Coberturas vegetais e adubação fosfatada no desenvolvimento e produtividade do feijoeiro cultivado no período de inverno em sistema plantio direto

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Épocas de semeadura de cultivares de feijoeiro no período de inverno sob diferentes palhadas no cerrado: produtividade e qualidade fisiológica de sementes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Comunidades de aves em um mosaico de Eucalyptus em Rio Claro, São Paulo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Chemical and biological properties of phosphorus-fertilized soil under legume and grass cover (Cerrado region, Brazil)

The use of cover crops has been suggested as an effective method to maintain and/or increase the organic matter content, while maintaining and/or enhancing the soil physical, chemical and biological properties. The fertility of Cerrado soils is low and, consequently, phosphorus levels as well. Phosphorus is required at every metabolic stage of the plant, as it plays a role in the processes of protein and energy synthesis and influences the photosynthetic process. This study evaluated the influence of cover crops and phosphorus rates on soil chemical and biological properties after two consecutive years of common bean. The study analyzed an Oxisol in Selvíria (Mato Grosso do Sul, Brazil), in a randomized block, split plot design, in a total of 24 treatments with three replications. The plot treatments consisted of cover crops (millet, pigeon pea, crotalaria, velvet bean, millet + pigeon pea, millet + crotalaria, and millet + velvet bean) and one plot was left fallow. The subplots were represented by phosphorus rates applied as monoammonium phosphate (0, 60 and 90 kg ha-1 P2O5). In August 2011, the soil chemical properties were evaluated (pH, organic matter, phosphorus, potential acidity, cation exchange capacity, and base saturation) as well as biological variables (carbon of released CO2, microbial carbon, metabolic quotient and microbial quotient). After two years of cover crops in rotation with common bean, the cover crop biomass had not altered the soil chemical properties and barely influenced the microbial activity. The biomass production of millet and crotalaria (monoculture or intercropped) was highest. The biological variables were sensitive and responded to increasing phosphorus rates with increases in microbial carbon and reduction of the metabolic quotient.

Arbuscular mycorrhizal fungal communities and soil aggregation as affected by cultivation of various crops during the sugarcane fallow period

Management systems involving crop rotation, ground cover species and reduced soil tillage can improve the soil physical and biological properties and reduce degradation. The primary purpose of this study was to assess the effect of various crops grown during the sugarcane fallow period on the production of glomalin and arbuscular mycorrhizal fungi in two Latosols, as well as their influence on soil aggregation. The experiment was conducted on an eutroferric Red Latosol with high-clay texture (680 g clay kg-1) and an acric Red Latosol with clayey texture (440 g kg-1 clay) in Jaboticabal (São Paulo State, Brazil). A randomized block design involving five blocks and four crops [soybean (S), soybean/fallow/soybean (SFS), soybean/millet/soybean (SMS) and soybean/sunn hemp/soybean (SHS)] was used to this end. Soil samples for analysis were collected in June 2011. No significant differences in total glomalin production were detected between the soils after the different crops. However, total external mycelium length was greater in the soils under SMS and SHS. Also, there were differences in easily extractable glomalin, total glomalin and aggregate stability, which were all greater in the eutroferric Red Latosol than in the acric Red Latosol. None of the cover crops planted in the fallow period of sugarcane improved aggregate stability in either Latosol.

Ruzigrass affecting soil-phosphorus availability

The objective of this work was to evaluate the effectiveness of ruzigrass (Urochloaruziziensis) in enhancing soil-P availability in areas fertilized with soluble or reactive rock phosphates. The area had been cropped for five years under no-till, in a system involving soybean, triticale/black-oat, and pearl millet. Previously to the five-year cultivation period, corrective phosphorus fertilization was applied once on soil surface, at 0.0 and 80 kg ha-1 P2O5, as triple superphosphate or Arad rock phosphate. After this five-year period, plots received the same corrective P fertilization as before and ruzigrass was introduced to the cropping system in the stead of the other cover crops. Soil samples were taken (0-10 cm) after ruzigrass cultivation and subjected to soil-P fractionation. Soybean was grown thereafter without P application to seed furrow. Phosphorus availability in plots with ruzigrass was compared to the ones with spontaneous vegetation for two years. Ruzigrass cultivation increased inorganic (resin-extracted) and organic (NaHCO3) soil P, as well as P concentration in soybean leaves, regardless of the P source. However, soybean yield did not increase significantly due to ruzigrass introduction to the cropping system. Soil-P availability did not differ between soluble and reactive P sources. Ruzigrass increases soil-P availability, especially where corrective P fertilization is performed.

Cycling of nutrients and silicon in pigeonpea and pearl millet monoculture and intercropping

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Crescimento de leguminosas utilizadas na adubação verde em diferentes níveis de sais na água de irrigação

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Dinâmica do nitrogênio em sistemas de produção sob semeadura direta

Pós-graduação em Agronomia (Agricultura) - FCA

Coberturas vegetais e doses de nitrogênio, associadas à inoculação com Azospirillum brasilense, no cultivo do milho na região de Cerrado

Pós-graduação em Agronomia - FEIS

Effects on soil chemical attributes and cotton yield from ammonium sulfate and cover crops

Fertilizer use in no-till systems must be aligned with a correct interpretation of soil chemical attributes and crop demands. The objectives of this work were evaluate the effects of pre-sowing application of ammonium sulfate (AS) and of cover crops on the yields and soil chemical attributes of no-till cotton (Gossypium hirsutum L. r. latifolium Hutch) over two harvesting years. The experiment was arranged in randomized complete block design, with the plots in strips, and the variables were three cover crops (Raphanus sativus L., Avena strigosa L. and Avena sativa L.) and four AS doses (0, 150, 300, and 450 kg ha-1) applied over millet dry biomass. The cotton in the experimental plots was manually harvested on April 25, 2007 and April 24, 2008. The soil samples were collected between cotton rows in all plots on May 5, 2007 and May 12, 2008, at depths of 0.0-0.05, 0.05-0.10, and 0.10-0.20 m for soil fertility analyses. The increasing doses of AS induced lower soil pH, and calcium (Ca) and magnesium (Mg) levels in the superficial soil layer, as well as higher exchangeable aluminum (Al) and sulfur (S) levels until a depth of 0.20 m. Seed cotton yields increased with increasing AS doses.

