José Zilton Lopes Santos

Normas DRIS multivariadas para avaliação do estado nutricional de laranjeira ‘Pera’ no estado do Amazonas

In order to use nutritional-composition diagnosis or the diagnosis and integrated recommendation system of multivariate relationships (DRIS) when assessing the nutritional status of the orange, it becomes necessary to define reference values that are suitable for indicating nutritional conditions. This study aimed to establish multivariate DRIS standards, and to evaluate their comparative performance in assessing the nutritional status of the Pera orange in the state of Amazonas against nutritional standards as defined in the literature. We evaluated the nutritional status of 120 commercial plots of a hybrid of the Pera orange and Rangpur lime, the reference values being defined from the group of plots. DRIS standards for nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), boron (B), copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn) were established and nutritional diagnosis by DRIS, combined with the comparative use of generic standards to those proposed in the literature, showed a low level of agreement when assessing the nutritional status of the Pera orange in the state of Amazonas.

Resposta do feijoeiro à adubação fosfatada em solos de cerrado com diferentes históricos de uso

The different periods of tillage and forms of management may influence the availability of nutrients, including P. The objective of this study was evaluate the beans plants response to phosphate fertilizer in four Cerrado Latosols with different land use history. Samples of a clayey dystrophic Red Latosol (LVd1), a high medium texture Red Latosol (LVd2), a medium dystrophic Red-Yellow Latosol (LVAd1) and a low medium texture Red-Yellow Latosol (LVAd2) were collected in 0-20 cm depth layer in cultivated areas and surrounding uncultivated areas (native Cerrado). For each type of soil and concomitantly one experiment was carried out in greenhouse. A completely randomized design in a 2 x 4 factorial arrangement (two land use history - cultivated an uncultivated, and four P doses) with four replication. The following P doses: 0, 120, 240, and 480 mg dm-3 were used on the source triple superphosphate. The addition of increasing P doses promoted increases in all components concerning growth of bean plants, mainly dry matter and P content. The formerly-cultivated condition improved the beans plants response to fertilization especially in the lower P dose and in this condition, a higher plant absorption was noticed. The land use history influence both absorption efficiency and P use efficiency by plants. However, conditions that promote greater absorption are opposite those that allow more efficient use of nutrient, mainly in the formerly-cultivated condition. The available P in the soil was more dependent on the physical, chemical and mineralogical characteristics than land use history.

Frações de fósforo no solo em resposta à adubação fosfatada em um Latossolo com diferentes históricos de uso

No sistema plantio direto existe tendencia de melhor aproveitamento do P, sobretudo em areas cultivadas ha mais tempo, mas ha, ainda, necessidade de confirmacao deste fato. Este trabalho teve como objetivo quantificar as fracoes inorgânicas e orgânicas de P e avaliar as respostas a diferentes doses de P do feijoeiro (Phaseolus vulgaris L.) e braquiaria (Brachiaria decumbens) cultivados em sucessao, em amostras de um Latossolo com diferentes historicos de uso. O experimento foi realizado em casa de vegetacao com amostras de um Latossolo Vermelho distrofico textura argilosa e oxidico, coletadas na profundidade de 0-20 cm. O experimento foi disposto em delineamento inteiramente casualizado, em esquema fatorial 2 x 4 com quatro repeticoes, com dois historicos de uso (solo agricola cultivado por longos periodos com calagem e adubacoes fosfatadas periodicas; e solo adjacente sob vegetacao de cerrado nativo) e quatro doses de P (0, 120, 240 e 480 mg dm-3, na forma de superfosfato triplo, com base no teor de P2O5 total). Foi realizado cultivo de feijao ate a colheita dos graos e, posteriormente, cultivo de braquiaria com dois cortes no momento de florescimento das plantas. As fracoes de P foram determinadas em amostras de solo das unidades experimentais, antes e apos a incubacao dos tratamentos e apos os cultivos do feijoeiro e da braquiaria. A adubacao fosfatada aumentou as formas inorgânicas de P no solo, as quais foram maiores nos solos com historico de cultivo e adubacao. Ela tambem aumentou as formas orgânicas de P no solo, as quais foram maiores nos solos adjacentes sem historico de cultivo e adubacao, nas maiores doses de P e apos cultivo de feijoeiro e braquiaria. As respostas do feijoeiro e da braquiaria a adubacao fosfatada foram menores nos solos com historico de cultivo e adubacao.

