THE USABILITY OF HYDROGEL IN INCREASING THE EFFICIENCY OF GYPSUM APPLIED TO SALINE-SODIC SOILS

This study aimed at the assessment of the usability of hydrogel in increasing the efficiency of gypsum applied to saline-sodic soils. The experiment was conducted under laboratory conditions in disturbed soil columns and was set-up in a completely randomized design with six hydrogel application rates (Control, 0.05%, 0.10%, 0.15%, 0.20% and 0.25% weight/weight (w/w) basis) and with three replications. Hydrogel application to saline-sodic soil had significant effects on leachate pH. The highest leachate pH’s were found in the final leachates in the order of 0.05%>0.10%>0.15%, as 9.12, 9.09, and 9.03, respectively. In all of the application rates tested, the highest electrical conductivity (EC) and Na+ leachate losses were obtained after first pore volume of leaching and then decreased gradually with further leaching. Relative to the control, hydrogel application in the rate of 0.05% increased the leaching of Na+ by 8.1% on total. However, due to the absence of statistically significant effects of the treatments on Na+ leaching, an improvement in soil exchangeable sodium percentage (ESP) and pH in saturation extract (pHe) values as an indicator of reclamation was not proven. Use of gypsum together with hydrogel increased saturated hydraulic conductivity of soils in the rates of 28.6%-42.6%, which is especially important for reducing the duration for amelioration of saline-sodic soils. Application of hydrogel to saline-sodic soils along with gypsum can be an efficient management option not only for reducing the risk of physiological drought, but also for reducing the amount of time to reclaim saline-sodic soils.

Melon cultivation irrigated with saline waters promote chemical alterations in an acrisol

The objective of the present study was to evaluate the salinization process and the changes in the chemical properties of an Acrisol cultivated with melon irrigated with water of different saline concentrations. The experiment was carried out in the field conditions using the experimental design of randomized blocks, arranged in split-plot. The plots were composed of salinity levels of irrigation water, expressed in terms of water electrical conductivity (ECw): 0.54; 1.48; 2.02 dS m-1; and the sub-plots for melon cultivars: Sancho and Medellín (Toad Skin), Mandacaru (Yellow), Nectar (Galia) and Sedna (Cantaloupe). Soil samples were collected at the beginning and end of the crop cycle to evaluate the changes in the physical-chemical properties of the soil. The electrical conductivity of saturation extract in the soil profile varied for each cultivar, observing high salinity values in soils with cultivars with lower water demand (Sedna and Nectar). The salinity of the soil was lower than the electrical conductivity of the irrigation water in the treatments with high values of ECw. The soil pH values showed little reaction in relation to the initial values. The exchangeable sodium percentage values were approximate twice the sodium adsorption ratio of the saturation stratum.

Improving the Efficiency of Ammonium Acetate Extraction of Soil Potassium by Saturation Extract Method

The K-status in soils and its availability to plants has close relationship with field capacity or saturated conditions. Hence, there is a need to know the available K status through saturation extract and other parameters governing K-availability which bears close relation to normal field situation under which plants are grown. To improve the efficiency of ammonium acetate method by saturation extract method, saturation extract parameters were studied in vegetable growing soils of Ranga Reddy and Mahaboobnagar districts of Telangana and are correlated with forms of potassium, soil physical and chemical properties to know the importance of these parameters in release and availability of K to plants. The saturation extract obtained from the soils was analysed for available potassium and Ca + Mg values. Different parameters of the saturation extract viz., CRK, BCK and USQI factor were calculated to know the availability of potassium to plants. Results of correlation between BCK and USQI with exchangeable and non exchangeable K showed that these parameters influence the release and availability of K to plants and also the correlation with soil characteristics clearly indicate that the quantity factor Kam, KL and intensity factors PBCK, BCK are important to assess available K status. These parameters derived from K extracted by NN NH4OAc and concentration ratio of K in the saturation extract of soil i.e. BCK and USQI factor served as better indices for assessing the K supplying status of soils than K extracted by different chemical methods.

