Optimizing herbicide selection for pre-emergence control of itchgrass and cypressvine morningglory in sugarcane.

The aim of this study was to assess the efficacy of herbicides in association to control Rottboellia exaltata and Ipomoea quamoclit during pre-emergence while also to evaluate the potential impact on the sugarcane. The experimental design employed a randomized block with seven treatments and four replications. The treatments were: 1 - no herbicide application; 2 - indaziflam + sulfentrazone; 3 - indaziflam + diclosulam; 4 - indaziflam + tebuthiuron; 5 - flumioxazin + diclosulam, 6 - flumioxazin + pyroxasulfone and 7 - clomazone + sulfentrazone. The evaluated parameters were: percentage of weeds control, green coverage percentage (Canopeo® system), weed biomass (g m-2), itchgrass height, and sugarcane tiller. Several herbicide associations have been proven effective alternatives for managing itchgrass and cypressvine morningglory. The most successful treatments for itchgrass control were indaziflam + tebuthiuron (100%) and indaziflam + diclosulam (97%), whereas for cypressvine morningglory, the betters were indaziflam + sulfentrazone (97%), indaziflam + diclosulam (98%), indaziflam + tebuthiuron (97%), flumioxazin + diclosulam (94%), and clomazone + sulfentrazone (96%). All treatments reduced the weed biomass, with indaziflam + tebuthiuron being the safest option for protecting sugarcane.

Optimizing foliar N-fertilization in sugarcane depends on plant genotype and nitrogen concentration.

Foliar N-fertilization (FNf) has emerged as a promising approach to synchronize plant nitrogen (N) demands and application timing, reducing the N losses to the environment associated with traditional soil-based fertilization methods. However, limited information exists regarding the effectiveness of FNf in sugarcane. This study aimed to optimize FNf in sugarcane by evaluating N-fertilizer recovery by the plant (NRP) and assessing potential toxicity effects. Four sugarcane genotypes were subjected to FNf using 15 N-urea at five nitrogen concentrations. NRP was assessed at five time points for roots, stalk, old leaves, 15 N-urea-fertilized leaves (15 NL), and unexpanded leaves (UEL). Leaf scorching, indicating FNf toxicity, was analyzed using morpho-anatomical and histochemical techniques. The results showed that FNf promoted high NRP, with an average recovery of 62.3%. Surprisingly, the redistribution of 15 N-urea did not follow the nitrogen uptake rate by sugarcane leaves, with an average of 41.3% of the total-NRP. The stalk emerged as the primary sink for 15 N-urea, followed by the UEL. Genotypes differed in the leaf scorching intensity, which increased with higher concentration of 15 N-urea. Genotypes also differed in the 15 N-urea uptake rate, down-regulated by the N content in the 15 NL. These findings emphasize that by carefully choosing the appropriate genotype and nitrogen concentration, FNf can significantly enhance N-fertilizer uptake, resulting in potential environmental and economic benefits.

Selectivity and control of Euphorbia heterophylla in sugarcane by herbicide in post-emergence.

To obtain good control of wild poinsettia (Euphorbia heterophylla) in post-emergence in sugarcane crop, we evaluate the herbicides association on post-emergence of E. heterophylla and the ratoon cane selectivity. The experimental scheme was in randomized blocks with 6 treatments and 4 replications. The treatments were: control; ametryn + mesotrione + sulfentrazone (1,500 + 144 + 800 g i.a ha-1); ametryn + mesotrione + diclosulan (1,500 + 144 + 200 g i.a ha-1); ametryn + mesotrione (2,500 + 144 g i.a ha-1: Highest dose); ametryn + mesotrione (2,000 + 144 g i.a ha-1: Lowest dose) and ametryn + mesotrione + diuron (1,000 + 144 + 1,250 g i.a ha-1). The percentage of control, dry mass, height and percentage of germination of E. heterophylla and injury level, yield and technological quality of sugarcane were evaluated. The best control of E. heterophylla was: ametryn + mesotrione +sulfentrazone; ametryn + mesotrione + diclosulan and ametryn + mesotrione (Lowest dose). As for the ratoon cane selectivity the best yield was achieved with the association ametryn + mesotrione +diclosulan. An appropriate association of herbicide molecules provides successful control of E. heterophylla, especially the association of sulfentrazone or diclosulan together with ametryn and mesotrione.

Fertilizer source and application method influence sugarcane production and nutritional status.

