Resumo A macrofauna edáfica deve ser mais bem estudada se quisermos aproveitar todo o seu potencial para a restauração de ecossistemas tropicais. Nós investigamos as mudanças de densidade e diversidade da macrofauna edáfica em uma cronossequência durante a sucessão secundária na Mata Atlântica. Nossos resultados mostram padrões claros de mudança. A densidade não aumentou ao longo da sucessão secundária, mas foi correlacionada com a cobertura de dossel. A diversidade foi caracterizada pela alta dominância de insetos sociais e equidade entre os demais grupos. Nós concluímos que a macrofauna edáfica tem alta capacidade de recolonizar florestas jovens e que sua recuperação é relativamente rápida se comparada a outras transformações ecossistêmicas.

Abstract Edaphic macrofauna must be better studied if we want to take advantage of their full potential for the restoration of tropical ecosystems. We investigated changes in edaphic macrofauna density and diversity along a secondary succession chronosequence in the Atlantic Forest. Our results show some clear patterns of change in soil macrofauna along the chronosequence. Density did not increase along secondary succession, but was correlated with canopy cover. Diversity was characterized by high dominance of social insects and evenness among other groups. We conclude soil macrofauna has a high capacity to recolonize young forests and that its recovery is considerably fast compared to other ecosystem transformations.

Foram conduzidos experimentos fatoriais cultivando P. elliottii em solução nutritiva destinados a estudar o efeito de macronutrientes na composição mineral, grossura da parede celular e concentração da celulose no xilema. Os sintomas de deficiencia dos elementos foram descri tos e registrados. O crescimento foi estimulado por N, P, K, Ca e Mg, sendo a maior resposta devida ao N. Somente o enxofre aumentou significativamente o teor de celulose. A grossura da parede celular diminuiu com altos níveis de N, Ca, Mg e S; os primeiros diminuiram o comprimento das fibras.

Sand culture experiments, using a sub-irrigation technique, were installed in order to find out the effects of the macronutrients N, P, K, Ca, Mg and S on growth, aspect, mineral composition, length of fibers, thickness of cell wall and cellulose concentration in slash pine. The aim was to obtain, under controlled conditions, basic information which could eventually lead to practical means designed to increase the rate of growth and to make of slash pine a richer source of cellulose. Nitrogen, Phosphorus, Potassium Experiment A 3 x 3 x 3 factorial design with two replicates was used. Nitrogen was supplied initially at the levels of 25, 50 and 100 ppm; phosphorus was given at the rates of 5, 10 and 20 ppm; potassium was supplied at the rates of 25, 50 and 100 ppm; six months after the experiment was started the first level for each element was dropped to zero. Others macro and all micronutrients were supplied at uniform rates. Fifteen hours of illumination per day were provided. The experimental technique for growing the slash pine seedlings proved quite satisfactory. Symptoms of deficiency of nitrogen, phosphorus and potassium were observed, described and recorded in photographs and water colors. These informations will help to identify abnormalities which may appear under field conditions. Chemical analysis of the several plant parts, on the other hand, give a valuable means to assess the nutritional status of slash pine, thus confirming when needed, the visual diagnosis. The correctness of manurial pratices, on the other hand, can be judged with the help of the analytical data tabulated. Under the experimental conditions nitrogen caused the highest increases on growth, as measured by increments in height and dry weights, whereas the effects of phosphorus and potassium were less marked. Cellulose concentration was not significantly affected by the treatments used. Higher levels of N seemed to decrease both length of fiber elements and the thickness of cell wall. The effects of P and K were not well defined. Calcium, Magnesium, Sulfur Experiment A 3 x 3 x 3 factorial design with two replicates was used. Calcium was supplied initially at the levels of 12.5, 25 and 50 ppm; magnesium and sulfur were given at the rates of 6, 12.5 and 25 ppm. Other macro and micronutrients were supplied at uniform rates, common to all treatments. Three months after starting the experiment the first level for each element was dropped to zero. Symptoms of deficiency of calcium, magnesium and sulfur were observed, described and recorded as in the case of the previous experiment. Chemical analysis were made, both for mineral content and cellulose concentration. Length of fibers and thickness of cell wall were measured. Both calcium and magnesium increase height, sulfur failing to give significant response. Dry weight was beneficially affected by calcium and sulfur. The levels of calcium, magnesium and sulfur in the needles associated with deficiency and maximum growth are comparable with those found in the literature. Cellulose concentration increased when the level of sulfur in the substrate was raised. The thickness of cell wall was negatively affected by the treatments; no effect was observed with regards to length of fibers.

