scholarly journals Least limiting water range in Oxisols under different levels of machine traffic

2018 ◽  
Vol 8 (2) ◽  
pp. 337-346
Author(s):  
Karina De Vares Rossetti ◽  
José Frederico Centurion

This work aimed, to evaluate the structural behavior of Oxisols based on the least limiting water range (LLWR) and establish relations with corn crop. The experiment was carried out in a randomized block design with five treatments and four replications. Soil samples collected at the layer of 0-0.20 m depth in a Haplustox (LVd) and an Eutrustox (LVef) were used. The compaction treatments consisted of T0= no additional compaction; T1 and T2= two and four passes with a 4 t tractor, respectively; T3 and T4 = two and four passes with a 10 t tractor, respectively. The range of LLWR variation in the LVd was the lowest one and varied from 0.01 to 0.04 m3 m-3, whereas in the LVef varied from 0.03 to 0.13 m3 m-3 for the critical soil penetration resistance (PRc) of 2 MPa. It was observed that critical bulk density (BDc) values were 1.76 and 1.40 Mg m-3 in the LVd and the LVef, respectively. The highest frequency of bulk density (BC ≥ BDc) occurred from the T1 to T4 (LVd) and from the T2 to T4, however, a reduction in corn yield was not observed. The determination of the LLWR was efficient and complementary for identifying more favorable or more impeditive conditions to compaction in the LVef for the corn crop development in relation to the LVd.

2009 ◽  
Vol 33 (6) ◽  
pp. 1627-1636 ◽  
Author(s):  
Márcio Gilberto Zangeronimo ◽  
Elias Tadeu Fialho ◽  
Luis David Solis Murgas ◽  
Raimundo Vicente de Sousa ◽  
José Augusto de Freitas Lima ◽  
...  

The aim of this work was to verify the effect of different levels of true digestible lysine (TDL) and crude protein (CP) on diets on the carcass composition of the swine in the nursery phase. Eighty piglets Landrace x Large White, barrows and females, with initial weight of 9.1±1.2 kg and final weight of 21.5±4.8 kg, weaned at the 28 days, allotted in groups of two during 35 days in the nursery. A randomized block design in factorial 2x4 (two levels of CP - 16 and 18% - and four of TDL - 0.7; 0.9; 1.1 and 1.3%) with five repetitions was used. After weighing, one animal of each stall was sacrificed and the carcass utilized for determination of water (CWP), protein (CPP) and lipid (CLP) percentage and deposition tax of the protein (DTP) and lipid (DTL). There were no differences for CWP, but there was had quadratic effect of the lysine levels on the CPP and DTP in the carcasses only in 18% CP diets, being 1.02% of TDL that propitiated the best result for DTP. There was no difference in 16% CP diets. For the CLP, there were no differences when 18% CP diets were utilized, however there was had quadratic effect with 16% CP diets, being 0.99% the level of TDL that provided the higher deposition. For the DTL, the 1.08 and 1.00% of TDL resulting in higher values in 18 and 16% CP diets, respectively. One concluded that 18% CP diets is the ideal and the 1.02% of TDL must be kept for the best carcass composition of swine in the initial phase.


2014 ◽  
Vol 32 (1) ◽  
pp. 51-59 ◽  
Author(s):  
L.B. Tavella ◽  
P.S.L. Silva ◽  
V.R. Oliveira ◽  
P.L.O. Fernandes ◽  
R.P. Sousa

The objectives of this study were to evaluate baby corn yield, green corn yield, and grain yield in corn cultivar BM 3061, with weed control achieved via a combination of hoeing and intercropping with gliricidia, and determine how sample size influences weed growth evaluation accuracy. A randomized block design with ten replicates was used. The cultivar was submitted to the following treatments: A = hoeings at 20 and 40 days after corn sowing (DACS), B = hoeing at 20 DACS + gliricidia sowing after hoeing, C = gliricidia sowing together with corn sowing + hoeing at 40 DACS, D = gliricidia sowing together with corn sowing, and E = no hoeing. Gliricidia was sown at a density of 30 viable seeds m-2. After harvesting the mature ears, the area of each plot was divided into eight sampling units measuring 1.2 m² each to evaluate weed growth (above-ground dry biomass). Treatment A provided the highest baby corn, green corn, and grain yields. Treatment B did not differ from treatment A with respect to the yield values for the three products, and was equivalent to treatment C for green corn yield, but was superior to C with regard to baby corn weight and grain yield. Treatments D and E provided similar yields and were inferior to the other treatments. Therefore, treatment B is a promising one. The relation between coefficient of experimental variation (CV) and sample size (S) to evaluate growth of the above-ground part of the weeds was given by the equation CV = 37.57 S-0.15, i.e., CV decreased as S increased. The optimal sample size indicated by this equation was 4.3 m².


