RESUMEN El objetivo de este trabajo fue evaluar la producción de semillas y la capacidad de oferta forrajera de calidad del Kumanda yvyra’i (Cajanus cajan L.) sometido a diferentes dosis de fertilización orgánica. Fue utilizado el diseño de bloques completos al azar (DBCA) con arreglo de parcelas subdividas con cuatro tratamientos y tres repeticiones. Los tratamientos consistieron en un testigo (0 kg ha-1), y tres dosis crecientes de gallinaza (5.000, 10.000 y 15.000 kg ha-1). Las variables evaluadas fueron altura de plantas (AP), masa verde (MV), masa seca (MS), cantidad de plantas (CP), número de vainas (NV), masa de vaina fresca y seco (PVf y PVs), producción de semillas (PS). No se observaron diferencias significativas entre las variables evaluadas, exceptuando para MV y MS, donde al nivel de 5.000 kg de gallinaza (T1), se observó la mayor producción (34.533,3 kg.MV ha-1 y 17.642,1 kg.MS ha-1) diferenciándose de los demás tratamientos (promedio: 24.925 kg.MV ha-1 y 13.890,6 kg.MS ha-1) y el testigo (24.050,0 kg.MV ha-1 y 13.134,5 kg.MS ha-1). En cuanto las demás variables; los promedios observados fueron los siguientes, AP: 2,12 m (S) y 2,10 m (F), CP: 19,4 pl m-2 (S) y 22,3 pl/m2 (F), NV: 800,9 vainas/m2 y 43,4 vainas/pl, PVf: 3946,7 kg ha-1 y PVs: 3694,4 kg ha-1, PS: 972.222,2 semillas ha-1. La fertilización orgánica no afecta significativamente las variables de altura y cantidad de plantas. La dosis de 5.000 kg ha-1 incrementó la materia verde y seca, en la producción semillera no se observaron diferencias estadísticas significativas en las variables evaluadas.

ABSTRACT This study was carried out to evaluate the seed production and the quality forage supply capacity by the pigeon pea (Cajanus cajan L.) subjected to different doses of organic fertilization. The design used was randomized complete blocks (RCBD) with arrangement of subdivided plots with four treatments and three repetitions. The treatments consisted of a control (0 kg ha-1), and three increasing doses of chicken manure (5.000, 10.000 and 15.000 kg ha-1). The variables evaluated were plant height (PH), green mass (GM), dry mass (DM), number of plants (NP), number of pods (NP), weight of fresh and dry pods (WPf and WPs), seed production (SP), nodules (NO). No significant differences were observed between the variables evaluated, except for GM and DM, where at the level of 5.000 kg of poultry manure (T1), the highest production was observed (34.533,3 kg.GM ha-1 and 17.642,1 kg.DM ha-1) differing from the other treatments (24,925 kg.GM ha-1 and 13,890.6 kg.DM ha-1) and the control (24,050.0 kg.GM ha-1 and 13,134.5 kg.DM ha-1). As for the other variables, the observed averages were for PH: 2,12 m (S) and 2,10 m (F), NPl: 19,4 pl m-2 (S) and 22,3 pl m-2 (F), NP: 800,9 pods m-2 and 43,4 pods/pl, WPf: 3946,7 kg ha-1 y WPs: 3594,4 kg ha-1, SP: 972.222,2 seeds/ha. No noteworthy nodulations were presented.

ABSTRACT The use of high doses of vinasse in sugarcane crop can cause modifications in the chemical characteristics of the soil. The aim of this study was to evaluate the effect of the application of high doses of vinasse on the chemical characteristics of an Ultisol cultivated with sugarcane for 210 days. The treatments used were doses equivalent to 0 (D0), 150 (D150), 300 (D300), 600 (D600) and 1200 (D1200) m3 ha-1 of vinasse plus a control treatment with mineral fertilization. The experimental design was completely randomized with six treatments and six repetitions. Exchangeable potassium (K), calcium (Ca), magnesium (Mg) and sodium (Na) contents, organic matter, cation exchange capacity, sodium adsorption ratio, exchangeable sodium percentage, electrical conductivity and pH were analyzed at 90, 120, 150 and 210 days after planting (DAP), in addition to microbial basal respiration at 210 days at depths of 0-0.20 and 0.20-0.40 m. Soil pH increased with the use of vinasse within the proper range for sugarcane, varying from 6.2 to 6.4. The highest K and Na contents were found at D600 and D1200; the highest K and Na availability occurred at 120 DAP and 150 DAP, respectively, indicating competition between these nutrients for exchange sites. Organic matter content was proportionally high according to the vinasse dose applied. D600 and D1200 doses increased Na content in the soil, with greater magnitude at the 0-0.20 m depth.