CULTIVO DO MILHETO IRRIGADO COM ÁGUA SALINA EM DIFERENTES COBERTURAS MORTAS

CULTIVO DO MILHETO IRRIGADO COM ÁGUA SALINA EM DIFERENTES COBERTURAS MORTAS AMITAIR FERREIRA LIMA1; GEOCLEBER GOMES DE SOUSA2; MARIA VANESSA PIRES DE SOUZA3; FRANCISCO BARROSO DA SILVA JUNIOR4; SILAS PRIMOLA GOMES2 E CLARISSA LIMA MAGALHÃES5 1 Engenheira agrônoma formada pela Universidade da Integração Internacional da Lusofonia Afro-Brasileira (Avenida da abolição, 3, Centro, 62.790-000, Redenção/Ce, Brasil). E-mail: [email protected] 2 Prof. Doutor, Instituto de Desenvolvimento Rural, Universidade da Integração Internacional da Lusofonia Afro-Brasileira (Avenida da abolição, 3, Centro, 62.790-000, Redenção/Ce, Brasil). E-mail: [email protected], [email protected] 3 Mestranda pelo programa de pós graduação em fitotecnia da Universidade Federal Rural do Semiárido, Campus Mossoró (Av. Francisco Mota, 572, Bairro Costa e Silva, CEP: 59.625-900, Mossoró/RN, Brasil). E-mail: [email protected] 4 Mestrando pelo programa de pós graduação em ciência do solo da Universidade Federal do Ceará, Campus do Pici (Av. Mister Hull, 2977, Pici, 60.021-970, Fortaleza/Ce, Brasil). E-mail: [email protected] 5 Discente no curso de agronomia da Universidade da Integração Internacional da Lusofonia Afro-Brasileira (Avenida da abolição, 3, Centro, 62.790-000, Redenção/Ce, Brasil). E-mail: [email protected] 1 RESUMO Objetivou-se com o presente trabalho, avaliar o crescimento e acúmulo de biomassa de plantas de milheto irrigadas com água salina em solo com diferentes coberturas. O experimento foi realizado em agosto de 2018, a pleno sol na horta didática da Universidade da integração internacional da Lusofonia Afro-Brasileira (UNILAB), Redenção, Ceará. O delineamento experimental foi inteiramente casualizado (DIC), em esquema fatorial 5x4, com 4 repetições. O primeiro fator referente aos valores de condutividade elétrica da água de irrigação - CEa: A1 (1,0 dS m-1), A2 (2,0 dS m-1), A3 (3,0 dS 11 m-1), A4 (4,0 dS m-1) e A5 (5,0 dS m-1), versus as coberturas adotadas, C1 (sem cobertura-controle), C2 (palha de arroz), C3 (bagana de cana-de-açúcar) e C4 (resíduos vegetais de espontâneas). Aos 35 dias após a semeadura, foram avaliadas: altura das plantas (AP), número de folhas (NF), diâmetro do colmo (DC), comprimento de raiz (CR), área foliar (AF), matéria seca da parte aérea (MSPA), da raiz (MSR) e total (MST), pH do solo e a condutividade elétrica do extrato de saturação do solo (CEes). O aumento da condutividade elétrica na água de irrigação, promoveu aumento da salinidade no extrato de saturação do solo, assim como reduções na emissão do número de folhas no milheto e o uso da cobertura morta amenizou os efeitos da salinidade contida na água, nas variáveis: MSPA, MSR, MST, DC e AP, sendo a cobertura de casca de arroz a alternativa mais eficiente na atenuação desses efeitos. Palavras-chave: Penissetum glaucum L., estresse salino, proteção do solo LIMA, A. F.; SOUSA, G. G.; SOUZA, M. V. P.; SILVA JUNIOR, F. B.; GOMES, S. P.; MAGALHÃES, C. L. CULTIVATION OF MILLET IRRIGATED WITH SALINE WATER IN DIFFERENT MULCHES 2 ABSTRACT The objective of this work was to evaluate the growth and accumulation of dry matter of millet plants irrigated with saline water in soil with different mulches. The experiment was carried out in August 2018, under full sun in the didactic garden of the University of the International Integration of Afro-Brazilian Lusophony (UNILAB), Redenção, Ceará. The experimental design was completely randomized (DIC), in a 5x4 factorial scheme, with four replicates. The first factor referring to the values of electrical conductivity of the irrigation water: A1 (1.0 dS m-1), A2 (2.0 dS m-1), A3 (3.0 dS m-1), A4 (4.0 dS m-1) and A5 (5.0 dS m-1), versus the coverages adopted, C1 (without cover), C2 (rice straw), C3 (sugarcane bagana) and C4 (vegetable spontaneous waste). At 35 days after sowing, plant height (AP), number of leaves emitted (NF), stalk diameter (DC), root length (CR), leaf area (AF), shoot dry matter (MSA), root dry matter (MSR), total dry matter (MST), soil pH and soil saturation extract electrical conductivity (CEs) were assessed. The increase in the electrical conductivity in the irrigation water promoted an increase in salinity in the soil saturation extract, as well as reductions in the number of leaves in the millet, and the use of the mulch reduced the effects of the salinity contained in the water in the following variables: MSPA, MSR, MST, DC and AP, with rice husk coverage being the most efficient alternative to mitigate these effects. Keywords: Penissetum glaucum L., saline stress, soil protection.

