Henrique Antunes de Souza

Carbono orgânico e agregação de um Latossolo Vermelho com colheita mecanizada de cana-de-açúcar

RESUMO - O uso intensivo dos solos com o cultivo da cana-de-acucar modifica significativamente as propriedades fisicas do solo. Assim, objetivou-se avaliar o efeito do manejo da cana-de-acuca r com colheita mecanizada sobre a agregacao de um Latossolo Vermelho distrofico tipico de textura argilosa, situado em Guariba (SP). Foram selecionadas quatro situacoes (ciclos) com manejo de cana-de-acucar colhida mecanicamente sem previa queima: cana-planta e canasoca de primeiro, segundo e terceiro cortes. Nas camadas de 0-0,10; 0,10-0,20 e 0,20-0,30 m de profundidade foram avaliados: diâmetro medio ponderado dos agregados (DMP), teores e estoques de carbono orgânico do solo. O manejo da cana-de-acucar com colheita mecanizada influencia o DMP do solo, cujos valores sao maiores no manejo envolvendo cana-planta e reduzem com o passar dos anos. Com o aumento da profundidade do solo, os estoques de carbono sao mais relacionados a densidade do solo do que aos teores de carbono. Palavras-chave: Saccharum officinarum. DMP. Estoque de carbono. Atributos fisicos.

Calagem e adubação boratada na produção de feijoeiro

The objective was to study the application of lime and boron on the chemical in an Oxisol in the nutritional status and yield. The doses of limestone were increasing, considering the saturation of bases 70%, corresponding doses: zero, 0.6; 1.2 (saturation of bases = 70%), 1.8 and 2.4 t ha- 1, respectively. The lime used had relative power of total neutralization (PRNT) = 131% (neutralization power, PN = 137% and reactivity, RE = 95%). The boron doses studied were equal to 0 (zero), 0.6; 1.2; 1.8, and 2.4 mg dm-3 of B, with reference to the definition of the same 1.2 mg dm-3 B (or 1.2 kg ha-1 B). It was used as a source boric acid (H3BO3) (17% B). At the time of flowering was assessed the nutritional status of plants and, at 90 days were evaluated soil fertility and yield. There was improvement in soil pH of the attributes, SB, V and the concentration of Ca and Mg, and B with the use of boron fertilization. The interaction of lime with boron fertilization increased the concentration of Ca, Mg and B in plants. The data presented demonstrate that the common bean was responsive to liming and boron fertilization, reaching good production rates with the use of 1.8 kg ha-1 of B with increasing doses of lime.

ADUBAÇÃO NITROGENADA E POTÁSSICA EM GOIABEIRAS ‘PALUMA’: I. EFEITO NA PRODUTIVIDADE E NA QUALIDADE Dos FRUTOS PARA INDUSTRIALIZAÇÃO

ABSTRACTThe nutrition of the orchards is the major factor of productivity, being necessary to know the proper doses of fertilizers and their influence on fruit quality attributes for industrialization. This study evaluated the effects of different doses of nitrogen and potassium on the productivity of guava trees and also on the values of pH, soluble solids (SS), titratable acidity (TA) and pulp/kernel ratio of guavas. The experiment was conducted at Vista Alegre do Alto, SPin an irrigated ‘Paluma’ guava orchard, 7 years old, managed with pruning during three consecutivecycles of production. The soil of the area was dystrophic Ultisol. The experimental design was the randomizedblocks, in factorial, with four nitrogen doses (0, 0.5, 1 and 2 kg of N plant-1) and four of potassium (0, 0.55, 1.1 and 2.2 kg of K2O plant-1), with three replications. Nitrogen fertilization increased productivity and the pH of the fruit, being explained by the quadratic polynomial regression models; reduced linearly the pulp/kernel ratio and do not influenced the SS and TA values. On the other hand, potassium fertilizationand N x K interaction had no significant effects on productivity and the other characteristics evaluated.

