Physical, chemical, and mineralogical attributes and organic fractions of biogenic aggregates of earthworms and toposequence of Inceptisol in semi-arid region

ABSTRACT Earthworms are known to improve soil fertility by altering the physicochemical properties of soil. However, the changes in properties of biogenic aggregates (produced by earthworms) in regions with different vegetation covers and soils of Inceptisol toposequence in the semi-arid region have not been studied. The objective of this work was to determine the variations of the physical, chemical, and mineralogical attributes and organic fractions of biogenic aggregates of earthworms under different vegetation covers and compare them to an Inceptisol toposequence in the semi-arid region of Pernambuco State, Brazil. For this study, four Inceptisol soil profiles were selected. The sampled points were P1-upper; P2-middle third; P3-middle third; and P4-lower slope, and the soils were collected at a depth of 0-0.20 m. The biogenic aggregates were found in the P3 samples collected from three areas with different vegetation covers: an area with mesquite tree vegetation (Prosopis juliflora [Sw] D.C.); an area with neem tree vegetation (Azadirachta indica A. Juss); and an area with forage palm and mesquite tree vegetation (Opuntia sp. and Nopalea sp.). Results indicate that the biogenic aggregates were in the form of irregular blocks with a size greater than 40 mm. As compared to Inceptisol samples, these aggregates tended to select particles of smaller diameter and exhibited higher concentrations of clay minerals. The chemical and organic fraction analysis revealed that the aggregates exhibited higher Ca2+, total organic carbon (TOC), labile and humic substances, regardless of the vegetation cover. The mineralogical analysis revealed that the action of earthworms did not change the quantity or type of clay minerals.

Selection strategies in agronomic characters in progenies F3:4 of transgenic soy RR

ABSTRACT The selection indexes aggregate information to multiple characters and, with this, they are able to carry out the selection of a set of variables simultaneously. The objective was to verify the genetic potential of agronomic traits and to select soybean F3:4 progenies based on different selection strategies. 123 progenies and the parents were sown in randomized blocks with two replications. The gains of direct selection by the indexes, the sum of “ranks” and the genotype-ideotype were lower for all characters when compared to the gains of direct and indirect selection. The rank sum index stood out for achieving the highest total gain with 37.11%. The index of the genotype-ideotype obtained a lower gain (-0.48%) for the character number of days for flowering compared to the sum index of “ranks” (-0.54%) and reached a negative gain for the attribute insertion height of the first pod with -1.82%. The genetic potential of the F3:4 population is high and allows different selection strategies to be applied to reach superior genotypes. The progenies UFU 72, UFU 116, UFU 86, UFU 45, UFU 117, UFU 56, UFU 5, UFU 106, UFU 6, UFU 4, UFU 73, UFU 101, UFU 96, UFU 90, UFU 123, UFU 116, UFU 88, UFU 65, UFU 70, UFU 3, UFU 69 and UFU 37 were selected by both selection indexes. The UFU 72, UFU 90, UFU 88 and UFU 69 progenies are agronomically superior both in direct and indirect selection, as in Mulamba and Mock (1978) sum of “ranks” selections and genotype-ideotype.

Revisiting the casing layer: Casing materials and management in Agaricus mushroom cultivation

ABSTRACT The cultivation of button mushroom has reached a high technological level in developed countries and is associated with high productivity indices. This technological level involves not only compost production and crop management but also the casing layer. Peat has been established as one of the most appropriate casing materials for the cultivation of button mushroom due to its excellent properties. However, good-quality peat is not available in all countries, and peat is not renewable, which reinforces the need for alternative materials. Therefore, studies on the casing layer should include its response to the induction of fruiting since this stage is where the main changes that lead to the formation of primordia occur. This review addresses the different aspects of fruiting induction of Agaricus mushrooms and the influence of the characteristics of the casing layer on mushroom production.

