Base saturation and corn hybrids under no-tillage system

The knowledge of the hybrids of suitable maize to each condicion of the ground in under no-tillage is of significant importance technique. To evaluate the response of corn hybrids to base saturation levels (V%), two experiments were performed with V% equal to 45 and 65, in cerrado areas of Uberaba, MG, Brazil, four years under no-tillage. A completely randomized block design was used, with four replications. Seven corn hybrids represent the treatments: Z 8474, BR3123, AG 122, C 333, D 657, Exceller and P 3071. The results showed that the base saturation of 65% contributed more for the increments in yield components and for the grain yield than the 45% base saturation level. The hybrids presented different yield responses, the highest beeing for the 65% base saturation treatment: P 3071 and Z 8474 and 2); for the 45% base saturation treatment: C 333. Choosing the right hybrids for each base saturation level is an important criterium to maximize corn yields under no-tillage in the cerrado region of Brazil.O conhecimento dos híbridos adaptados a cada condição de reação do solo em sistema plantio direto é de significativa importância técnica. Para avaliar o comportamento de híbridos de milho sob sistema plantio direto, quanto a alguns componentes de rendimento, submetidos a níveis de saturação por bases, foram conduzidos dois experimentos no V% 45 e V% 65 em área com 4 anos em sistema plantio direto, na região dos cerrados, em Uberaba, MG. Os experimentos foram desenvolvidos no delineamento em blocos ao acaso, com quatro repetições. Os sete tratamentos foram constituídos pelos seguintes híbridos de milho: Z 8474, BR 3123, AG 122, C 333, D 657, Exceller e P 3071. Na média dos híbridos de milho estudados a saturação por bases de 65% foi a que mais contribuiu para os incrementos nos componentes do rendimento e nos rendimentos de grãos. Os híbridos apresentaram comportamento diferenciado no rendimento de grãos, destacando-se na saturação por bases 65%, os híbridos P 3071 e o Z 8474 e no nível 45% destacou-se o híbrido C 333. A utilização de híbridos específicos para cada nível de saturação por bases mostrou-se uma importante ferramenta para a maximização do rendimento da cultura do milho em sistema plantio direto no cerrado

Ecological Response to Global Change: Changes in C:N:P Stoichiometry in Environmental Adaptations of Plants

This review aims to discuss the state of the art of the stoichiometric ratio of foliar nutrients and their impact on adaptive mechanisms of plants to environmental change. Plant stoichiometry is an excellent way to study the multiple ratios across the nutrients in plants and their ecological interactions with the environment. It plays an important role in clarifying the responses of plants to various changes and their adaptation to different environments. However, anthropic activity can change the stoichiometric ratios of plants. In recent decades, anthropic activities have altered the cycle of nitrogen (N), phosphorous (P) and carbon (C) in plants. This is due to excessive fertilizer application, increased global warming and increased atmospheric CO2 emissions, which can quickly limit the increase of production in plants, as they affect the process of acclimatization, which involves a series of changes in plant metabolism at different levels of organization (molecular, biochemical, anatomical and morphological). In this sense, in this new scenario of changes, new plant responses to stoichiometric changes and adaptive processes in the ecosystem have to be reviewed

Desenvolvimento inicial e estado nutricional do maracujazeiro em resposta à aplicação de lodo têxtil

In the treatment of liquid effluents of the textile industry the textile sludge results as residue. This work aimed at evaluating the effect of sludge application to the substrate of production of passion fruit cuttings in the development, and nutritional status of plants. Experimental design used was randomized blocks with five treatments and four replications. The textile sludge was applied in the doses of 10, 15, 20 and 30 g per pot (dry base), corresponding 10, 15, 20 and 30 t ha-1, respectively, and a control without application. Plants were fertilized with N, P, K, Zn and B at 300, 450, 150, 5, and 0.5 mg dm-3, respectively. The experimental unit was represented by pots with 2 dm3 of a Red Latosol (Oxisol) (V = 29%). After 100 days the textile sludge corrected soil acidity. However, in doses superior to 10 t ha-1 it caused plants death. The textile sludge increased the content of N, K, S, B, Mn and Zn, reduced Ca and Mg content, and it didn't alter Cu and Fe content of passion cuttings dry matter.O processo de tratamento de efluentes líquidos da indústria têxtil gera, como resíduo, um lodo de características orgânicas com concentração significativa de sódio e potássio. Objetivou-se quantificar os efeitos da aplicação do lodo ao solo, sobre o desenvolvimento inicial do maracujazeiro, e avaliou-se o crescimento e o estado nutricional das plantas. O delineamento experimental foi em blocos ao acaso, com quatro repetições de cinco tratamentos, que consistiram na aplicação de lodo têxtil, nas doses de 10, 15, 20 e 30 g vaso-1 (base seca), correspondentes a 10, 15, 20 e 30 t ha-1, respectivamente, além da testemunha sem aplicação do resíduo. As mudas receberam adubação básica com N, P, K, Zn e B, nas doses de 300, 450, 150, 5, e 0,5 mg dm-3, respectivamente. A unidade experimental foi constituída por vasos com 2 dm3 de amostra de um Latossolo Vermelho distrófico (V = 29%). Após 100 dias da semeadura, o lodo têxtil corrigiu a acidez do solo. Entretanto, em doses superiores a 10 t ha-1, promoveu a morte das plantas. O lodo têxtil aumentou os teores de N, K, S, B, Mn e Zn, diminuiu os de Ca e Mg e não alterou os de Cu e Fe da parte aérea das mudas

