ABSTRACT The application of new management techniques with the objective of implementing in agriculture, such as the use of growth-promoting and/or plant-protecting microorganisms and micronutrients, appears as an alternative. Thus, the aim of the study was to evaluate the potential of Trichoderma atroviride in association with doses of B, analyzing the effects on nutritional contents, yield components and productivity. The study was carried out in the field, in a randomized block design in a 4 × 5 factorial scheme, whose treatments were combined, consisting of foliar application of T. atroviride in three phenological stages (V5, R1 and R5) and no application (SEM), and five doses of B (0, 500, 1000, 1500 and 2000 g ha-1). The data obtained were submitted to ANOVA and, when significant, the study of polynomial regression and Tukey’s test was carried out, followed by Pearson’s linear correlation analysis (p < 0.05). The use of the microorganism and doses of B did not result in a significant increase in the growth and productive yield of soybean (Glycine max (L.) Merr.), but the application of the micronutrient significantly increased the number of pods per plant and the foliar content of B. Positive correlations were observed between plant height and pod insertion height (r = 0.51***), pod with branches (r = 0.68***), grains with branches and pod (r = 0.69*** and 0.95*** respectively), as well as a negative correlation between 100-grain mass and plant height (r = -0.24*), and a non-correlation for yield and leaf content of B.

O uso de biofertilizante combinado com composto orgânico e fontes naturais de fósforo pode resultar em maior eficiência da adubação. Objetivou-se avaliar o efeito da torta de filtro associada com fosfato natural de rocha e biofertilizantes, sobre a população de microrganismos do solo, os teores de fósforo no solo, nas plantas e a produção de matéria seca da cultura do milho. O experimento foi realizado em casa de vegetação utilizando-se milho cultivar DKB 390 VTPRO II, cultivado em vasos de 5 dm³ contendo Ultisol (Argissolo Vermelho Amarelo Distrófico). Avaliaram-se sete tratamentos, sendo: controle (somente o solo); solo adicionado de fosfato de rocha (FR); torta de filtro; FR e torta de filtro; FR, torta de filtro e Biopack Sc®; FR, torta de filtro e Embrafós: FF organic Plus® e; FR, torta de filtro e Azotofos. O delineamento experimental foi o inteiramente casualizado, com três repetições. Avaliaram-se a altura de plantas, diâmetro do colmo, número de folhas por planta, massa seca das plantas, populações dos microrganismos no solo e o teor de fósforo do solo e nas plantas. Os solos com torta de filtro, fosfato natural e biofertilizantes apresentaram maior população de bactérias totais; porém, não aumentaram a massa seca, o teor de fósforo no solo e o acúmulo de fósforo na parte aérea das plantas quando comparado somente ao uso da torta de filtro e fosfato natural. A torta de filtro na adubação promoveu maior teor de fósforo no solo e acúmulo pelas plantas, maior crescimento das plantas e maior população microbiana do solo, em relação aos tratamentos com ausência de torta.

The use of biofertilizers combined with organic compost and natural sources of phosphorus may result in increased fertilizer efficiency. The aim was to evaluate the effect of the use of the filter cake with natural rock phosphate and biofertilizers on the population of microorganisms of the soil, the content of phosphorus in soil and plants and the production of dry matter of corn crop. The experiment was developed at greenhouse, using corn DKB 390 VTPRO II cultivar, sowed in pots of 5 dm³ containing Ultisol. Seven treatments were evaluated: only the soil; soil with phosphate rock (PR); filter cake; PR with filter cake; PR with filter cake and Biopack Sc®; PR with filter cake and Embrafós: FF organic Plus® and PR with filter cake and Azotofos. The experimental design was completely randomized, with three repetitions. The height, diameter of the stem, number of leaves and dry biomass of the plants, and the populations of microorganisms were determined, the content of phosphorus in soil and plants was also determined. The soils with filter cake, natural phosphate and biofertilizers presented higher population of total bacteria; however, they did not increase the mass dries, the phosphorus concentration in the soil and accumulation of phosphorus in the aerial part of the plants when compared only to the use of filter cake and natural phosphate. The filter cake in the fertilization promoted higher phosphorus content in the soil and accumulation for the plants, higher growth of the plants and microbial population in the soil, in relation to the treatments with filter cake absence.

