundárias. No geral a sua distribuição vai desde a base do limbo até aos 2/3, aproximadamente, do seu comprimento. Na face ventral da fôlha, as domácias exibem uma elevação abaulada e na dorsal situam-se na área da axila, e em um plano um pouco mais elevado que o limbo, mostrando no centro um orifício de forma variável. Em cortes medianos, a domácia revela-se constituida de uma câmara embutida no mesofilo, a qual se comunica com o exterior por um canal; êste por sua vez, termina numa bôca que se abre na epiderme inferior do limbo. Histològicamente a domácia consta de uma epiderme, procedente do limbo e da nervura, e de um tecido parênquimatoso envolvente, composto de algumas camadas de células, o qual confina com os tecidos do mesofilo. Topogràficamente a domácia situa-se entre os seguintes tecidos da estrutura foliar: sistema vascular principal, nervura secundária, parênquima lacunoso lateral e parênquima lacunoso superior. Sua posição com relação às regiões mencionadas fica perfeitamente definida, determinando-se as distâncias que vão do centro da câmara até elas.
Resumo:
This paper deals with different types of fertilizer applications in coffee hill in the moment of transfering the plants to the field. During the first year, irrigation was applied in the dry season. After one year, the following characters were analised: plant height; plant diameter; number of productive branches; lenght and number of nodes in the first branch of the plant. The results obtained can be summarized as follows: the irrigation employed did not affect the treatments and mineral fertilizers combined with organic fertilizer were better than the others treatments used for comparisons.
Resumo:
Com a finalidade de se conhecer a distribuição de S35 em cafeeiro, o presente experimento foi conduzido em casa de vegetação e em campo. No primeiro caso "plantinhas" de café, de 6 meses de idade foram mantidas em solução nutritiva e receberam: a) S35 na superfície inferior das fôlhas do 3.° par; b) S35 na solução. No ensaio (a), as "plantinhas" foram divididas em suas partes constituintes (raízes, caule, fôlhas novas e fôlhas velhas), sendo que as fôlhas foram subdivididas em pecíolo, limbo e nervuras. O ensaio (b) era formado por 3 grupos de "plantinhas": - 1) estudo da migração, como em (a); 2) autoradiografia; 3) verificação da lavagem de S35 das fôlhas, sob chuva artificial. No experimento conduzido em campo utilizamos cafeeiros de 4 anos de idade e o enxofre radioativo foi fornecido por pulverização foliar. Os resultados demonstram a pouca mobilidade do enxofre pela planta e que: 1) o S35 migra das fôlhas velhas principalmente para as fôlhas novas e muito pouco para as raízes; 2) das raízes o S35 se distribui para os demais órgãos da planta, concentrando-se principalmente nas fôlhas mais velhas; 3) os dados obtidos pela detecção da radioatividade nas várias partes da planta foram corroborados pela autoradiografia; 4) o enxofre é lavado das fôlhas pela água das chuvas.
Resumo:
In order to study the phosphorus availability from various phosphates fertilizers an experiment was performed according to the biological seedling method of Neubauer. The physico-chemical properties of the soil "terra roxa-misturada", a red soil derived from basaltic rocks are given in the Portuguese text. Rice (Oryza sativa, L.) instead of rye (Secale cereale, L.) was used. Five replications of each of the following treatments were made: 1 - check, with 350 g of sand 2 - 350 g of sand plus 100 g of soil 3 - 350 g of sand and plus 100 g of soil plus 40 mg of P2O5, from superphosphate. 4 - 350 g of sand plus 100 g of soil plus 40 mg of P2O5. from Olinda (Brazil) phosphorite. 5 - 350 g of sand plus 100 g of soil plus 40 mg of P2O5 from Florida (U. S. A.) phosphorite. 6 - 350 g os sand plus 100 g of soil plus 40 mg of P2O5 from Hyperphosphate, a commertial name of a North African (Gafsa) phosphorite. 7 - 350 g of sand plus 100 g of soil plus 40 mg of P2O5 from Araxá (Brazil) apatite. After 18 days of growth, the roots and tops of rice seedlings were harvested and analysed for phosphorus, and the results are summarized in table 1. Table 1 - Milligrams of P2O5 determined in rice seedlings. Treatments Mean of 5 replications mg of P2O5 1 ..................... 24.196 2 ..................... 23.850 3 ..................... 30.724 4 ..................... 27.620 5 ..................... 27.480 6..................... 30.210 7 ..................... 26.032 The least significant difference at the 5% level by Tukey's procedure for comparisons among the treatments means is 1.365 mg of P(2)0. It is interesting to observe that rice plants did not take any phosphorus from the soil according to he data of the treatments n.° 1 and n.° 2. This can be explained by the high phosphorus fixing capacity of the soil "terra roxa misturada".
