Elaine Reis Pinheiro Lourente

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) and four Si rates (0, 240 and 410 mg dm). 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.

Efeito residual da aplicação de silicato de cálcio nos atributos químicos do solo e na produtividade da cana-soca

Trabalhos de pesquisa no Brasil e em outros paises, com a utilizacao de silicato de calcio, vem mostrando resultados promissores na cultura da cana- de- acucar. Este trabalho objetivou avaliar o efeito residual da aplicacao do silicato de calcio como material corretivo de acidez do solo, nos atributos quimicos do solo e na produtividade da primeira soqueira de cana-de-acucar. O trabalho foi desenvolvido, em condicoes de campo, na Fazenda Escola da Anhanguera de Dourados-MS, com a variedade SB803250. O delineamento experimental utilizado foi em blocos casualizados, com quatro repeticoes. Os tratamentos foram constituidos de doses distintas de silicato de calcio (0, 700, 1400, 2800, 5600 kg ha -1 ). No solo, a amostragem foi realizada aos 24 meses apos a aplicacao do silicato de calcio, nas camadas de 0-0,2- e 0,20-0,40 m de profundidade, determinando os atributos quimicos para fins de fertilidade do solo e a produtividade da cana-soca. O silicato de calcio promoveu efeito residual benefico nos atributos de acidez do solo apos 24 meses da aplicacao. A aplicacao do silicato de calcio, em pre-plantio, promoveu efeito residual positivo na produtividade da soqueira da cana-de-acucar.

Nutritional Status of Cotton Plant Assessed by Compositional Nutrient Diagnosis (CND)

The use of compositional nutrient diagnosis (CND) to assess the nutritional status of cotton crop is quite important to improve knowledge on plant nutritional requirement and assist the fertilizer recommendation. The aim of this chapter is to introduce the possibility of using CND for cotton crop. This method has scarcely been used to assess the nutritional status of cotton plant although a few results have indicated that it can be promising. In fact, CND methodology seems to be better in the nutritional diagnosis than traditional methods such as sufficient range (SR) and critical value approach (CVA). Its efficiency has increased with the possibility of applying multivariate analysis, principal component analysis (PCA), canonical correlation, and so on. The application of PCA possibility to note some interactions among the nutrients is important for understanding the dynamics of nutrients in plants.

Rotação de culturas e relações com atributos químicos e microbiológicos do solo e produtividade do milho

Soil management practices exert important influence on biological and biochemical properties of soil. This work aimed to valuate the impact of crop rotation on soil biochemical and microbiological attributes, as well and influence on corn crop yield. The experiment was carried out during 2005/06 crop season, in Dourados – MS, Brazil. Experimental design was randomized blocks with treatments established in sub-divided plots with tree replications, which seasons were plots and management systems were sub-plots. Studied seasons were winter and summer and no tillage systems were represented by five crop rotation schemes, which involved the cultures of hairy vetch, bean, oat, forage turnip, soybean, crotalaria, corn, sorghum, pearl millet, sunflower and, in conventional tillage, with corn in winter and with soybean in summer. Native vegetation constituted one treatment and, with conventional tillage, it was used as ecosystem of reference as control for comparison between possible alterations in chemical and microbiological attributes with the establishment of a system more conservationist for soil management. There was a positive correlation among Norg, Corg, Porg and C-BMS contents with chemical attributes of soil fertility, which shows interdependence between chemical and biology of soil. The elimination of native vegetation and the substitution for cultivation system after that reduce the C-BMS. In Cerrado conditions, studied cultivation systems increased phosphorus content in soil. Crop rotation influenced corn yield after the cultivation of determined species as crotalaria and vetch in crop rotation.