The objective of this study was to evaluate the effect of phosphorus sources in the absence and presence of earthworm humus on tillering, forage production and P accumulation of Panicum maximum cv. grass Mombasa. The experiment was conducted in 5 dm³ pots in a greenhouse located at the University of Mato Grosso, Alta Floresta - MT, Brazil. The treatments were arranged in a 4x2 + 1 with four replications, four P sources: simple superphosphate (SS) (18% soluble P2O5), Bayovar rock phosphate (BRP) (14% soluble P2O5), Top- Phos 280 HP (TP) (28% soluble P2O5) and bone meal (BM) (9.6% soluble P2O5), in the absence and presence of earthworm humus, and the control treatment (no P). At 46 days after emergence (DAE) the number of tillers were counted and at 46, 65 and 80 DAE cuts were made to evaluate the accumulation of dry matter and P accumulation. Application of the phosphorus sources, simple superphosphate and bone meal associated with earthworm humus resulted in higher dry matter accumulation of Mombasa grass and higher total phosphorus accumulation in the three cuts, in relation to isolated application of these phosphorus sources. The presence of humus did not influence tillering of the grass however more soluble sources promoted greater tillering.

El objetivo de este trabajo fue evaluar el efecto de fuentes de P en la ausencia y presencia de lombricompuesto sobre el macollaje, la producción de forraje y la acumulación de P del pasto Panicum maximum cv. Mombasa. El experimento fue realizado en vasos de 5 dm³ en invernadero localizada en la Universidad del Estado de Mato Grosso, Alta Floresta-MT, Brasil. Los tratamientos fueron ordenados en esquema factorial 4x2 + 1 con cuatro repeticiones, siendo cuatro fuentes de P: superfosfato simple (SS) (18% de P2O5 soluble), fosfato natural de Bayóvar (FNB) (14% de P2O5 soluble), Top- Phos 280 HP (TP) (28% de P2O5 soluble) y harina de huesos (FO) (9,6% de P2O5 soluble); en ausencia y en presencia de lombricompuesto, y un tratamiento control (sin P). A los 46 días después de la emergencia (DAE) se contó el número de macollos y a los 46, 65 y 80 DAE se realizaron tres cortes para la evaluación de la acumulación de materia seca y acumulación de P. La aplicación de las fuentes de fósforo el solapamiento simple y la harina de huesos asociados al humus de gusano proporcionaron una mayor acumulación de materia seca del pasto Mombasa y una mayor acumulación de fósforo en un total de tres cortes en relación con la aplicación aislada de estas fuentes de fósforo. La presencia de lombricompuesto no influenció el macollaje del pasto, sin embargo, las fuentes más solubles promovieron mayor cantidad de macollos.

Abstract The method used to dry plant tissue samples may modify its nutrient content, and results in incorrect diagnostic of crop nutritional status. The hypothesis was that microwave drying method does not affect the nutrient content of leaves neither the interpretation of the results, as compared to oven-drying procedure. In this study we evaluated the effect of microwave drying of eucalyptus (Corymbia Citriodora (Hook.)) and rubber trees (Hevea brasiliensis Muell. Arg.) leaves on dry matter and macronutrient content, as compared to oven drying. The study was performed in a laboratory at the Department of Soils and Fertilizers of Universidade Estadual Paulista “Julio de Mesquita Filho”, UNESP, Jaboticabal-SP-Brazil. The experiments were: one using leaf samples of eucalyptus and other using leaf samples of rubber trees. The experimental design was completely randomized and treatments were drying in conventional oven and in microwave oven, with 10 repetitions. Data were analyzed using ANOVA and treatments means were compared with F test and Tukey test (p≤0.05). The dry matter and the macronutrient content of each sample were determined. There were no differences between the drying methods on leaf nutrient content, except for N content of rubber trees. Similar dry matter content was obtained for rubber trees and eucalyptus samples. Microwave drying is useful as an alternative method to dry plant tissues samples aiming to its chemical analysis.

