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Amostragem para avalia？？o da fertilidade do solo em fun？？o do instrumento de coleta das amostras e de tipos de preparo do solo
Oliveira, Fábio Henrique Tavares de;Arruda, Jandeilson Alves de;Silva, Ivandro de Fran？a da;Alves, Jailson do Carmo;
Revista Brasileira de Ciência do Solo , 2007, DOI: 10.1590/S0100-06832007000500014
Abstract: the measures of the average and variability of soil fertility indexes can vary with the sampling tool and soil tillage type. soil sampling methods must be developed that are more reliable to represent the real conditions of soil fertility. this study aimed at an evaluation of the effects of the cutting shovel and hand auger on measures of average and variability of the soil fertility index (a) under no-tillage (nt) and conventional tillage (ct), (b) to estimate the minimum number of simple samples to form a composite sample and (c) to test the hypothesis that the arithmetic average of simple samples is equal to the result of the chemical analysis of the composite sample. chromic luvisol samples were collected in a control experiment of soil tillage type, planted with corn. in a 81 m2 plot under nt 48 simple soil samples were collected, 24 with a cutting shovel (perpendicularly to the furrow and in-between two furrows) and 24 with auger hole, in controlled sampling (four samples collected in the planting furrow, 8 to 10 cm away from the furrow and 12 in-between the furrows), close to the points of sampling with the cutting shovel. the procedure was repeated in a second plot under ct. composite samples of different numbers of simple samples (4, 8, 12, 16 and 24 simple samples/composite samples), with three repetitions were prepared for each combination of soil tillage type - collection tool. the ph and the contents of p, k+ ca2+, mg2+ and organic matter (om) were determined in all simple and composite samples. the variability of the evaluated characteristics in samples collected with auger hole was greater than with the cutting shovel, independent of the soil tillage type. for both collection tools, the decreasing order of variability was: p > mg2+ > k + > ca2+ > om > ph. the medium fertility of a field under nt or under ct after the crop and before subsequent soil preparation can be evaluated with the auger hole, substituting the cutting shovel, if the composite samp
Acúmulo de matéria seca, absor？？o e exporta？？o de micronutrientes em variedades de bananeira sob irriga？？o
Hoffmann, Ricardo Bezerra;Oliveira, Fábio Henrique Tavares de;Gheyi, Hans Raj;Souza, Adailson Pereira de;Arruda, Jandeilson Alves de;
Ciência e Agrotecnologia , 2010, DOI: 10.1590/S1413-70542010000300002
Abstract: to estimate the demand of micronutrients for the banana plants (musa spp.), it is essential to know the amounts of dry matter and micronutrients accumulated in the plant and exported by the bunch. the objective of this study was to evaluate the accumulation of dry matter and micronutrients by six banana varieties under irrigation. plants of grande naine, pacovan, pacovan-apodi, prata-an？, terrinha and gross michel varieties grown in double rows, with a density equivalent to 1,666 plants per hectare were sampled. at harvest four plants of each variety were selected for sampling of mother-plant, which was divided into rhizome, pseudostem, petiole, leaf blade, stalk and fruits. the plant parts were weighed to determine the fresh weight of each part and a sample of about 700 g of each part was collected to determine dry weight and contents of micronutrients. the samples were washed quickly with tap water and later with distilled water and placed in a greenhouse for pre-drying and afterwards conditioned in paper bags were put in an oven of forced circulation of air for obtaining the dry matter and subsequent determination of the contents of b, cu, fe, mn and zn. the varieties pacovan, prata an？ e pacovan apodi accumulated greater amounts of dry matter and micronutrients, when compared to the varieties grande naine, gross michel e terrinha, observing the following decreasing order of accumulation and export of micronutrients: mn > fe > b > zn > cu.
Produtividade e acúmulo de nitrato nos frutos de abobrinha em fun？？o da aduba？？o nitrogenada
P？rto, M？nica Lima Alves;Puiatti, Mário;Fontes, Paulo Cezar Rezende;Cecon, Paulo Roberto;Alves, Jailson do Carmo;Arruda, Jandeilson Alves de;
Bragantia , 2012, DOI: 10.1590/S0006-87052012005000020
Abstract: despite zucchini nutritional and commercial importance, few studies have been carried out with the nitrogen fertilization of the culture. the objective of this research was to evaluate the zucchini yield (cv. caserta) and nitrate accumulation in the fruits as a function of the nitrogen fertilization. the experiment was set in a randomized block design with five rates of mineral n (0; 50; 100; 200 and 400 kg ha-1), with four replications. the number of fruits per plant, average fruit mass, fruit yield and nitrate accumulation in the fruits were significantly affected (p<0.01) by n rates. the maximum number of fruits per plant (7.7 units), mean fruit weight (240 g fruit-1) and fruit yield (29.88 t ha-1) were obtained with 323, 265 and 331 kg ha-1 of n, respectively. the maximum economical efficiency rate of n for the culture of the zucchini was 322 kg ha-1, resulting in a fruit yield of 29.86 t ha-1. the nitrate content in the zucchini fruits presented linear increment as a function of n rates. at the highest n rate, the nitrate content in the fruit fresh matter was 162 mg kg-1. this nitrate contents value does not represent risk for human health.