2018 ◽  
Vol 48 (2) ◽  
Author(s):  
Ana Cristina Bittar ◽  
Elen de Lima Aguiar-Menezes ◽  
José Guilherme Marinho Guerra ◽  
Janaína Ribeiro Costa Rouws ◽  
Luiz Augusto de Aguiar ◽  
...  

ABSTRACT: Grasshoppers of the families Acrididae and Romaleidae (Orthoptera) are among the insects that defoliate heliconias and have been gaining status as pests of commercial crops of these plants in Brazil. The objectives of the present study were to identify the grasshopper defoliating heliconias in the municipality of Santo Antônio de Pádua, RJ (Brazil), to evaluate the effect of different levels of shade on the population of this grasshopper and the production parameters of heliconias, and to determine if this grasshopper has an oviposition preference among the heliconias evaluated. The experiment was in a completely randomized block design, in subdivided plots (four levels of shade in the plot, 0%, 30%, 50% and 80%, and four species of Heliconia: H. psittacorum, H. stricta, H. wagneriana and H. psittacorum x H. spathocircinata ‘Golden Torch’ in the subplot), with four replications. The grasshopper was identified as Cornops frenatum frenatum (Acrididae). An increase in shade resulted in a decrease in the number of oviposition holes from the grasshopper and the number of lateral buds. Shade did not influence the number of C. f. frenatum nymphs and adults and the number of flower stems. H. wagneriana was the most preferred species for oviposition by C. f. frenatum. Results suggested using screens to shade heliconia plants can help control C. f. frenatum populations, however, the light requirements of the heliconias should be considered to guarantee productivity.


2016 ◽  
Vol 83 (0) ◽  
Author(s):  
Jesus Guerino Töfoli ◽  
Ricardo José Domingues ◽  
Walter Jacobelis Jr. ◽  
Marina Pacheco Lombardi Tortolo

ABSTRACT: Late blight (Phytophthora infestans ) is among the most important and destructive diseases in potato cultivation. Aiming to evaluate the efficacy of the new fungicide ametoctradin, mixed with dimethomorph and metiram, an experiment was carried out in commercial potato crops (Ágata cultivar) in Pilar do Sul, São Paulo state, Brazil, during the growing season in 2013. A randomized block design was used, with 4 replications, on plots of 15 m2. Applications were carried out using a backpack sprayer with a spray-bar under 3 bar of constant pressure. The application volume varied from 300 L to 600 L.ha-1 based on crop development. The variables evaluated were leaf severity (0 to 100%), area under the disease progress curve, and yield. Ametoctradin + dimethomorph (1.25 L.ha-1) provided significant control of late blight, exceeding benthiavalicarb + fluazinam, dimethomorph + metiram, dimethomorph + pyraclostrobin, cymoxanil + mancozeb, metalaxyl-M + mancozeb, ametoctradin + metiram, and pyraclostrobin + metiram, although similar to ametoctradin + dimethomorph (1.00 L.ha-1), fluopicolide + propamocarb, and fenamidone + propamocarb. Ametoctradin + metiram resulted in moderate control, which was always similar to the standard. Ametoctradin and its associations represent a new alternative for the management of potato late blight.


1970 ◽  
Vol 37 (1) ◽  
pp. 10-16
Author(s):  
S Barua ◽  
MJ Khan ◽  
AKFH Bhuiyan ◽  
MN Islam ◽  
SS Islam