Mineralização do nitrogênio proveniente da aplicação do resíduo da indústria processadora de goiabas em Argissolo

Information on the mineralization of residues are important for proper management of these materials in agricultural areas. The objective was to evaluate the mineralization of nitrogen from the residue of guava processing industry, applied in a Ultisol cultivated with guava trees. Soil samples and the residue were placed in polyethylene pots with a capacity of 0.25 dm 3 . Around 100 g of soil plus waste were weighed in each treatment (doses of residue: 0, 9, 18 and 36 t ha -1 ), with such a procedure being performed in triplicate. The maximum incubation period was 11 weeks, with analyses at 0, 7, 14, 28, 42, 56, 70, 84, 98, 112 and 126 days of treatment. The soil+residue humidity was adjusted to 70% of the soil water retention capacity and monitored daily by weighing the pots. The inorganic nitrogen was measured in each evaluation time. It can be stated that the N mineralization or release is slow and there is not rapid availability of nitrogen. Over the period of 126 days, the mean fraction of mineralization was 23% with the half-life of 73 days.

Guava Waste to Sustain Guava (Psidium guajava) Agroecosystem: Nutrient “Balance” Concepts

The Brazilian guava processing industry generates 5.5 M Mg guava waste year−1 that could be recycled sustainably in guava agro-ecosystems as slow-release fertilizer. Our objectives were to elaborate nutrient budgets and to diagnose soil, foliar, and fruit nutrient balances in guava orchards fertilized with guava waste. We hypothesized that (1) guava waste are balanced fertilizer sources that can sustain crop yield and soil nutrient stocks, and (2) guava agroecosystems remain productive within narrow ranges of nutrient balances. A 6-year experiment was conducted in 8-year old guava orchard applying 0–9–18–27–36 Mg ha−1 guava waste (dry mass basis) and the locally recommended mineral fertilization. Nutrient budgets were compiled as balance sheets. Foliar and fruit nutrient balances were computed as isometric log ratios to avoid data redundancy or resonance due to nutrient interactions and the closure to measurement unit. The N, P, and several other nutrients were applied in excess of crop removal while K was in deficit whatever the guava waste treatment. The foliar diagnostic accuracy reached 93% using isometric log ratios and knn classification, generating reliable foliar nutrient and concentration ranges at high yield level. The plant mined the soil K reserves without any significant effect on fruit yield and foliar nutrient balances involving K. High guava productivity can be reached at lower soil test K and P values than thought before. Parsimonious dosage of fresh guava waste should be supplemented with mineral K fertilizers to recycle guava waste sustainably in guava agroecosystems. Brazilian growers can benefit from this research by lowering soil test P and K threshold values to avoid over-fertilization and using fresh guava waste supplemented with mineral fertilizers, especially K. Because yield was negatively correlated with fruit acidity and Brix index, balanced plant nutrition and fertilization diagnosis will have to consider not only fruit yield targets but also fruit quality to meet requirements for guava processing.

Uso fertilizante do subproduto da agroindústria processadora de goiabas II: estado nutricional e produção de goiabas

The knowledge about the dynamics of nutrients from the application of organic waste is needed, especially in order to recycle, since the quantity of these materials has increased rapidly over time. Thus, this study aimed to assess the nutritional status and yield of guava, depending on application of by-product from the guava processing industry. The experimental was a randomized block design with five treatments and four replications, the doses of by-product were equal zero, 9, 18, 27 and 36 t ha-1 (dry weight of the material). There were five applications of waste in 2006, 2007, 2008, 2009 and 2010. It was evaluated the nutritional status of guava (macronutrients and micronutrients), as well as fruit production for six consecutive years. The application of by-product in guavas processing industry promoted changes in the nutritional status and fruit production. Doses of by-product increased foliar content of N, Mg and Mn. Fruit yield increased linearly as a function of residue doses. The effects of the by-product were observed primarily in the soil, then in the leaf contents and finally in the production of fruits along the seasons.

