Operational parameters of soybean seeding in santa fe system

The use of no tillage system associated with the crop-livestock integration is an alternate managing that promotes the accumulation of dry matter in the soil, an essential fact to make the system sustainable and profitable. The aim of this study was to evaluate the operational performance of a planter-tractor set on maize straws intercropped with Urochloa, in different seeding modes. The soybean crop was seed on the intercropping of two forage species (Urochloa brizantha and Urochloa ruziziensis) in five cropping systems: MBL (Maize with Urochloa in the maize seeding row, mixed with base fertilizer and deposited at 0.10 m), MBE (Maize with Urochloa seeded between rows at the same day of seeding maize), MBC (Urochloa between rows of maize seeded with the covering fertilizer at the V4 stage), MBLA (Maize with Urochloa by broadcast seeding at the V4 stage ) and MS (Single Maize: control). The following variables were evaluated: dry mass of maize straw, dry mass of forages and total dry mass of straw; and for the operational parameters the speed of seeding, wheel slippage, traction force and average power at the drawbar. The results showed that the amount of straw produced by maize intercropping with Urochloa, interferes in the operational performance of the tractor-planter at the operation of soybean seeding, i.e., areas with higher amount of straw promote greater energy demand, as well as higher wheel slippage.

Fungicide application using a trailing boom in soybean fields

The objective of this study was to determine the effects in the yield of soybean crop utilizing a trailing boom sprayer for chemical control of late season diseases. The experimental design was randomized blocks with 04 treatments, which consisted of applying fungicides with a traditional sprayer, trailing boom, the traditional sprayer plus the trailing boom simultaneously and control (without fungicide aerial application) in 05 repetitions per treatment. The variables evaluated were: final plant population, pods per plant, grains per pod, weight of one thousand grains and yield. It was concluded that the control of foliar diseases with fungicides presented weight of one thousand grains and yield significantly higher than the average of plots without fungicide application. The trailing boom did not significantly affect the yield compared to the technology currently used.

Designing and manufacturing of a soybean harvest residue picker

ABSTRACT Soy harvest matches seasons with shortage of dry matter supply for ruminant feeding in most Brazilian soy-growing areas. Agricultural machinery-producing companies must have market perception, observing new opportunities and developing equipment to meet costumers’ needs. This paper aims to design, build, and test a device to collect soybean crop residues from the combine cleaning mechanism, consisting mainly of vegetable straw (chaff), and the other plant parts (stems) remain being deposited onto the ground. For equipment designing, we made use of the architectural design methodology proposed in the reference model for the agricultural machinery development process. The equipment was designed and built following the proposed methodology, then installed and put into operation in a John Deere 1165 combine. After initial testing and few adjustments, the device showed satisfactory chaff-collecting performance. The equipment consists of a screw conveyor assembled transversely to the combine and a centrifugal fan assembled on the side. The collected chaff is dumped into a trailer towed by tractor.

Morphological and physiological alterations induced by lactofen in soybean leaves are reduced with nitric oxide

Lactofen is a diphenylether herbicide recommended to control broad-leaved weeds in soybean (Glycine max) fields and its mechanism of action is the inhibition of protoporphyrinogen-IX oxidase (Protox), which acts in the chlorophyll biosynthesis. This inhibition results in an accumulation of protoporphyrin-IX, which leads to the production of reactive oxygen species (ROS) that cause oxidative stress. Consequently, spots, wrinkling and leaf burn may occur, resulting in a transitory crop growth interruption. However, nitric oxide (NO) acts as an antioxidant in direct ROS scavenging. Thus, the aim of this work was to verify, through phytometric and biochemical evaluations, the protective effect of NO in soybean plants treated with the herbicide lactofen. Soybean plants were pre-treated with different levels of sodium nitroprusside (SNP), a NO-donor substance, and then sprayed with 168 g a.i. ha-1 lactofen. Pre-treatment with SNP was beneficial because NO decreased the injury symptoms caused by lactofen in young leaflets and kept low the soluble sugar levels. Nevertheless, NO caused slower plant growth, which indicates that further studies are needed in order to elucidate the action mechanisms of NO in signaling the stress caused by lactofen in soybean crop.

Selectivity of glyphosate tank mixtures for RR soybean

An active ingredients mixture of different action mechanisms is an essential tool to prevent or manage areas with resistant weeds. However, it is important that such a mixture provides adequate selectivity to the crop. The aim of this work was to evaluate glyphosate selectivity to glyphosate-resistant (RR) soybean, and also verify if there is selectivity in mixtures with other active ingredients applied postemergence aimed at new control strategies, which might be used in RR soybean cultivation. The herbicides and respective rates (g ha-1) evaluated were: glyphosate (720, 960, 1,200, and 1,440), and the mixtures of glyphosate (960) with cloransulam-methyl (30.24), fomesafen (125), lactofen (72), chlorimuron-ethyl (12.5), flumiclorac-pentyl (30), bentazon (480), or imazethapyr (80). All treatments were applied in postemergence when the soybean crop was at V2 to V3 stage. Treatments with glyphosate or in mixtures with postemergent herbicides showed visual effects of phytotoxicity when applied to the glyphosate-resistant soybean. Effects such as reduction in plant height, crop closure, number of pods per plant, and hundred grain weight could be observed. However, the effects related to plant development were mostly transient and did not persist during the crop cycle. Among the studied treatments, only the mixture of glyphosate and lactofen was not selective to the crop, promoting negative effects on most characteristics analyzed and consequently reducing grain yield.