Resumen El método usado para secar muestras de tejido vegetal puede modificar su contenido de nutrientes, lo cual resulta en un diagnóstico incorrecto del estado nutricional del cultivo. La hipótesis fue que un método de secado con microondas no afecta el contenido de nutrientes en las hojas, ni la interpretación de los resultados, comparado con secado con calor. En este estudio evaluamos el efecto del secado en microondas sobre la materia seca y el contenido de macronutrientes de hojas de eucalipto (Corymbia Citriodora (Hook.)) y caucho (Hevea brasiliensis Muell. Arg.), comparado con el secado en horno. El estudio se realizó en el laboratorio del Departamento de Suelos y Fertilizantes de la Universidad Estadual Paulista “Julio de Mesquita Filho”, UNESP, Jaboticabal-SP-Brasil. Los experimentos se establecieron: uno con muestras de hojas de eucalipto y otro con hojas de árboles de caucho. El diseño experimental fue completamente al azar, los tratamientos fueron dos secado en horno convencional, y en horno microondas, con 10 repeticiones. Los datos se analizaron con ANDEVA y las medias de tratamiento se compararon con la prueba de F y la de Tukey (p≤0.05). La materia seca y el contenido de macronutrientes de cada muestra fueron evaluados. No hubo diferencias entre los métodos de secado sobre el contenido de nutrientes foliares, excepto el contenido de N en las muestras de árboles de caucho. La materia seca en las muestras de caucho y eucalipto fue similar. El secado por microondas es útil como un método alternativo para muestras de tejidos vegetales y con el objetivo de análisis químicos.

Abstract Mombasa grass is very demanding and responsive to soil fertility. The objective of the present study was to evaluate forage production and the correlation among crude protein and the green color index of leaves of Megathyrsus maximum cultivar Mombasa in function of nitrogen levels. The study was conducted using 5 dm-3 pots in a greenhouse at the Universidade Estadual Paulista - UNESP, Jaboticabal, São Paulo. The experimental design consisted of randomized blocks with five treatments and four replications. Treatments were nitrogen rates (0, 62.5, 125, 250 and 500 mg dm-3 of N), corresponding to 0, 125, 250, 500 and 1000 kg ha-1 of N. We evaluated the production of grass dry matter, the green color index, the accumulation of nitrogen and crude protein content in the shoot. Nitrogen fertilization increased forage production, crude protein, nitrogen accumulation and green color index of Mombasa grass. There is high correlation of the green color index with the crude protein content.

Resumo O capim Mombaça é muito exigente e responsivo em fertilidade do solo. Objetivou-se avaliar a produção de forragem e a correlação entre a proteína bruta com o índice da cor verde da folha de Megathyrsus maximum cultivar Mombaça, em função de doses de nitrogênio. O estudo foi realizado em vasos de 5 dm³ conduzido em casa de vegetação na Universidade Estadual Paulista - UNESP, Jaboticabal, São Paulo. Utilizou-se o delineamento experimental de blocos inteiramente casualizados com cinco tratamentos e quatro repetições. Os tratamentos foram constituídos por doses de nitrogênio (0, 62,5, 125, 250 e 500 mg dm-3 de N), correspondentes a 0, 125, 250, 500 e 1.000 kg ha-1 de N. Foram avaliados a produção de matéria seca do capim, o índice da cor verde, o acúmulo de nitrogênio e o teor de proteína bruta na parte aérea. A adubação nitrogenada aumentou a produção de forragem, teor de proteína bruta, acúmulo de nitrogênio e índice da cor verde no capim Mombaça. Existe alta correlação do índice da cor verde com o teor de proteína bruta.