Fósforo em solos representativos do estado da paraíba: II- disponibilidade de fósforo para plantas de milho
Farias, Daise Ribeiro de;Oliveira, Fábio Henrique Tavares de;Santos, Djail;Arruda, Jandeilson Alves de;Hoffmann, Ricardo Bezerra;Novais, Roberto Ferreira;
Revista Brasileira de Ciência do Solo , 2009, DOI: 10.1590/S0100-06832009000300016
Abstract: the soil fertility laboratories of the state of paraíba use only mehlich-1 as extractant to evaluate soil available p, independently of the soil weathering degree. since most soils of the state are less weathered than elsewhere in brazil, the efficiency of mehlich-1 and of other extractors to evaluate the plant p availability must be tested. the objective of this study was to evaluate the efficiency of mehlich-1 (m-1), mehlich-3 (m-3), bray-1 (b-1) and mixed ion exchange resin (rti) as extractants for the quantification of available p for corn plants in soils of the state of paraíba. samples of 12 representative soils of the state were collected in the 0- 30 cm layer (six with higher and six with lower weathering degree), with a wide variation of physical and chemical properties. rates of 0; 43.75; 87.5; 175 and 350 mg dm-3 p were applied to the soils pa, pve, la, rl, tx, sx and ry. to the soils pac and rr rates of 0; 37.5; 75; 150 and 300 mg dm-3 p were applied. for the soils pva, pvd and vx the p rates were 0; 51.25; 102.5; 205 and 410 mg dm-3. the experiment was carried out in a greenhouse and the applied p rates were homogenized in 100 % of the soil volume of each pot (3 dm3). corn plants were cultivated for 30 days and the critical p levels in the soil were determined by the extractors as well as the critical p level in the plant. regardless of the applied p dose, m-3 extracted the most p from the soils while b-1 extracted the least. at low p doses, m-1 and rti extracted similar p quantities, but at higher doses rti extracted more p than m-1. opposite to what was verified for the plant and for rti, for the extractants m-1, m-3 and b-1 the p recovery rate was correlated with fcp. on the other hand, the critical p levels in the soil by the extractants m-1, m-3 and b-1 and the critical p levels in the plant were not correlated with soil properties that determine fcp. an opposite pattern was observed for the critical p levels in the soil by rti. since there was a g
Fósforo em solos representativos do estado da paraíba: I- isotermas de adsor？？o e medidas do fator capacidade de fósforo
Farias, Daise Ribeiro de;Oliveira, Fábio Henrique Tavares de;Santos, Djail;Arruda, Jandeilson Alves de;Hoffmann, Ricardo Bezerra;Novais, Roberto Ferreira;
Revista Brasileira de Ciência do Solo , 2009, DOI: 10.1590/S0100-06832009000300015
Abstract: knowledge on the phosphorus capacity factor (pcf) of soils of the state of paraíba is important to improve the interpretation of the available phosphorus (p) content and the recommendation of phosphate fertilization in soils of the state. the objective of this study was to evaluate the parameters of p adsorption isotherms (langmuir and freundlich) by the techniques of non-linear regression and linearization, in soil samples of the state of paraíba, and to correlate the values of these parameters with chemical and physical soil properties. samples of 12 representative soils of the state of paraíba were collected in the 0-30 cm layer (six soils with a higher and six with a lower weathering degree), with a wide variation of values of physical and chemical properties within each group of six soils. the hyperbolic model of the langmuir isotherm was adjusted by the technique of non-linear regression (single region) and of linearization (first region and second region). correlation analyses were performed with the values of isotherm parameters and soil properties that reflect the fcp. in all soils, the model adjusted by non-linear regression fitted the data best, in comparison with the same model adjusted by linearization. in the most weathered soil group, the values of maximum adsorption capacity of phosphate (cmap) were highly correlated with the contents of remaining (equilibrium) phosphorus (r = -0.95**), free fe oxyhydroxides (r = 0.90**) and water retention (r = 0.88**), but did not correlate with the clay content (r = 0.64ns). within the group of less weathered soils, the cmap values were correlated with the contents of equilibrium phosphorus (r = -0.99**), water retention (r = 0.93**) and clay content (r = 0.97**), but did not correlate with free fe oxyhydroxides (r = 0.10ns).