A CALAGEM NA NUTRIÇÃO E NO DESENVOLVIMENTO DO SISTEMA RADICAL DA CARAMBOLEIRA

The liming can affect the development of the system root of the carambola with implications in the absorption of nutritious. It was aimed at to evaluate the effects of the limestone application in the chemical properties of the soil, in the nutrition of the plant and in the development of the system root of the carambola, cultivated in a Latosol Red acid distrofic. For this, limestone doses were analyzed, zero (control); 3.705 and 7.410 t ha-1, in soil samples collected, in the planting line, to 75 cm of the trunk, in layers of 0-20 and 20-40 cm of depth. The limestone was applied in at planting, incorporate (0-30 cm of depth). During 2o and 3o year of culture of the carambola, the effect of the liming in the soil and the nutrition of the fruit had been accompanied by. In 3o year of culture of the carambola, beyond the chemical analysis of the soil and leves (Ca), it was evaluated dry substance and text of Ca of the root of the fruit. The determination of the concentration of Ca in the soil is an indicative for the diagnosis of the growth potential to radical in carambola in formation phase.A calagem pode afetar o desenvolvimento do sistema radical da caramboleira com implicações na absorção de nutrientes. Objetivou-se avaliar os efeitos da aplicação de calcário nas propriedades químicas do solo, na nutrição da planta e no desenvolvimento do sistema radical da caramboleira, cultivada em um Latossolo Vermelho distrófico ácido. Para isso, testaram-se diferentes doses de calcário, 3,705 e 7,410 t ha-1, em amostras de solo coletadas, na linha de plantio, a 75 cm do tronco, nas camadas de 0-20 e 20-40 cm de profundidade. A testemunha constou de solo sem aplicação de calcário. O calcário foi aplicado em pré-plantio, e incorporado até 30 cm de profundidade. Durante o 2o e 3o ano de cultivo da caramboleira, acompanharam-se os efeitos da calagem no solo e na nutrição da fruteira. No 3o ano de cultivo da caramboleira, além da análise química do solo e das folhas quanto ao nível de cálcio, avaliou-se a matéria seca e teor de Ca das raízes da fruteira. A determinação da concentração de Ca no solo é um indicativo para o diagnóstico do potencial de crescimento radical em caramboleira em fase de formação

Edaphic mesofauna, some studies done: a review.

