No presente artigo são relatados os resultados obtidos em seis ensaios realizados entre 1944 e 1955 no Estado de São Paulo, com o fim de estudar o efeito fertilizante da mucuna preta (Stizolobium sp.) intercalada na cultura do milho. Os tratamentos comparados foram: sem adubo; calcário; fósforo e potássio; calcário, fósforo e potássio; mucuna; calcário e mucuna; fósforo, potássio e mucuna; calcário, fósforo, potássio e mucuna. Esta foi semeada entre as linhas do milho, após o início do florescimento deste, sendo incorporada ao solo, de mistura com a palhaça do cereal, algumas semanas depois da colheita das espigas. A adubação com fósforo mais potássio aumentou significativamente a produção do milho em quatro localidades. Em regra a presença do calcário não modificou o efeito dessa adubação, mas a da mucana o tornou mais pronunciado. Em média do período que durou cada ensaio o calcário praticamente não aumentou a produção. Notou-se, porém, que nos ensaios mais prolongados seu efeito tendeu a melhorar com o decorrer dos anos. O efeito da mucuna foi significativo e positivo em Tatuí, Capão Bonito e Pindorama, mas foi nulo em Limeira e ligeiramente negativo em Engenheiro Hermilo. Em Pindamonhangaba, cujo ensaio só durou um ano, ela não poderia ter efeito fertilizante. No início dos ensaios a resposta à mucuna pouco se modificou com a presença do calcário ou da adubação com fósforo mais potássio; nos últimos anos, porém, ela se tornou mais pronunciada na presença dessa adubação ou daquele corretivo. O modo de aplicação do corretivo e dos adubos parece ter retardado consideravelmente sua influência sobre o efeito da leguminosa. Os resultados obtidos indicam que em regra o efeito da inter-calação da mucuna é excelente em solos repetidamente cultivados, mas variável, por vezes muito pequeno, nus que permaneceram incultos por vários ano.

This paper reports the results obtained in gix trials conducted in different zones of the State of São Paulo and designed to study mainly the effect of under-sowing the com crop, grown without rotation, with velvet beans (Stizolobium sp.). While one of the trials, at Piadamonhangaba, was interrupted after the first crop, the others, located at Capão Bonito, Pindorama. Tatuí, Limeira, and Engenheiro Hermilo, were conducted respectively for 10, 10, 9, 5 and 3 years. The treatments compared were the following: none; ground limestone; phosphorus and potassium; limestone, phosphorus and potassium; velvet beans; limestone and velvet beans; phosphorus, potassium and velvet beans; limestone, phosphoruB, potassium and velvet beans. The phosphorus and potassium fertilizers were applied annually in the furrows opened for the corn seed; the limestone was applied also annually and in the mentioned furrows, except in the last three years of the trials of Capão Bonito, Pindorama and Tatuí, when it was broadcast. The velvet beans were sown in a row between each pair of corn rows, after the beginning of the taaseling stage, and were turned under with the stovers few weeks after the harvest of the corn ears. In most of the experiments the corn yields were fairly to highly increased by the application of phosphorus plus potassium. The response to limestone was generally very small when judged by the averages of the whole period of each trial; it was observed, however, that in the longer trials it tended to grow better as the years passed, mainly in the presence of velvet beans. Excluding Pindamonhangaba, whose trial was conducted for only one season, the under-sowing of velvet beans increased significantly the corn yields at Tatuí, Capão Bonito and Pindorama, but not at Limeira and Engenheiro Hermilo. In the general averages of each of the experiments of Tatuí, Capão Bonito and Pindorama the response to the addition of velvet beans was practically the same in the absence or presence of either limestone or phosphorus plus potassium; during the last years, however, it was fairly better in the presence of both the amendment or the fertilizers. The application of these near the corn but far from the velvet bean plants seems to have delayed considerably their favorable influence on the effect of the leguminous. At Engenheiro Hermilo the velvet beans failed to grow, apparently because the soil was poor, the leguminous was not directly fertilized and the experiment was of short duration. The velvet beans grew fairly well at Limeira; but this trials was located on a pasture and it seems that the soil was well supplied with nitrogen. The results obtained indicate that the effect of under-sowing velvet beans is generally excellent in soils repeatedly cropped in the previous years, but doubtful in areas that have been fallow for some time.