Residual herbicides in weed management for glyphosate-resistant soybean in Brazil

In agricultural production systems where the glyphosate-resistant soybean crop (Glycine max) is grown and the practice of crop rotation with alternative herbicides is not adopted, the exclusive and continuous use of glyphosate has led to the occurrence of resistant weed populations that may limit or compromise the benefits of this technology. Thus, the efficacy of weed management programs, including the use of residual herbicides (sulfentrazone, flumioxazin, imazethapyr, diclosulan, chlorimuron and s-metolachlor) applied in preemergence and followed by in-crop postemergence applications of glyphosate (PRE-POST) were compared to glyphosate postemergence only programs - POST. The study was conducted across nine locations during the 2009/2010 and 2010/2011 growing seasons. PRE-POST programs were efficient in the control of Amaranthus viridis, Brachiaria plantaginea, Bidens pilosa, Commelina benghalensis, Eleusine indica, Euphorbia heterophylla and Raphanus raphanistrum, with the level of control being similar when comparing the program with two applications of glyphosate POST. Some PRE-POST programs were not efficient in controlling Cenchrus echinatus, Ipomoea hederifolia and Ipomoea triloba. Sulfentrazone and diclosulam PRE-POST programs improved the control of Ipomoea triloba compared to sequential applications of glyphosate alone. No significant differences in soybean yield were observed between any of the herbicide treatments or study locations. The use of residual herbicides in preemergence followed by glyphosate in-crop postemergence provides consistent weed control and reducing early season weed competition. Furthermore, these programs utilize at least two herbicide modes of action for herbicide use diversity, which will be needed to stay ahead of resistance build-up, regardless of when weeds may appear.

Phytosociological variability of weeds in soybean field

Understanding spatial distribution of weeds in the crop enables to perform localized herbicide applications, increasing the technical and economic efficiency of operations and reducing environmental impacts. This work aimed to characterize the spatial and phytosociological variability of weeds occurring in soybean commercial field. It was conducted in an agricultural area located at the municipality of Boa Vista das Missões - RS, during the 2010/2011 harvest season. The area, that had been managed under no-tillage with soybean monoculture (summer) for five years, was divided in regular squares of 50 x 50 m (0.25 ha), totalizing 356 points. For species identification, 0.5 x 0.5 m sample squares were used. During the survey, 1,739 individuals were identified, distributed in 19 species of 13 families. The weed species Cardiospermum halicacabum, Digitaria horizontalis, Urochloa plantaginea and Raphanus raphanistrum showed the highest population variation in the area; however, only C. halicacabum, U. plantaginea and R. raphanistrum stood out based on the Importance Index Value (IVI). Localized management strategies considering the spatial variability of weed species placed in the Magnoliopsidas and Liliopsidas group show a high potential for use in soybean crop. The results show that the sampling method through regular grid was capable of characterizing the occurrence, population density and spatial variability of weed species in soybean crop.

Does the resistance to glyphosate herbicide affect the competitive ability of ryegrass with soybean?

The objective this work was to investigate the competitive ability between resistant and susceptible ryegrass biotypes and of these with soybean crop. Four experiments were carried under greenhouse, in a completely randomized design with four replications, in 2011 and 2012. Treatments were arranged in additive series and replacement series assay. In each series, the proportions among ryegrass resistant and susceptible plants related to soybean were: 100:0, 75:25, 50:50, 25:75 e 0:100. Leaf area and shoot dry mass were evaluated. Competitiveness statistical analysis consisted in applying diagrams to the replacement series and alternative interpretations of the competitiveness indexes. The soybean crop had equivalent competitiveness to the susceptible ryegrass biotype and inferior to the resistant biotype, while the biotypes, both susceptible and resistant to glyphosate, present equivalent competitive ability. In general, the intraspecific competition is more harmful to ryegrass when in competition with soybean, while interspecific competition is predominant for culture.

CHEMICAL CONTROL OF WHITE CLOVER IN SOYBEAN CROPS

ABSTRACTWhite clover is tolerant to many herbicides, making difficult a chemical control of this species during soybean crop establishments. The objective of this research was to select herbicides applied postemergence to control white clover in soybean and know the effects of this control on soybean yield. Seven herbicides were assessed, applied postemergence, with or without sequential application of glyphosate, and two control treatments (no control and total control of white clover). Glyphosate (with two sequential applications), fomesafen (with a sequential application of glyphosate), chlorimuron-ethyl and lactofen have shown a satisfactory control of white clover (above 80%). The lower control efficiency has resulted in lower production of soybeans.