Fra？？es de fósforo inorganico do solo e suas correla？？es com o fósforo quantificado por extratores e pelo milho
Souza Júnior, Reginaldo Fidelis de;Oliveira, Fábio Henrique Tavares de;Santos, Hemmannuella Costa;Freire, Fernando José;Arruda, Jandeilson Alves de;
Revista Brasileira de Ciência do Solo , 2012, DOI: 10.1590/S0100-06832012000100017
Abstract: the fractionation of inorganic phosphorus (pi) is important to evaluate in which forms phosphorus is sorbed to soil, because the efficiency of an extractant of available p in soils depends on its capacity to extract each fraction of soil pi. this study evaluated the contents of pi fractions in representative soils of the state of paraiba and their relationship with the chemical and physical characteristics of these soils, as well as the correlation between the pi fractions and p extracted from soils by maize plants and mehlich-1, mehlich-3, bray-1, and by ion exchange resin extractors. the experiment was conducted in a greenhouse in a randomized block design and tested 12 soils, with and without p application, in three replications. after the application of p doses (75, 88 and 103 mg dm-3) in 3.0 dm-3, soil samples were incubated in polyethylene pots for three weeks with distilled water (50% of total porosity of each soil). plant-available p was determined by four chemical extractants and the fractionation of pi performed in sub samples of 0.2 dm-3 per pot. the fractions p-al and p-fe were predominant in highly weathered soils and in less weathered soils with lower ph and ca2+, while p-ca was preferentially found in alkaline soils with very high ca2+ contents. phosphorus extracted by maize plants as well as mehlich-1, ion exchange resin and bray-1 were found in p-h2o and p-al fractions, while p extracted by mehlich-3 was more correlated with p-ca fraction. p extracted by mehlich-1 and bray-1 was more correlated with p absorbed by plants, while p extracted by bray-1 was low in soils with high ca2+ contents and high ph. in general, mehlich-1 quantified p similar to ion exchange resin, even in ca2+ -rich soils with high ph values.
Eficiência de extratores de potássio disponível em solos do estado da Paraíba com graus de desenvolvimento pedogenético diferentes
Medeiros, Jailma dos Santos de;Oliveira, Fábio Henrique Tavares de;Arruda, Jandeilson Alves de;Vieira, Montesquieu da Silva;Fontes, Maurício Paulo Ferreira;
Revista Brasileira de Ciência do Solo , 2010, DOI: 10.1590/S0100-06832010000100019
Abstract: potassium availability for plants depends on the contents of the k forms present in the soils (non exchangeable, exchangeable and soluble k), which vary according to the degree of pedogenetic development of soils. the objective of this study was to evaluate k availability in soils with different degrees of pedogenetic development, based on the extraction of k from the soils with different extractants and with corn plants. samples of the surface layer (0-30 cm) were collected from 12 representative soils in the state of paraiba, of which six were more and six less developed. to the three replications of all 12 soils, five k doses (0; 50; 100; 200, and 300 mg dm-3) were applied in the form of kcl in solution and incubated for 21 days. following, a sub-sample of 0.2 dm-3 of each soil was taken to determine the content of available k by the extractors mehlich-1, mehlich-3 and ion exchange resin. then, corn was grown on the soils in a greenhouse for 30 days and the dry matter production and k plant content evaluated. the extractants mehlich-1, mehlich-3 and ion exchange resin extracted similar k amounts in the more developed soils. in the group of less developed soils, the extractants mehlich-1 and mehlich-3 extracted not very different k amounts, but much greater amounts than by ion exchange resin, especially in the soils with higher clay content and a larger proportion of 2:1 minerals. unlike the extractants mehlich-1 and mehlich-3, ion exchange resin was not well-related with the exchangeable k content in the less developed soils. in this soil group, mehlich-1 correlated best with the plant k content. in most soils the dry matter production of the plant did not increase with increasing k doses, but in all soils the k plant content increased in response to k fertilization.