RESUMO O uso de doses elevadas de vinhaça no cultivo da cana-de-açúcar modifica os atributos químicos do solo. Objetivou-se com o presente trabalho avaliar o efeito da aplicação de doses elevadas de vinhaça sobre características químicas de um Argissolo Amarelo cultivado com cana-de-açúcar. Os tratamentos consistiram na aplicação de doses equivalentes a 0 (D0), 150 (D150), 300 (D300), 600 (D600) e 1200 (D1200) m3 ha-1 de vinhaça e mais uma testemunha. O delineamento experimental adotado foi inteiramente casualizado, com seis tratamentos e seis repetições. Avaliou-se a concentração de potássio (K), cálcio (Ca), magnésio (Mg) e sódio (Na) trocável, matéria orgânica, Capacidade de Troca Catiônica, Razão de Adsorção de Sódio, Porcentagem de Sódio Trocável, Condutividade Elétrica e pH aos 90, 120, 150 e 210 dias após o plantio (DAP), além da respiração basal microbiana aos 210 dias. O experimento foi conduzido em vasos com capacidade de 100 L. O pH do solo aumentou com a aplicação da vinhaça dentro da faixa considerada como adequada para a cana-de-açúcar, variando de 6,2 a 6,4. O K e Na apresentaram maiores concentrações em D600 e D1200; as maiores disponibilidades de K e Na no solo ocorreram, respectivamente, aos 120 e 150 DAP, indicando competição entre os elementos pelos sítios de troca. O teor de matéria orgânica foi proporcionalmente elevado conforme a dose de vinhaça aplicada. As doses D600 e D1200 aumentam a concentração de Na no solo, com maior magnitude na profundidade 0 – 0,20 m.

ABSTRACT Soil quality, measured through its chemical, physical and microbiological attributes, changes as a result of anthropic sensations and becomes an important tool to assess environmental quality. The objective of this study was to determine and evaluate the Quality Index of an Ultisol in a long-term (17-yr) plots under different management systems in the Coastal Tablelands of Sergipe State, in Northeastern, Brazil. Main effects were conventional tillage (CT), no-tillage (NT), and minimum tillage (MT) distributed cultivated strips with corn as the main crop. Split-range treatments were randomly distributed and cultivated with cowpea beans (Vigna unguiculata), sunn hemp (Crotalaria juncea), pigeon pea (Cajanus cajan), and millet (Pennisetum glaucum). A forest soil was used as reference, compared to the soil samples of the cultivated area. The Soil Quality Index (SQI) for the 0-0.10 m layer was calculated by the additive method. There were changes in soil properties between the different management systems, and between the experimental soil and the reference area. The highest SQI was obtained from the forest area (67.1) followed by the NT treatment (65.5), MT (65.1) and CT treatment (61.0). The lowest SQI was observed in the CT treatment previously cultivated with pigeon pea (56.5). Among the evaluated soil functions, maintenance of homeostasis had the greatest influence on the SQI. The higher acidity of the forest soil helps to explain the origin of the limitations of the soil in the cultivated area that occupies the same type of soil, tolerated by the adoption of conservationist managements.

RESUMO A qualidade do solo, medida por meio de seus atributos químicos, físicos e microbiológicos, muda em função das interações antrópicas e torna-se uma importante ferramenta para avaliar a qualidade ambiental. O objetivo deste estudo foi determinar e avaliar o Índice de Qualidade de um Argissolo em parcelas de longo prazo (17 anos) sob diferentes sistemas de manejo nos Tabuleiros Costeiros do Estado de Sergipe, Nordeste do Brasil. Os principais efeitos foram plantio convencional (CC), cultivo minimo (CM) e plantio direto (MT) distribuídos em faixas cultivadas com milho como cultura principal. Os tratamentos fracionados foram distribuídos aleatoriamente e cultivados com feijão-caupi (Vigna unguiculata), crotalária (Crotalaria juncea), feijão guandu (Cajanus cajan) e milheto (Pennisetum glaucum). Um solo florestal foi utilizado como referência. O Índice de Qualidade do Solo (IQS) para a camada de 0-0,10 m foi calculado pelo método aditivo. Houve mudanças nas propriedades do solo entre os diferentes sistemas de manejo, e entre o solo do experimento e a área de referência. O maior IQS foi obtido da área de floresta (67,1) seguido do tratamento PD (65,5), CM (65,1) e tratamento CC (61,0). O menor IQS foi observado no tratamento CC previamente cultivado com feijão guandu (56,5). Dentre as funções avaliadas do solo, a manutenção da homeostase teve a maior influência no IQS. A maior acidez do solo florestal ajuda a explicar a origem das limitações do solo na área cultivada que ocupa o mesmo tipo de solo, exigindo a adoção de manejos conservacionistas.