Filter cake enriched with biofertilizer (associated with fertilizer phosphate) can increase the available phosphorus, and thus improve the absorption of phosphorus and dry matter accumulation by plants. The objective of this study was to evaluate the effect of phosphorus sources in the absence and presence of filter cake (enriched with biofertilizer or not enriched) on the soil population of microorganisms, soil phosphorus content, phosphorus accumulation in the aerial portion of the plant and production of dry matter in sugar cane plants. The experiment was performed in a greenhouse using sugar cane as the test plant. A completely randomized design was adopted with a 3×3+1 factorial arrangement and three repetitions. The treatments consisted of the application of three phosphorus sources (50 mg dm-3 of P, soluble in citric acid), (i.e., triple superphosphate, reactive phosphate of Bayóvar® and natural phosphate of Araxá), combined with three filter cake treatments (enriched/not enriched with biofertilizer and no filter cake as a control). The experimental unit consisted of a pot (20 dm³) filled with samples of an Oxisol soil containing two plants. Ninety days after the transplantation, samples were evaluated in terms of the soil phosphorus content and the populations of bacteria, fungus and phosphate solubilizer microorganisms. After one hundred and twenty days, the production of dry mass and accumulation of phosphorus were evaluated. The triple superphosphate associated with filter cake enriched with biofertilizer stood out relative to the use of cake only in terms of increasing the phosphorus content in the soil, the phosphorus accumulation in the plant and the dry mass production in sugar cane plants.

La cachaza enriquecida con biofertilizante asociado con fertilizantes de fosfato pueden aumentar el fósforo disponible, la absorción por las plantas y la acumulación de materia seca. Este trabajo tuvo como objetivo evaluar el efecto de fuentes de fósforo enriquecidas o no con cachaza y microorganismos en la población de microorganismos del suelo, la disponibilidad de fósforo en el suelo, acumulación de fósforo en la parte aérea de la planta y la producción de materia seca en las plantas de caña de azúcar. El experimento fue desarrollado en invernadero, con la prueba de la planta de caña de azúcar. Se adoptó un diseño experimental completamente aleatorizado, con tres repeticiones en arreglo factorial 3×3+1. Los tratamientos consistieron en la aplicación de tres fuentes de fósforo (50 mg dm-3 de P, solubles en ácido cítrico): superfosfato triple, fosfato reactivo Bayóvar® y fosfato natural de Araxá, combinadas con la cachaza enriquecida con biofertilizante o no enriquecida, sin cachaza y el tratamiento control. La unidad experimental consistió de macetas (20 dm³), llenadas con muestras de un Oxisol, conteniendo dos plantas. A los 90 días se evaluó el contenido de fósforo en el suelo, las poblaciones de bacterias y de hongos y los microorganismos solubilizadores de fosfato. A los 120 días se avaluó la producción de materia seca y acumulación de fósforo. El superfosfato triple asociado con la torta de filtro enriquecido con biofertilizante se destacó en relación con el uso de solo la torta, aumentando el contenido de fósforo en el suelo, la acumulación de fósforo para la planta y la producción de masa seca en las plantas de caña de azúcar.

The indirect measurement of chlorophyll is a diagnostic method of nitrogen in plants and its accuracy can be influenced by hour at which the reading is taken, the position of the leaflets in the plant and the portion where it is done on the leaflet reading. The objective was to evaluate the effect of hour reading, the position of the terminal leaflet on the leaf and the portion of the leaflet in the indirect of estimation of chlorophyll content index (CCI) with the use of chlorophyll meter. The experiment was performed with the cultivation of potato (S. tuberosum L.), Agate variety in the county of Ituverava São Paulo state, Brazil and consisted of 27 treatments in a factorial scheme 3 x 3 x 3 with four replications of 16 plant each, with a random distribution. The treatments were: three assessment times (08:00 am, 12:00 pm and 4:00 p.m.), three positions of leaflets on leafs (third, fourth and fifth) and three portions of the leaflet (basal, middle and distal). The evaluation of the CCI in the leaves of potato plants should be done in the leaflets of the third and fourth branch from top to bottom, regardless of the portion used leaflets, the 8:00 a.m. hours and 60 days after planting the crop. Indirect quantification of chlorophyll is a reliable tool and with potential to guide management of nitrogen fertilizer for crop.

