Helder Barbosa Paulino

Produção de fitomassa de diferentes espécies de cobertura e suas alterações na atividade microbiana de solo de cerrado

The objective of this study was to evaluate the phytomass yield of nine species of cover crops of the soil and to verify the alterations in the activity and microbial biomass of Cerrado soil, in the State of Goias, Brazil. The work was developed from March to December, 2004, being sowed the following covering species: Avena strigosa, Cajanus cajan, Crotalaria juncea, Lablab purpureum, Pennicetum americanum, Raphanus sativus, Guizotia abyssinica, Canavalia ensiformis, Crotalatia spectabilis and an area in fallow considered with reference. In the occasion of the flower phytomass yield was determined and starting from August it leaves of this was conditioned in sacks of polyethylene to evaluate the decomposition tax, being in the soil for 120 days. During this period, in every month, they were evaluating the carbon of the microbial biomass and the microbial respiration of the soil. The Cajanus cajan, Pennicetum americanum, Canavalia ensiformis and Guizotia abyssinica are shown as the most promising species for phytomass yield, while the Avena strigosa, Crotalaria juncea and the Raphanus sativus present the smallest phytomass yield. The areas under Pennicetum americanum residues, Raphanus sativus, Crotalatia spectabilis and the fallow affect the carbon of the microbial biomass negatively. Area under resting provided to smallest phytomass yield, reduction in the carbon of the microbial biomass and larger loss of carbon, being this practice no suitable for the Cerrado region.

Atributos físicos de um Neossolo Quartzarênico e um Latossolo Vermelho sob diferentes sistemas de manejo

The objective of this work was to evaluate the effect of different management systems in soils physical attributes of a Typic Quartzipisamment and of a Rhodic Hapludox. Evaluations were made for the soil density, the total volume of pores and the mechanical resistance to the penetration of the soil. Both management systems and the use of the soil promoted increase in the density of the soil, decrease of the total volume of pores and variation of the resistance of the soil to the penetration. The Typic Quartzipisamment presented decrease of the macroporosity.

P-sorption and desorption in Savanna Brazilian soils as a support for phosphorus fertilizer management

Phosphorus (P) sorption by soils is a phenomenon that varies depending on soil characteristics, influencing its intensity and magnitude, which makes it a source or drain of P. The objective of this study was to determine the Maximum Phosphorus Adsorption Capacity (MPAC) and desorption of P from soils under native Savanna Brazilian and verify the correlation between MPAC and P Capacity Factor (PCF) with the chemical and physical properties of these soils. The study was conducted in seven soils under native Savannas. The Langmuir isotherms were adjusted from the values obtained in sorption assays, being evaluated the MPAC, the energy adsorption (EA) and PCF, which was calculated according to the levels of P-adsorbed and P-sorbed. Values of MPAC were classified as high in most soils, ranging from 283 up to 2635 mg kg-1 of P in the soil and were correlated with soil organic matter, clay, silt, sand, base saturation and pH. The PCF was higher in soils where the MPAC was also higher. The use of only one attribute of soil (clay content) as a criterion for the recommendation of phosphated fertilization, as routinely done, is susceptible to errors, needing the use of more attributes for a more accurate recommendation, as a function of the complexity of the interactions involved in the process.

Fungos micorrízicos arbusculares em campos de murundus após a conversão para sistemas agrícolas no cerrado