ABSTRACT The objective of this study was to investigate the acidic soil physical and chemical alteration associated to vinasse application under laboratory conditions. The experiment was distributed in a factorial scheme (5 × 3), in a completely randomized design, with four replicates. The beneficial effects of five vinasse doses (without vinasse [0, only water], 50, 100, 150, and 200 m3/ha) in enhancing the physical and chemical properties of three acidic soils: Oxisol (SO), Ultisol (SU), and Argisol (SA) were studied after 30 days of incubation. Soil samples were collected in the 0-20 cm depth layer to determine physical and chemical properties such as pH (CaCl2), total acidity (AT), exchangeable acidity (Al3+), base cations (K+, Ca2+, and Mg2+), sums of bases (SB), cations exchange capacity (CIC), base saturation index (V%), and saturation of potassium (K), calcium (Ca), magnesium (Mg), and aluminum (Al). Results indicated that vinasse application enhanced the physical and chemical properties of the studied soils, since pH, base cations, SB, CIC, V%, and saturation of K, Ca, and Mg were increased, while AT, Al3+, and Al saturation were decreased. The most important effects in the improvement of physical and chemical properties of acidic soils were observed with a dose of 200 m3/ha of vinasse. The findings of this study suggest that vinasse could be a low-cost effective strategy as an alternative source for balancing soil acidity and would be an appropriate option for minimizing environmental pollution.

RESUMEN El objetivo de este estudio fue investigar las alteraciones físicas y químicas de los suelos ácidos asociadas a la aplicación de vinaza en condiciones de laboratorio. Los efectos beneficiosos de cinco dosis de vinaza (sin vinaza [0, solamente agua], 50, 100, 150 y 200 m3/ha), fueron estudiadas en el mejoramiento de las propiedades físicas y químicas de tres suelos ácidos: Oxisol (SO), Ultisol (SU) y Argisol (SA), después de 30 días de incubación. Las muestras de suelos fueron recolectadas en la capa de 0-20 cm de profundidad para la determinación de propiedades físicas y químicas como pH (CaCl2), acidez total (AT), acidez intercambiable (Al3+), cationes bases (K+, Ca2+ y Mg2+), suma de bases (SB), capacidad de intercambio catiónico (CIC), índice de saturación de las bases (V%), y saturación de potasio (K), calcio (Ca), magnesio (Mg) y aluminio (Al). Los resultados indicaron que la aplicación de vinaza mejoró las propiedades físicas y químicas de los suelos estudiados, porque se incrementaron tanto el pH como los cationes bases, la SB, la CIC, el V% y la saturación de K, Ca y Mg, y disminuyeron la AT, Al3+ y saturación de Al. Además, los efectos más importantes en el mejoramiento de las propiedades físicas y químicas de los suelos ácidos se observaron en la dosis de 200 m3/ha de vinaza. Los hallazgos de este estudio sugieren que la vinaza podría ser una estrategia efectiva de bajo costo como fuente alternativa para balancear la acidez del suelo y constituiría una opción apropiada para disminuir la contaminación ambiental.

Abstract The objective of this work was to evaluate the application of silicate ultramafic alkaline rock, with different granulometry, as an alternative potassium source on the increase of soil fertility and on the nutritional status and biomass yield of the alfalfa and centrosema crops. The used soil was a Typic Ultisol with 27.4 mg dm-3 K and 733 g kg-1 clay. The experimental design was completely randomized, in a 4 × 2 + 1 factorial arrangement. The treatments consisted of two granulometries (<0.3 and 0.3-2.0 mm) of alkaline ultramafic rock (4.0% K2O), four K rates (0, 100, 150, and 300 mg kg-1), and an additional treatment with the application of 150 mg kg-1 K in the form of KCl (58% K2O). Both legumes were grown in a greenhouse and subjected to five successive harvests. In comparison with KCl, the application of silicate rock has the potential to increase K uptake and root and shoot dry weight yield in alfalfa and centrosema. Granulometry does not affect rock use efficiency, and alfalfa presents a better K efficiency recovery in the soil after successive harvests compared with centrosema; the inverse is observed for K use and K uptake efficiencies.

