Sérgio Gustavo Quassi de Castro

New agronomic practices are emerging in the green cane system to utilize sugarcane (Saccharum officinarum L.) straw for energy cogeneration, which necessitates its removal from the soil surface. This study has three main objectives: (1) evaluate the population dynamics and composition of Jamaican crabgrass (Digitaria horizontalis Willd.) and large crabgrass [Digitaria sanguinalis (L.) Scop.] under different sugarcane straw amounts, with and without herbicide treatment; (2) assess the development of sugarcane under different straw amounts; and (3) determine the amount of sugarcane straw that should be kept on the soil surface after harvest to ensure that it does not compromise the chemical control for Digitaria spp. in ratoon cane in a green cane system. We conducted this research at two experimental sites, one at the beginning and the other during the middle of the harvest season, over a span of 2 yr. Our primary treatments consisted of different amounts of sugarcane straw after harvest on the soil surface (0, 5, 10, and 15 Mg ha⁻¹), while secondary treatments included the herbicide application (sulfentrazone + tebuthiuron for the beginning of harvest season and isoxaflutole + tebuthiuron for the middle of harvest season). The Digitaria spp. exhibited higher density (four times more) and dry matter (two times more) in scenarios with a lower sugarcane straw amount (5 Mg ha⁻¹) on the soil surface and no herbicide application. However, a higher straw amount (15 Mg ha⁻¹) contributed to reduced Digitaria spp. infestation and to improved sugarcane yield. According to this research, it is essential to maintain at least 10 Mg ha⁻¹ of sugarcane straw on the soil surface and remove only 5 Mg ha⁻¹ for energy cogeneration.

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 (R) 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.

Purpose: Nitrogen fertilizer management is an important agricultural tool that must be optimized to promote sustainable practices since the nitrogen-fertilizer recovery by plants (NRP) is low, leading to nitrogen losses to the environment. In sugarcane, N-fertilization has been investigated over the years but little attention has been given to N-fertilizer application methods. Sugarcane crop production and environmental impact regarding N-fertilizer application methods (i.e., applied onto the sugarcane straw layer and incorporated into the soil) were investigated in the present study aiming to achieve an environmental-friendly cropping system. Methods: Sugarcane yield and NRP, N₂O emissions, relevant components of the soil microbiological community and N-fertilizer retention in soil layers were quantified. The experiment was carried out in field conditions where N-fertilizer application methods using ¹⁵N-labelled ammonium nitrate (¹⁵NH₄¹⁵NO₃) were compared to a control treatment with no N-fertilization. Results: Incorporation of N-fertilizer into the soil increased the sugarcane yield by 17% (two-year average) compared to N-fertilizer applied onto the sugarcane straw layer, which was similar to control treatment. There was an increase in NRP-fertilizer of 79% due to the application of N-fertilizer incorporated into the soil. Furthermore, soil incorporation of N-fertilizer decreased N₂O emission by 22% with the fertilizer N emission factor reduced four-fold. The N₂O emissions were mostly associated with ammonium-oxidizing bacteria (AOB). Conclusions: Our results show that application of N-fertilizer incorporated into the soil is an environmental-friendly N-fertilization management which will improve agricultural sustainability and reduce environmental impacts. Graphical

Background A new agronomic management is used in sugarcane fields, due to the removal of part of the layer of straw on the soil surface for the cogeneration of energy, culminating in variable amounts of straw. Objective The objective was to evaluate the population dynamics of weeds in different scenarios of straw removal; to evaluate the weed control and selectivity of sugarcane; to determine the amount of sugarcane straw that must remain in the soil to facilitate weed control [...] Abstract Background A new agronomic management is used in sugarcane fields, due to the removal of part of the layer of straw on the soil surface for the cogeneration of energy, culminating in variable amounts of straw. Objective The objective was to evaluate the population dynamics of weeds in different scenarios of straw removal; to evaluate the weed control and selectivity of sugarcane; to determine the amount of sugarcane straw that must remain in the soil to facilitate weed control

Sugarcane cultivation uses many chemical inputs to ensure good yields, which puts local water resources under pressure. Grey water footprint (GWF) is a widely used indicator of the volume needed to assimilate a pollutant load in a water body. However, the GWF relies on leaching runoff fractions, which are empirically determined. We hypothesize that these fractions might not represent the true magnitude of the Brazilian sugarcane environment and that management practices can further reduce this fraction loaded into the environment. In two field trials, we measure the herbicides and nitrate loaded into the environment through in situ measurements, determine their loss fractions, compare them with some empirical models, calculate the GWF, and estimate the potential for nitrate pollution attenuation with the adoption of split and incorporated nitrogen application. Both hypotheses are confirmed. For nitrate, our results suggest that the leaching runoff fraction used in most GWF studies is overestimated by about two times, impacting the GWF estimation for the Brazilian sugarcane environment. However, the same conclusion was not possible for herbicides due to the low diversity of the analyzed molecules. In addition, the fertilizer management application reduced the nitrate load on the environment, which the GWF did not necessarily detect.

La tomografía computarizada de haz cónico (CBCT) ha cambiado la forma en que se practica la radiología oral, mejorando la calidad diagnóstica, la precisión de los procedimientos quirúrgicos y su capacidad para proporcionar datos volumétricos de estructuras anatómicas y entidades patológicas son fundamentales para la mejora pronóstica, especialmente considerando que el volumen puede ser interpretado. como marcador biológico. En este manuscrito describimos un caso clínico en el que el CBCT ha aportado una gran cantidad de detalles, lo que permite determinar el plan de tratamiento más preciso.

Currently sugarcane is cultivated in Brazil in intensive mechanization during all cultural practices, since planting, harvesting until fertilizer applications. In this sense, to increase the sugarcane yield which it was stagnant along the last 5 years, it is necessary looking for alternatives to management the crop and maximize the yield gain. One alternative is trough the adjustment the N-fertilization in green cane crop according to the IPNI guidelines—“4R Nutrient Stewardship System” (International Plant Nutrition Institute—IPNI) program which seeks to apply fertilizer in the right location, at the right time, in the right amount and the right source. Therefore, the main goal of this chapter is shows these alternatives and the yield gains that it was obtained in researches during 2013–2017.