J. Romano Gallo

Alguns estudos preliminares sôbre possíveis problemas de fertilidade, em solos de diferentes campos cerrados de São Paulo e Goiás

Este trabalho representa uma primeira contribuicao para o estudo da fertilidade dos solos de campos cerrados. Tais solos, que ocupam importante superficie do territorio nacional, apresentam muitas vezes boas propriedades fisicas e regulares disponibilidades de agua, que parecem estar em desacordo com a pobreza da vegetacao neles desenvolvida. Uma deficiencia ou um agudo desequilibrio de nutrientes deve, pois, estar envolvido. De fato, a cultura em vasos permitiu verificar uma acentuada deficiencia em fosforo nas amostras estudadas, assim como um menor crescimento do capim que nao recebeu nitrogenio. A producao foi tambem menor em todos os quatro solos de Goias, quando se omitiram, num tratamento, enxofre, cobre, zinco, ferro, boro e molibdenio.

Amostragem em cana-de-açúcar, para fins de analise foliar

A group of 576 leaf samples of cane, variety CB.41/76. was collected form a 23 NPK factorial experiment in order to determine the most raliable sampling technique as a basis for the local conditions of the State of Sao Paulo. The selection of tissues for analysis was carried out on the plantation with respect to the age at sampling time (4, 5. 6, 7, 8 and 9 months in age), leaf part (blades, blades with midribs removed, and sheaths), and leaf position (leaves +1, +2, +3 and +4). This included the four youngest visible-dewlap leaves on the cane top, numbered according to the system of Kuijper. After each tissue was analyzed for N, P, K, Ca and Mg, the data were examined statistically, taking into account the response to the element supplied as fertilizer, as indicated by cane yields at harvest. As a result of these studies and considering the amount of work required in the laboratory tests and in taking samples in the field, it is suggested, for foliar analysis purposes, to select the leaf of position +3 in plant 4 and 8-9 months old: from the selected leaves the middle 8 inches of the leaf-blades with the midribs stripped furnish the most suitable material for total ntrogen, phosphorus, potassium, calcium and magnisium determinations. The use of one-sample technique at 4 months affords low operating costs. However, the use of two-sample technique is probably more suitable to indicate the nutritional status of sugar cane under the condition of soil and climate in the State of Sao Paulo, where the cane is usually harvested at 16-18 months.

Composição inorgânica das fôlhas de laranjeira baianinha, com referência à época de amostragem e adubação química

O presente trabalho representa a primeira contribuicao ao estudo da diagnose foliar dos citros, para as nossas condicoes. Sao estudadas as variacoes nos teores de nitrogenio, fosforo, potassio, calcio e magnesio nas folhas de laranjeira baianinha enxertada sobre cavalo de laranja caipira (Citrus sinensis, Osbeck), de um experimento de adubacao iniciado em 1947 na Estacao Experimental de Limeira, do Instituto Agronomico, e apresentadas as tendencias das curvas de concentracao para esses elementos. Alem disso, o estudo em apreco teve por objetivo verificar os efeitos da adubacao nitrogenada, fosfatada e potassica sobre o nivel daqueles constituintes, nas folhas. Os resultados obtidos mostraram que a composicao quimica das folhas foi sensivelmente modificada com a idade das mesmas e pela adubacao.The results reported herein represent the first step in diagnosing the nutrient status of citrus trees by means of foliar analysis, for the average conditions of the State of Sao Paulo. A study was made concerning the seasonal variation in nitrogen, phosphorus, potassium, calcium and magnesium levels of spring-cycle Baianinha orange leaves. The trees were budded on sweet orange rootstock (Citrus sinensis Osbeck) in a foctorial fertilizer experiment started in 1947. The mineral composition changed with the age of leaves. Generally the N, P, K, and Mg contents decreased, while Ca increased fast in the young leaves and remained without great variation until the end of the cycle. Leaves 3 to 6 and 10 months old are suitable for sampling if referred to respective standards. Nitrogen and phosphorus levels in leaves increased linearly with fertilizer application, while potassium increases were due only to o single dosis. Application of fertilizer containing nitrogen shows o tendency to reduce the levels of P and K, and to increase Mg in the leaves. The simple superphosphate applied decreased the levels of N and K, and increased Ca in the leoves. There was a decline in Ca and Mg contents of leaves with potassium fertilizer application. The following negative correlations between leaf nutrients were found to be significant: 1) nitrogen and phosphorus; 2) nitrogen and calcium; 3) potassium and calcium; 4) potassium and magnesium.

