Time filter

Source Type

Science, Brazil

Da Silva S.C.,University of Sao Paulo | Gimenes F.M.A.,Institute Zootecnia | Sarmento D.O.L.,Uniao Pioneira de Integracao Social | Sbrissia A.F.,UDESC CAV | And 3 more authors.
Journal of Agricultural Science | Year: 2013

The ability to adapt to a range of edaphic conditions favours the widespread use of marandu palisade grass in high as well as low input systems of animal production in Brazil. However, little information exists regarding the influence of grazing management practices on sward structure and the carry-over effects on animal responses. The present experiment was planned to evaluate animal behaviour, herbage intake (HI) and nutritive value, herbage accumulation and body weight gain (BWG) of beef cattle heifers grazing marandu palisade grass subjected to intensities of continuous stocking management. Treatments corresponded to four sward surface heights (SSH: 100, 200, 300 and 400 mm) and were allocated to experimental units (1200 m2 paddocks) according to a randomized complete block design with four replications. Herbage accumulation rate (HAR) varied with season of the year and SSH, with highest and lowest values recorded during summer and winter, respectively. During the summer, herbage accumulation was larger on swards managed at 200, 300 and 400 mm, with the opposite occurring during winter/early spring. Stocking rate (SR) and number of grazing days (GD) followed a similar seasonal pattern of variation, with values decreasing as SSH increased. Crude protein (CP) and in vitro organic matter digestibility (IVOMD) of hand-plucked herbage decreased as SSH increased from 100 to 400 mm, while the inverse happened with BWG (from 0·190 to 0·930 kg/day, respectively). Bite mass (BM) increased and rate of biting and grazing time (GT) decreased as SSH increased, with daily HI being larger on tall (300 and 400 mm) relative to short (100 and 200 mm) swards. Grazing management affected the nutritive value and the amount of herbage consumed, particularly through changes in BM. However, variations in intake were relatively more important than variations in nutritive value in influencing animal performance, highlighting the importance of providing favourable harvest conditions for grazing animals by establishing adequate sward targets for management. © Cambridge University Press 2012. Source

Dalbo M.A.,Epagri Estacao Experimental de Videira | Bettoni J.C.,UDESC CAV | Gardin J.P.P.,Epagri Estacao Experimental de Videira | Basso C.,Epagri Estacao Experimental de Cacador
Revista Brasileira de Fruticultura | Year: 2015

Grapevine ‘Isabel’ grafted on rootstock ‘SO4’ and ‘IAC 766’ and planted on ungrafted Nitosol were treated annually with increasing concentrations of K2O, 0; 60; 120 and 180 kg ha-1 for 5 wine-growing seasons (2007/08 , 2008/09 , 2009/10 , 2010/11 and 2011/12). The experimental design was banded with five replications, with six plants per replication and the treatments in a 4×3 factorial design, with 12 treatments, corresponding to four doses of potassium fertilization and the three rootstocks. The stage of berries peel color change, stems were collected to determine the nutrient content in the grape leaves. At the time of harvest it was evaluated vegetative and productive behavior, such as productivity, weight pruning, Ravaz index, and analytical characteristics of berries, total soluble solids, titratable acidity and pH were evaluated. Increased potassium fertilization does not represent a gain in productivity in cv. Isabel nor the accumulation of soluble solids in grapes. K and Mg in petioles of grapes are influenced by the form of cultivation ( grafted or ungrafted ).’Isabel’ vines grown on ungrafted have less capacity to accumulation of K and higher of Mg in the petioles. Under the conditions of the soil that was developed the research is not justified potassium fertilization of the vineyard. © 2015, Sociedade Brasileira de Fruticultura. All rights reserved. Source

Knoblauch R.,Epagri. Rod. Antonio Heil | Ernani P.R.,Santa Catarina State University | Gatiboni L.C.,Santa Catarina State University | Walker T.W.,Mississippi State University | And 3 more authors.
Revista Brasileira de Ciencia do Solo | Year: 2014