Resumo:
WATER-CULTURE EXPERIMENTS. Two water-culture experiments were carried out to study the absorption and the translocation of radiozinc in young coffee plants as influenced by two factors, namely, concentration of heavy metals (iron, man ganese, copper and molybdenum) and method of application. Inert zinc was supplied at an uniform rate of 0. 05 p. p. m.; the levels of iron supply were 0, 1.0, and 10.0 p. p.m.; manganese was supplied in three doses 0, 0.5, and 5.0 p. p.m.; copper- 0, 0. 02, and 0. 2 p. p. m.; molybdenum- 0, 0. 01, and 0. 1 p. p. m. When applied to the nutrient solution the activity os the radiozinc (as zinc chloride) was 0. 15 microcuries per plant. In the study of the leaf absorption, Zn65 was supplied at the level of 0. 10 microcuries per plant; in this case the radioative material was brushed either on the lower or on the upper surface or both two pairs of mature leaves. The absorption period was 8 weeks. The radioactivity assay showed the following results: 1 - Among the heavy metals herein investigated the iron concentration did not affect the uptake of the radiozinc; by raising the level of Mn, Cu and Mo ten times, the absorption dropped to 50 per cent and even more when compared with the control plants; when, however, these micronutrients were omitted from the nutrient solution, an increase in the uptake of zinc was registered in the minus Cu treatment only. The effects of high levels of Mn, Cu and Mo probably indicate an interionic competition for a same site on a common binding substance in the cell surface. 2 - The absorption of the radiozinc directly applied to the leaf surface reached levels as high as 8 times that registered when the root uptake took place. Among the three methods of application which have been tried, brushing the lower surface of the leaves proved to be the most effective; this result is easily understood since the stomatal openings of the coffee leaves an preferentially located in the lower surface - in this treatment, about 40 per cent of the activity was absorved and around 12 per cent were translocated either to the old or to the newer organs. Chemical analyses for heavy metals, were carried out only in the plants received Zn65Cl2 in the nutrient solution; the results were as follows; 1 - Control plants had, per 1,000 gm, of dry weight the following amounts in mg.: Zn- 48 in the roots and 29 in the tops; Fe- 165 in the roots and 9 in the tops; Mn- 58 in the roots and 15 in the tops, Cu- 15 in the roots and 1. 2 in the tops; Mo- 2. 8 in the roots and 0. 45 in the tops. 2 - The effect of different levels of micronutrients in the composition of the plants can be summarized as follows: Fe and Zn- when omitted from the nutrient solution, the iron and zinc contents in the roots decreased, no variation being noted in the tops; the higher dosis caused an accumulation in the roots but no apparent effect in the tops; Mn- by omitting this micronutrient a decrease in its content in the roots was noted, where as the concentration in the tops was the same; Mo- no variation in roots and tops contents when molybdenum was omitted; higher dosis of manganese and molybdenum increased the amounts formed both in the roots and in the tops. 3 - The influence of the different concentrations of micronutrients heavy metals on the zinc content of the coffee plants can be described by saying that: Fe and Mo- no marked variation; Mn- no effect when omitted, reduced amount when the high dosis was supplied; Mn- when the plants did not receive manganese the zinc content in roots and tops was the same as in the control plants; a decrease in the zinc content of the total plant occurred when the high dosis was employed; Cu -the situation is similar to that described for manganese. Hence, results showed by the chemical analyses roughly correspond to those of the radioactivity assay; the use of the tracer technique, however, gave best informations along this line. SOIL-POTS EXPERIMENTS. The two types of soils which when selected support the most extensive coffee plantations in the State of São Paulo, Brazil: "arenito de Bauru", a light sandy soil and "terra roxa legitima", a red soil derived from basalt. Besides NPK containing salts, the coffee plants were given two doses of inert zinc (65 and 130 mg ZnCl2 per pot) and radiozinc at a total activity of 10(6) counts/minute. The results of the countings can be summarized as follows: 1 - When plants were grown in "arenito de Bauru" the activity absorbed as per cent of the total activity supplied was not affected by the dosis of inert zinc. The highest value found was around 0. 1 per cent. 2 - For the "terra roxa" plants, the situation is almost the same; there was, however, a slight increase in the absorption of the radiozinc when 130 mgm of ZnClg2 was given: a little above 0. 2 per cent of the activity supplied was absorbed. The results clearly show that the young coffee plants practically did not absorb none of the zinc supplied; two reasons at least could be pointed out to explain such a fact: 1 - Zinc fixation by an exchange with magnesium or by filling holes in the octahedral layer of aluminosilicates, probably kaolinite; 2 - No need for fertilizer zinc in the particular stage of life cycle under which the experiment was set up. The data from chemical analysis are roughly parallel to the above mentioned. When one attempts to compare - by taking data herein reported zinc uptake from nutrient solution, leaf brushing or from fertilizers in the soil, a practical conclusion can be drawn: the control of zinc deficiency in coffee plants should not be done by adding the zinc salts to the soil; in other words: the soil applications used so extensively in other countries seem not to be suitable for our conditions; hence zinc sprays should be used wherever necessary.