Levantamento do estado nutricional de canaviais de São Paulo, pela análise foliar

Estudo da composicao das folhas de cana-planta e de cana-soca de primeiro corte, em diferentes regioes canavieiras do Estado de Sao Paulo. Amostras de duas variedades, em duas idades, de cana-planta, e numa de soca, foram analisadas para doze elementos: N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, Mo e Zn. Pelo levantamento nutricional foi feita a distribuicao dos teores de cada elemento, por frequencia. A evidencia das variacoes na composicao das folhas, permitiu a interpretacao das analises com base nas faixas criticas de teores admitidas para cada amostragem e variedade. Os elementos K, Mg, N, P, S e Fe foram os que apresentaram maior porcentagem na faixa de carencia.

Levantamento de cafèzais do Estado de São Paulo pela análise química foliar II: Solos Podzolizados de Lins e Marília, Latossolo Roxo e Podzólico Vermelho Amarelo-Orto

Em amostras de 134 cafezais, distribuidos nos principais grupos de solos do Estado de Sao Paulo, colhidas em tres estacoes do ano, foram determinados 12 elementos quimicos essenciais, sodio e aluminio. A percentagem de cafezais deficientes em nitrogenio foi superior a 80% em todos os solos. No Podzolizado de Lins e Marilia, o segundo elemento em falta foi o ferro. No Latossolo Roxo, depois do nitrogenio, a maior deficiencia foi a de potassio e zinco; no Podzolico Vermelho Amarelo-Orto, a de boro.

Determinação de cálcio e de magnésio em plantas, por fotometria de chama de absorção

As concentracoes de calcio e magnesio em extratos de plantas podem ser determinadas por fotometria de chama de absorcao com a precisao e exatidao requeridas, mediante a adicao de lantânio na concentracao de 0,1 %,como agente protetor. Para obtencao dos dados utilizou-se um espectrofotometro Perkin-Elmer, modelo 303, equipado com sistema digital de leitura.

Absorção de nutrientes pela batatinha

A marcha da absorcao dos elementos nutritivos essenciais pela batatinha (Solanum tuberosum L.) foi estudada em plantas cultivadas em vasos de barro, interna, mente vidrados, e com capacidade para 10 quilos de terra. Em cada 10 dias, durante todo o ciclo vegetativo, eram colhidas plantas e analisados os teores de N, P, K, Ca, Mg e S. Todas as plantas receberam os mesmos cuidados em tratos culturais, fitossanitarios e agua. Propiciaram-se, ainda, iguais condicoes de fertilidade, dando-se a todos os vasos adubacao completa, inclusive com os micronutrientes necessarios ao bom desenvolvimento e producao da batata. Os resultados obtidos mostram que a batata absorve em grande quantidade o nitrogenio e o potassio, sendo o ultimo em maior proporcao. Dos outros elementos estudados, o fosforo, o calcio, o magnesio e enxofre, sao absorvidos em pequenas quantidades, nao ultrapassando nenhum deles 16 kg/ha. Os dados mostram ainda que as quantidades totais necessarias de nitrogenio, potassio, magnesio e enxofre sao absorvidas pela cultura, ate completar 50 dias apos a germinacao, enquanto o fosforo e o calcio sao requeridos desde o inicio ate o final do ciclo vegetativo da planta.

A análise foliar na nutrição do milho: I - Correlação entre analise de fôlhas e produção

A correlation between foliar analysis and yield of corn was established, based on 31 fertilizer experiments conducted during the period of 1962-64, at 16 different localities of the State of Sao Paulo. In these trials five levels each of N, P2O5 and K2O were used; plots with and without sulfur were also included. Arranging in groups all the trials showing positive coefficients of correlation for total nitrogen (24 trials) and phosphorus (26 trials), the following correlations for total nitrogen (24 trials) and phosphorus (26 trials), the following correlations were found in each case: nitrogen, r = 0.51**, y - 4.26 + 28.66 x; phosphorus, r = 0.47**, y = 43.21 + 160.83 x. As the K content of levaves was affected mainly by soil type, the correlations for leaf potassium were obtained separately special consideration being given to this circumstance. The nitrate content of midribs, required for best yields, varies in the same year from locality to locality and in the same site, from year to year. This uncontrollable variability, of course, makes the interpretation of nitrate data difficult. The plants not receiving sulfur averaged low yields and had lower sulfate--sulfur content in the leaves. [The normal ones had 40 kg S per hectare but all plots received a central dose of 60 kg per hectare of each N or P2O5, and 30kg per hectare of K2O] . It seems that the mean values for calcium and magnesium in leaves, obtained from the range of levels which provides high yields, may be indicative of normal composition. Limiting leaf nutrient values associated with 80 per cent maximum yields in the field are as follows: nitrogen (N), 2.90%; phosphorus (P), 0.230%; potassium (K) - latosolic B terra roxa type of soil, 1.70%; gravelly podzolized soils, 2.80%; other soil types, 2.10- 2.70%.