Doses de nitrogênio no acúmulo de nitrato e na produ？？o da alface em hidroponia
P？rto, M？nica LA;Alves, Jailson do C;Souza, Adailson P de;Araújo, Raunira da C;Arruda, Jandeilson A de;Tompson Júnior, Ubaldo A;
Horticultura Brasileira , 2012, DOI: 10.1590/S0102-05362012000300030
Abstract: lettuce production in hydroponic system presents growing expansion in brazil, but still there are problems of quality and risk of nitrate accumulation. this work was carried out to evaluate the lettuce production and nitrate accumulation in hydroponic system depending on the increasing levels of nitrogen in the nutrient solution. the experiment was conducted in greenhouse of the universidade federal da paraíba, brazil. the lettuce plants were grown in nutrient solution containing increasing levels of n (11, 13, 15, 17, 19 and 21 mmol l-1) during a 25-day period. an entirely randomized design with four replications was used. plant total yield (ptt), plant commercial yield (pcm) and nitrate contents in the fresh matter of roots, stems and leaves of the lettuce were evaluated. there were no significant effects of increasing levels of n in nutrient solution on ptt and pcm, average values of 357.3 and 352.5 g/plant being observed, respectively. the increased levels of n in nutrient solution increased linearly nitrate content on all lettuce parts. the nitrate content reached 659, 623 and 615 mg/kg in the fresh matter of roots, stems and leaves, respectively, at the highest n level. nevertheless, the maximum nitrate content observed in leaves was far below the risk level for human health.
Nitrate production and accumulation in lettuce as affected by mineral Nitrogen supply and organic fertilization
P？rto, M？nica L;Alves, Jailson do C;Souza, Adailson P de;Araújo, Raunira da C;Arruda, Jandeilson A de;
Horticultura Brasileira , 2008, DOI: 10.1590/S0102-05362008000200019
Abstract: lettuce is one of the leading vegetables in brazil. however, studies concerning its fertilization for the northeastern region of the country are still scarce. this work was carried out to evaluate the effects of mineral nitrogen supply and organic fertilization on the production and nitrate accumulation in lettuce, cultivar elba, in the semi-arid zone of paraíba, brazil. a randomized block design, with four replications, was used to test five doses of cattle manure (30; 60; 90; 120, and 150 t ha-1), five doses of n supplied as urea (30; 60; 90; 120, and 150 kg ha-1), and a control without fertilization. along with mineral n, the other nutrients were also supplied using mineral sources. no additional nutrients were supplied where organic fertilization was used. lettuce yield was significantly higher when organic fertilization was used, compared to the mineral nutrient supply. taking into account most of the fertilization doses recommended for growing lettuce in the brazilian northeastern states, n mineral fertilization in sandy soils with low organic matter contents can be fully replaced by organic fertilization with cattle manure. plant total (pty) and commercial yield (pcy) as affected by the mineral n supply fitted into a quadratic model, in which the doses 94.5 and 95.7 kg ha-1 corresponded to respectively the highest pty (381.9 g plant-1) and pcy (321.6 g plant-1). where organic fertilization was used, pty and pcy fitted into a linear model. therefore, the highest pty (523.9 g plant-1) and pcy (449.48 g plant-1) were observed at the highest manure doses. nitrate content on roots, stems, and leaves increased linearly with nitrogen and manure application. in roots, the nitrate content (mg kg-1 of fresh matter) reached 93.96 (n mineral (nm)) and 65.09 (organic fertilization (of)); in stems, 183.45 (nm) and 98.22 (of); and in leaves, 121.98 (nm) and 75.62 (of). the maximum nitrate content observed in leaves was far below the risk level for human health.
índice SPAD para o diagnóstico do estado de nitrogênio na cultura da abobrinha
P？rto, M？nica L;Puiatti, Mário;Fontes, Paulo Cezar R;Cecon, Paulo R;Alves, Jailson do C;Arruda, Jandeilson A de;
Horticultura Brasileira , 2011, DOI: 10.1590/S0102-05362011000300009
Abstract: the employment of spad index for n status diagnosis of crops has been largely studied in recent years. however, conclusive studies about its usefulness in zucchini plants were not found in literature. the objective of this study was to evaluate the employment of spad index for n status diagnosis of zucchini plants (cv. caserta). the experiment was carried out in vi？osa, minas gerais state, brazil, in a randomized block design with five rates of mineral n (0, 50, 100, 200 and 400 kg/ha), with four replications. at the early flowering stage, total chlorophyll concentration, spad index and total n concentration in the fourth fully expanded leaf from the apex of zucchini plants were evaluated. the total chlorophyll concentration, spad index and total n concentration in zucchini leaves increased following a quadratic model as a function of the n rates. the estimated critical levels of total chlorophyll concentration, spad index and total n concentration on zucchini leaves responsible for maximum fruit yield were 5.12 mg/g of fresh matter, 55.62 units and 3.97 dag/kg of dry matter, respectively. significant linear and positive correlation between the evaluated characteristics was observed. the results indicate that the spad index can be used for n status diagnosis of zucchini plants
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