Resumo em Inglês:

ABSTRACT: The mapping of sugarcane yield is still not as widely available as it is for grain crops. Sugarcane harvesters cut and process the cane in a single or maximum of two rows, facilitating the monitoring of cane yield and its behavior on a small scale. This study tested a method for sugarcane yield data cleaning, investigating if the data recording frequency influences the characterization of yield variations in mapping high-resolution spatial data within a single row. Four data sets from yield monitors of single row harvesting were used. A cleaning process with global and anisotropic filtering in a single sugarcane row was applied. The local outlier cleaner compares the yield value of a point with its nearest neighbors within the same row. Even after the elimination of outliers, there is great variation in yield between the rows, and this variation is much smaller in a single row. A frequency of 2 Hz was required for identifying and characterizing small yield variations within the sugarcane rows whilst other frequencies tried (0.2 and 0.1 Hz) resulted in loss of information on yield variability within the row. The difference between the root mean square error (RMSE) of ordinary kriging (OK) and inverse distance weighting (IDW) techniques is large enough to suggest the use of an individual yield line. Individual yield lines saved information in the data generated by the yield monitor unlike IDW and OK interpolation methods which omitted information over short distances within the rows and compromised the quality of high-resolution maps.

Resumo em Inglês:

ABSTRACT: The citrus scale insect Praelongorthezia praelonga (Douglas), a major pest of citrus and other economically important crops, has only two commonly documented natural enemies: an entomopathogenic strain of the fungus Colletotrichum nymphaeae (Pass.) Aa and several parasitoids. The entomopathogenic strain of C. nymphaeae, formerly recognized under the synonym C. gloeosporioides f. sp. ortheziidae, is under development for commercial application as a biological control agent in citrus in Brazil-the top exporter of citrus globally. The synonomy of C. gloeosporioides f. sp. ortheziidae with C. nymphaeae remains based on limited DNA sequence data and without morphological study. To qualify for future approval as a biological control agent by federal agencies in Brazil and the European Union, the circumscription of a microorganism must be explicit and without ambiguities. Herein, through morphological study and phylogenetic analysis of five DNA regions we clarify the circumscription and affinity of entomopathogenic C. nymphaeae and describe it as a new variety.

Resumo em Inglês:

ABSTRACT: Enhancing the plant rhizosphere microbial community function by increasing plant diversity in the field is a promising strategy for enhancing agricultural sustainability. This study evaluated the effectiveness of the intercropping of wheat in controlling cucumber Fusarium wilt disease. Bacterial community diversity and abundance in cucumber rhizosphere were estimated by high-throughput amplicon sequencing and quantitative polymerase chain reaction (PCR). Results showed that the intercropping of wheat inhibited the severity of cucumber seedling Fusarium wilt disease, increased the alpha diversity and altered the composition of the bacterial community in cucumber rhizosphere. Compared with monocropped cucumber, intercropped cucumber had higher relative abundances of Anaerolineae, Deltaproteobacteria, Phycisphaerae and Planctomycetacia, and lower Alphaproteobacteria and Cyanobacteria. Moreover, the intercropping of wheat promoted bacterial genera with plant-beneficial potential (e.g. Pseudomonas, Haliangium and Archangium spp.) in cucumber rhizosphere. Quantitative PCR confirmed that Pseudomonas spp. abundance was higher in intercropped cucumber rhizosphere than in monocropped cucumber rhizosphere. Overall, the intercropping of wheat decreased the severity of Fusarium wilt of cucumber and promoted potential plant-beneficial microbes in cucumber rhizosphere.

Resumo em Inglês:

ABSTRACT: Gladiola is an important cut flower worldwide and scheduling field gladiola production is largely dependent on planting at the correct time since its development is controlled by the air temperature. The aim of this study was to configure a planting window of gladiola in order to harvest spikes to be sold on All Souls' Day and Mother's Day holidays in the state of Rio Grande do Sul, Brazil, taking into account the El Niño Southern Oscillation (ENSO) phases. The PhenoGlad model, a dynamic process-based simulation model that simulates gladiola phenology on a daily time step was used in this study. Daily minimum and maximum temperatures over 55 years (1961-2015) from 18 weather stations across Rio Grande do Sul state, Brazil, were used as input data in the PhenoGlad model. The optimum planting window was simulated for each maturity group, location and ENSO phase. For harvesting on All Souls' Day, the optimum planting window had greater variation among the different ENSO phases. For Mother's Day, only Very Strong El Niño events affected the development of gladiola, indicating the weak signal of the phenomenon at this time of the year. A case study in a commercial farm demonstrated the importance of these results for farmers. The planting window for production on Mother's Day in a Neutral year was successfully configured. Determining the optimum planting window by considering the ENSO effect led to a more precise scheduling of gladiola production in southern Brazil.