Composição química do feijoeiro e absorção de elementos nutritivos, do florescimento à maturação

The purpose of this investigation was to gain information on the rate of dry matter production and nutrient absorption of bean plants. Samples of fertilized and unfertilized bean plants, grown on «terra-roxa-misturada» type of soil at Campinas and under field conditions, were taken at various stages of growth. They were divided in roots, stems, leaves and fruits and have been analyzed for N, P, K, Ca, Mg, and S. At maturity the seeds were separated from the pods and analyzed separately. With the exception of calcium in the leaves, the percentage of all mineral elements tended to reach a maximum in the various plant parts at about blooming and pod-forming stage. The total seeds and pods contained more nitrogen and phosphorus, and less calcium, magnesium and sulphur throughout the season. The percentages of potassium, calcium and magnesium in leaves were higher than in other plant parts. Total sulphur content was higher in the roots than in leaves, stems or pods plus seeds. Nitrogen and potassium were absorbed in greater total amount than phosphorus and other elements. The unfertilized mature plants contained 29 and 23 kg of nitrogen and potassium respectively per hectare. Phosphorus was absorbed in a smaller amount than any other nutrient studied. The maximum absorption rate changed according to the element and was modified by treatment. In fertilized plants the maximum rate of uptake of calcium and magnesium from the soil ocurred during the interval 33 to 44 days from sowing; potassium, 44 to 53 days; and nitrogen, phosphorus and sulphur, 53 to 65 days, the period of growth of seed in the pod. Table 7 shows the distribution of total nutrient in roots, stems, leaves, and pods plus seeds in the mature plant. Data presented in the foregoing pages suggest certain practical considerations of interest. Environmental conditions during the early growth stages were generally favorable, but a deficiency in precipitation that occurred in the period of pod formation and seed development depressed the yield. However, fertilization promoted an increase in the uptake of nutrients, dry matter production, and in yield of bean. Since only the level of phosphorus was higher in the plant of the fertilized plot, it is assumed that phosphate fertilization induced such increase. Analytical results indicate that relatively large quantities of bases will be removed from the land if the entire bean plant is harvested, whereas if seeds alone are harvested only nitrogen and phosphorus are removed in relatively large amounts. The soil becomes most impoverished by the removal of potassium, nitrogen being less affected due to a partial supply from fixation of atmospheric nitrogen. The results showing that nitrogen absorption rate is maximum at the time the seeds are developed suggest that a delayed nitrogen application for beans might be desirable since the plant needs at this stage may not be satisfied by nitrogen fixation alone. This late nitrogen application would not interfere with the early steps of the symbiotic process.

Influência da variedade e do porta-enxêrto, na composição mineral das fôlhas de citros

The influence of five different combinations scion-rootstock for two scion varieties on the percentage of nitrogen, phosphorus, potassium, calcium, and magnesium in citrus leaves is reported. Leaves from fruiting shoots of two spring flushes were taken from Baianinha and Pera oranges trees (Citrus sinensis Osbeck) on two experimental orchards located in the Experiment Station of Limeira, State of Sao Paulo. The rootstocks On which they are budded and used for this study were: Pera orange, and sweet orange (C. sinensis Osb.), Rangour lime (C. reticulata Blanco X C- aurantifolia Swing (?)), rough lemon (C. limon Burm. f. X (?)), and Cleopatra mandarin (C. reticulata Blanco). In the spring of 1957 when the leaf sampling was started the trees on sweet orange, Rangpur lime and rough lemon rootstocks were 21 years old and those an Pera and mandarin rootstocks 7 years old, but only plants of the same age were compared. Fertilization was uniform in all plots and the soil apparently very uniform. Confidence limits for the mean results of inorganic composition of leaves 3 to 6 months old of two flushes are presented. Seasonal changes in nutrient composition of leaves ore olso shown. The leaves of both scion varieties differed in their principal mineral constituents. The major difference was found in the potassium content. Leaves of Baianinha orange trees contained relatively more potassium than Pera orange leaves. The composition of leaves changed according to the rootstock species. Differences in potassium, calcium, and magnesium levels in leaves of the some scion variety were found to be significant when Pera orange and Cleopatra mandarin were the rootstocks. Variations in the composition of scion leaves in the older combinations could be associated with virus disease tolerance and longevity of species. In view of the results obtained, other factors such as virus diseases, longevity, etc. besides varietal effects and selectivity of rootstocks to absorb nutrients, must be taken into account in attempting to associate the results of foliar analysis with fertilizer utilization by citrus trees.