Gypsum application in lowlands : soil chemical alterations and response of irrigated rice and soybean

Estudos que avaliam a resposta dos cultivos agrícolas às modificações do solo com a gessagem são relativamente abundantes, mas concentrados majoritariamente em terras altas. Este trabalho objetivou avaliar a acidez e a disponibilidade de fósforo (P) e potássio (K) do solo e a produtividade do arroz irrigado e da soja, cultivados em terras baixas, com aplicação de doses de gesso agrícola. Os experimentos foram conduzidos em um Planossolo Háplico (Triunfo/Rio Grande do Sul). Os tratamentos consistiram em seis doses de gesso agrícola (0,00; 0,25; 0,50; 1,00; 2,00; e 4,00 t ha-1) e o delineamento experimental foi o de blocos casualizados. O solo foi coletado após a colheita das lavouras, nas camadas de 0–5, 5–10, 10–20 e 20–40 cm. O pH em água, a acidez potencial (H+Al) e o P disponível (Mehlich 1) não foram alterados com a aplicação de gesso agrícola. Após o cultivo de arroz irrigado e na camada de 0–5 cm, houve aumento do teor de K disponível (Mehlich 1) para doses até 1,00 t ha-1 e diminuição do teor para doses maiores (2,00 e 4,00 t ha-1). Após o cultivo de soja, o teor de K disponível não foi alterado com a gessagem. A aplicação de gesso agrícola não influenciou a produtividade do arroz irrigado e da soja na safra avaliada, onde não houve déficit hídrico.Studies that evaluate the crop responses to the soil modifications intermediated by gypsum application are relatively abundant, but most of them are performed in highlands. Such studies are still scarce in lowlands. The objective of our study was to evaluate soil acidity and phosphorus (P) and potassium (K) availability, as well as crop (irrigated rice and soybean) yields, as a function of different rates of gypsum application in lowland. The experiments were conducted in a Planosol (Triunfo, Rio Grande do Sul, Brazil). The treatments consisted of six gypsum rates (0.00, 0.25, 0.50, 1.00, 2.00 and 4.00 t ha-1) and the experimental design was in randomized blocks with four replications. The soil was sampled after crop harvests, in the 0–5, 5–10, 10–20 and 20–40 cm layers. The soil pH (in water), the potential acidity (H+Al) and the available P (Mehlich 1) were not affected by gypsum application. After the irrigated rice cropping and in the soil layer of 0–5 cm, the available K (Mehlich 1) contents was impacted by the gypsum application, with increase in content for rates up to 1.00 t ha-1 and decrease in content for higher rates (2.00 and 4.00 t ha-1). After the soybean cropping, the available K content was not affected by gypsum application. The gypsum application did not impact irrigated rice and soybean yields in the evaluated season, which did not present water deficit

Integrating the pastoral component in agricultural systems

This paper aims to discuss the impact of the introduction of pastures and grazing animals in agricultural systems. For the purposes of this manuscript, we focus on within-farm integrated crop-livestock systems (ICLS), typical of Southern Brazil. These ICLS are designed to create and enhance the synergisms and emergent properties have arisen from agricultural areas where livestock activities are integrated with crops. We show that the introduction of the crop component will affect less the preceding condition than the introduction of the livestock component. While the introduction of crops in pastoral systems represents increasing diversity of the plant component, the introduction of animals would represent the entry of new flows and interactions within the system. Thus, given the new complexity levels achieved from the introduction of grazing, the probability of arising emergent properties is theoretically much higher. However, grazing management is vital in determining the success or failure of such initiative. The grazing intensity practiced during the pasture phase would affect the canopy structure and the forage availability to animals. In adequate and moderate grazing intensities, it is possible to affirm that livestock combined with crops (ICLS) has a potential positive impact. As important as the improvements that grazing animals can generate to the soil-plant components, the economic resilience remarkably increases when pasture rotations are introduced compared with purely agriculture systems, particularly in climate-risk situations. Thus, the integration of the pastoral component can enhance the sustainable intensification of food production, but it modifies simple, pure agricultural systems into more complex and knowledge-demanding production systems

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

Cabbage and fermented vegetables : From death rate heterogeneity in countries to candidates for mitigation strategies of severe COVID-19