La medición indirecta de la clorofila es un método de diagnóstico del nitrógeno en plantas y su precisión puede ser influenciada por la hora en que se hace la lectura, por la posición del foliolo en la planta y porción donde se realiza la lectura en el foliolo. El objetivo fue evaluar el efecto del horario de lectura, la posición terminal del foliolo en las hojas y la porción del foliolo en la estimación indirecta del Índice de contenido de clorofila (ICC) con el uso del clorofilómetro. El experimento se realizó con el cultivo de papa (S. tuberosum L.), variedad Ágata, en el municipio de Ituverava, estado de São Paulo, Brasil y constó de 27 tratamientos, en un esquema factorial 3 x 3 x 3 con cuatro repeticiones de 16 plantas cada una, con una distribución aleatoria. Los tratamientos fueron: tres horarios de evaluación (08:00 am, 12:00 pm y 16:00 pm), tres posiciones de foliolos en las hojas (tercera, cuarta y quinta) y tres porciones del foliolo (basal, medio y distal). La evaluación del ICC en las hojas de las plantas de papa debe realizarse en los foliolos de la tercera y cuarta hoja, independientemente de las áreas foliares utilizadas, en el horario de las 08:00 am y a los 60 días después de plantado el cultivo. La cuantificación indirecta de la clorofila representa una herramienta fiable y con potencial para guiar el manejo de fertilizante nitrogenado para el cultivo.

The enrichment of an organic compound with biofertilizers of microorganisms (solubilizing phosphorus bacteria, BSF) can improve the properties of phosphate fertilizers applied to soils to increase nutrient availability. The experimental design was randomized complete blocks with a factorial 4x2 +1 arrangement of treatments: 1) four sources of phosphorus: phosphate rock, natural phosphate, triple superphosphate (TSP) and Cuban phosphate rock; 2) two sources of bio-fertilizer prepared from filter cake (cane waste) enriched with microorganisms and no enrichment; 3) and an absolute control (no filter cake or fertilizer); repeated three times. Data was analyzed with ANOVA and treatment means were compared using Tukey (p≤ 0.05). Assessments of available P (Bray-2 and Oniani methodology) and the quantification of total and solubilizing bacteria and fungi in the soil were performed 30, 60 and 90 d after starting the experiment. After 60 d, the population of BSF was lower in the control (p≤0.05) and the content of P (Bray-2) was higher for SFT (p≤0.01). The application of the bio-fertilizer increased the P content compared to the control. At 90 d P (Bray-2) increased with the SFT treatment, which also increased (p≤ 0.01) P in the soil at 60 and 90 d regardless of the presence of microorganism-enriched bio-fertilizer. The use of filter cake enriched with microorganisms associated with different sources of P, and applied to the soil with a high content of P, did not change the soil populations of total and solubilizing bacteria and fungi in the short term. TSP promoted the highest levels of P in the soil, irrespective of the presence of the organic compound enriched with P solubilizing microorganisms.

El enriquecimiento de un compuesto orgánico con biofertilizantes a base de microorganismos (bacterias solubilizadoras de fósforo, BSF) puede mejorar las propiedades de los fertilizantes de fosfato aplicados a los suelos para mayor disponibilidad de nutrimentos. El diseño experimental fue bloques completos al azar en un arreglo factorial de tratamientos 4x2+1: 1) cuatro fuentes de fósforo: roca fosfatada, fosfato natural, superfosfato triple (SFT) y roca fosfórica cubana; 2) dos fuentes de biofertilizante preparadas a base de cachaza enriquecida con microorganismos y sin enriquecimiento; y 3) un testigo absoluto (sin cachaza ni abonado); repetido tres veces. Los datos se analizaron con ANDEVA y las medias de tratamientos se compararon con la prueba de Tukey (p≤0.05). Las evaluaciones de P disponible (metodología Bray-2 y Oniani) y las cuantificaciones de las bacterias totales y solubilizadoras y de hongos en el suelo se realizaron 30, 60 y 90 d después de iniciar el experimento. Después de 60 d, la población de BSF fue menor en el testigo (p≤0.05) y el contenido de P (Bray-2) fue mayor para SFT (p≤0.01). La aplicación del biofertilizante aumentó el contenido de P comparado con el testigo. A los 90 d el P (Bray-2) aumentó con el tratamiento SFT, el cual aumentó (p≤0.01) el P en el suelo a los 60 y 90 d independientemente de la presencia del biofertilizante enriquecido con microorganismos. El uso de cachaza enriquecida con microorganismos asociada con diferentes fuentes de P, y aplicadas al suelo con alto contenido de P, no alteró las poblaciones de bacterias totales y solubilizadoras y hongos del suelo a corto plazo. El SFT promovió los mayores niveles de P en el suelo, independientemente de la presencia del compuesto orgánico enriquecido con microorganismos solubilizadores de P.