Morphophysiological responses of young oil palm plants to salinity stress

The objective of this work was to assess the morphophysiological characteristics and the ionic imbalance in the substrate, roots, and leaves of young oil palm (Elaeis guineensis) plants under different levels of saline stress, following a substrate salinization protocol in which the level of salt was known. Bifid oil palm plants were subjected to different NaCl rates (0.0, 0.5, 1.0, 1.5, and 2.0 g NaCl per 100 g substrate on a dry basis), and their morphophysiological responses were evaluated for a period of 12-14 days. This protocol generated different levels of stress due to the gradients of electrical conductivity and water potential in the saturation extract of the substrate, according to the added NaCl. Based on the rates of real evapotranspiration and leaf gas exchange, the osmotic effect of the salt reflected negatively on leaf temperature, on the chlorophyll content index, and on the chlorophyll fluorescence variables. The increase in Na and Cl levels in the saturation extract culminated with the increasing availability of Ca, K, and Mg in the solution and their accumulation in the leaves. However, the plants poorly absorbed Na and Cl. The obtained results are indicative that, for a better characterization of the osmotic and ionic phases of salinity stress, it is necessary to reduce the applied level of salinity stress and to increase the evaluation period.

RFJ Spatial variability in fertigated coffee yields and plant nutrients in soil saturation extracts

The spatial distribution and levels of available plant nutrients (elements) in the soil can limit coffee yield and must be evaluated for effective crop management. Therefore, we analyzed spatial variability in yield and plant nutrients in the saturation extract of a clayey Oxisol cropped with fertigated coffee. The experiment was carried out on 14 hectares of coffee in Monte Carmelo, Minas Gerais, Brazil. Soil samples were collected (0 - 0.2m layer) at 61 regular grid points (spaced 50x50m) and used to determine plant nutrients in the saturation extract. Coffee yield was also determined at these points. Descriptive statistics were calculated for each variable and geostatistics were used to build a spatial variability model representing the physical attributes of the soil. Variographic analysis was performed using semivariograms. These showed that yield and soil chemistry varied throughout the study site. Thus, the maps generated from geostatistics can be useful tools for soil management in fertigated coffee crops.

Physiological behavior of melon cultivars submitted to soil salinity1

ABSTRACT Melon is one of the most important vegetables for the Brazilian foreign trade. However, in semi-arid areas, the irregular rainfall, excessive use of fertilizers and, especially, poor quality water contribute to the soil salinization, becoming a limiting factor and damaging the photosynthetic apparatus, as well as affecting yield. This study aimed to evaluate the physiological behavior of melon cultivars submitted to soil salinity. For that, an experiment was conducted in a greenhouse, using a randomized block experimental design, in a 3 x 5 factorial scheme, with the first factor related to melon cultivars (Iracema, Goldex and Natal) and the second one related to soil salinity levels (0.3 dS m-1, 1.3 dS m-1, 2.3 dS m-1, 3.3 dS m-1 and 4.3 dS m-1 of electrical conductivity), with four replications. For soil salinization, a saturation extract with initial soil salinity of 0.3 dS m-1 was obtained, while the other levels were prepared by adding NaCl to the soil. The physiology of melon plants is negatively affected by the increased salinity in the soil. The evaluated cultivars do not show differences in tolerance for the physiological response to soil saline stress.

SPATIAL CONTINUITY OF ELECTRICAL CONDUCTIVITY, SOIL WATER CONTENT AND TEXTURE ON A CULTIVATED AREA WITH CANE SUGAR

ABSTRACT Spatial variability of soil attributes affects crop development. Thus, information on its variability assists in soil and plant integrated management systems. The objective of this study was to assess the spatial variability of the soil apparent electrical conductivity (ECa), electrical conductivity of the saturation extract (ECse), water content in the soil (θ) and soil texture (clay, silt and sand) of a sugarcane crop area in the State of Pernambuco, Brazil. The study area had about 6.5 ha and its soil was classified as orthic Humiluvic Spodosol. Ninety soil samples were randomly collected and evaluated. The attributes assessed were soil apparent electrical conductivity (ECa) measured by electromagnetic induction with vertical dipole (ECa-V) in the soil layer 0.0.4 and horizontal dipole (ECa-H) in the soil layer 0.0-1.5 m; and ECse, θ and texture in the soil layers 0.0-0.2 m and 0.2-0.4 m. Spatial variability of the ECa was affected by the area relief, and had no direct correlation with the electrical conductivity of the saturation extract (ECse). The results showed overestimated mean frequency distribution, with means distant from the mode and median. The area relief affected the spatial variability maps of ECa-V, ECa-H, ECse and θ, however, the correlation matrix did not show a well-defined cause-and-effect relationship. Spatial variability of texture attributes (clay, site and sand) was high, presenting pure nugget effect.