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.

A presente pesquisa foi realizada visando esclarecer dúvidas surgidas quando da determinação dos valores "T" (capacidade total do solo para bases de dupla troca), "S" (bases suscetíveis de dupla troca) e "H" (hidrogênio suscetível de dupla troca) de solos que receberam altas doses de vinhaça Tais valores, quando determinados pelo processo recomendado por A O. A. C. (2), desviam-se dos normais passando "S" (parte) a ser maior do que "T" (todo). Diversas porções de um mesmo solo depois de convenientemente preparadas foram tratadas em vasos de ferro zincado com doses crescentes de vinhaça como segue: Primeiro grupo (vasos 1, 2, 3 e 4): testemunhas; Sgundo grupo (vasos 5, 6, 7 e 8): incorporação de vinhaça em volume equivalente a 250.0001 por hectare; Terceiro grupo (vasos 9, 10, 11 e 12): idem ao anterior aumentando as dos»\s para 500.0001; Quarto grupo (vasos 13, 14, 15 e 16): idem com 750.0001; Quinto grupo (vasos 17, 18, 19 e 20): idem com 1.000.0001. Efetuada a incorporação e depois de sêcos ossolos à sombra, dos mesmos foram retiradas amostras (4 para cada tipo) para as respectivas análises. Estas compreenderam determinações de "T", "S" e "H" por diversos processos, baseados em lixiviação com acetato de amônio neutro e normal, com cloreto de amônio normal e cloreto de bário normal. Foram, ainda, efetuadas determinações para verificação de sais solúveis. Também foram verificados os índices pH e a possibilidade de volatilização de amoníaco durante os processos de lavagem dos solos com álcool concentrado para a retirada de excesso de reativo. Os resultados obtidos foram estudados estatisticamente revelando principalmente que a incorporação de vinhaça ao solo determina neste um aumento de seus valores "T", "S" e índice pH, e diminuição de "H". Revelaram ainda que nos solos tratados com altas doses de vinhaça o valor "T" não deve ser determinado com processos ligados a amônio-saturação (cloreto), uma vez que êste radical peptizando e solubilizando a matéria orgânica do solo faz com que se consigam valores aquém dos reais. Esta interferência é tão grande que pode conduzir ao absurdo de se ter "S" maior do que "T". Os catiônios bivalentes como cálcio e bário, apesar dos inconvenientes que apresentam, são os recomendados para êste caso.

This research aims to elucidate some doubts concerning the determination of the "T" value (total capacity of exchangeable base), the "S" value (exchangeable bases) and the "H" value (exchangeable hydrogen) in soils receiving heavy amounts of vinasse (waste product obtained in distilleries after the alcohol has been distilled off). In fact, it is known that in this case the values of "S" are sometimes larger than the corresponding values of "T", which is clearly absurd. Vinasse was applied to equal amounts of soil kept in iron pots. Four replications of the folowing treatments were obtained: 1st treatment: Control; 2nd treatment: Equivalent to 250.000 liters of vinasse per hectare; 3rd treatment: Equivalent to 500.000 liters of vinasse per hectare; 4th treatment: Equivalent to 750.000 liters of vinasse per hectare; 5th treatment: Equivalent to 1.000.000 liters of vinasse per hectare; Four samples were obtained from each of the 20 pots; after the soil was dried up in the shade "T", "S" and "H" were determined in each sample, by research methods including leaching with normal solution of amonium acetate, amonium chloride and barium chloride. Soluble salts and pH were determined also, and the possibility of loss of NH3 when washing the soil with alcohol was checked up and recognized to be non-existent. The data thus obtained were submitted to statistical analysis, which showed that indeed the values of "T", "S" and pH do augment with increasing amounts of vinasse, while "H" decreases. The authors concluded also that the methods using amonium saturation (either with amonium acetate or amonium chloride) should not be used for soils receiving large amounts of vinasse, since the peptization and solubilization of abundant organic matter leads then to underestimation of the value of "T". This underestimation is so serious that sometimes the value of "T" obtained is less than the corresponding value of "S" Therefore, bivalents cathions like calcium and barium are recommended for this case, notwithstanding their defects.

