Plantio direto de repolho sobre a palhada de adubos verdes num sistema sob manejo orgânico

Publicado também na: Revista Brasileira de Agroecologia, v. 2. n. 2, p. 872-875, out. 2007. (SEP 028)

Dynamic of Phosphorus Fractions in Typic Quartzipsamment Soil Cropped With Bean.

Phosphorus is the most limited nutrient in Brazilian soils for plant growth, resulted of low availability and poor P content in bedrock. The aim of the study was to evaluate the dynamic of P fractions in a sand soil typical Quartzipsamment cropped with common bean under the effects of P and Si-fertilizer rates. The research was carried out in a soil with sand texture and clay mineralogy constituted mainly by kaolinite, classified as Neossolo Quartzarênico Órtico típico (RQo). The greenhouse location was the campus of Universidade Federal de Lavras located in the city of Lavras, state of Minas Gerais, Brazil (approximately 21°13′46.54″ S and 44°58′26.30″ W, average altitude 932 m above sea level). The experimental design used was entirely random, arranged in a 4 × 3 factorial design, with four repetitions, with amount of 48 experimental units. The treatments included four P rates (0, 80, 240 and 410 mg dm-3) and four Si rates (0, 240 and 410 mg dm-3). Phosphorus fractions in soil are little affected by Si-fertilizer rates. P uptakes by bean plants are correlated to the labile and moderately labile fractions. P-fertilizer rates increment majority the stable P fraction in soil and in lower proportion the labile and moderately labile P fractions in soil. Po-NaHCO3 is the only that contributes to bean plant nutrition

Phosphorus Fractions and Their Transformations in Entisol.

The availability of phosphorus in the soil is a factor that directly interferes with its absorption by plants. This availability can be influenced by the texture, dose of the phosphate fertilizer and the time of contact with the soil. This study aimed to quantify the organic and inorganic fractions of P accumulated in a sandy soil receiving doses of phosphorus, incubated and grown with rice. The experimental design was a completely randomized design, in a 4 × 3 factorial scheme, with four replicates, and four P doses (0, 80, 240, and 410 mg dm-3) and three evaluation times (before sowing, after harvest, and incubated). Soil samples were collected before, after incubation, and after rice harvesting, and then submitted to a chemical fractionation of P. P fractions were influenced by soil collection times. The inorganic fractions prevailed before sowing and after incubation, and the organic fractions prevailed after harvest. Phosphate fertilization favored mineralization of organic P and redistributes the inorganic and organic P fractions, between labile and non-labile compartments. The application of phosphate fertilizer in an Entisol Quartzipsamment contributes to the accumulation of inorganic fractions, especially in the most labile fractions.Made available in DSpace on 2018-12-27T23:38:29Z (GMT). No. of bitstreams: 1 Phosphorusfractionsandtheir.pdf: 941390 bytes, checksum: ff286e3e5e496e2550bbcdda5bee3ece (MD5) Previous issue date: 2018-12-27bitstream/item/189359/1/Phosphorus-fractions-and-their.pd

Best Management Practices (BMPs) for Nitrogen Fertilizer in Forage Grasses.

There is a concern about the growing population and limitation in natural resources which are taking the population to direct its agricultural systems into a more productive and efficient activity, looking to avoid a negative impact on the surrounding environment. The industry energy expended to produce nitrogen (N)-fertilizer is considered an indirect consumption of energy in agriculture, which is higher with an increasing forage yield. Nitrogen is the key nutrient associated with high-yielding production in forage grass and grain crops. The aim of this chapter is to introduce the best management practices (BMPs) for N-fertilizer application in forage grasses to improve N-use efficiency, since the most economical way to feed livestock is forage plants where its potential biomass production is not well explored. The BMPs basically follow three management practices: (1) soil nutrient availability and forage requirement, (2) fertilizer application, and (3) decrease in nutrient losses from soil. In order to take a decision on applying N-fertilizer to accomplish forage grasses production with social, economic, and environmental benefits, the N-fertilizer use in forage grasses is going to follow the ?Right rate, Right source, Right place, and Right time (4R) nutrient stewardship.? The application of the 4R?s nutrients stewardship is directly associated with economic, social, and environmental impact. The capacity of the 4R?s implementation worldwide turns into a best guide to improve the striving of better N-use efficiency in forage grass. The 4R?s are interrelated; thus, the recommendation of N-fertilizer rates cannot be prescribed without the combination of the 4R?s where a whole system to be followed should be considered to decide about N-fertilizer in pasture. Consequently, any decision in one of the 4R?s is going to affect the expected N-fertilizer results and dry matter production.bitstream/item/189383/1/Best-management-practices-BMPs.pd

Phosphorus Fractions and Their Transformations in Entisol.

The availability of phosphorus in the soil is a factor that directly interferes with its absorption by plants. This availability can be influenced by the texture, dose of the phosphate fertilizer and the time of contact with the soil. This study aimed to quantify the organic and inorganic fractions of P accumulated in a sandy soil receiving doses of phosphorus, incubated and grown with rice. The experimental design was a completely randomized design, in a 4 × 3 factorial scheme, with four replicates, and four P doses (0, 80, 240, and 410 mg dm-3) and three evaluation times (before sowing, after harvest, and incubated). Soil samples were collected before, after incubation, and after rice harvesting, and then submitted to a chemical fractionation of P. P fractions were influenced by soil collection times. The inorganic fractions prevailed before sowing and after incubation, and the organic fractions prevailed after harvest. Phosphate fertilization favored mineralization of organic P and redistributes the inorganic and organic P fractions, between labile and non-labile compartments. The application of phosphate fertilizer in an Entisol Quartzipsamment contributes to the accumulation of inorganic fractions, especially in the most labile fractions

Phosphorus and silicon fertilizaer rates effects on dynamics of soil phosphorus fractions in oxisol under common bean cultivation.

The purpose of this research was to evaluate the effects of P and Si fertilizer rates in dynamic of P fractions in clay soil under greenhouse. The research was carried out in a Dystroferric Red Latosol of a very loamy texture from Lavras city, Minas Gerais State, Brazil. The experimental design was entirely randomized, arranged in 4 × 3 factorial design, with four repetitions. The treatments included four inorganic fertilizer P rates (0, 110, 330 and 560 mg dm-3) and three Si rates (0, 110, 330 and 560 mg dm-3). The preview application of Si fertilizer did not contribute to decrease P desorption. Possibly, the silicate has lower affinity with the bound sites of adsorption than phosphates. The effects of inorganic fertilizer P were higher in increasing the moderately labile and labile P inorganic fractions. Among the organic P fractions, the NaHCO3-Po fraction was the only one that contributes to plant nutrition. The Hedley sequential phosphorus fractionation promoted information about different pools where P was accumulated in the soil after common bean cultivation. The highest amount of P was obtained in stable P fraction, followed by moderately labile and labile P fraction. The moderately labile P fraction decreased after common bean cultivation possibly due to the time of P contact in the soil and redistribution to stable P fraction. The labile form was the lowest P pool in soil; nevertheless the increase in fertilizer P rates increases the amount of P content in labile fraction.201