PERCOLADO DE ATERRO SANITÁRIO NO CULTIVO DA MAMONEIRA: ALTERAÇÕES QUÍMICAS EM ARGISSOLO VERMELHO-AMARELO

PERCOLADO DE ATERRO SANITÁRIO NO CULTIVO DA MAMONEIRA: ALTERAÇÕES QUÍMICAS EM ARGISSOLO VERMELHO-AMARELO* JERÔNIMO ANDRADE FILHO1; NILDO DA SILVA DIAS2; RAFAEL OLIVEIRA BATISTA3; JOSÉ FRACISMAR DE MEDEIROS2; JOSÉ AMILTON SANTOS JÚNIOR4; ANA LUÍZA LIMA FERREIRA5 *Artigo extraído da Tese de Doutorado do primeiro autor 1Instituto Federal de Ciência e Tecnologia do Rio Grande do Norte, Rua Raimundo Firmino de Oliveira, 400 - Conj. Ulrick Graff, Mossoró-RN, CEP: 59.628-330, Email:[email protected] 2Departamento de Ciências Agronômicas e Florestais, Universidade Federal Rural do Semiárido, Av. Francisco Mota, 572 - Bairro Costa e Silva, Mossoró-RN, CEP: 59.625-900, Email: [email protected]; [email protected] 3Departamento de Engenharia e Ciências Ambientais, Universidade Federal Rural do Semiárido, Av. Francisco Mota, 572 - Bairro Costa e Silva, Mossoró-RN, E mail: [email protected] 4Departamento de Engenharia Agrícola, Universidade Federal Rural de Pernambuco, R. Manuel de Medeiros, s/n - Dois Irmãos, Recife - PE, CEP: 52171-900, E mail: [email protected] 5Escola Superior de Agricultura Luiz de Queiroz, Av. Pádua Dias, 11 - Cx. Postal 9 - Piracicaba – SP, CEP: 13418-900 E mail: [email protected] 1 RESUMO O aproveitamento agrícola do percolado de aterro sanitário pode mitigar certos impactos ambientais, sobretudo quando eventuais alterações químicas no solo são monitoradas. Dito isto, em Mossoró-RN (5º11’31’’S, 37º20’40’’O), entre setembro de 2014 e janeiro de 2015, desenvolveu-se esta pesquisa, com o objetivo de quantificar alterações nas características químicas de um Argissolo vermelho-amarelo Eutrófico cultivado com plantas de mamona (Ricinus communis L.) que receberam aplicação de percolado de aterro sanitário. O experimento foi conduzido em blocos casualizados com cinco tratamentos e quatro repetições; do total da demanda hídrica da cultura, aplicou-se inicialmente percentuais (0; 20; 40; 60 e 80%) de percolado de aterro sanitário e, em seguida, o restante em água de abastecimento. Concluiu-se que com o incremento do percentual de percolado aplicado houve aumento do pH e no quantitativo de Ni, Cd e Pb, assim como os teores de Ca e Cu foram reduzidos nos primeiros 0,20 m. A condutividade elétrica do extrato de saturação, e o quantitativo de Fe e Cu não variou ao longo do perfil, entretanto, verificou-se aumento na capacidade de troca catiônica (CTC) - até a dose de 60% de percolado, e do percentual de sódio trocável (PST) – embora sempre abaixo de 15%. A variação no quantitativo de Mn, Zn, Ni, Cd e Pb não ultrapassou os limites impostos pela legislação vigente. Palavras-chave: resíduo líquido, metais pesados, sustentabilidade ANDRADE FILHO, J; DIAS, N. S; BATISTA, R.O; MEDEIROS, J.F; SANTOS JUNIOR, J.A; FERREIRA, A.L.L LANDFILL PERCOLATION IN CASTOR BEAN ULTIVATION: CHEMICAL CHANGES IN RED-YELLOW ARGISOL 2 ABSTRACT The agricultural use of landfill percolation can mitigate certain environmental impacts, especially when possible chemical changes in the soil are monitored. Thus, in Mossoró, RN (5º11’31'”S, 37º20’40” W), between September 2014 and January 2015, this research was developed with the objective of quantifying changes in the chemical characteristics of a Eutrophic red-yellow agrisol cultivated with castor bean plants (Ricinus communis L.) that received landfill percolation. The experiment was conducted in a randomized block with five treatments and four replicates; percentages (0%, 20%, 40%, 60% and 80%) of percolated landfill were initially applied, followed by water supply. It was concluded that, with the increase of the percolation percentage applied, there was an increase in pH and in the quantity of Ni, Cd and Pb, while the Ca and Cu contents were reduced in the first 0.20 m. The electrical conductivity of the saturation extract, and the quantitative Fe and Cu did not vary along the profile. Nevertheless, there was an increase in CTC – up to 60% of the percolation, and exchangeable sodium percentage (ESP) – albeit always below 15%. The variation in the quantity of Mn, Zn, Ni, Cd and Pb did not exceed the limits imposed by the current legislation. Keywords: liquid waste, heavy metals, sustainability