This paper is a joined publication of the Depts. of Genetics and of Technology, of the E. S. A. "Luiz de Queiroz", Universidade de São Paulo, and deals with the variation of the percentage oil content in the whole seeds, the embryos and the seed-coat of 28 varieties of castor-beans (Ricinus communis, L.). Primarily, the authors, as a justification of this paper, make reference to the applications which castor-oil has in industry, medicine, etc. In accordance with the weight of 100 seeds, the varieties of castor-beans were classified into 3 classes : small seeds (100 seeds less than 30 g), medium seeds (100 seeds between 30 g and 60) and large seeds (100 seeds more than 60 g). The percentage of oil in the seed, embryo and seed-coat, the dimensions of the seeds and the weight of 100 seeds are given for every variety in table 1. In order to obtain an estimate of the variability for the methods of determination of the oil percentage, in the 3 differents parts of the seeds and also in the 3 groups of seeds, the coefficient of variability was calculate (table 2). It is showed that the variation in the seed and embryo is low and that in the seed-coat is very high. The analysis of variance, with regard to the difference among the 3 types of seeds (small, medium and large), among the 3 parts of the seed (whole seed, embryo and seed-coat) and residual error, is given in table 3. Only, the oil content of whole seeds among types of seeds was significant at the 5% level. The t test among the correspondent means is not significant for the difference between medium and large seeds is significant between both these types (medium and large) and small seeds. The fiducial limits in relation to the mean of the oil percentage in the 3 differents types of seed, show that there is one variety (n. 1013-2), which has a percentage of oil, in the medium type of seed, significantly at the 5% level (table 4), higher than the general mean. Since the distribution of the percentage of oil in the seedcoat is discontinuous, 5 groups were established (table 5). All the differences between groups are significant (table 6). For practical purposes, when we have to remove the seed coat, one should eliminate those varieties which loose at least 3% of oil by this procedure. There is a significant linear correlation at 5% level between the percentage of oil in the seed and in the embryo, of the smali and medium type of seeds (table 7), and also, when taking the 3 types together (lower part of table 7), one finds that the same is true. Also, the correlation between the percentages of oil in the embryo and in the seed-coat of the 3 types together is significant at 5% level. According to the results obtained in relation to the percentage in 28 varieties studied, it can be recommended, for breeding purposes, to work only with those varieties which belong to the medium and the large types of seeds.

Considering the economic importance of the sugar industry among ourselves, the authors carried out a field experiment (Latin square) with Co 290 sugar cane, on a white sandy soil of Piracicaba, State of São Paulo, Brazil, applying NaCl in increasing rates (from 6.8 to 54.5 grams per plant), in order to study the effects of chlorides, on productivity and on the composition of juice. No toxic or stimulating effect was found, and there was no change in yield, in degree of purity of the juice, in general aspect of plants or in colour of leaves and culms. No difference was observed between potassium sulphate or chloride, as source of potash for sugar cane culture. Data collected and the literature cited suggest: (a) that the use of the variety Co 290 is indicated for soils rich in chlorine, such as the saline soils of the North-east and Atlantic Coast of Brazil; (b) that it is necessary to extend studies in Research Institutes and Agricultural Experiment Stations of the country to verify the behaviour of other varieties of sugar cane in the types of soils mentioned, especially with respect their yielding capacity. The authors are already planning such investigations.