Os autores apresentam, de forma sucinta, os principais delineamentos e processos de análise estatística utilizados na experimentação com o cafeeiro no Instituto Agronômico. Consideram quatro grupos de experimentos: experimentos de adubação, ensaios de variedades, ensaios de progênies e outros ensaios. No primeiro grupo discutem, além dós experimentos mais antigos com delineamentos sistemáticos, outros mais recentes, já com delineamentos casualizados. Consideram um experimento fatorial, o qual forneceu resultados conclusivos em poucos anos, indicando a conveniência de serem mudados alguns tratamentos. No segundo, discutem uma experiência sistemática de variedades analisada por W. L. Stevens (3). No terceiro, discutem a evolução dos delineamentos usados para a comparação de progênies e, finalmente, no quarto grupo, consideram os delineamentos para experimentos de espaçamento e outros, assim como os estudos sôbre a eficiência de parcelas com tamanhos diferentes.

An outline is given of the designs and procedures of statistical analysis followed in coffee experiments at the Instituto Agronômico de Campinas. Four groups of experiments are considered: 1) fertilizer tests; 2) varietal trials; 3) progeny tests; and 4) miscellaneous experiments. Under 1) the writers discuss old experiments with systematic layouts and more recent ones with randomized designs. A factorial experiment supplied conclusive results within a few years. The problem of changing some of the treatments arose in one of the experiments, and the solution proposed by the writers is discussed. Under 2) the treatment of data used by W. L. Stevens (1949) in the analysis of a systematic experiment comparing coffee varieties is commented in detail. The evolution in designs used for progeny comparisons is discussed under 3). In early tests progenies were compared on the basis of rows of 20 plants without replications; later the designs were changed to replicated plots of 4 plants per plot, and more recently to plots of a single plant with a higher number of replications. The results of spacing trials and of tests comparing several methods of planting-coffee are discussed under 4.) The plot size for coffee experiments is also discussed,, based on individual yield records from a planting of the Bourbon variety.

This paper was written primarily to illustrate the process of fitting constants to non-orthogonal data. The design of the experiment, on the pruning of lower branches of coffee-trees, was systematic (see plan at the beginning). Three constants were fitted, representing respectively the treatment contrast, the difference between upper and lower half of the field and the linear gradient of fertility across the field. The use of the residual sum of squares for the estimation of error is not, of course, logically correct but it is unlikely to lead to seriously wrong conclusions if caution is exercised. In the event, the procedure failed to eliminate any soil heterogeneity (see Analysis of Variance, p. 288). Inspection of the data showed that much of the heterogeneity would have appeared in a quadratic term in the gradient. When, as here, the number of data is very small, it is particularly dangerous to allow the data to suggest the scheme of adjustment, because this will lead to an over-estimation of the precision of the experiment. The conclusion was that not pruning the lower branches of tree gave an increase in yield of 104 ± 50 kg (dry fruits) per plot, with a general mean of 743 kg per plot.

A detailed statistical analysis of a balanced, incomplete block experiment with insecticides to control tomato spotted wilt is given. The effect of the treatments was studied in relation to stand an yield. The angular transformation was used for stand, and the analysis of stand and yield was made with and without the inter-block information. The results indicated that all insecticides tested, viz. Rhodiatox, Fosfern, Hexason 2510 M, Toxaphene, and tartar emetic reduced the number of plants killed by spotted wilt. The higher the concentration of the insecticides the better was the gain in stand. Some insecticides had a detrimental effect on the plant, at, high concentrations. In relation to yield the treatments could be placed in two groups : a) a group in which ilemage caused by the treatment was greater than the benefit, resulting from a better stand with no gain in yield ; b) a group in which there was also a gain in yield.

This paper describes an experiment with factorial design and two levels of treatment, used in testing fertilizer applications for tobacco seed beds. The fertilizers employed were : Chilean nitrate, superphosphate, potassium chloride, and cotton seed meal. Tobacco plants were grown in ten liter clay pots containing a steam sterilized soil composed of equal parts* of thoroughly mixed sub-soil and surface washed sand. Each of the sixteen treatments tested was applied to six pots and these were divided into three replications of two pote each. Measurements of height and weight of the plants were taken about two months after the seed germinated. An analysis of the data obtained is presented and shows that under the conditions of the test, all fertilizer applications which contained phosphate had a significant influence on plant growth. The NPK treatment was found to be the most advantageous. It was further determined that nitrogen and potash had a significant effect on plant growth in a group of eight treatments analyzed.