Resumo O objetivo deste trabalho foi avaliar a aplicação de rocha silicática ultramáfica alcalina com diferentes granulometrias, como fonte alternativa de potássio no aumento da fertilidade do solo e no estado nutricional e na produção de biomassa das cultura de alfafa e centrosema. O solo utilizado foi um Argissolo Amarelo distrófico com 27,4 mg dm-3 de K e 733 g kg-1 de argila. O delineamento experimental foi inteiramente casualizado, em arranjo fatorial 4 × 2 + 1. Os tratamentos consistiram em duas granulometrias (< 0,3 e 0,3-2,0 mm) da rocha ultramáfica alcalina (4,0% de K2O), na aplicação de quatro doses de K (0, 100, 150 e 300 mg kg-1) e de um tratamento adicional com a aplicação de 150 mg kg-1 de K na forma de KCl (58% de K2O). Ambas as leguminosas foram cultivadas em casa de vegetação e submetidas a cinco cortes sucessivos. Em comparação ao KCl, a aplicação da rocha silicática apresenta potencial para aumentar a absorção de K e a produção de matéria seca de raízes e da parte aérea da alfafa e da centrosema. A granulometria não altera a eficiência de uso da rocha, e a alfafa apresenta maior eficiência de recuperação de K do solo após cortes sucessivos em comparação à centrosema; o inverso é observado para eficiências de uso e absorção de K.

RESUMO Os solos leves possuem maior suscetibilidade ao processo de degradação e necessitam ser explorados de forma conservacionista, evitando assim sua rápida degradação. Objetivou-se com o estudo avaliar as propriedades físico-hídricas de um Argissolo sob plantio direto e integração lavoura-pecuária no Cerrado da região leste do estado do Maranhão. Os manejos avaliados foram uma área sob sistema de plantio direto há quatorze anos (soja/milheto) e três áreas com diferentes históricos de adoção do sistema de integração lavoura-pecuária (ILP) sob plantio direto (soja/milheto), sendo a diferença os tempos de entrada com ILP (2, 4 e 8 anos), além de uma área de cerrado nativo, considerado testemunha. A coleta do solo foi realizada em junho de 2018 nas profundidades de 0,00-0,10; 0,10-0,20; 0,20-0,30; 0,30-0,50 m. Foram coletadas amostras deformadas e indeformadas, para determinação das variáveis: densidade do solo, porosidade, resistência à penetração, curva de retenção e capacidade de água disponível. Os dados foram submetidos ao cálculo das médias e de intervalo de confiança (95 %). A área com histórico recente de integração lavoura-pecuária apresentou melhor densidade, porosidade, resistência a penetração e capacidade de armazenamento e água disponível. O plantio direto há quatorze anos apresenta alta resistência a penetração, menor porosidade e baixa capacidade de armazenamento de água. O sistema integrado (ILP) melhora a qualidade das propriedades físico - hídricas, sendo o sistema com maior capacidade de água disponível para as plantas.

ABSTRACT Light soils are more susceptible to degradation and need to be exploited in a conservational manner, thus avoiding rapid degradation. The objective of this study was to evaluate the physical-hydraulic properties of an Ultisol under no-tillage and crop-livestock integration in the Cerrado of eastern Maranhão state, Brazil. The evaluated managements were one area under no-tillage system for fourteen years (soybean/ millet) and three areas with different histories of adoption of the crop-livestock integration (CLI) system under no-tillage (soybean/millet), with the difference being: times of entry with CLI (2, 4 and 8 years), as well as a native Cerrado area, considered a control. Soil collection was carried out in June 2018 at depths of 0.00-0.10, 0.10-0.20, 0.20-0.30 and 0.30-0.50 m. Disturbed and undisturbed samples were collected to determine the following variables: bulk density, porosity, resistance to penetration, retention curve and available water capacity. Data were subjected to the calculation of means and confidence intervals (95%). The area with a recent history of crop-livestock integration showed better density, porosity, resistance to penetration, water storage capacity and available water. No-tillage for fourteen years leads to high resistance to penetration, less porosity and low water storage capacity. The integrated system (CLI) improves the quality of the physical- hydraulic properties and the values found are similar to those observed in an area under native vegetation.