Introduction: The contrasting weather conditions throughout the sugarcane harvest period in south-central Brazil (April to November) influence fertilization management in sugarcane ratoon. Methods: Through field studies carried out over two cropping seasons, we aimed to compare the performance of sugarcane at sites harvested in the early and late periods of the harvest season as a function of fertilizer sources associated with application methods. The design used in each site was a randomized block in a 2 x 3 factorial scheme; the first factor consisted of fertilizer sources (solid and liquid), and the second factor consisted of application methods (above the straw, under the straw, and incorporated into the middle of the sugarcane row). Results: The fertilizer source and application method interacted at the site harvested in the early period of the sugarcane harvest season. Overall, the highest sugarcane stalk and sugar yields at this site were obtained with the incorporated application applying liquid fertilizer and under straw applying solid fertilizer, with increments of up to 33%. For the site harvested in the late period of the sugarcane harvest season, the liquid fertilizer promoted a 25% higher sugarcane stalk yield compared to the solid fertilizer in the crop season with low rainfall in the spring, while in the crop season with normal rainfall, there were no differences between treatments. Discussion: This demonstrates the importance of defining fertilization management in sugarcane as a function of harvest time, thereby promoting greater sustainability in the production system.

Testing of Automated Photochemical Reflectance Index Sensors as Proxy Measurements of Light Use Efficiency in an Aspen Forest.

Commercially available autonomous photochemical reflectance index (PRI) sensors are a new development in the remote sensing field that offer novel opportunities for a deeper exploration of vegetation physiology dynamics. In this study, we evaluated the reliability of autonomous PRI sensors (SRS-PRI) developed by METER Group Inc. as proxies of light use efficiency (LUE) in an aspen (Populus tremuloides) forest stand. Before comparisons between PRI and LUE measurements were made, the optical SRS-PRI sensor pairs required calibrations to resolve diurnal and seasonal patterns properly. An offline diurnal calibration procedure was shown to account for variable sky conditions and diurnal illumination changes affecting sensor response. Eddy covariance measurements provided seasonal gross primary productivity (GPP) measures as well as apparent canopy quantum yield dynamics (α). LUE was derived from the ratio of GPP to absorbed photosynthetically active radiation (APAR). Corrected PRI values were derived after diurnal and midday cross-calibration of the sensor's 532 nm and 570 nm fore-optics, and closely related to both LUE (R² = 0.62, p < 0.05) and α (R² = 0.72, p < 0.05). A LUE model derived from corrected PRI values showed good correlation to measured GPP (R² = 0.77, p < 0.05), with an accuracy comparable to results obtained from an α driven LUE model (R² = 0.79, p < 0.05). The automated PRI sensors proved to be suitable proxies of light use efficiency. The onset of continuous PRI sensors signifies new opportunities for explicitly examining the cause of changing PRI, LUE, and productivity over time and space. As such, this technology represents great value for the flux, remote sensing and modeling community.

Functional outcomes after patellar autologous osteochondral transplantation.

PURPOSE: The aim of the present study was to assess clinical evaluation of patients who underwent autologous osteochondral transplantation of the patella. METHODS: This prospective study assessed outcomes of 20 patients who underwent patellar autologous osteochondral transplantation at four time-points: preoperatively, 3 days, 6 months, and 2 years after surgery. The following outcomes were assessed at each time-point: pain (VAS), gait, swelling, trophic status, muscle strength, patellar mobility, and range of motion. The Tegner scale was also applied for each time-point. RESULTS: All parameters improved, except for patellar mobility, which did not show any change. Pain score decreased from 7.1 (SD 2.3) to 2.4 (SD 2.6) at the 2-year assessment; limping decreased from 70 % before surgery to 15 % 2 years later; swelling scores decreased from an average of 1.8 (SD 0.8) 3 days after surgery to 0.5 (SD 0.7) at the 2-year assessment; muscle strength increased from 3.9 (SD 0.8) to 4.7 (SD 0.7) points at final follow-up; and the range of motion increased from 84 (SD 16.2) to 132 (SD 10.7) degrees 2 years later. Tegner score before surgery ranged from 0 to 5, and after 2 years, it ranged from 5 to 9. CONCLUSION: Autologous osteochondral transplantation for the treatment of patellar chondral lesion was associated with significant improvement in pain, gait, swelling, and range of motion 2 years after surgery, achieving scores similar to uninjured knees. Most of them were able to return to sports activity after 6 months (recreational level) and 2 years (competitive level). LEVEL OF EVIDENCE: IV.

Unusual case of a surgically treated ACL tear in a 4-year-old patient.

Anterior cruciate ligament injury in children is an increasingly common disease. We report a rare case of surgical treatment of a 4-year-old patient who presented with an anterior cruciate ligament tear after a high-energy trauma followed by chronic spontaneous subluxation during knee flexion and extension. An extra-articular ligamental reconstruction technique was performed and the child is clinically well 4 years after surgery. Historically, non-surgical treatment has been the main treatment option, however, the indication for surgical reconstruction is increasing as we better understand the histological characteristics of the immature skeleton.