Resumo:
In this paper the authors have studied the manganese absorption by the sugar cane plant, variety Co 419, in samples cut monthly, from the 6th to 15th month of life in the climate prevailing at Piracicaba, State of Sao Paulo, Brazil. From October to February (6 th to 10 th month of the plant life), which coincided with the rainy season, the manganese content was higher in the stalk than in the leaves, for both treatments, fertilized and unfertilized. There was a sharp decrease in manganese content in the stalks, after February, in both reatments. In the leaves there was little variation in manganese content throughout the plant tissue. The stalks from the unfertilized plots had a larger variation in manganese content, specially from the 6 th to the 10 th month. In the leaves of the sugar cane from the unfertilized plots, the manganese content varied from 116 to 220 ppm, whereas in the fertilized treatments thire was a variation from 150 to 220 ppm. From these results, althoug not being a foliar analyses, and considering the easy availability of manganese in acid soils, there must be enough of it, if we consider 40 ppm (EVANS, 1955) as a minimum for healthy plants.
Resumo:
Cotton (variety I. A. C. 11) was grown on a sandy soil under two treatments, namely: (1) NPK + lime and (2) no fertilizers. Three weeks after planting a systematic sampling of entire plants was done every other week. In the laboratory determinations of dry weight were made and afterwards the various plant partes were submitted to chemical analyses, nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S) being determined. The aim of this work was to obtain information on the periods in which the absorption of the several macronutrients was more intense, this providing a clue for time of application of certain mineral fertilizers. Data obtained hereby allowed for the following main conclusions. The initial rate of growth of the cotton plant, judged by the determinations of dry weight, is rather slow. Seven weeks after planting and again five weeks two distinct periods of rapid growth take place. The uptake of macronutrients is rather small until the first flowers show up. From there on the absorption of minerals is intensified. From the time in which fruits are being formed to full maturity, the crop draws from the soil nearly 75 percent of the total amount of elements required to complet life cycle. This seams to point out the need for late dressings of fertilizers, particularly of those containing N and K. The following amounts of element in Kg/ha were absorbed by the fertilized plants: N - 83.2 P - 8.1 K - 65.5 Ca - 61.7 Mg - 12.8 and S - 33.2. The three major macronutrients, namely, N. P and K are exported as seed cotton in the following proportions with respect to the total amounts taken up by the entire crop: N - 1/3, P - 1/2 and K - 1/3.