Resumo em Inglês:

ABSTRACT: Urea is a common non-protein supplement used in ruminant feed; however, excessive consumption may lead to poisoning by NH3. Although the slow release of urea into the rumen has shown to be an essential aspect for ruminant feed, to date only a few studies have addressed this matter. In this study we examined the influence of five different NH3-N slow release systems based on clay-urea nanocomposites on the fiber digestibility of low-quality forage (sugarcane straw) in vitro. Physical properties of nanocomposites were evaluated and their effects on digestibility were tested in vitro using pristine urea as a positive control (level of 1 % of DM of sugarcane straw sample) and sugarcane (with no additives) as a negative control. Ammonia release and digestibility were evaluated at 12, 24, 36, 48, 72 and 96-h. Generally, all nanocomposites increased (p < 0.05) digestibility of fiber over control under all the conditions stipulated, but the samples with hydrogel content were more expressive. We concluded that an ideal release rate and optimum environment for microbial synthesis are necessary to maximize the digestion of sugarcane.

Resumo em Inglês:

ABSTRACT: There is an increasing interest in the application of geophysical surveys to assess the soil water content (SWC) variation in both spatial and temporal scales. In this work, a geophysical survey was carried out at an experimental farm in dry and wet conditions. We determined the SWC data measured with the gravimetric method, apparent electrical conductivity by electromagnetic induction (EMI) and amplitude of Ground Penetrating Radar (GPR) data at different frequencies. Geophysical sensors are an efficient tool for soil mapping at high resolution; however; there is a need to improve the knowledge on their capabilities and limitations under field conditions, especially for GPR. The geophysical survey provides an example of the application of these techniques to evaluate the spatial variability of SWC in two different water conditions. The contribution of geophysical data in understanding the spatial variability of SWC was investigated applying both the traditional analysis and spatial techniques. The results indicated that the geophysical data captured the spatial variation of SWC in non-invasively way especially in dry condition. However, they also showed the complex interplay between factors controlling SWC and geophysical responses and the drawbacks of geophysical sensors under inhomogeneous water conditions. Our findings also highlighted that EMI survey provides the potential to map the SWC variability within a relatively short time. The results obtained in this research are important from the agronomical viewpoint, since they allow increasing efficiency of irrigation practices, which is important in times characterized by climate change.

Resumo em Inglês:

ABSTRACT: Ethyl carbamate (EC) (NH2COOCH2CH3) is found in cachaça, and its presence in the beverage is conspicuous for its toxicity. Copper, the metal of choice used in the construction of stills, is also considered a beverage contaminant and is often related to the presence of EC in beverages. The study aimed to monitor the quality of cachaça by measuring the presence of copper and EC, and comparing the influences of sugarcane cultivation systems on the concentration of these contaminants. The varieties, RB 867515, RB 962869 and RB 85553, were cultivated under the following management systems: planting without fertilization; organic planting; and conventional planting. For cultivation, a completely randomized design in a factorial scheme of 3 varieties × 3 managements was used as experimental planning, in 4 replications. The concentrations of copper and EC in beverages were evaluated and submitted to univariate analysis of variance (p ≤ 0.05). The organic and conventional systems presented no significant variations in copper content, both of which are recommended for the planting of sugarcane as raw material for cachaça. From amongst the varieties evaluated, RB966928 presented the lowest concentrations of copper for the organic and conventional systems, and was the most recommended for the production of cachaça. To evaluate the EC concentration (μg L–1) in the cachaças produced, all beverages were considered in accordance with national legislation. Significant differences were observed between them, but the conventional and organic systems are favored for deployment in the cultivation of sugarcane as the raw material of cachaça. The same applies to the RB966928, RB867515 and RB855453 varieties.

Resumo em Inglês:

ABSTRACT: The main goal set by researchers in this article was to gather knowledge on the structure of the basic biometric features of tree-rings of two species of poplars, belonging to different sections of Aegeiros – Populus xcanadensis and Tacamahaca – Populus maximowiczii, and to define and understand the correlation between weather and annual increment. A supplementary objective of the article was to determine pointer years of species found in individual populations. Our research used the standard methodology applied in dendroclimatology. In the analysis of correlation of the tree species studied, stronger statistically significant relationships were obtained in terms of precipitation-increment compared to temperature-increment. The annual increment in the Canadian poplar was enhanced by wet autumns and winters, especially by the rainfall in Oct and Dec in the previous year, as well as in Apr of this year. The tested Maximovich's poplars tested preferred rainfall during spring going into summer, especially in June of this year. Seven specific pointer years were determined for the Canadian poplar, comprising 4 positive (1987, 2008, 2010, 2012) and 3 negative years (2000, 2011, 2014). For P. maximowiczii, 11 pointer years were determined, i.e. 5 positive years (1987, 1991, 1999, 2009, 2012) and 6 negative (1984, 2000, 2002, 2010, 2013, 2015). In the pointer years, monthly sums of atmospheric precipitation and the average monthly air temperatures differed from the multi-year period. In the process of forming the secondary growth of the wood of the studied poplar species, the predominant role was played by atmospheric precipitation.