La descontaminación de las muestras de hojas de cultivos pulverizados con pesticidas y soluciones nutritivas es importante para el análisis foliar. Este estudio evaluó el efecto de diferentes métodos de lavado en hojas de café y de sorgo que habían sido pulverizadas con zinc, con y sin surfactante. Siete días más tarde, las hojas se recogieron y se lavaron. El diseño experimental fue completamente aleatorizado, en esquema factorial 2 x 2 x 3 + 2, con tres repeticiones. El primer factor representa aplicaciones foliares de zinc con o sin surfactante; el segundo representa el número de lavados (1 ó 2), y el tercero la concentración de la solución de lavado (detergente + ácido clorhídrico) en (0 + 0 mL L-1; 1,0 + 3,5 mL L-1 y 2,0 + 7,0 mL L-1). El último factor representa dos tratamientos adicionales sin lavar (zinc rociado con y sin surfactante). El surfactante refuerza el contacto entre el zinc y el follaje y mejora la absorción. El lavado es un tratamiento previo indispensable para el análisis foliar, y nuestro estudio mostró que un solo lavado con detergente + ácido clorhídrico ( 1,0 + 3,5 mL L-1) fue el método de lavado más eficaz para el café y el sorgo

Decontaminating leaf samples from crops sprayed with pesticides and nutrient solutions is important for foliar analysis. This study evaluated the effect of different washing methods in coffee and sorghum foliage that had been sprayed with zinc (with or without surfactant). The plants were sprayed with a 3 g L-1 zinc sulfate solution, with and without surfactant. Seven days later, leaves were collected and washed. The experiment was completely randomized in a 2 x 2 x 3 + 2 factorial, with three replications. The first factor represents foliar zinc applications with or without surfactant, the second represents the number of washes (1 or 2) and the third represents the concentration of the wash solution (detergent + hydrochloric acid) at (0 + 0 mL L-1; 1.0 + 3.5 mL L-1 and 2.0 + 7.0 mL L-1). The last one represents two additional treatments without washing (zinc sprayed with and without surfactant). Surfactant strengthens contact between zinc and foliage and enhances absorption. Washing is an indispensable pretreatment for leaf analysis and our study showed that a single wash with detergent + hydrochloric acid (1.0 + 3.5 mL L-1) was the most effective washing method for coffee and sorghum

O uso de biofertilizantes associados a composto orgânico e rocha fosfatada pode aumentar a disponibilidade de fósforo no solo, pelo aumento da população de micro-organismos. Objetivou-se avaliar o efeito do uso da torta de filtro enriquecida com fosfato natural e preparados de biofertilizantes na população de micro-organismos e no teor de fósforo de um Latossolo Vermelho distrófico. O experimento foi realizado em casa-devegetação, utilizando-se delineamento experimental inteiramente casualizado, em esquema fatorial 7x3 (sete tratamentos e três épocas de avaliação), com três repetições. Os tratamentos consistiram de amostras de solo com adições de torta de filtro decomposta e rocha fosfatada de Araxá enriquecida com microorganismos provenientes dos biofertilizantes Biopack, Embrafos e Azotofos; solo com adições de torta de filtro e rocha fosfatada de Araxá, sem enriquecimento com micro-organismos; solo com torta de filtro; solo com rocha fosfatada; e somente solo (controle). Avaliou-se, aos 30, 60 e 90 dias após a instalação do experimento, o teor de fósforo disponível no solo e a população de micro-organismos. A presença de torta de filtro enriquecida com fosfato natural e com biofertilizantes promoveu aumento na população de bactérias do solo, havendo variações no tempo. A torta de filtro também proporcionou aumento na população de fungos e micro-organismos solubilizadores de fosfato. A curto prazo, a adição de torta de filtro enriquecida com fosfato natural contribuiu para o aumento do teor de fósforo solúvel no solo.