Thermal comfort of beef cattle in the state of Mato Grosso do Sul, Brazil

ABSTRACT Evaluation of the comfort and animal welfare parameters enables determining the best environmental conditions for livestock creation. The present study was aimed to determine the thermal comfort index for beef cattle using interpolation techniques for the State of Mato Grosso do Sul during extreme summer and winter seasons for a period of 10 years. The analysis was performed on the climatic variables data provided by the National Institute of Meteorology, Brazil. The maximum (THImax) and minimum (THImin) temperature and humidity indices (THIs) of 28 weather stations distributed across the state were calculated, and the thematic maps of the THIs (maximum and minimum) calculated for the summer and winter seasons were prepared. The results revealed a state of emergency in the two largest animal-producing cities in the state; namely, Corumbá and Ribas do Rio Pardo, while two other cities, Chapadão do Sul and Costa Rica emerged as favorable regions for the production of beef cattle. The Spline method used in the present study, therefore, proved to be a suitable tool for analyzing a small number of weather stations distributed over a large territorial area.

Physiological, biochemical, and ultrastructural aspects of Coffea arabica L. seeds under different cryopreservation protocols

ABSTRACT Cryopreservation is a technique that may potentially conserve the germplasm of species of the Coffea genus for an indeterminate time. The aim of this study was to evaluate the physiological, biochemical and ultrastructural characteristics of cryopreserved seeds of Coffea arabica L., cultivar Catucaí amarelo IAC 62, which was subjected to different protocols regarding dehydration, precooling, cooling, rewarming and cathode water use. According to each protocol, the seeds were subjected to fast or slow drying to moisture contents of 17 or 20% (wet basis), cooled in different ways, and then immersed in liquid nitrogen for 24 hours. Different rewarming times in a water bath were also used. Physiological, biochemical and ultrastructural analyses were performed on the seeds after the cryopreservation steps. Moisture content at a 17% wb is the key factor for the cryopreservation of Coffea arabica L. seeds, which have better physiological quality and better preserved cell structures. Precooling of coffee seeds before immersion in liquid nitrogen does not provide advantages compared to direct immersion. The rewarming times tested (2, 4, and 6 minutes) and cathode water use did not cause changes in the physiological and biochemical quality or in the cell structures of Coffea arabica L. cryopreserved seeds. The pattern of cell structure observed in all seeds indicates that the damage from cryopreservation is less drastic in the cells of the embryos than in those of the endosperm, with the latter less tolerant to the stresses of dehydration, precooling, and rewarming.

Water restriction in different phenological stages and increased temperature affect cowpea production

ABSTRACT Water deficit and high temperatures are abiotic factors that most limit plant growth and development. However, its effects depend on crop development stage and on stress duration and intensity. Thus, the objective of was to evaluate the development of cowpea subjected to water restriction in different phenological stages and to increase in air temperature. The experiment was conducted with the cultivar ‘Carijó’, in growth chambers, in a 4 x 3 x 2 factorial arrangement, corresponding to levels of water availability (25, 50, 75, and 100%,), phenological stages (vegetative, flowering and pod filling) and temperature regimes (T°1: 20-26-33 °C e T°2: 24.8-30.8-37.8 °C), respectively. Reduction of water availability in the vegetative and flowering stages caused decrease in grain production. The percentage of aborted flowers was higher in plants maintained under an increased temperature of +4.8 °C, with consequent reduction in grain production. Higher water availability values favored shoot and root dry mass production. Increase of 4.8 °C did not affect shoot and root dry mass but reduced water use efficiency by about 83%. The highest enzymatic activities of CAT, GPX and SOD were found in plants subjected to the temperature of +4.8 °C. Only APX showed lower enzymatic activity with increasing temperature. The cv. ‘Carijó’ is more sensitive to the 4.8 °C increase in air temperature than to water deficits.

Environmental degradation risk by water erosion in a water producer Colombian Andes basin

ABSTRACT Globally, soil degradation by water erosion has become one of the major environmental problems in tropical regions, especially under the severe environmental conditions of the Andes. This study aims to detail the soil risk to degradation by water erosion in a water producer basin located in the Tropical Colombian Andes (Combeima River basin), applying the RUSLE model, discussing how to minimize the erosion processes under its environmental conditions (steep slope, climatic variability, soil classes and properties diversity, and alternative land uses). RUSLE was applied with the support of GIS to estimate current and potential risk to soil erosion in the basin, allowing the identification of areas more prone to degradation. It was found that currently, 50.5% of the basin’s area presents, on average, annual soil losses greater than 25 Mg ha-1 yr-1, meaning a very high risk to water erosion, with 30.4% showing a severe risk (> 100 Mg ha-1 yr-1). It was possible to conclude that the current land uses and soil management systems have not been effective in mitigating soil erosion, mainly when situated in steep topography. Therefore, it is necessary sustainable planning for the conservation of soil, water, organic carbon, plant nutrients, and other elements (not-nutrients) in this tropical Andes region.