Resumo em Inglês:

ABSTRACT: The root system architecture (RSA) of plants and its functioning play a fundamental role in a number of plant growth mechanisms including water and nutrient uptake. Optimization of the RSA is important for stable and increased plant productivity under adverse conditions. Despite its great importance, studying the RSA is notoriously laborious because of the difficulty of accessing the rooting system of plants. We developed a root phenotyping platform, PhenoRoots, which allows for the non-invasive study of plant RSA. The system was built using inexpensive material and was designed to provide medium throughput. Substrate or soil-filled rhizotrons are used to grow plantlets, whose roots are directly visible through a glass plate. An experiment conducted on a panel of twenty Upland cotton (Gossypium hirsutum L.) varieties demonstrated the usefulness of the platform in assessing RSA traits. A number of traits, destructive and non-destructive, related to the RSA were measured and statistically analyzed. The non-destructive traits based on image analysis of roots were more accurate and showed high correlation with the time-consuming destructive measurements. The platform allowed for capturing the phenotypic and genetic variability found in the panel of cotton varieties, and to define three contrasting RSA patterns. PhenoRoots provides an inexpensive alternative to the medium throughput analysis of RSA traits in plants.

Resumo em Inglês:

ABSTRACT: Presence of the ALMT1 (aluminum-activated malate transporter) gene confers resistance to aluminum toxicity in Triticum aestivum (common wheat). No resistant cultivars of Triticum turgidum ssp. Durum Desf. (durum wheat) have been registered in Brazil. The aim of this study was to map the ALMT1 through application of the FISH (fluorescence in situ hybridization) technique in five wheat genotypes, common and durum, from the Active Germplasm Bank (AGB) of the Instituto Agronômico (IAC): BH 1146, P19, P33, Anahuac, and IAC 1003. FISH-ALMT1 signals were registered in Anahuac (sensitive) chromosomes and in BH 1146, P19, and P33 (resistant) chromosomes. In the three resistant genotypes, a characteristic double FISH signal was found, located in different chromosomes of the complements: in BH 1146 in chromosome 5D, in P19 in 3B, and in P33 in 6B. This FISH - ALMT1 mapping allows for introgression of aluminum resistance in sensitive cultivars through breeding programs using introgression lines containing these carrier chromosomes.

Resumo em Inglês:

ABSTRACT: Chemical and physical properties of soil can be altered with the successive application of liquid swine manure (LSM), also known as slurry. Therefore, monitoring the impact of LSM is essential to an assessment of the potential agronomic and environmental benefits and risks associated with management practices. The aim of this study was to evaluate the effects of LSM on the chemical and physical attributes of soil under pasture (Cynodon spp.), located in southern Brazil. Four areas were sampled: three areas cultivated with Cynodon spp. pasture with successive applications of 200 m3 ha–1 y–1 of LSM for three, eight and 15 years; and untreated native forest as a reference. The soil attributes evaluated were: organic carbon (OC), active (pH water) and potential acidity (H + Al+ 3), nutrient availability (i.e., P, K, Ca, Mg, Cu and Zn), soil bulk density, macro, micro and total porosity. Successive applications of LSM on pasture reduced soil active acidity, and increased the soil organic C and plant-available N, P, Ca, Mg, Cu and Zn contents. These effects were more intense with time and in the shallowest layers, i.e. 0-10 cm. Excessive increases in P, Cu and Zn in the soil should be carefully monitored to minimize the contamination risks to soil, ground and surface waters. Soil physical attribute changes were more associated with land use (pasture versus native forest) than LSM use, and LSM applications induced slight improvements in the soil structural quality over time.

Resumo em Inglês:

ABSTRACT: Spectroscopic techniques have great potential to evaluate soil properties. However, there are still questions regarding the applicability of spectroscopy to analyze soil phosphorous (P) availability, especially in tropical soils with low nutrient contents. Therefore, this study evaluated the possibility to estimate P availability in soil and its pools (labile, moderately labile and non-labile) via Vis-NIR spectroscopy based on intra-field calibration. We used soils from two different locations, a plot experiment that received application of phosphate fertilizers (Field-A) and a cultivated field where a grid soil sampling was performed (Field-B). We used the technique of diffuse reflectance in the visible and near-infrared (Vis-NIR) to obtain the spectra of soil samples. Predictive modeling for P availability and labile, moderately labile and non-labile pools of P in soil were obtained via partial least squares (PLS) regression; classification modeling was performed via Soft Independent Modeling of Class Analogy (SIMCA) on three P availability levels in order to overcome the limitation on quantifying P via Vis-NIR spectroscopy. We found that isolating P contents as the only variable (Field-A), Vis-NIR spectroscopy does not allow estimating P pools in the soil. In addition, quantification of P available in the soil via predictive modeling has limitations in tropical soils. On the other hand, estimating P content in soil through classes of availability is a feasible and promising alternative.