Resumo:
The authors carried out 3 experiments on the sampling of sugar cane for technological determinations, one with each of the varieties Co 419, CB 40-69 and CB 41-58, in Piracicaba, State of São Paulo, Brasil. The main intent of the project was to compare 2 methods of sampling, namely: 1) Method A, where the sample is a hill (CATANI et al, 1959) or, more generally, 20 stalks all together in a randomly selected point of the furrow; 2) Method B, where 20 stalks are taken, from 20 points evenly spread but on the whole plot. Coefficients of variation for 20 stalk samples Variety Characteristic 20 stalks per hill 1 stalk per hill Brix 4.8% 1.9% Pol 6.4% 2.5% CB 40-69 Coefficient of purity 2.1% 0.83% Available sucrose 7.3% 2.7% Weight 6.6% 6.9% Brix 5.3% 1.8% Pol 7.6% 2.6% Co 419 Coefficient of purity 2.9% 1.0% Available sucrose 8.6% 3.0% Weight 21.2% 6.5% Brix 2.8% 1.4% Pol 4.1% 1.9% CB 41-58 Coefficient of purity 1.8% 0.8% Available sucrose 5.0% 2.2% Weight 10.9% 6.2% For the 3 varieties studied and for the data on Brix, pol, coefficient of purity, available sucrose and weight, analyses of variance were carried out. Further computations led to the following coefficients of variation. For available sucrose, which is probably the most important characteristic studied, the average coefficient of variation for the 3 varieties was 2.7%, for the case of method B, that is, 20 stalk samples, one stalk per hill. Assuming this coefficient of variation, in a trial with 5 treatments and 6 replications, in randomised blocks, the least significant difference among treatment means, at the 5% level, would be 4.7% of available sucrose by Tukey's test, and 3.3% by the t test. For the case of method A the average coefficient of variation is 7.0% and, in similar conditions, the least significant difference would be 15.1% by Tukey's test, and 12.1% by the t test. Since differences of available sucrose among treatments in experiments with fertilizers seldom are higher than 3 or 4% of the mean (PIMENTEL GOMES & CARDOSO, 1958), method B with a 20 stalk sample per plot gives more or less the minimum amount of cane to be sampled for technological determinations. In experiments with varieties, however, where differences may be assumed to be higher, a sample of 10 to 20 stalks one per hill, can be enough.
Resumo:
Leaf samples from coffee plants under three different fertilizations, namely NPK, NP and PK, were collected for chemical analysis. It was found that the contents of N, K, Ca, Mg and S in the first, second, third and fourth pair of leaves were the same from the statistical point of view. On the onder hand, there was a significant effect of the position of the leaf in the branch on the P content, which was higher in the first pair. With the exception of the P level ,the four pairs of leaves are chemically uniform. Nevertheless it is not considered as convenient to mix all kinds of leaves into one sample, since the composition may vary a great deal when sampling is done some other time, such as the period of fruit growing. It is recommended therefore that either the third or the fourth pair leaves should be collected for routine work in foliar diagnosis.
Resumo:
Guarea trichilioides L.4, (= Guarea guara (N.J. Jacquin) P. Wilson) é uma meliácea arbórea silvestre, fornecedora de madeira vermelha e conhecida, na região de São José do Rio Preto, pelo nome de "Marinheiro". Foi estudado o balanço hídrico desta planta na estação seca, pelo método das pesagens rápidas de folíolos destacados, verificando-se que, nas condições consideradas, não houve, praticamente, restrição acentuada da transpiração nas horas mais desfavoráveis do dia. A transpiração relativa foi bastante elevada, comparável aquela de outras árvores da mesma formação e bem superior à das árvores da floresta pluvial tropical. A transpiração cuticular foi baixa, comparável à da maioria das árvores da citada floresta pluvial e bem inferior àquela de muitas plantas permanentes do cerrado. O movimento hidroativo dos estômatos foi relativamente rápido na fase inicial, tornando-se, porem, bastante vagaroso antes de atingir o valor da transpiração cuticular. O deficit de saturação foi pequeno, comparável ao das árvores da floresta pluvial. O estudo do balanço hídrico e da estrutura foliar levam a considerar Guarea trichilioides como uma árvore da floresta tropical não adaptada a suportar condições de seca intensa.
