Eulene Francisco da Silva

INOCULAÇÃO DO FEIJOEIRO COM RHIZOBIUM TROPICI ASSOCIADA À EXSUDATO DE MIMOSA FLOCCULOSA COM DIFERENTES DOSES DE NITROGÊNIO

The aim of this work was to evaluate the effect of the Rhizobium inoculation, associated with seed exudates of Mimosa flocculosa, under different rates of nitrogen fertilization was evaluated in bean crops following soybean (Glycine max L. Merril) and corn (Zea mays L.). The experimental design was randomized blocks with four replications, with treatments arranged in sub-divided parcels. The parcels were constituted of two summer crops preceding the common bean crop: soybean and corn. In the sub-parcels three treatments involving inoculation of the common bean seeds were considered: control treatment without inoculation; bean seeds inoculated with Rhizobium tropici, strains CIAT 899 and PRF 81, and the association of Rhizobium with the exudates of the Mimosa flocculosa seeds. The sub-subparcels received of four doses of nitrogen fertilization applied on covering: 0, 40, 80 and 120 kg ha-1 N. The inoculation of Rhizobium associated with the addition of exudates of Mimosa flocculosa seeds resulted in higher shoot dry weight. Besides that, the nitrogen fertilization, on the tested doses, reduced, in a linear way, the nodulation of the bean plant. It was also verified that corn as a preceding crop for bean has contributed to the increase of the weight of 100 grains, while the addition of combined N did not contribute to the improvement on the number of beans per plant, neither of the grain yield of bean plants, independent of the dose that was used.

Frações lábeis e recalcitrantes da matéria orgânica em solos sob integração lavoura‑pecuária

The objective of this work was to evaluate the soil total organic carbon (TOC) and total nitrogen (TN) stocks, C and N in labile and recalcitrant fractions of the soil organic matter (SOM), and the C management index, in soils under integrated crop-livestock (ICL) system after four (ICL4) and eight years (ICL8) of settlement. For comparison purposes, other management systems were used: pasture and crop under no tillage (NT), besides native vegetation. The experiment was carried out in a completely randomized block design, with five replicates. The crop-livestock established in a period of eight years can reach a new steady state equivalent to the no-tillage with 23 years of implementation. There was accumulation in total organic carbon of 101.0 (ICL8) and 104.2 Mg ha -1 (NT), and N total stock of 5.5 (ICL8) and 5.8 Mg ha -1 (NT) in the 0-30 cm layer, as well as increase in the stock of labile and recalcitrant C and N fractions of SOM. For crop-livestock with eight years, the C management index of 88 was higher than other management systems, and not different from native vegetation (0-10 cm), however, it was similar to NT in the analysis of the entire profile (0-30 cm).

PEDOGÊNESE E CLASSIFICAÇÃO DE SOLOS DA FAZENDA EXPERIMENTAL “RAFAEL FERNANDES” NO MUNICÍPIO DE MOSSORÓ, RN

The Rafael Fernandes experimental farm is located in the Alagoinha district, northwest of Mossoró, State of Rio Grande do Norte, Brazil, over two pedogenic formations of different edaphic characteristics, thus needing a more detailed description of its soil types, since this area hosts several experimental fields for researches on agriculture. The objective of this work was to characterize the morphological, physical, chemical and mineralogical features of the most representative soils of this farm, in order to understand its pedogenesis and define its classifications. The whole area was surveyed in order to assess its more representative pedogenic formations. Three soil profiles were classified and described, from which samples were collected in all horizons for physical, chemical and mineralogical analysis. The parent materials and the relief were the determining factors for pedogenic processes of desilication, podzolization and laterization, generating the three main soil types of the area, which were classified up to the 4 th categorical level and described as: Typic Rhodustults (P1), Rhodic Haplustox (P2) and Typic Plinthustalfs (P3).

Estudo nutricional da canafístula (II): eficiência nutricional em função da adubação com nitrogênio e fósforo

The objective of this study was to evaluate the effect of combined levels of N and P in nutrient content and nutritional efficiency in seedlings of canafistula (Peltophorum dubium Spreng. Taub.) on Oxisol. The experiment was carried out in pots of 4 dm 3 , with treatments arranged in 4x4 factorial scheme, four N levels (0, 20.82, 41.64 and 62.46 mg kg -1 N) and four P levels ( 0, 41.72, 83.72 and 125.16 mg kg -1 of P 2 O 5 in a randomized block design with three replications. The highest levels of N and P showed higher accumulation of nutrients in both the shoot and root while for the micronutrients that effect was caused only by P. The species showed high nutritional requirement for N, P used more efficiently and supply of nutrients is greater for shoot seedling.

Cultivo de gladíolos em função das doses de calcário e potássio

Para o cultivo do gladiolo no Cerrado, caracterizado por solos de baixa fertilidade e elevada acidez, faz-se necessario o uso de corretivo agricola e fertilizacao, especialmente a potassica. Assim, o objetivo desta pesquisa foi avaliar o efeito de diferentes doses de calcario e de potassio na producao comercial de plantas de gladiolo, cultivadas em um Latossolo Vermelho Distroferrico. O experimento foi conduzido na UFGD, em Dourados (MS). O delineamento experimental constou de blocos casualizados com quatro repeticoes, sendo que a unidade experimental foi composta por duas plantas de gladiolos, cultivar Peter Pears, cultivadas em vaso plastico de 5 L. Os tratamentos foram arranjados em parcelas subdivididas, sendo que nas parcelas foram alocadas as cinco doses de calcario dolomitico (0, 1, 2, 4 e 8 t ha-1) e, nas sub-parcelas, as cinco doses de K2O (0, 20, 40, 80 e 160 kg ha-1), utilizando-se como fonte o cloreto de potassio (KCl). Determinaram-se o comprimento das folhas, o inicio da floracao, a durabilidade e o numero de botoes florais, a altura da planta e o comprimento das espigas. Apos a floracao, avaliou-se a materia fresca, comprimento e diâmetro dos cormos produzidos e o teor de nutrientes da parte aerea. O comprimento das folhas, inicio da floracao e durabilidade dos botoes florais nao foram influenciados pela calagem nem pela adubacao potassica. O excesso de K e CaCO3 foram prejudiciais a altura da planta e ao comprimento da espiga floral, reduzindo o numero de botoes florais e o diâmetro dos cormos produzidos; doses elevadas de K2O diminuiram a absorcao de magnesio pelas plantas. Conclui-se que as doses de calcario e potassio estudadas nao foram eficientes para produzir plantas de gladiolo classificadas comercialmente como extras.