Large differences in COVID-19 death rates exist between countries and between regions of the same country. Some very low death rate countries such as Eastern Asia, Central Europe, or the Balkans have a common feature of eating large quantities of fermented foods. Although biases exist when examining ecological studies, fermented vegetables or cabbage have been associated with low death rates in European countries. SARS-CoV-2 binds to its receptor, the angiotensin-converting enzyme 2 (ACE2). As a result of SARS-CoV-2 binding, ACE2 downregulation enhances the angiotensin II receptor type 1 (AT(1)R) axis associated with oxidative stress. This leads to insulin resistance as well as lung and endothelial damage, two severe outcomes of COVID-19. The nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is the most potent antioxidant in humans and can block in particular the AT(1)R axis. Cabbage contains precursors of sulforaphane, the most active natural activator of Nrf2. Fermented vegetables contain many lactobacilli, which are also potent Nrf2 activators. Three examples are: kimchi in Korea, westernized foods, and the slum paradox. It is proposed that fermented cabbage is a proof-of-concept of dietary manipulations that may enhance Nrf2-associated antioxidant effects, helpful in mitigating COVID-19 severity.Peer reviewe

Nrf2-interacting nutrients and COVID-19 : time for research to develop adaptation strategies

There are large between- and within-country variations in COVID-19 death rates. Some very low death rate settings such as Eastern Asia, Central Europe, the Balkans and Africa have a common feature of eating large quantities of fermented foods whose intake is associated with the activation of the Nrf2 (Nuclear factor (erythroid-derived 2)-like 2) anti-oxidant transcription factor. There are many Nrf2-interacting nutrients (berberine, curcumin, epigallocatechin gallate, genistein, quercetin, resveratrol, sulforaphane) that all act similarly to reduce insulin resistance, endothelial damage, lung injury and cytokine storm. They also act on the same mechanisms (mTOR: Mammalian target of rapamycin, PPAR gamma:Peroxisome proliferator-activated receptor, NF kappa B: Nuclear factor kappa B, ERK: Extracellular signal-regulated kinases and eIF2 alpha:Elongation initiation factor 2 alpha). They may as a result be important in mitigating the severity of COVID-19, acting through the endoplasmic reticulum stress or ACE-Angiotensin-II-AT(1)R axis (AT(1)R) pathway. Many Nrf2-interacting nutrients are also interacting with TRPA1 and/or TRPV1. Interestingly, geographical areas with very low COVID-19 mortality are those with the lowest prevalence of obesity (Sub-Saharan Africa and Asia). It is tempting to propose that Nrf2-interacting foods and nutrients can re-balance insulin resistance and have a significant effect on COVID-19 severity. It is therefore possible that the intake of these foods may restore an optimal natural balance for the Nrf2 pathway and may be of interest in the mitigation of COVID-19 severity

Sulfur to flooded rice in the depressão central region of Rio grande do sul state, Brazil

A região da Depressão Central do Rio Grande do Sul caracteriza-se por apresentar vastas áreas com solos arenosos e cultivadas intensivamente com arroz irrigado há várias décadas. Os altos índices de produtividade obtidos em arroz irrigado atualmente, associados aos baixos teores de matéria orgânica desses solos e às práticas de fertilização utilizadas, constituem condições favoráveis à manifestação da deficiência de enxofre (S). Com o objetivo de determinar a necessidade de aplicação desse nutriente para o arroz irrigado, foi realizado o presente trabalho em 12 locais da região da Depressão Central, nas safras 2004/05 e 2005/06, onde foi testada a resposta do arroz irrigado à adição de doses de S. Os teores de enxofre no perfil do solo foram relacionados aos teores de matéria orgânica, porém, não o foram aos teores de argila; os mananciais hídricos (rios e barragens) não aportaram quantidade relevante de S à cultura. O arroz irrigado respondeu positivamente, em enxofre absorvido pelas plantas e rendimento de grãos, à adição de S em solos com teores de S-SO4 2- de até 7,3 mg dm-3. O teor crítico desse nutriente no solo foi estabelecido como sendo em torno de 9,0 mg dm-3. As doses de máxima eficiência técnica e econômica foram de, respectivamente, 31,25 e 24,74 kg de S ha-1 e corresponderam a ganho em rendimento de arroz semelhante.The region of Depressão Central of the Rio Grande do Sul state, Brazil, is characterized for presenting large sandy soils areas that have been intensively cultivated with flooded rice in the last decades. The high rice yield levels currently achieved, associated to low organic matter contents of these soils and fertilization practices, constitute favorable conditions for the appearance of sulfur (S) deficiency. With the purpose of determining the necessity of this nutrient for the flooded rice in that region, a study was carried out during 2004/05 and 2005/06 seasons to determine the response of the flooded rice to the addition of different rates of S. The sulfur content in the soil profile was related to the organic matter, but not to the clay content; the used water sources (rivers and dams) did not supply relevant amount of S to the plants. The flooded rice increased in S uptake and grain yield, with the applied rates of S to the soil content up to 7,3 mg of S dm-3. The critical content of this nutrient in the soil was established as being 9,0 mg dm-3. The most efficient technical and economic doses were of, respectively, 31,25 and 24,74 kg of S ha-1, that resulted in a very similar rice yield gain