Abstract Introduction: The soil is a complex ecosystem considered the one inhabits where a number of organisms, microorganisms, minerals, organic matter, water and air live, physical, chemical and biological activities take place in it. Objective: To analyze updated information on research that addresses the role of the mesofauna in relation to soil quality. Methodology: Documentary sources were used to search the bibliographic documents. A bibliographic search was carried out until September 2021 based on: writing scientific articles and books, making an analytical and critical reading of the information on edaphic fauna with an emphasis on the last decade. The information was taken from the internet using the search engine "academic Google", Dialnet and the Wiley Online Library. Results: oribatid mites and collembola are the most abundant arthropods and with the highest specific diversity in the soil, they are diverse groups, biological indicators of soil quality, it is favored by agroecological practices such as coverage and it is affected by the indiscriminate use of agrochemicals. Conclusions: the mesofauna is favored by agroecological practices such as the association of crops, plant covers and the incorporation of crop residues, use of organic inputs such as compost, implementation of easily degradable plants, zero tillage, bare soils. And it is mainly affected by the exploitation of a single plant species with high applications of agrochemicals, climatic changes, anthropic disturbances of the edaphic environment, changes in land use, soils without cover and mechanized soil preparation. Keywords: Litter; decomposition; bioindicators; soil biology; organic material.Introduction: The soil is a complex ecosystem considered the one inhabits where a number of organisms, microorganisms, minerals, organic matter, water and air live, physical, chemical and biological activities take place in it. Objective: To analyze updated information on research that addresses the role of the mesofauna in relation to soil quality. Methodology: Documentary sources were used to search the bibliographic documents. A bibliographic search was carried out until September 2021 based on: writing scientific articles and books, making an analytical and critical reading of the information on edaphic fauna with an emphasis on the last decade. The information was taken from the internet using the search engine "academic Google", Dialnet and the Wiley Online Library. Results: oribatid mites and collembola are the most abundant arthropods and with the highest specific diversity in the soil, they are diverse groups, biological indicators of soil quality, it is favored by agroecological practices such as coverage and it is affected by the indiscriminate use of agrochemicals. Conclusions: the mesofauna is favored by agroecological practices such as the association of crops, plant covers and the incorporation of crop residues, use of organic inputs such as compost, implementation of easily degradable plants, zero tillage, bare soils. And it is mainly affected by the exploitation of a single plant species with high applications of agrochemicals, climatic changes, anthropic disturbances of the edaphic environment, changes in land use, soils without cover and mechanized soil preparation.

Economic aspects of phosphorus application to the corn crop

Estudos econômicos da adubação fosfatada fazem-se necessários, em razão da sua participação expressiva no custo de produção da cultura do milho, especialmente em solos sob vegetação de cerrado e face à competitividade da atividade no mercado globalizado. Assim, objetivou-se avaliar alguns aspectos econômicos de modos de aplicação da adubação fosfatada a lanço e sulco simples comparados ao modo alternativo em sulco duplo, utilizando o híbrido de milho BR 3123. Os tratamentos foram constituídos pelos modos de aplicação em sulco duplo, sulco simples e a lanço nas doses: 0; 0,50; 0,75; 1,00; 1,25; 1,50 vez a dose recomendada para adubação de manutenção para o milho, ou seja, 90 kg de P2O5 ha-1. Para a análise, considerou-se o preço médio da década de 90 para a tonelada do milho e do superfosfato triplo em R$189,33 e R$494,32, respectivamente, e o custo operacional total de R$752,90 ha-1. O aumento das doses de adubo fosfatado, em geral, incrementou a produção, o valor da produção e a receita líquida por hectare; a aplicação do adubo fosfatado a lanço não se mostrou viável economicamente; o modo alternativo em sulco duplo permitiu maior receita líquida e uma relação benefício/custo 17,7$86.06 and US$224.69, respectively), and the total operating cost of US$342.22 ha-1. In general the increase of the phosphorus rate boosted the yield and the net income per hectare; the cast fertilizer aplication by hand proved to be economically unfeasible. The double furrow treatment resulted, on the average, in a higher net income and a cost/benefit ratio exceeding by 17.7% that of the single furrow application mode

Alterations of the colour and of the degree of floculation of a Dark-Red Latosol under conditions of continuous cultivation of sugar cane

Objetivou-se avaliar o grau de modificação de algumas propriedades físicas e da cor do horizonte superficial de um Latossolo Vermelho-Escuro textura média, submetido ao cultivo contínuo com cana-de-açúcar durante 25 anos, em Jaboticabal, SP. Os tratamentos foram constituídos por dois tipos de uso do solo, ou seja, ausência de cultivo (vegetação nativa) e cultivo intenso com cana-de-açúcar e por três profundidades no perfil, 0-10, 10-20 e 20-30 cm. O cultivo intenso e contínuo alterou a cor do solo na camada de 0-10 cm de 2,5YR 2,5/4 na ausência de cultivo para 2,5YR3/4 e degradou a macroestrutura, reduzindo o grau de floculação da argila do solo.The study aimed at assessing the degree of modification of certain physical properties and of the colour of the superficial soil layer of a Dark-Red Latosol of medium texture, subjected to the continuous cultivation of sugar cane during 25 years in Jaboticabal, SP, Brazil. The treatments consisted of two types of soil use, i.e. absence of cultivation (native vegetation) and intense cultivation with sugar cane, at three depth levels of 0-10, 10-20 and 20-30 cm. The continuous cultivation altered the colour of the level 0-10 cm from 2.5YR2.5/4 (absence of cultivation) to 2.5YR3/4, and impaired the macro structure and lessened the degree of flocculation of the soil's clay