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O presente trabalho relata um experimento em que foram verificados os efeitos fitotóxicos do herbicida 2-cloro-2', 6'-dietil-N-(metoximetil) acetanilida (CP 50144) em plántulas de gergelim (Sesamun indicum L.) e feijão (Phaseolus vulgaris L.), cultivados em solução nutritiva 0,5-Hoagland. 0 herbicida foi aplicado às folhas, nas doses respectivas de lug/10l, 5ug/ 10l, 25yg/10l, 125ug/10l, 250yg/10l e 500ug/10l. Para o tratamento às raízes, ele foi adicionado à solução nutritiva, nas doses de 1 ppm, 5 ppm, 25 ppm, 125 ppm, 625 ppm e 3125 ppm, respectivamente. O tratamento foliar revelou penetração lenta, tanto nas fôlhas de gergelim como nas de feijão, com pequena translocação e forte ação de contato, especialmente nas concentrações mais elevadas, superiores à da saturação (148 ppm). A absorção pelas raízes e lenta, tanto para o gergelim como para o feijão. Entretanto, o gergelim mostrou-se altamente tolerante ao CP 50144, até a concentração de 125 ppm, inclusive, não tendo demonstrado nenhum sintoma de injuria. Acima dessa concentração, o gergelim foi fortemente injuriado, tendo mostrado fortes sintomas de ação de contato, nas raízes, e sintomas gerais de intoxicação, na parte aerea, que levaram as plantas a morte. O feijão mostrou-se bastante sensível à ação do CP 50144, tendo apresentado forte sintomatologia de intoxicação, tanto por contato como por translocação apoplástica. São descritos os sintomas de fitotoxicidade do herbicida, para as duas plantas. O herbicida CP 50144 e altamente seletivo para o gergelim, mostrando-se bastante promissor para essa cultura. O herbicida mostrou ação inibidora da distensão celular, nas folhas novas de feijão. É interessante que se realizem estudos fitoteratológicos e fitofisiológicos com este herbicida, cujo modo de ação ainda nao e bem conhecido.
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No presente trabalho são relatados os estudos sobre sete cultivares pertencentes a espécie Cucurbita moschata, objetivando a descrição botânica, em virtude de não terem sido ainda caracterizados taxonomicamente, muito embora largamente conhecidos e cultivados como plantas de valor econômico. Os trabalhos de melhoramentos dos cultivares estudados vem sendo feito desde 1942, pela Seção de Olericultura do Instituto Agronômico de Campinas. Empregamos sementes provenientes de polinização controlada, cedidas graciosamente pela Seção de Olericultura do Instituto Agronômico de Campinas. O planejamento estatístico obedeceu à distribuição de bloco ao acaso, utilizando-nos de 7 cultivares e com 10 repetições. A descrição botânica dos cultivares baseou-se nas características morfológicas dos órgãos vegetativos e reprodutivos, considerando-se: a - a forma, as dimensões, a presença de estrias longitudinais e indumento da haste principal. b - as dimensões e indumento do pecíolo. o ângulo foliar formado pelas nervuras externas da base do limbo e sua grandeza, o comprimento dos seus lados (nervuras), a presença ou ausência de manchas prateadas do limbo, a largura e o comprimento do limbo da folha. c - as formas de gavinhas. d - para as flores masculinas e femininas: o comprimento do pedúnculo, o comprimento do tubo e lóbulos do cálice e sua forma, o comprimento do tubo e lóbulos da corola, o diâmetro da parte superior do tubo da corola, o diâmetro entre os ápices dos lóbulos da corola, o comprimento do filete e da antera e a forma desta para as flores masculinas e dimensões, posições, formas e indumento do ovário, comprimento e coloração dos estigmas, a forma do disco nectarífero situado na base do estilete, para as flores femininas. e - dimensões, forma, coloração, constituição, consistência e espessura da polpa do fruto. f - dimensões, forma e coloração da semente e forma do hilo. g- a análise estatística foi feita para alguns caracteres de valor taxonômico como: Folhas: comprimento do pecíolo, grandeza do ângulo foliar da base do limbo, largura e comprimento do limbo. Flor masculina: comprimento do pedúnculo. comprimento do tubo e lóbulos da corola, diâmetro da parte superior do tubo da corola. Flor feminina: comprimento do pedúnculo, comprimento do ovário, comprimento do tubo da corola e lóbulos da corola e diâmetro da parte superior do tubo da corola.
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This paper deals initially with the role of mineral fertilizers in increasing agricultural production: the relationship between the two variables is illustrated within global, regional national and local contexts. The pattern and trends in fertilizer usage in Brazil are presented next, namely: increase in consumption in the period 1950/72; regional distribution; consumption as related to crops and cultivated land. It is shown that in less than a quarter or century fertilizer use has increased in the country nearly 12 fold, whereas world consumption was raised 7 fold, thus exceeding estimates based in several criteria. Steps taken to secure the raise in fertilizer consumption above the historical trend are discussed: research experience for outlining fertilization recomendations; the transfer of the knowledge to the farmer by the extension work both official and private; the credit policy and special incentives for the purchase of fertilizer; the national policy for minumum proces of agricultural products; the implantation of a national fertilizer industry. It is considered that the Brazilian experience adapted to similar local conditions in other developing countries, presents a possibility for achieving beneficial results without inflationary reflexes in the economy.