The murundu fields (Campos de Murundus) are characterized by mounds occurring in some parts of the Cerrado (Brazilian tropical savanna) biome with important ecological functions for the maintenance of soil sustainability. Conversion to agricultural systems may lead to changes in physical, chemical, and biological soil properties not yet assessed, such as reduction in the biodiversity of arbuscular mycorrhizal fungi. The aim of this study was to evaluate how the conversion of mound fields into agricultural areas changes the community of arbuscular mycorrhizal fungi (AMF). Treatments consisted of three agricultural areas subjected to the same agricultural management and use in a chronosequence (seven, 11, and 14 years) and two in the mound fields, sampling at the top (TM) and between the mounds (EM)). AMF spores were extracted and counted, and AMF species were identified by morphological characteristics. The total AMF recovered was 27 species, made up of nine species of the Acaulosporaceae family, one Ambisporaceae, seven Glomeraceae, two Claroideoglomeraceae, and eight Gigasporaceae. Of this total, the species Acaulospora scrobiculata , Glomus macrocarpum , and Gigaspora sp occurred in all areas in the two years studied. The species Acaulospora melle a, Acaulospora cavernata , Acaulospora colombiana , Glomus diaphanum , Scutellospora reticulata , and Scutellospora sp only occurred in the mound fields. The conversion of mound fields into an agricultural area modified the occurrence and composition of the arbuscular mycorrhizal fungi community, and the species Acaulospora scrobiculata , Glomus macrocarpum , Gigaspora sp, and Claroideoglomus etunicatus occurred in all areas. The non-occurrence of some species in the crop areas, such as the species Acaulospora cavernata , Acaulospora columbiana , Rhizophagus diaphanus , Scutellospora reticulata , and Scutellospora sp, represents a loss of diversity of these fungi. Therefore, this study is the first report of the occurrence and community structure of AMF in the mound field vegetation type. It contributes to better understanding of AMF in the Cerrado biome and shows that the changes introduced by conversion of the area alter the occurrence and diversity of arbuscular mycorrhizal fungi.

USO DA ADUBAÇÃO FOLIAR NITROGENADA E POTÁSSICA NO ALGODOEIRO

ABSTRACT NITROGEN AND POTASSIUM IN FOLIAR APPLICATION ON COTTON CROPThe present work was conducted in Selviria county (MS-Brazil), in the agricultural year of 1998/99,for evaluating nitrogen and potassium foliar application to supplement sowing fertilization on cotton(IAC 22) crop. A randomized complete block design with 13 treatments and four replications was used.The treatments were constituted by a control (without foliar application) and nitrogen and/orpotassium foliar applications two, four, six or eight weeks after beginning of flowering. The urea wasused as source of N and potassium chloride as source of K. Urea in the concentration of 10% andpotassium chloride at 4% were applied at a rate of 250 L.ha -1 . Height of plants, nodule number, numberof reproductive branches, boll per plant, 30 boll mass, yield and fiber percentage were evaluated. It isconcluded that the N doses increased the yield and decreased the fiber percentage. There was noevaluated response to the application of K or NK.

Occurrence and species richness of mycorrhizal fungi in soil under different land use1

Abstract: This study aimed to assess the impact of different land uses on the spore density and richness of arbuscular mycorrhizal fungi (AMF) in a Red Latosol of a tropical savanna biome in Brazil (“Cerrado”). Ten soil samples and roots were obtained from a riparian forest, a pasture, an annual crop production system with no tillage, and a coffee plantation in dry and wet seasons. Spores were extracted, counted, and identified from field soils, and roots were stained to assess mycorrhizal colonization. A total of 42 AMF species were detected in all four land uses. The genus Acaulospora had the largest number of species (18), followed by Glomus (6) and Gigaspora (5). Gigaspora decipiens and Gigaspora margarita were present in all areas, regardless of the sample period. Gigaspora decipiens was the species most frequently recovered and contributed to the majority of spores in coffee plantations and riparian forest. Cetraspora pellucida was dominant in the area of no tillage and Acaulospora tuberculata in the pasture. Low species richness was detected in soils under the coffee plantation, with AMF communities dominated almost exclusively by members of Gigasporaceae. We conclude that the area under the coffee plantation caused a reduction in the richness of AMF species and promoted a dominance of a single family AMF compared with the pasture area.