Incorporation of rice straw into the soil just before flooding for water-seeded rice can immobilize mineral nitrogen (N) and lead to the production of acetic acid harmful to the rice seedlings, which negatively affects grain yield. This study aimed to evaluate the formation of organic acids and variation in pH and to quantify the mineral N concentration in the soil as a function of different times of incorporation of rice straw or of ashes from burning the straw before flooding. The experiment was carried out in a greenhouse using an Inceptisol (Typic Haplaquept) soil. The treatments were as follows: control (no straw or ash); incorporation of ashes from previous straw burning; rice straw incorporated to drained soil 60 days before flooding; straw incorporated 30 days before flooding; straw incorporated 15 days before flooding and straw incorporated on the day of flooding. Experimental units were plastic buckets with 6.0 kg of soil. The buckets remained flooded throughout the trial period without rice plants. Soil samples were collected every seven days, beginning one day before flooding until the 13th week of flooding for determination of mineral N- ammonium (NH4 +) and nitrate (NO3 -). Soil solution pH and concentration of organic acids (acetic, propionic and butyric) were determined. All NO3 - there was before flooding was lost in approximately two weeks of flooding, in all treatments. There was sigmoidal behavior for NH4 + formation in all treatments, i.e., ammonium ion concentration began to rise shortly after soil flooding, slightly decreased and then went up again. On the 91stday of flooding, the NH4 + concentrations in soil was 56 mg kg-1 in the control treatment, 72 mg kg-1for the 60-day treatment, 73 mg kg-1for the 30-day treatment and 53 mg kg-1for the ash incorporation treatment. These ammonium concentrations correspond to 84, 108, 110 and 80 kg ha-1of N-NH4 +, respectively. When the straw was incorporated on the day of flooding or 15 days before, the concentration of N-NH4 + in the soil was 28 and 54 mg kg-1, equivalent to an accumulation of 42 and 81 kg ha-1 of N-NH4 +, respectively. There was formation of acetic acid in which toxic concentrations were reached (7.2 mmol L-1) on the 15th day of flooding only for the treatment with straw incorporated on the day of flooding. The pH of the soil solution of all the treatments increased after flooding and this increase was faster in the treatments with incorporation of straw, followed by the ash treatment and then the control. After 60 days of flooding, however, the pH values were around 6.5 for all treatments, except for the control, which reached a pH of 6.3. Rice straw should be incorporated into the soil at least 30 days before flooding; otherwise, it may immobilize part of the mineral N and produce acetic acid in concentrations toxic to rice seedlings. Source

Bertol I.,Santa Catarina State University | Ramos R.R.,UDESC CAV | Barbosa F.T.,University of La Coruna | Ramos J.C.,UDESC CAV | Bandeira D.H.,UDESC CAV
Revista Brasileira de Ciencia do Solo | Year: 2013

Water erosion is the major cause of soil and water losses and the main factor of degradation of agricultural areas. The objective of this work was to quantify pluvial water erosion from an untilled soil with crop rows along the contour, in 2009 and 2010, on a Humic Dystrupept, with the following treatments: a) maize monoculture; b) soybean monoculture; c) common bean monoculture; d) intercropped maize and bean, exposed to four simulated rainfall tests of on hour at controlled intensity (64 mm h-1). The first test was applied 18 days after sowing and the others; 39, 75 and 120 days after the first test. The crop type influenced soil loss through water erosion in the simulated rainfall tests 3 and 4; soybean was most effective in erosion control in test 3, however, in test 4, maize was more effective. Water loss was influenced by the crop type in test 3 only, where maize and soybean were equally effective, with less runoff than from the other crops. The soil loss rate varied during the runoff sampling period in different ways, demonstrating a positive linear relationship between soil and water loss, in the different rainfall tests. Source

Zanini G.D.,UDESC CAV | Santos G.T.,UDESC CAV | Sbrissia A.F.,Santa Catarina State University
Revista Brasileira de Zootecnia | Year: 2012

The objective of this study was to assess the accumulation and morphological composition of forage in Aruana Guineagrass (Panicum maximum cv. Aruana) swards subjected to intermittent stocking with sheep. Experimental treatments when grazing was introduced included low (95%) and high (98%) incident light interception and low (10 cm)- and high (15 cm)-residue height and were allocated to experimental units (196 m2 fenced areas) in a completely randomized 2 × 2 factorial arrangement with three replicates. Treatments were imposed between January and May 2009. More frequent grazing cycles (95% light interception) resulted in better control of stem elongation, lower proportion of dead plant material and invasive plants, and higher proportions of leaf blades in the grazing strata, compared with less frequent grazing cycles (98% light interception). Grass managed with 95% light interception combined with 10 and 15 cm post-grazing height and grass managed at 98% light interception combined with 15 cm post-grazing height did not show differences in forage accumulation rate. These results indicate that more frequent (30 cm pre-grazing height) and less severe (15 cm post-grazing height) grazing cycles provided animals with high leaf blade mass and low stem mass forage. © 2012 Sociedade Brasileira de Zootecnia. Source

Discover hidden collaborations