Soil suction has been regarded by soil scientists as an aspect of increasing importance and has been used as an important source of information in agriculture since early last century. Its knowledge helps improve human actions not only in aspects relating to vegetation and agriculture, but also concerning slope stability. Increasingly sophisticated tensiometers have been designed to measure soil suction. This study describes the state of the art in the evolution of tensiometers, aside from the development of a tensiometer […]

The advance of the agricultural frontier, characterized by the conversion of natural ecosystems into cultivated areas, was intensified in the last decades. Most of the practices used to manage soils cause changes in the soil quality and soil organic matter (SOM) dynamics. Studying the impact of different management systems is essential to choose the most adequate soil management practices. This study aimed to evaluate different SOM fractions and carbon and nitrogen storage of a very clayey typic dystroferric Red Latosol […]

Restinga is a typical vegetation on quartzitic, sandy, nutrient-poor parent materials along the Brazilian coast.. Podzolization is the main pedogenic process in restinga soils and Spodosols and Quartzipsamments with incipient podzolization are the most common soils. Podzolization is frequently studied in cold climate regions, while mineralogical studies of Spodosols in tropical climate on quartzitic parent material are scant. In this work, soils under restinga vegetation on the Ilha do Cardoso-SP, Brazil were studied to identify the mineralogical assembly of silt […]

Endophytic diazotrophic bacteria are capable of promoting maize growth through biological nitrogen fixation (BNF) or by the production of plant hormones. The aim of this study was to characterize diversity of endophytic bacteria in maize at sites with different climate and soil conditions in Rio Grande do Sul, Brazil. A PCR-RFLP approach and sequence analysis of nifH Cluster I clone libraries were used to assess diversity in maize plants. The Shannon-Weaver and Equitability indices were calculated to estimate the diazotroph […]

Nitrogen is an essential nutrient for common bean. However, there are still doubts about which source and level should be used to supply crops with this nutrient via sidedressing application in no-tillage systems. The objective of this work was to evaluate the influence of sources and doses of sidedressed nitrogen on common bean nutrition and grain yield (Phaseolus vulgaris L.) under no-tillage, on a Rhodic Nitisol. It was used a randomized complete block design with four replications, in a 2×4 […]

Presently, approximately 60 % of the grain crop area in Paraguay is under no-till (NT). With the expansion of NT in the country, some doubts were raised with respect to the obsoleteness of fertilizer recommendations, especially regarding phosphorus (P). The last P fertilizer recommendation had been established for conventional soil tillage system 15 years earlier. The main objective of this work was to update phosphate fertilizer recommendations for wheat, corn and soybean under NT. Seven different locations in eastern Paraguay were evaluated […]

Soil acidity is one of the most important constraints to agricultural production in the tropics. For this reason, the objective of this research was to evaluate the effects of soil liming on the performance of guava (Psidium guajava L.) trees. The experiment took place at the Citrus Experimental Station in Bebedouro, state of São Paulo, Brazil. The soil was a Typic Haplustox (V = 26 % in the 0 to 20 cm layer) between August 1999 and July 2006. The following doses of limestone were […]

The size distribution, the quantity and stability of soil aggregates are important parameters to evaluate the soil structure, which plays a relevant role in soil-plant relationships. Vinasse when applied on soil stimulates microbial activity because of its organic matter content. This activity may increase mucilage production and improve the aggregation and soil structural stability. The objective of this study was to evaluate the aggregate stability in an Oxisol treated with different vinasse doses. The study was carried out at the […]

In perennial agriculture, such as coffee plantation, weeds are controlled by hand, mechanized, and chemical weeding and their combinations. Methods that differ in terms of efficiency and costs have been evaluated; however, the influence of these methods on the soil chemical conditions has not been studied, particularly in the long term. This study aimed to evaluate the effect of different weed control methods on soil acidity components of a coffee plantation on a dystroferric Red Latosol in an experiment installed […]

Despite numerous reports on plant growth-promoting rhizobacteria (PGPR), there are few of them explaining their mode of action. It is possible that some plants promote bacterial colonization in the rhizosphere to facilitate plant-bacterium interaction, as if there were a certain mutual specificity. The objective of this study was to verify if lettuce plants promote root colonization by fluorescent pseudomonads, in comparison with other plants and with Bacillus spp. Roots of lettuce and some other vegetables were sampled in different properties […]