RESUMO Considerando as perdas de fósforo (P) no solo pelo processo de adsorção e que o uso do biocarvão parece promissor do ponto de vista agrícola, objetivou-se com este estudo avaliar o processo de adsorção de P pelo solo Argissolo incubado com diferentes doses de biocarvão através de estudo cinético e isotérmico. O experimento foi realizado com biocarvão de cama de aviário pirolisado a 350 °C. O Argissolo foi incubado com doses crescentes de biocarvão, de 0,0 a 61,95 t ha-1. Após 60 dias, foram avaliadas a taxa de adsorção de fósforo, e cinética e isotermas de adsorção. Os resultados mostraram que o solo apresentou a maior capacidade de adsorção de fósforo (1,105 mg g-1). O biocarvão não foi um bom adsorvente de P; independente das doses aplicadas, liberou P para a solução de equilíbrio. O modelo de Langmuir foi o melhor para descrever a adsorção de P. A cinética de adsorção de P se ajustou bem ao modelo de pseudo-segunda ordem, mostrando que a adsorção é controlada quimicamente. Esses resultados sugerem que o biocarvão pode aumentar a disponibilidade de P no solo, limitando a adsorção, portanto, pode ser usado como fertilizante e/ou condicionador de solo.

ABSTRACT Considering the losses of phosphorus (P) in the soil by the adsorption process and that the use of biochar seems promising from the agricultural point of view, the aim of this research was to evaluate P adsorption by the Ultisol incubated with different biochar doses through kinetic and isothermal study. The experiment was carried out with poultry litter biochar pyrolyzed at 350 °C. Ultisol was incubated with increasing biochar doses, from 0.0 to 61.95 t ha-1. After 60 days, the phosphorus adsorption rate, kinetics and adsorption isotherms were evaluated. The results showed that the soil had the highest capacity to adsorb phosphorus (1.105 mg g-1). Biochar was not a good P adsorbent; regardless of the applied doses, it released P to the equilibration solution. Langmuir model was better at describing the adsorption of P. The pseudo-second order model fitted well to the adsorption kinetics of P, showing that the adsorption is chemically controlled. These results suggest that biochar can increase the availability of P, limiting adsorption; therefore, it could be used as a fertilizer and/or soil conditioner.

RESUMO: Os sistemas integrados de produção agropecuária possuem potencial de incrementar a matéria orgânica, com reflexos nas concentrações de carbono e de nitrogênio no solo. O objetivo do trabalho foi avaliar estoques de carbono e nitrogênio e seus compartimentos em um Argissolo Amarelo Distrocoeso típico sob plantio direto e integração lavoura-pecuária no Leste maranhense. Os manejos avaliados foram: sistema de plantio direto em sucessão há 14 anos (soja/milheto), três áreas com diferentes históricos de sucessão com a adoção do sistema integração lavoura-pecuária (ILP), sendo dois, quatro e oito anos, além de uma área de Cerrado nativo. Foram coletadas amostras de solo nas profundidades de 0,00-0,10; 0,10-0,20; 0,20-0,30; 0,30-0,50 metros para análise de teores e estoques totais de carbono (C) e de seus compartimentos (físico e químico), nitrogênio (N) e da biomassa microbiana do solo e respiração basal. Os resultados revelam maior teor e estoque de C e N nas áreas com ILP. A substância húmica predominante foi a humina e maiores concentrações do carbono associado a minerais estiveram presentes na área sob ILP mais recente (dois e quatro anos). A adoção da ILP, mesmo que recente, proporciona incrementos imediatos nas concentrações de C e suas frações em função do emprego de forrageiras. O plantio direto há 14anos e ILP há oito anos são sistemas com maior índice de manejo do C, como, também, apresentam maior atividade biológica do solo, devido à maiores estabilidade destes sistemas.