Estudo nutricional da canafístula (I): crescimento e qualidade de mudas em resposta à adubação com nitrogênio e fósforo

Canafistula is an important native forest species, found in Cerrado, which still lacks on nutritional information and obtaining quality seedlings. Therefore, this study aimed to evaluate the effects of the addition of nitrogen and phosphorus on initial growth and seedling quality of canafistula (Peltophorum dubium Spreng. Taub.) grown in Oxisol. The experiment was carried out in 4 dm 3 pots with treatments arranged in 4x4 factorial scheme, with four N levels (0, 20.82, 41.64 and 62.46 mg kg -1 N) and four P levels (0, 41.72, 83.72 and 125.16 mg kg -1 of P 2 O 5 ) in a randomized block design with three replications. Were evaluated the growth characteristics (height, stem diameter and dry mass of shoots and roots) and quality parameters of seedlings (ratio height/diameter RAD; ratio dry mass of shoot / root dry weight RPAR, and Dickson Index). There was significant interaction between N and P for all growth characters and quality parameters evaluated. The highest level of N and P showed higher growth of seedlings. However, regarding the quality of seedlings, the Dickson index indicated that the phosphorous is the most important element.

Temporal decomposition sampling and chemical characterization of eucalyptus harvest residues using NIR spectroscopy and chemometric methods

Near-infrared (NIR) spectroscopy and chemometric methods were used to predict the chemical properties of decomposing eucalyptus harvest residues to better understand the decomposition process of these materials. Leaves, twigs, branches, and bark from a decomposition experimental set up in commercial plantations were sampled for one year. The contents of carbon (C), nitrogen (N), extractives (EX), acid-soluble lignin (SL), Klason insoluble lignin (KL) and holocellulose (HC) were determined by the reference method in the collected samples. Principal component analysis (PCA) was employed to distinguish the types of harvest residues throughout the decomposition period. Multi-residue regression models were built from the NIR spectra using partial least squares regression (PLS). Two feature selection methods, i.e., ordered predictors selection (OPS) and genetic algorithm (GA), were applied and compared. The OPS and GA did not differ statistically; however, compared with the GA, OPS was more computationally efficient and selected fewer variables. Using the PLS-OPS models, the root mean square errors of prediction (RMSEP) for C, N, EX, SL, KL and HC were 19.70, 0.08, 0.74, 0.39, 28.13 and 33.99, respectively, and the prediction correlations (Rp) for these properties were 0.94, 0.99, 0.99, 0.99, 0.96 and 0.98, respectively. PLS-discriminant analysis (PLS-DA) was used to classify the samples over the decomposition time and provided a good separation. Some mismatches obtained in the modeled classes were explained by the differences in the decomposition rate and changes in the chemical composition of the different harvest residue components that were evaluated. The results showed the feasibility of NIR spectroscopy and chemometric methods to evaluate the chemistry of decomposing eucalyptus harvest residues, indicating that these methods can be used as rapid and inexpensive alternatives to conventional methods to help understand the decomposition process.

Inceptisol Physicochemical Attributes in the Caatinga Biome Agroforestry Systems

We evaluated two areas of sustainable management within the Caatinga and one area of conventional agricultural cultivation to compare their physicochemical attributes with those of native forest. The management strategies were as follows: (1) thinning of savanna; (2) thinning of strips; (3) conventional tillage with plowing and harrowing; and (4) native forest. The main indicators of physicochemical quality of the environments were bulk density, porosity, clay amount, phosphorus content, cation exchange capacity, and organic matter. The use of soil for agricultural purposes resulted in a reduction of soil organic matter, regardless of the tillage system. Even though the management strategy, which involved thinning of savanna, further increased the soil phosphorus content and compaction, it did not reach critical values that limit crop development.

Adubação fosfatada no desenvolvimento de Hemerocallis fulva L.

In clayey Oxisol from the Brazilian Cerrado, where there is high P fixation, the phosphorus fertilization is necessary to increase the growth and flowering of ornamental plants. Thus, the objective of this study was to analyze the development of Hemerocallis as affected by phosphorus application in clayey Oxisol (Typic Haplustox). The experiment was conducted at the Gardening area of University Federal of Grande Dourados (UFGD) in Dourados-MS, Brazil. The experimental design was a randomized block with four replications. The treatments consisted of four P2O5 rates (0, 250, 500, 1000 kg ha-1) using simple superphosphate as source. The experimental unit was composed of one Hemerocallis fulva ‘Flore Pleno’ plant, grown in a plastic pot (5 liters). Phosphorus fertilization increased linearly the concentration of phosphorus in the soil; the plant had maximum absorption (5.26 g kg-1) with the calculated dose of 727 kg ha-1 P2O5. H. fulva has a root system that develops best under high availability of P, however, for aerial part, the maximum of shoots fresh mass (451.1 g) was obtained with 427 kg ha-1 of P2O5. Number of flower buds, flower diameter and height flower stalks were higher in the presence of phosphorus.