DRIS Norms for Pera Orange

Chemical analysis of leaves is an effective tool for detecting nutritional imbalances and providing data for fertilizer recommendations. Therefore, it is extremely important to establish criteria for interpreting these results. The DRIS (Diagnosis and Recommendation Integrated System) method is an alternative to the interpretation of results of leaf analysis as it allows the calculation of indexes for each nutrient, using its relations with others and comparing them with a reference population. Thus, we aimed to establish preliminary DRIS norms, by both Beaufils’s and Jones’s methods, and to derive critical levels and nutrient sufficiency ranges in the leaf tissue for Pêra orange, by studying a commercial crop in the growing conditions of the São Paulo state. The methods (Beaufils and Jones) differed in the limiting nutrients in the Pêra orange orchard. The use of regional norms must be prioritized because of differences between the management methods applied. In the methods used, the nutrients that had a greater number of concordant cases in decreasing order: Mn > Mg > B > N > Cu > Fe > Zn > K > P > Ca. Amplitudes related to the DRIS methods used were narrower than the conventional literature.

Efeitos de diferentes tipos de poda nos teores de nutrientes em flores e frutos de goiabeira

Um melhor conhecimento das diferencas entre os teores de nutrientes, em funcao do tipo de poda empregada na cultura da goiaba, pode permitir compreensao mais adequada dos processos fisiologicos nessa frutifera. A analise de flores e uma ferramenta que pode ser utilizada para auxiliar na avaliacao do estado nutricional das culturas, especialmente as perenes. Assim, avaliaram-se os efeitos de diferentes tipos de poda nos teores de nutrientes em flores e frutos (em diferentes estadios de desenvolvimento e, em diferentes partes das goiabas). O estudo foi realizado em Vista Alegre do Alto, em pomares de goiabeiras ‘Paluma’. Foram coletados flores e frutos em pomares distintos, sendo um deles conduzido sob poda drastica e outro sob poda continua. Os frutos foram coletados em dois estadios (chumbinho e maduro) e divididos em parte proximal e distal, sendo a parte proximal voltada para o pedunculo. As flores tambem foram coletadas nos mesmos pomares da coleta de frutos, amostrando-se a parte proximal e basal das flores. Foi realizado o teste F e, quando necessario, aplicado o teste de Scott-Knott a 5%. Verificou-se que, de maneira geral, ha diferencas nutricionais para flores e frutos em relacao ao tipo de poda empregada, sendo que a poda drastica proporciona maiores teores de nutrientes, em comparacao com a poda continua. Em relacao a parte amostrada observou-se, principalmente para os frutos, que ha diferencas entre a parte proximal e distal, bem como para os diferentes estadios de coleta dos frutos.

Folha diagnótica para avaliação do estado nutricional do feijoeiro

The bean is a nutrient demanding plant, either due to the small and shallow root system or due to the short cycle. A study with doses of lime and boron was conducted and correlations were made between two types of leaf (+1 and +3) of the bean with the contents of these elements in plants and production, aiming to establish the most appropriate leaf for diagnosis of nutritional status. The experiment was conducted in greenhouse conditions employing bean seeds cv. BRS Talisma. Lime rates considering the saturation of bases (70%), were calculated as zero, half the standard dose, dose to increase V = 70% (default), one and a half and twice the standard dose, while the boron amounts used were: zero, 0.6, 1.2, 1.8 and 2.4 mg B dm-3. At the time of flowering, diagnostic leaves +1 and +3 (mature leaves from the apex) were collected along with sampling of a plant (aerial part) per pot and the measurement of production. Through correlations it was verified that nutrients, calcium, magnesium and boron in the leaf +3 showed higher correlation coefficients with levels in the plant and production data.

Application of a byproduct of guava processing in an Ultisol, in the presence and absence of mineral fertilization.

There is a relative lack of technical studies on the adequate management of organic wastes from food processing. The aim of this study was to evaluate the effect of applying doses of a byproduct from guava processing, in the presence and absence of mineral fertilization, on the fertility of a an Ultisol (or Red-Yellow Argisol) under laboratory conditions. An entirely randomized 5x2 factorial experimental design was used with five byproduct doses, in the presence and absence of mineral fertilization, with four repetitions, for a total of 40 experimental units. Under the experimental conditions, the attributes pH, OM, K, Mg, BS, T, V, B, Fe, Zn and S-SO42- were affected by the guava byproduct doses, as well as by the presence or absence of mineral fertilization. With the use of this fertilization, the variables OM, K, H+Al, T, Fe and Zn increased more as a function of byproduct dose than in the absence of fertilization. The results obtained demonstrate the potential of using this waste material in the cycling and supply of nutrients.