Operational parameters of soybean seeding in santa fe system

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Phosphorus sources and fractions in an oxisol under no-tilled soybean

A dinâmica do P no solo pode ser modificada em sistemas com semeadura direta. Os agricultores brasileiros vêm aplicando fósforo na superfície do solo para otimizar a operação de máquinas, embora não seja uma prática recomendada pela pesquisa. Foi conduzido um experimento para estudar os efeitos da aplicação de duas fontes de fósforo na superfície do solo e no sulco de semeadura da soja. Os tratamentos consistiram da aplicação ou não de 80 kg ha-1 de P total como fosfato natural reativo e superfosfato, aplicados na superfície do solo, sobre os resíduos da cultura anterior. Na semeadura da soja, tratamentos adicionais (80 kg ha-1 de fosfato natural ou superfosfato) foram aplicados ao sulco de semeadura. O solo foi amostrado até 40 cm de profundidade, antes da semeadura da soja e após a colheita. Uma amostra controle foi tomada de área adjacente, sem cultivo. Houve aumento nos teores de P até 40 cm de profundidade, após a colheita da soja, de modo que o aumento foi observado principalmente no P ligado ao Ca e no P orgânico. Entretanto houve decréscimo nos teores de P ligado ao Fe. A adubação com ambas as fontes de fosfato levaram a um decréscimo nos teores de P ocluso na superfície do solo quando comparada com a área sem cultivo.

Morphological and physiological alterations induced by lactofen in soybean leaves are reduced with nitric oxide

O lactofen é um herbicida difeniléter recomendado para controlar plantas daninhas de folhas largas em campos de soja (Glycine max) e seu mecanismo de ação é a inibição da protoporfirinogênio-IX oxidase (Protox), que atua na biossíntese de clorofilas. Essa inibição resulta em um acúmulo de protoporfirina-IX, o que leva à produção de espécies reativas de oxigênio (ROS), causando estresse oxidativo. Conseqüentemente, podem ocorrer manchas, enrugamento e queima das folhas, o que leva à paralisação temporária do crescimento da cultura. Porém, o óxido nítrico (NO) atua como um antioxidante na eliminação direta das ROS. Assim, o objetivo deste trabalho foi verificar, por meio de avaliações fitométricas e bioquímicas, o efeito protetor do NO em plantas de soja tratadas com o herbicida lactofen. Plantas de soja foram pré-tratadas com diferentes doses de Nitroprussiato de Sódio (SNP), substância doadora de NO, e então pulverizadas com 168 g a.i. ha-1 lactofen. O pré-tratamento com SNP foi benéfico, pois o NO reduziu os sintomas de injúria causados pelo lactofen nos folíolos jovens e manteve baixos teores de açúcares solúveis. Porém, o NO proporcionou crescimento mais lento das plantas. Desta forma, posteriores estudos são necessários para elucidar os mecanismos de ação do NO na sinalização do estresse promovido pelo lactofen na cultura da soja.

Transformacoes na producao de graos no Brasil Meridional no periodo 1950-1979.

A general survey on the transformations which occurred during 1950-1979 in the cultivated area and in the yield of five agricultural products. The only significant transformation which occurred in the grain production in southern Brazil was the expansion of the soybean crop which is related to its use as an industrial raw material and as an external trade product.-after English summary

Effect of nozzle angle and air-jet parameters in air-assisted sprayer on biological effect of soybean asian rust chemical protection

Aiming at improving the efficiency control of Phakopsora pachyrhizi, this research evaluated different application techniques, using spray deposits and yield parameters of soybean crop. Two experiments were carried out in the experimental area of FCA/UNESP - Botucatu, SP, Brazil, in the soybean crop, Conquista variety, in the 2006/2007 season. The first experiment was arranged in random blocks with eight treatments and four replications. The treatments were conducted in factorial arrangement 4×2 (four air levels 0, 9, 11 and 29 km/h combined at two nozzle angles 0 and 30°) using AXI 110015 nozzles. Ten plants on each plot were selected for sampling spray deposits. Artificial targets were fixed on plants, two in the top and another two in the bottom part of plants (abaxial and adaxial leaf surface each one). For deposit evaluations, a cupric tracer was used and the amount of deposits was determined by a spectrophotometer. The second experiment was carried out in the same place and the treatments were of the same arrangement as the previous experiment, including control treatment (untreated plants). The spraying with triazole fungicide was realized in R2 and R5.2 growth stages of soybean with 142 l/ha spray volume. The nozzle angled of 30° combined with maximum air speed promoted the highest spray deposits on the soybean crop and influenced positively the control of the soybean Asian rust as well in the productivity of this crop.

Distribuição espacial de Pratylenchus brachyurus em soja no leste do Maranhão

Pós-graduação em Agronomia (Ciência do Solo) - FCAV