Desempenho de sulcadores no desenvolvimento e produtividade da soja em solo submetido a diferentes níveis de compactação

On the national scene, soybean crop occupies a prominent position in cultivated area and volume production, being cultivated largely in the no tillage system. This system, due to the intense traffic of machines and implements on its surface has caused soil compaction problems, which has caused the yield loss of crops. In order to minimize this effect the seeder-drill uses the systems to opening the furrow by shank or the double disc type. The use of the shank has become commonplace for allowing the disruption of the compacted surface layer, however requires greater energy demand and may cause excessive tillage in areas where there is not observed high levels of compaction. Thus, this study aimed to evaluate the effects of furrowers mechanisms and levels of soil compacting on traction requirement by a seeder-drill and on the growing and productivity of soybean in an Oxisol texture clay, in a two growing seasons. The experimental design consisted of randomized blocks with split plots with the main plots composed of four levels of soil compaction (N0 – no tillage without additional compaction, N1, N2 and N3 – no tillage subjected to compaction through two, four and six passes with tractor, respectively) corresponding to densities of soil 1.16, 1.20, 1.22 and 1.26 g cm-3, and subplots by two furrowers mechanisms (shank and double disc) with four replicates. To evaluate the average, maximum and specific traction force requested by the seeder-drill, was used a load cell, with capacity of 50 kN and sensitivity of 2 mV V-1, coupled between the tractor and seeder-drill, whose data are stored in a datalogger system model CR800 of Campbell Scientific. In addition, were evaluated the bulk density, soil mechanical resistance to penetration, sowing depth, depth and groove width, soil area mobilized, emergence speed index, emergence operation, final plant stand, stem diameter, plant height, average number of seeds per pod, weight of 1,000 seeds, number of pods per plant and crop productivity. Data were subjected to analysis of variance, the mean of furrowers were compared by Tukey test (p≤0.05), while for the factor soil compaction, polynomial regression analysis was adopted, selected models by the criterion of greater R2 and significance (p≤0.05) of equation parameters. Regardless of the crop season, penetration resistance increase as soil compaction levels up to around 0.20 m deep, and bulk density influenced the sowing quality parameters, however, did not affect the crop yield. In the first season, there was a higher productivity with the use of the shank type. In the second crop season, the shank demanded greater energetic requirement with the increase of bulk density and opposite situation with the double disc. The locking of sowing lines allow better performance of the shank to break the compacted layer.

Silagem do bagaço de sorgo sacarino

Brazilian sweet sorghum is used to generate ethanol and the bagasse is burned in industrial boilers or deposited on soil polluting the environment. This study evaluated the performance of sorghum plants and its bagasse silage nutritional value aiming to use it in the ruminant nutrition. Experiments were set up on the UTFPR campus at Dois Vizinhos-PR. The first trial was established on October 2nd, 2012 using the genotypes ADV 2010, Hunnigreen, Sugargraze, Volumax, BR 505, 503, 501 and the second trial at 2013 on November 27th assessing the materials ADV 2010, Sugargraze, Hunnigreen, EX 5110, BR 506, 508, 509 and 511. Experimental was laid out as a randomized block design with three replications. Results were analyzed through ANOVA comparing the averages by Duncan test at 5% error probability. As field variables were evaluated: plant height (Pl hei), green mass production (GM Prod), percentage of leaves, stems and panicles in relation to the plant, stems production without straw (Prod stems with straw), whole stems production (Who stems Prod), stem diameter (Stem diam), juice production (Juice prod) and Brix degree (oBrix). After juice plant extraction, forage bagasse was crushed and packed in silos for 60 days and green matter yield was estimated (GM). In bagasse silage gauged to buffer capacity (BC), dry matter (DM), mineral matter (MM), crude protein (CP), ether extract (EE), total carbohydrates (TC), non-fibrous carbohydrates (NFCH), neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin (LIG ) and digestibility "in vitro" (DIGIV). There was no significant difference (P> 0.05) between genotypes regarding to green matter production and on average, the second crop yield was lower and reflected in the reduction of bagasse production. Bagasse silage DM was of 32.3% and 33.1%; NDF 73% and 65.8%, crude protein 3.8% and 5.9; pH 3.7 and 3.7; TC and 9.8 and 10.7. mg MS-1; the amount of NFCH was 11.1 and 13.5%; DIG of DM 36.9 and 62.4% for the respectively to the bagasse produced from materials grown in the 2012/2013 and 2013/2014 seasons. Hybrid genotypes had a better agronomic performance while the varieties were more efficient in bromatological indexes. And despite the high percentage of NDF and the low protein level, it is possible to feed ruminants with this coproduct.