Níveis críticos e faixas de suficiência nutricional em laranjeira-pêra na Amazônia Central obtidas pelo método DRIS

The nutritional status of orange trees depends of reference values that are appropriate to reflect their nutritional condition. The objective this work was to assess the nutrient reference values and evaluated the nutritional status of sweet orange trees in several orchard fields of Central Amazonia (municipalities of Iranduba, Manacapuru, Manaus, Presidente Figueiredo and Rio Preto da Eva). We used the Diagnosis and Recommendation Integrated System for multivariate relation (DRIS) method to establish the nutrient reference values. The nutritional status of 120 commercial orchards of orange grafted on rangpur lime was evaluated by the sufficiency ranges defined from the set of nutritionally balanced plants. For macronutrients, the nutritional sufficiency ranges were (g kg-1): 28-30 (for nitogen, N); 1.6-1.7 (phosphorus, P); 7-9 (potassium, K); 26-29 (calcium, Ca); 3.6-4.0 (magnesium, Mg); 1.7-2.0 (sulfur - S) and for micronutrients (mg kg-1): 47-56 (boron, B); 8-10 (copper, Cu); 84-93 (iron, Fe); 12-13 (manganese, Mn); 14-16 (zinc, Zn). For macronutrients, the critical levels were (g kg-1): 28 (for N); 1.6 (P); 7 (K); 26 (Ca); 3.6 (Mg); 1.7 (S) and for micronutrients (mg kg-1): 47 (B); 8 (Cu); 84 (Fe); 12 (Mn) and 14 for Zn. Nutritional standards obtained by the DRIS methods are in disagreement with the normal ranges proposed in the literature for most nutrients. In about 50% of orchards, the elements P, K, Ca, S, B, Cu e Fe were found below the critical levels. This suggests that orange producers in Central Amazonia should pay more attention to these elements when planning fertilization practices.

Lime and Nutrients Effects on Jatropha curcas Cultivated on an Amazonian Soil

ABSTRACT We evaluated the effects of macronutrient and micronutrient omission, and of liming, on Jatropha curcas (JC) in greenhouse study. The experimental design was a factorial combination of 2 liming treatments (nil or 4.5 t. ha−1 of dolomitic lime) x 7 combinations of fertility status, with five replications. The concentrations and uptake of nutrients by JC plants follow the order: nitrogen > potassium > calcium ≥ Magnesium > sulfur > phosphorus > iron > boron > manganese > zinc > copper (N > K > Ca ≥ Mg > S > P > Fe > B > Mn > Zn > Cu), but the growth of JC plants was negatively affected mainly by omission of macronutrients, in the following order: P > N = K = S, on limed soil. Phosphorus is the most critical element for development. JC is responsive to micronutrients only when applied together with macronutrients. Potassium chloride is not recommended as K+ source for JC crop. Lime is recommended to improve growth and nutritional status of JC plants.

CRESCIMENTO INICIAL DE ITAÚBA E MACACAÚBA EM RECIPIENTES DE DIFERENTES TAMANHOS

The dimensions of the container affect both the production cost and the quality of seedlings of forest species, and the pattern of response of these depends on the specificity of the species. The objective of this study was to evaluate the effect of size of containers on the initial growth of forest species Mezilaurus itauba Taub. ex Mez and Platymiscium ulei Harms. Two experiments were conducted concomitantly in nursery conditions, using the completely randomized design with five replicates. The treatments comprised of six sizes of containers: 20 cm x 15 cm (T1), 20 cm x 20 cm (T2), 23 cm x 20 cm (T3), 25 cm x 20 cm (T4), 30 cm x 20 cm (T5) and 33 cm x 23 cm (T6). After 90 days of growth, the size of containers affects differently the quality of the seedlings of both the species. The size of container 25 x 20 cm is more appropriate for the cultivation of macacauba species while the best response to itauba was obtained for the container 33 x 23 cm. On the other hand, the containers 20 x 15 cm and 20 x 20 cm should not be used for any of the tested species.

Phosphorus Sources: Effects on Growth and Phosphorus Fractions of Curauá (Ananas erectifolius L. B. Smith)

This work aimed to evaluate the effects of different phosphorus (P) sources on the initial growth and distribution of P fractions in curauá’s (Ananas erectifolius L. B. Smith) plants under greenhouse conditions. The treatments evaluated the effect of 250 mg dm−3 of P on curauá plants using five P sources: triple superphosphate (TSP), Yoorin termophosphate (YTP), Arad rock phosphate (ARP), Araxá rock phosphate (AR), and phosphoric acid (PA), plus treatment control (without P supply). The initial growth of curauá was positively affected by P supply; however, the different P sources had similar effects on nutrient uptake and growth of curauá plants. Curauá plants accumulate P preferentially as organic fraction.