The use of biofertilizers associated with organic compound and phosphate rock can increase the availability of phosphorus in the soil, due to the increase of the microorganisms population. This study aimed at evaluating the effect of filter cake enriched with rock phosphate and biofertilizers preparations on the microorganisms population and phosphorus content of a Haplustox soil. The experiment was conducted in a greenhouse, in a completely randomized experimental design, in a 7x3 factorial scheme (seven treatments and three sampling times), with three replications. Treatments consisted of soil samples with decomposed filter cake and Araxá rock phosphate enriched with microorganisms from the biofertilizers Biopack, Embrafos and Azotofos; soil with filter cake and Araxá rock phosphate not enriched with microorganisms; soil with filter cake; soil with rock phosphate; and single soil (control). The soil phosphorus content and microorganisms population were evaluated at 30, 60 and 90 days after the experiment installation. The use of filter cake enriched with rock phosphate and biofertilizers increased the soil bacteria population, with variations in time. The filter cake also increased the fungi population and phosphate solubilizing microorganisms. In the short term, the addition of filter cake enriched with rock phosphate contributed to the increase of the soil soluble phosphorus content.

Com a expansão da cana-de-açúcar em áreas de Cerrado, há necessidade de se estudar o manejo da adubação, principalmente do fósforo (P), pois é o nutriente que mais limita a produção, neste ecossistema. Objetivou-se, com este trabalho, comparar o efeito de fontes de fósforo (P), em duas variedades de cana-de-açúcar. O experimento foi realizado em Alta Floresta (MT), em Latossolo Vermelho-Amarelo distrófico. O delineamento experimental utilizado foi o de blocos casualizados, em esquema fatorial 4x2, sendo avaliados os fatores fontes de P (farinha de ossos, fosfato de Arad e superfosfato triplo), na dose de 100 kg de P2O5 ha-1, acrescidas de uma testemunha sem aplicação do nutriente, e as variedades IAC 86 2480 e SP 79 101, com quatro repetições. Foram avaliados a altura de plantas, diâmetro de colmos, número de perfilhos, produtividade (matéria fresca e seca), eficiência do teor de P na planta, extração de P e viabilidade econômica, na escolha da fonte e ºBrix. A adubação fosfatada influenciou o número e altura de plantas, concentração de P na planta, produtividade de matéria fresca e seca. Quanto às fontes estudadas, houve semelhança nos resultados encontrados, mas com maior eficiência para a farinha de ossos, que promoveu maior acúmulo de P na planta e maior extração pela cultura, e apresentou maior viabilidade econômica. A variedade IAC 86 2480 apresentou médias superiores às da SP 79 1011, em todos os parâmetros avaliados.

Due to the expansion of sugarcane in areas of Cerrado (Brazilian savannah), it is necessary to study the fertilization management, mainly for phosphorus (P), since it is the nutrient that most limits yield, in this ecosystem. The aim of this study was to compare the effect of phosphorus sources over two sugarcane cultivars. The study was carried out in Alta Floresta, Mato Grosso State, Brazil, in a Hapludox soil. The experimental design was randomized blocks, in a 4x2 factorial scheme, being evaluated the effect of P sources (bone flour, Arad phosphate, and triple superphosphate), at a 100 kg P2O5 ha-1 dose, a control without nutrient application, and the IAC 86 2480 and SP 79 1011 cultivars, with four replications. Plant height, stem diameter, tiller number, yield (fresh and dry matter), P content efficiency on the plant, P extraction, and economic viability were evaluated for selecting source and ºBrix. Phosphorus fertilization affected plant number and height, P concentration, and fresh and dry matter yield. Concerning the sources studied, similar results were found, but with higher efficiency for bone flour, which increased the P concentration and extraction, as well as economic viability. The IAC 86 2480 cultivar showed higher averages than the SP 79 1011, for all parameters evaluated.