ABSTRACT: Integrated agricultural production systems have the potential to increase organic matter content, which is reflected in the soil carbon (C) and nitrogen (N) concentrations. Here, we evaluated the C and N stocks and its compartments in a typical distro cohesive yellow Ultisol under the no-till (NT) and crop-livestock integration (CLI) systems, in eastern Maranhão. Five areas with different management strategies were evaluated, more specifically, one area was managed under the NT system in succession for 14 years (soybean/millet), three areas had different CLI system adoption histories (i.e., CLI was adopted 2, 4, or 8 years prior to sample collection); and finally, one area consisted of native Cerrado (savannah) vegetation. Soil samples were collected at depths of 0-0.10, 0.10-0.20, 0.20-0.30, and 0.30-0.50 m,to analyze the content and total stocks of carbon (C) and its compartments (physical and chemical), N content, soil microbial biomass, and basal respiration. Results revealed higher content and stock of C and N in areas with CLI. The principal humic substance reported was humin, and higher concentrations of C associated with minerals were present in areas under more recent CLI adoption (2 and 4 years). We demonstrated that the adoption of CLI, even if recent, leads to immediate increases in the concentrations of C and its fractions as a result of using forage crops. NT for 14 years and CLI for 8 years exhibited higher levels of C management and higher soil biological activity due to the greater stability of these systems.

ABSTRACT The aim of this study was to evaluate the physical quality of the soils by evaluating the variation of soil penetration resistance, resulting from tillage with chiseling in the planting row and in total area, and the possible interferences of the managements in sugarcane yield. The study was carried out in southeastern Brazil, in areas under Oxisol and Ultisol, which are the two soils with the greatest representativeness of sugarcane cultivation in the country. The treatments consisted of soil tillage in total area and localized tillage in the sugarcane planting row, with 10 replicates. Undisturbed soil samples were collected in the 0-0.10, 0.10-0.20, and 0.20-0.40-m soil layers in sugarcane rows and interrows in both soil types for penetration resistance determination in laboratory. Samplings were carried out at three times, the first after soil tillage, the second after sugarcane planting, and the third six months after planting. Compared to the system with tillage in total area, localized tillage promoted higher values of soil penetration resistance in sugarcane interrows. However, this was not enough to reduce the crop yield. In the planting row, there are no differences between tillage types for soil penetration resistance. Localized soil tillage in sugarcane crop is a conservation and sustainable alternative that can replace soil tillage in total area, not interfering in the PR determined in the crop row and not altering the stem yield, regardless of the soil type.

RESUMO As substâncias húmicas (SH) têm se mostrado eficazes em incrementar a produtividade de hortaliças. O objetivo deste trabalho foi avaliar o efeito de bioestimulantes comerciais ricos em ácidos húmicos (AH) e fúlvicos (AF), obtidos de leonardita, na eficiência agronômica da cultura de alface e teor de nutrientes na planta. Foi realizado um experimento em casa-de-vegetação em vasos de 2,5 L com amostras de Argissolo, aos quais foram aplicados bioestimulantes comerciais ricos em AH e em AF, isoladamente e em combinação com o fertilizante mineral NPK. A aplicação dos bioestimulantes à base de SH associada à fertilização mineral na cultura da alface apresentou os maiores valores das variáveis estudadas: altura e diâmetro de plantas, número de folhas por planta e comprimento de raiz. A combinação do bioestimulante rico em AF e o fertilizante mineral aumentou a produção da alface em relação à aplicação isolada do fertilizante inorgânico. A aplicação combinada dos bioestimulantes ricos em AF e em AH com o fertilizante NPK influenciou a absorção de K e Fe pelas plantas, e seu acúmulo na parte aérea. Nossos resultados sugerem que as SH potencializam o efeito nutricional do fertilizante mineral, quando aplicadas conjuntamente.

ABSTRACT Humic substances (HS) have proved to be effective in improving the productivity of vegetable crops. We examined the effect of commercial biostimulants rich in humic (HA) and fulvic acids (FA) obtained from leonardite on agronomic efficiency and nutrient content in the leaves of lettuce (Lactuca sativa). A greenhouse experiment was carried out employing 2.5-L pots containing Ultisol samples that were supplied with commercial biostimulants rich in HA and FA, alone and in combination with NPK mineral fertilizer. The application of HS biostimulants associated to mineral fertilization to the lettuce plants provided the greatest values of the studied variables, namely: plant height and diameter, leaf number per plant and root length. The combination of FA biostimulants and mineral fertilization increased the lettuce productivity relative to the inorganic fertilizer alone. The combined application of rich biostimulants FA and HA with NPK fertilizes influenced K and Fe uptake by the plants, and their accumulation in the aerial portion. Our results suggest that HS products potentialize the nutritional effect of the mineral fertilizer, when applied in combination.

