Volume 31, Number 6, 2007

In view of the importance of knowing fruit micronutrients export from the soil, and the season in which its coffee-plant demand is higher, the accumulation of B, Cu, Fe, Mn and Zn in fruits as well as the variation in the leaf content of the elements in productive branches of Arabic coffee was studied. The trial was performed in the period between anthesis and maturation at two altitudes. The experiment consisted of the coffee (Coffea arabica L.) variety Catuaí IAC […]

Crurves of fruit nutrient accumulation are tools for estimating the peaks of nutrient demand and the nutrient export form the soil. The accumulation of dry matter (DM), Ca, Mg and S was studied in fruits of Coffea arabica (L.) in the period between anthesis and maturation at four altitudes of cultivation, as well as the variation in the leaf content of the elements in productive branches. The experiment consisted of the coffee variety Catuaí IAC 44 cultivated at 720, 800, 880 […]

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 high rice grain yields ensured by sprinkler irrigation have encouraged the use of higher fertilizer doses, mainly the nitrogen fertilizers. However, an improper management of nitrogen fertilization may result in plant lodging. Application of plant regulators may redirect assimilates to grain production while limiting the vegetative growth. This study aimed to: evaluate the influence of the growth regulator Ethyl-trinexapac on plant growth parameters and on 15N accumulation and distribution in the whole plant and plant components, and determine the […]

A field experiment was conducted in Nova Porteirinha, MG, Brazil, in a dystrophic Red Yellow Latossol, to detect the response of the banana tree ‘Prata Anã’ to Zn doses through soil and critical Zn levels in soil and leaves. Four Zn doses were applied, corresponding to 0, 10, 20 and 40 kg ha-1 year-1 , using zinc sulfate as source. The treatments were arranged in a randomized block design, with three repetitions per block, totaling 36 experimental plots. The following traits were evaluated: […]

Two field experiments were carried out in Porto Feliz, SP, Brazil, to test the hypothesis that in soils with low clay content, sugarcane genotype RB83 5486 has a better root system distribution than genotype RB83-5089. The two soils used were classified as Typic Kandiudalf and Typic Hapludox. Between the third and fifth ratoon (2002 to 2004), the development of the sugarcane genotypes RB83-5486 and RB83-5089 was evaluated by determining the chemical and physical soil attributes, crop nutritional status, root distribution in […]

Dry matter production of winter annual pastures is usually low due to the limited soil nutrient availability, which can be amended by the use of liquid swine manure (LSM). This experiment, carried out from May to November 2003, aimed to evaluate the efficiency of LSM in the production and accumulation of dry matter, and N-leaf concentration of an oat/Italian rye grass mixture, as well as the effect on some chemical attributes of an Oxisol in the soil layers 0-5, 5-10 […]

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 […]

The distribution of phosphorus forms in the different soil compartments (labile, little labile and non-labile) is very influenced by geochemical and biological processes and by human activities. To evaluate the effect of liming and cattle manure on soil phosphorus forms, four experiments were carried out in an entirely randomized design, in a 4 x 5 factorial layout with four repetions, in a greenhouse. The treatments consisted of four liming levels (0; 0.5; 1 and 2 times the recommended dose to reach V […]