Liberação de nutrientes da palhada de forrageiras consorciadas com milho e sucessão com soja

In tropical regions there is rapid decomposition of plant material deposited on the soil, and the ability to recycle nutrients through this decomposition is one of the most important aspects of cover crops. The aim of this study was to evaluate the yield and nutrient release from forage crops intercropped with maize for silage, and soybean in succession. The study was conducted in the experimental area of Universidade Estadual Paulista, Ilha Solteira campus, Brazil. The experiment consisted of maize for silage intercropped with four forage species (Urochloa brizantha cv. Marandu, Urochloa ruziziensis, Panicum maximum cv. Tanzania, and Panicum maximum cv. Aries) sown in three modalities: in the maize row, together with fertilizer; broadcast at maize sowing; and broadcast in the V4 stage of maize, in a randomized block design in a 4 x 3 factorial arrangement with four replications. The evaluation of nutrient release was performed during the soybean cropping that followed the intercropping by the litter bag method at 30, 60, 90, and 120 days after sowing of soybean. Panicum maximum cv. Tanzania showed higher dry matter yield when sown by broadcasting at maize sowing. Sowing of forages in the maize row, and through broadcasting at maize sowing led to greater dry matter yield for straw formation. Intercropping of maize with forages in the autumn is an alternative for increasing the amount of straw and cycling of macronutrients in a no-till system. Potassium was the nutrient with the greatest accumulation in the forage straws (up to 150 kg ha(-1)), with 100 % release at 90 days after sowing soybean. The forage straws are thus an excellent alternative for cycling of this nutrient. Panicum maximum cv. Tanzania sown by broadcasting at the time of maize sowing showed greater phosphorus cycling (13 kg ha(-1)). Panicum maximum cv. Tanzania broadcast in the V4 stage of maize is the option with least potential for straw production and nutrient cycling, while the other options (forages and sowing modalities) have higher potential for use, at the criteria of machine availability for setting up intercropping with corn.

Produção de soja e milho cultivados sobre diferentes coberturas

The no-tillage system is an important technique for maintaining and restoring the productive capacity of conventionally managed soils and degraded areas. The aim of this study was to evaluate the production of soy and maize grown on the straw of five cover crops and on spontaneous vegetation. The experiments were carried out in Votuporanga, in the state of Sao Paulo and in Selviria, in Mato Grosso do Sul, Brazil, in March 2008, after conventional soil preparation. The experimental design was of randomised blocks with four replications, using the following cover crops in different amounts of seed per hectare, to make up the treatments: Sorghum bicolor - 6, 7 and 8 kg ha(-1); Pennisetum americanum - 10, 15 and 20 kg ha(-1); Sorghum sudanense - 12, 15 and 18 kg ha(-1); S. bicolor and S. sudanense hybrid - 8, 9 and 10 kg ha(-1); and Urochloa ruziziensis - 8, 12 and 16 kg ha(-1). A control treatment with spontaneous vegetation was also used. After management of the cover crops, soy was planted in the first year of the study, and maize sown in the second, both under a no-tillage system. The dry matter accumulated by the different cover crops, and the agronomic characteristics of the soy and maize were all evaluated. It was concluded that the different cover plants proved to be good options for preceding the soy crop in Votuporanga, SP and the maize in Selviria, MS, and that the different amounts of seed used for each cover crop resulted in differences in relation to the agronomic characteristics of the crops of soy and maize.

Weed suppression in the formation of brachiarias under three sowing methods

The success of conservation systems such as no-till depends on adequate soil cover throughout the year, which is possible through the use of cover crops. For this purpose the species belonging to the genus Urochloa has stood out by virtue of its hardiness and tolerance to drought. Aiming ground cover for the no-till system, the objective was to evaluate the establishment of two species of the genus Urochloa, in three sowing methods, in the weed suppression and the sensitivity of these forages to glyphosate. The study design was a randomized block with a 2 x 3 x 3 factorial arrangement, in which factor A was composed of Urochloa ruziziensis and Urochloa hybrid CIAT 36087 cv. Mulato II, factor B was formed by sowing methods: sown without embedding, sown with light embedding and sown in rows, and factor C was composed of three doses of glyphosate (0.975, 1.625 and 2.275 kg ha(-1) of acid equivalent). For determination of weed suppression, assessment of biomass yield and soil cover was performed, by brachiaria and weeds, at 30, 60, 90, 120 and 258 days after sowing. Visual assessment of the desiccation efficiency at 7 and 14 days after herbicide application was performed. It is concluded that embedding Urochloa seeds stands out in relation to sowing in the soil surface. Urochloa ruziziensis is more efficient in the dry weight yield, weed suppression, in addition to being more sensitive to glyphosate herbicide.

Ciclagem do nitrogênio relacionada ao sistema de produção

Pós-graduação em Agronomia (Agricultura) - FCA