The study was undertaken to investigate the effects of concentrate supplementation with different protein levels on intake, digestibility and growth performance of Red Chittagong (RC) heifers fed urea molasses straw (UMS) based diet. Twelve RC heifers having average live weight of 124.83±43.15 kg and aged between 8 to 14 months were selected for 90 days feeding trial. Animals were divided into four groups having three animals in each and were randomly assigned to four dietary treatments in a Randomized Block Design (RBD). The experimental diets were formulated using urea molasses straw (UMS), German grass (Echinochloa grousgalli) with or without concentrate mix (having different levels of protein). All the animals received UMS ad libitum and German grass at the rate of 20% of total DM intake. In addition to UMS and German grass of control diet T0, animals on diets T1, T2 and T3 were supplied with concentrate mixture at the rate of 10% of DM intake containing 15, 20 and 25% CP, respectively. Average daily DM intake was 2.65, 3.06, 2.62 and 2.86 kg/100 kg LW for diets T0, T1, T2 and T3, respectively and the difference was non significant (P>0.05). The digestibility of DM, CP, EE, NFE and digestible nutrients (DCP, DEE and DNFE) for diets T1, T2 and T3 was significantly higher than those for diet T0. The daily average liveweight gain of RC heifers fed diets T0, T1, T2 and T3 were 100, 275, 333 and 291 g respectively (P<0.01). Concentrate mixture having 20% crude protein may be supplemented at the rate of 10% of DM intake per day for optimum growth of Red Chittagong heifers. DOI: http://dx.doi.org/10.3329/bjas.v37i1.9861 BJAS 2008; 37(1): 10-16


2019 ◽  
Vol 11 (9) ◽  
pp. 21
Author(s):  
Guilherme V. Pimentel ◽  
Silvino G. Moreira ◽  
Mateus O. T. de Avila ◽  
Antonio Henrique F. de Carvalho ◽  
Alessandro A. P. da Silva ◽  
...  

Maize hybrids have different levels of tolerance to the herbicide nicosulfuron, depending on the dose, the environment, the phenological stage of the plant and the timing of nitrogen fertilization, and phytotoxic effects can occur without proper management. There is also limited information on the selectivity of current genetically modified hybrids for other recommended herbicides, such as tembotrione. Thus, the objective of this study was to evaluate the effects of herbicides (tembotrione and nicosulfuron) and the timing of nitrogen fertilization on the yield of maize hybrids. The experimental design was a randomized block design, in a 4 &times; 2 factorial arrangement, with 4 replicates. The treatments consisted of four treatments [weeding; nicosulfuron + atrazine (20 and 32 + 1250 g ha-1 ai) and tembotrione + atrazine (75.6 + 1250 g ha-1 ai)] and two nitrogen fertilization times (0 and 7 days after application). Maize hybrids P30F53 Leptra, DKB 230PRO3 and KWS 9004PRO2 were assessed in two growing seasons (1st and 2nd harvest) during the 2016/2017 growing season. The percentages of weed control; phytotoxicity at 7, 14 and 21 days after application (DAA); plant height; number of rows per ear; and yield at harvest were evaluated. All herbicides were more effective in controlling weeds at the 1st harvest because of favourable climatic conditions. Nitrogen fertilization can be carried out on the same day as the application of the herbicides nicosulfuron and tembotrione with no reduction in yield for the hybrids P30F53 Leptra, DKB 230PRO3 and KWS 9004PRO2.


2015 ◽  
Vol 39 (6) ◽  
pp. 1603-1610 ◽  
Author(s):  
Antonio Higino Frederico Pereira ◽  
Antonio Carlos Tadeu Vitorino ◽  
Eber Augusto Ferreira do Prado ◽  
Anderson Cristian Bergamin ◽  
Munir Mauad ◽  
...  

ABSTRACT The expansion of the sugarcane industry in Brazil has intensified the mechanization of agriculture and caused effects on the soil physical quality. The purpose of this study was to evaluate the limiting water range and soil bearing capacity of a Latossolo Vermelho distroférrico típico (Rhodic Hapludox) under the influence of different tractor-trailers used in mechanical sugarcane harvesting. The experiment was arranged in a randomized block design with five replications. The treatments consisted of green sugarcane harvesting with: harvester without trailer (T1); harvester with two trailers with a capacity of 10 Mg each (T2); harvester with trailer with a capacity of 20 Mg (T3) and harvester and truck with trailer with a capacity of 20 Mg (10 Mg per compartment) (T4). The least limiting water range and soil bearing capacity were evaluated. The transport equipment to remove the harvested sugarcane from the field (trailer) at harvest decreased the least limiting water range, reducing the structural soil quality. The truck trailer caused the greatest impact on the soil physical properties studied. The soil load bearing capacity was unaffected by the treatments, since the pressure of the harvester (T1) exceeded the pre-consolidation pressure of the soil.