PHOSPHORUS FRACTIONS AND AVAILABILITY IN A HAPLIC PLINTHOSOL UNDER NO-TILLAGE SYSTEM IN THE BRAZILIAN CERRADO

Soil use and fertilizer management as well as cropping systems influence phosphorus (P) availability in the soil. This study evaluated P fractions and availability in a chronosequence of anthropic influence in a Haplic Plinthosol, in sites under no-till for different time periods: seven (NT7), eleven (NT11), and sixteen (NT16) years. Labile P concentrations in the soil accounted for 10%, 8%, and 9% of the total P for treatments NT7, NT11, and NT16, respectively. The labile P values ranged between 99 and 122 mg dm-3andindicatied no time in no-tillage influence on labile P under in the studied Plinthosol. However, moderately labile P contents increased with time: NT7 < NT11 < NT16 (237, 341, and 375 mg dm-3, respectively). This increased followed the elevation in iron oxide contents, indicating a relationship between mineralogy and P accumulation. Regardless of no-tillage period, P contents extracted by Mehlich-1 were lower, underestimating the available P content, when compared with the extraction using a P selective resin. The stocks of labile P were sufficient to maintain high crop yields, according to the recommendations for the Cerrado region. Even if labile P contents are reduced, when adopting no-till system, the contents and stocks of P in the soil after several years were high enough to provide for adequate crop yields.

Arbuscular mycorrhizal fungus in microbial activity and aggregation of a Cerrado Oxisol in crop sequence

Soil structure has major influence on ecosystem sustainability and plant growth. Arbuscular mycorrhizal fungi (AMF) are an important functional group of soil microbiota, acting in the process of aggregation, especially in agroecosystems and related to the production and plant diversity. AMF are widely distributed in tropical agroecosystems and are extremely important for development of many agricultural crops. The present study evaluated the effect of inoculation with Glomus macrocarpum in different crop sequences on plant growth, microbial activity and aggregation of a Cerrado Oxisol. The study was conducted in a completely randomized design in a4 x 4 factorial scheme. Treatments consisted of four conditions of elimination and/or introduction of AMF (NS-NI: non-sterilized and non-inoculated; NS-I: non-sterilized and inoculated; S-NI: sterilized and non-inoculated; andS-I: sterilized and inoculated) and four crop sequences (Panicum maximum/Panicum maximum, Brachiaria ruziziensis/ soybean, sorghum/soybean and Stylosanthes spp./soybean). Inoculation favored growth of Stylosanthes spp. by increasing plant growth in up to 91% when inoculated. None of the grasses benefited from G. macrocarpum introduction. We observed that G. macrocarpum inoculation associated with indigenous AMF increased microbial biomass, phosphatase activity, mean geometric diameter and mean weighted diameter. The results indicated the beneficial effects of inoculation, which reflected in soil structure improvement and, hence, to agroecosystems sustainability.

Atributos de solo sob pastejo rotacionado em função da aplicação de cama de peru

Poultry litter applications can improve biological, physical, and chemical soil attributes. This study aimed at evaluating the effect of sequential turkey litter doses on properties of soil under a rotational grazing system with Brachiaria decumbens L., in Portelândia, Goias State, Brazil. The experiment was carried out in a split-plot randomized blocks design, with four replications. Treatments consisted of turkey litter doses [no litter, 8.7 Mg ha -1 (2008), 16.5 Mg ha -1 (2008 + 2009), and 30.9 Mg ha -1 (2008 + 2009 + 2010)], for plots, with the two highest doses resulting from the accumulation of litter applications, and three sampled soil depths (0-5 cm, 5-10 cm, and 10-20 cm), for split-plots. Sequential applications of turkey litter doses improved soil fertility, increasing the pH, P, K, and base saturation rates, as well as organic carbon, total and particulate nitrogen contents, and decreasing aluminum saturation. Lower doses of turkey litter stimulated the soil microbial activity, promoting the mineralization of the organic matter particulate fraction, however, there was no effect on soil aggregation.

Pós-graduação em ciência do solo na região amazônica: uma possível realidade

The present study aimed to verify the existence of graduate programs dealing with the theme of Soil Science and related fields, as well as the profile of professors in these programs in the Amazon region of Brazil, in order to facilitate the future development of research in Soil Science. In this region 13 Graduate Programs were found, with 39 subjects offered adhering to the theme of Soil Science, taught by 36 professors, thereby indicating that there are qualified professors for the opening of a Graduate Program in Soil Science. To achieve this objective, policies of incentives and funding designed to strengthen research groups which focus on the development of regional Soil Science will contribute to the reduction of disparities, the generation of research of regional importance, the training of human resources of high quality, and the fixation of doctors in the region.