Water and soil salinity and its influence on irrigated rice

As lavouras de arroz cultivadas nas Planícies Costeiras do Rio Grande do Sul podem ser afetadas pela salinidade, devido tanto à gênese dos solos, quanto à deposição de sais pela água da irrigação, especialmente da Laguna dos Patos. A salinidade do solo pode prejudicar a emergência e o desenvolvimento da cultura, o que pode ser agravado pela aplicação de fertilizante potássico. Este trabalho teve como objetivos: a) mapear a ocorrência de solos afetados por sais nas Planícies Costeiras do Rio Grande do Sul; b) determinar a possibilidade de uso da água para o cultivo de arroz irrigado nessas regiões; c) avaliar o efeito do manejo do cloreto de potássio sobre essa cultura em solos com diferentes níveis de salinidade; d) avaliar a dinâmica de cátions básicos na solução desses solos e, e) estabelecer o nível crítico à salinidade na emergência. Para o mapeamento da salinidade, foram coletadas 766 amostras de solo, para análise de indicadores de salinidade. A partir dessas amostras, estimou-se o volume de água possível de ser adicionado aos solos sem causar dano à cultura, em função da salinidade da água da Laguna dos Patos. A análise dos efeitos da salinidade e do manejo do potássio sobre a cultura e dessa sobre a dinâmica de cátions, foi realizada a partir de experimentos de campo em solos com quatro níveis de salinidade. A determinação do nível crítico à salinidade na emergência foi realizada em casa de vegetação, no International Rice Research Institute. Os maiores níveis de salinidade do solo foram verificados na Planície Costeira Externa e porção sul da Planície Costeira Interna, sendo que nesses locais a restrição ao uso da água foi maior. Em solos previamente afetados pela salinidade, a aplicação de doses de potássio para alta produtividade na linha de semeadura prejudica o estabelecimento da cultura e o rendimento de arroz. A utilização de água não salina contribui para a diminuição da salinidade desses solos. O nível crítico do arroz para a salinidade na emergência é elevado em relação aos períodos vegetativo e reprodutivo, sendo superior a 20 dS m-1.by salinity due to both, genesis of the soils and deposition of salts by irrigation water, especially from the Laguna dos Patos. Soil salinity can affect emergence and development of rice, which can be enhanced by application of potassium fertilizer. This study aimed to: a) map the occurrence of salt affected soils in such Coastal Plains, b) determine the possibility of the use of Laguna dos Patos´ water for rice irrigation in these regions, c) evaluate the effect of potassium chloride management on this crop in salt affected soils, d) evaluate the dynamics of basic cations in the soil solution of these soils, and e) establish the critical level of salinity on rice seed emergence. For the salinity mapping, 766 soil samples were taken for analysis of salinity indicators. From these samples, the volume of water of the Laguna dos Patos that can be added to the soil without causing damage to the crop was estimated. The analysis of the effects of salinity and potassium management on rice and on the dynamics of cations, was done from field experiments on soils with four salinity levels. The determination of the critical level of salinity on emergence was made in a greenhouse experiment at the International Rice Research Institute. The highest levels of soil salinity were found in the Outer Coastal Plain and in the southern portion of Inner Coastal Plain, having in these sites, higher restriction on water use. In soils previously affected by salinity, row application of potassium rates for high productivity negatively affects crop establishment and rice yield. The use of non saline water contributes for reducing the salinity of these soils. The critical level of salinity for rice during emergence is high in relation to vegetative and reproductive periods, being superior than 20 dS m-1