RESUMO Na plantação de cana-de-açúcar, o Imazapic tem sido usado em pré ou pós-emergência, isoladamente ou em combinação com outros herbicidas. Quando aplicado ao solo em pré-emergência, o Imazapic pode sofrer os processos de sorção, lixiviação e/ou degradação por efeitos físicos, químicos e biológicos, além de ser absorvido por plantas daninhas. O objetivo deste trabalho foi avaliar a interação e mobilidade do herbicida Imazapic no solo onde foram utilizadas colunas de solo com um Argissolo Amarelo distrófico (YUd) e um Latossolo Vermelho-Amarelo distrófico (RYOd) do Nordeste do Brasil. O maior potencial de adsorção do RYOd está associado ao maior teor de argila, maiores concentrações de Fed e Feo e pH ácido do solo. O modelo CDE - 2 de dois sítios de sorção representou adequadamente os dados experimentais das curvas de eluição do Imazapic para os solos RYOd e YUd. A partir dos coeficientes de partição Kd para RYOd e YUd, altos valores do índice GUS (5,94 e 7,04, respectivamente) foram calculados, confirmando o alto potencial de lixiviação da molécula Imazapic nesses solos.

ABSTRACT In the plantation of sugarcane, Imazapic has used pre- or post-emergence, alone or in combination with other herbicides. When applied to the soil in pre-emergence, Imazapic can undergo the sorption, leaching and/or degradation processes due to physical, chemical and biological effects, besides being absorbed by weeds. The objective of this work was to evaluate the interaction and mobility of the Imazapic herbicide in the soil where the soil columns with a dystrophic Yellow Ultisol (YUd) and a dystrophic Red-Yellow Oxisol (RYOd) from northeastern Brazil were used. The higher adsorption potential of the RYOd is associated with higher clay content, higher Fed and Feo concentrations, and soil acidic pH. The CDE – 2 sorption sites model adequately represented the experimental data from the Imazapic breakthrough curves to the RYOd and YUd soils. From the Kd partition coefficients for RYOd and YUd, high values of the GUS index (5.94 and 7.04, respectively) were calculated, confirming the high leaching potential of the Imazapic molecule in these soils.

ABSTRACT: This study evaluated P pools after nine years of successive application of either pig slurry (PS) or deep pig litter (DL) in a no-till Ultisol from southern Brazil. The experiment was established in Dec 2002 with the treatments control, application of 90 and 180 kg N ha−1 N as PS and as DL. In Mar 2010, soil samples were taken at six layers up to 30 cm deep. Total organic and inorganic P were assessed by the ignition method, and P compounds classes were evaluated by 31P-NMR spectroscopy. Total soil P increased proportionally with the P amount applied via DL and PS. Only DL application increased soil organic P, mainly at the highest dose and in the uppermost soil layers. The application of high doses of manure to these soils under no-till to meet crop N demands significantly increased P accumulation at the soil surface, especially with DL. This, in turn, increases the risk of contamination of water bodies due to P transfer from soil to rivers via runoff. The ignition method overestimates organic P compared to P-NMR. The highest proportion of organic P estimated by the ignition and P-NMR methods, at surface layers in the control suggests that inorganic P is added to the plots treated, increasing inorganic P and decreasing organic P. Moreover, with no P additions to the control, inorganic soil P is removed by plants, causing an apparent increase in the organic P proportion.

RESUMO Objetivou-se com este estudo avaliar a alteração nos teores de metais em um Ultisol, cultivado com palma forrageira (Nopalea cochenillifera) e irrigado com diluições de água produzida de petróleo tratada. O experimento foi montado no delineamento em blocos casualizados, com cinco tratamentos (T1 - 100% de água subterrânea; T2 - 75% de água subterrânea mais 25% de água produzida; T3 - 50% de água subterrânea mais 50% de água produzida; T4 - 25% de água subterrânea mais 75% de água produzida; e T5 - 100% de água produzida), com cinco repetições. O trabalho foi conduzido em 25 vasos de 20 L dentro de casa de vegetação, em Mossoró, RN. Aos 240 dias após o plantio foram coletadas amostras do solo, nas profundidades de 0 a 0,10 m e de 0,10 a 0,20 m, para avaliação dos metais Fe, Mn, Cu, Zn, Cr, Ni, Cd e Pb. O uso de diluições da água produzida do petróleo tratada não acarretou contaminação do solo cultivado com palma forrageira em relação aos metais, sendo que no T2 houve os menores aportes de metais. Ocorreu aumento significativo de Cr e Pb no solo, indicando que a aplicação de água produzida do petróleo tratada não deve ser realizada de forma contínua em uma mesma área.