2019 ◽  
pp. 1375-1382
Author(s):  
Tulio Martinez Santos ◽  
Edna Maria Bonfim Silva ◽  
Tonny José Araújo da Silva ◽  
Ana Paula Alves Barreto Damasceno

Soil compaction is a big limitation to food production in agriculture. Wood ash is an agro-industrial residue generated by the burning of biomass in boilers for energy production. It can be used as a corrective agent and fertilizer of the soil. In this context, the objective of this study was to evaluate the root system of safflower cultivated under bulk density levels and wood ash doses in dystrophic Oxisol. The experiment was conducted in a greenhouse with a randomized block design under a 5x5 factorial scheme composed of 5 wood ash doses (0, 8, 16, 24, 32 g dm-3) and 5 bulk density levels (1.0, 1.2, 1.4, 1.6, 1.8 Mg m-3) with 4 replicates. The soil was collected from 0-0.20 m depth layer. Later it was incubated with the respective wood ash doses. Each experimental unit consisted of a pot made of three PVC (polyvinyl chloride) rings, in which the layers of 0.1-0.2 m were compacted. At 75 days after emergence, the plants were cut, their roots washed and the volume and dry mass checked. The results were submitted to analysis of variance and subsequent regression test, both at 5% probability. Soil densities negatively influenced the root system development and culture of safflower. Application of wood ash doses of 20 to 24 g dm-3 significantly improved root development of plant.


Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1549
Author(s):  
Bruno Maia Abdo Rahmen Cassim ◽  
Antonio Pedro Martins Machado ◽  
Daniel Fortune ◽  
Fernando Rodrigues Moreira ◽  
Éder Júnior De Oliveira Zampar ◽  
...  

The objective of the study was to evaluate the effect of foliar application of urea and urea-formaldehyde, triazone-based fertilizers on soybean and corn crops. Four experiments were carried out, two on soybeans, one on first season corn, and the other on second season corn. The experiments were conducted using a randomized block design, with 5 treatments studied: T1—control without application of foliar nitrogen (N); T2—foliar application of conventional urea solution and three treatments with Hexion foliar fertilizers based on urea-formaldehyde and triazone (N-Hexion®), with varying levels of N and slow-release components; T3—Hexion 1; T4—Hexion 2; and T5—Hexion 3. The foliar application of conventional urea showed no statistically significant difference in relation to the control for the yield components and grain yield for the soybean crops in seasons 2018–2019 and 2019–2020. Urea-formaldehyde/triazone treatments showed a significant increase in yield for soybeans in the 2018–2019 season compared to the control and to conventional urea. Nitrogen fertilizers with high percentages of slow-release compounds promote nitrogen release more slowly, which led to no significant increase in yield for Hexion 1. No statistical differences were observed in the corn yield for the first and second crop.


Poljoprivreda ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 17-24
Author(s):  
Miro Stošić ◽  
Vladimir Zebec ◽  
Maciej Kluz ◽  
Boris Ravnjak ◽  
Tomislav Vinković ◽  
...  

A stationary field experiment of a reduced soil tillage was implemented at a Hypogley (Hypogleyic soils A–Gso–Gr soil horizon sequence) soil type of Eastern Croatia during three seasons and set up as a split-plot randomized block design in four repetitions. The tillage systems (TS) were as follows: 1) conventional tillage, i.e., plowing at 30 cm (CT), 2) disking up 10-12 cm (DT), 3) soil loosening up to 35 cm (LT), 4) no-tillage (NT). The experiment was designed to compare the penetration resistance (PR), soil moisture (SM), and bulk density (BD) at different TSs and soil depths. A cone penetrometer was used to measure the PR with 10 prods per TS, accompanied with a measurement of SM with a soil auger on every 10 cm, with four samples up to a 40-cm depth. The BD was determined by metal cylinders on every 10 cm up to a 30-cm depth, being weighed and dried thereafter to obtain an absolutely dry sample, and then calculated using absolutely a dry soil sample mass (m_s) and the soil volume (V). The PR and SM were significantly influenced by the TS and soil depth. The CT had the significantly lowest PR at all depths, while the DT has manifested a significantly higher PR at a soil depth amounting to 10 to 20 cm. The PR on NT were significantly diverse from the CT at all soil depths. The BD varied significantly concerning the TS and the soil depth. Subsequent to the three years, the CT had a significantly smaller BD at a depth amounting from 0 to 10 cm, and a significantly higher BD at 20- to 30-cm depth, compared to reduce the TS.


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