Air temperature estimation techniques in Minas Gerais state, Brazil, Cwa and Cwb climate regions according to the Köppen-Geiger climate classification system

ABSTRACT Air temperature significantly affects the processes involving agricultural and human activities. The knowledge of the temperature of a given location is essential for agricultural planning. It also helps to make decisions regarding human activities. However, it is not always possible to determine this variable. It is necessary to make a precise estimate, using methods that are capable of detecting the existing variations. The aim of this study was to develop models of multiple linear regression (MLR), artificial neural network (ANN), and random forest (RF) to estimate the mean (Tmean), maximum (Tmax), and minimum (Tmin) monthly air temperatures as a function of geographic coordinates and altitude for different localities in Minas Gerais state, Brazil, with climatic classification Cwa or Cwb. The average monthly data (Tmean, Tmax, and Tmin), over a period of 30 years, were collected from 20 climatological stations. The MLR was able to estimate the Tmax with accuracy. However, the predictive capacity of estimating Tmean and Tmin was low. The algorithms RF and ANN were used to estimate Tmean, Tmax, and Tmin with high accuracy. The best results were obtained using the RF model.

Ethiopian coffee germplasm is a valuable resistance gene pool to brazilian Pseudomonas syringae PVS garcae and tabaci

ABSTRACT Seven wild accessions of Coffea arabica from Ethiopia prospected by FAO Coffee Mission 1964-1965 were investigated concerning the resistance to 18 Brazilian strains and two Kenyan strains of Pseudomonas syringae pv. garcae and four P. syringae pv. tabaci strains, causal agents of bacterial halo blight and bacterial leaf spot, respectively. The cultivars of C. arabica IPR 102, resistant to the diseases, and Mundo Novo IAC 376-4, susceptible, were used as experimental controls. Our results indicated that the Ethiopian accessions presented high levels of resistance to all Brazilian strains of P. syringae pv. garcae but were susceptible to infection caused by Kenyan strains, which causes different levels of severity in wild accessions and experimental controls. Ethiopian accessions were also considered resistant to the four P. syringae pv. tabaci strains, with low susceptibility observed, one point on the severity scale, in access E-268 in response to a strain of the bacterium.

Distribution of non-structural carbohydrates in the vegetative organs of upland rice

ABSTRACT Rice is one of the main foods consumed by half of the world’s population. The rice crop requires plenty of water, but upland rice is cultivated in a non-flooded environment, although its productivity is lower than that of lowland rice. Rice grains mostly consist of starch, which is synthesized from the non-structural carbohydrates imported from the vegetative organs. The long-term storage of carbohydrates plays a remarkable role in maintaining the supply of photoassimilates during grain filling if photosynthesis does not meet energy demand. Therefore, the dynamics of non-structural carbohydrates is central to the productivity of rice crops. The present study aimed to determine the non-structural carbohydrate content and soluble carbohydrate profiles in different vegetative organs of upland rice of the genotype BRS Esmeralda. The content was determined at the end of vegetative development. The identification and quantification of carbohydrates were performed by high-performance anion-exchange chromatography with pulsed amperometric detection. Fully expanded leaf blades, expanding leaf blades, and expanding stems exhibited the soluble carbohydrate content of 59.7, 53.3, and 52.3 mg g-1 DM, respectively. The stem was found to be the main organ for the long-term storage of non-structural carbohydrates, wherein the starch content was 36.1 mg g-1 DM. It also contained soluble carbohydrates such as glucose, fructose, and sucrose. The non-structural carbohydrates were found in low amounts in the roots, showing that this organ does not store long-term carbohydrates.