ABSTRACT The objective of this study was to evaluate changes in soil metal contents in an Ultisol cultivated with forage cactus (Nopalea cochenillifera) irrigated with diluted treated oil produced water (TOPW). The experiment was conducted in a randomized block design with five replications. The treatments consisted of 100% underground water (T1); 75% underground water plus 25% TOPW (T2); 50% underground water plus 50% TOPW (T3); 25% underground water plus 75% TOPW (T4); and 100% TOPW (T5). The plots consisted of 25 pots of 20 L in a greenhouse, in Mossoró, RN, Brazil. Soil samples from the 0-0.10 m and 0.10-0.20 m layers were collected at 240 days after planting, and Fe, Mn, Cu, Zn, Cr, Ni, Cd, and Pb contents were evaluated. The use of irrigations with diluted TOPW caused no contamination of the soils cultivated with forage cactus by the evaluated metals. T2 presented the lowest metal contents. Cr and Pb contents in the soil were significantly high, indicating that the application of TOPW should not be used continuously in the same area.

ABSTRACT The objective of this study was to evaluate the influence of minerals in the clay fraction on physical attributes of Yellow Ultisol cultivated with sugarcane and prepared with two different treatments: chiseling across the entire area and chiseling only in planting rows. The samples were collected from four layers of soil at eight months after planting. We assessed the texture of the soil, levels of iron extracted by dithionite-citrate-bicarbonate (DCB) and ammonium acid oxalate (AAO), ratio of kaolinite/(kaolinite + gibbsite), soil bulk density, and soil penetration resistance. The first area showed a higher ratio of kaolinite/(kaolinite + gibbsite) and the second area had greater levels of iron extracted by DCB. Levels of iron extracted by DCB were inversely correlated with soil bulk density and penetration resistance, while the kaolinite/(kaolinite + gibbsite) ratio was directly correlated with soil bulk density and penetration resistance. The area with a greater kaolinite/(kaolinite + gibbsite) ratio had higher values of soil bulk density and soil penetration resistance and the area with higher levels of iron showed lower values of soil bulk density and soil penetration resistance. The mineralogy influenced the soil's physical attributes, while soil preparation treatments did not.

Resumen Los objetivos de este estudio fueron realizar la calibración y determinar las ecuaciones de calibración de dos sensores de humedad de suelo ECH2O para un suelo Ultisol colectado en el Municipio de Pesqueira-PE, localizado en el Semiárido Brasileño. El estudio se llevó a cabo en baldes plásticos de 5 litros implementados en ambiente protegido en la Universidad Federal Rural de Pernambuco, Recife-PE, donde se realizó el monitoreo diario de la humedad del suelo durante 51 días, desde la humedad de saturación hasta el secado natural. Los autores verificaron que los sensores ECH2O presentaron una respuesta exponencial a la variación de humedad de suelo obteniendo R2>0,97. Valores de RMSE variaron de 0,065 a 0,012 m3 m-3 para el sensor 5TE y de 0,045 a 0,011 m3 m-3 para el EC-5. Los investigadores concluyeron que las ecuaciones de calibración obtenidas fueron más precisas que las ecuaciones de fábrica para ese tipo de suelo.

Abstract The objectives of this study were to perform the calibration and determine the calibration equations of two ECH2O soil moisture sensors, for an Ultisol, collected in the Municipality of Pesqueira-PE located in Brazilian semi-arid region. The study was carried out in 5-liter plastic containers in a protected environment at the Federal Rural University of Pernambuco, Recife-PE, where soil moisture was daily monitored for 51 days from saturation moisture to natural drying. The authors verified that the ECH2O sensors showed an exponential response to the variation of soil moisture, obtaining R2>0.97. RMSE values ranged from 0.065 to 0.012 m3 m-3 for the 5TE sensor and from 0.045 to 0.011 m3 m-3 for the EC-5 sensor. The researchers concluded that the calibration equations obtained were more accurate than the factory equations for that type of soil.