Eficiencia agronómica y económica del fosfato decantado como función del encalado en hierba marandu : (Brachiaria brizantha)

The decanted phosphate (DP) is an environmental liability for the fertilizer industries and its use as a phosphate fertilizer has been suggested in agriculture. However, there are few researches that studies its efficiency. In this sense, this experiment was conducted in a greenhouse with the main objective to evaluate the agronomic efficiency and the relative economic efficiency of decanted phosphate (DP) in the presence and absence of lime during three growth periods of Brachiaria brizantha cv. Marandu (marandu grass). In addition, the critical levels of P were determined in soil and shoots of plants. The indices Equivalent Triple Superphosphate medium (EqTS medium) e Relative Economic Efficiency (REE) were calculated in order to evaluate the efficiency of DP and triple superphosphate (TS). The critical levels of P were set when relative production was 90%. The DP efficiency indices were more than 100% when not applied liming. The liming reduces the agronomic and economic efficiency of DP. The P critical levels in soil and shoots of the marandu grass were 15 mg dm-3 and 1.2 g kg-1, respectively.El fosfato decantado (FD) es una responsabilidad ambiental para las industrias de fertilizantes y se ha sugerido su uso como fertilizante de fosfato en la agricultura. Sin embargo, hay pocas investigaciones que estudien su eficacia. En este sentido, este experimento se realizó en un invernadero con el objetivo principal de evaluar la eficiencia agronómica y la eficiencia económica relativa del fosfato decantado (FD) en presencia y ausencia de cal durante tres períodos de crecimiento de Brachiaria brizantha cv. Marandu (hierba marandu). Los niveles críticos de P se determinaron en el suelo y los brotes de las plantas. El índice equivalente superfosfato triple medio (EqST medio) y la eficiencia económica relativa (EER) se calcularon para evaluar la eficacia de FD y superfosfato triple (ST). Los niveles críticos de P se establecieron cuando la producción relativa fue del 90%. Los índices de eficiencia del FD fueron más del 100% cuando no se aplicó el encalado. El encalado reduce la eficiencia agronómica y económica de FD. Los niveles críticos de P en el suelo y en la parte aérea de la hierba marandu fueron 15 mg dm-3 y 1,2 g kg-1, respectivamente.Fil: Tiraboschi Leal, Fábio. Universidad Estadual de Sao Paulo (Brasil)Fil: Mendes Coutinho, Edson Luiz. Universidad Estadual de Sao Paulo (Brasil)Fil: Coelho França, Ana Beatriz. Universidad Estadual de Sao Paulo (Brasil

Portable chlorophyll meter in monitoring and management of nitrogen in common bean cultivars

More sustainable practices involving biological nitrogen fixation (BNF) and the use of portable chlorophyll meter in fertilization management are promising to increase nitrogen (N) use efficiency in the common bean crop. This study aimed to monitor N managements using a portable chlorophyll meter and its effects on agronomic attributes of Carioca-type common bean cultivars with indeterminate and determinate growth habits (‘IPR Campos Gerais’ and ‘IAC Imperador’). The experiment was carried out in a randomized block design (RBD), in a 2 × 9 factorial scheme, with four replicates. The first factor consisted of the cultivars and the second factor of the N management. The data were subjected to analysis of variance by F test and, when necessary, the means were grouped by the Scott-Knott test at 5% probability level. The use of portable chlorophyll meter is a viable alternative for N monitoring and management in common bean, allowing the reduction of top-dressing N application, regardless of the cultivar used. Highlights The use of portable chlorophyll meter is a viable alternative for nitrogen monitoring and management in common bean. Management with chlorophyll meter reduced the need for chemical fertilizer application, saving 105 kg ha-1 of urea. Further studies are needed to better understand this technology under conditions with different genotypes, soils and production systems.More sustainable practices involving biological nitrogen fixation (BNF) and the use of portable chlorophyll meter in fertilization management are promising to increase nitrogen (N) use efficiency in the common bean crop. This study aimed to monitor N managements using a portable chlorophyll meter and its effects on agronomic attributes of Carioca-type common bean cultivars with indeterminate and determinate growth habits (‘IPR Campos Gerais’ and ‘IAC Imperador’). The experiment was carried out in a randomized block design (RBD), in a 2 × 9 factorial scheme, with four replicates. The first factor consisted of the cultivars and the second factor of the N management. The data were subjected to analysis of variance by F test and, when necessary, the means were grouped by the Scott-Knott test at 5% probability level. The use of portable chlorophyll meter is a viable alternative for N monitoring and management in common bean, allowing the reduction of top-dressing N application, regardless of the cultivar used. Highlights The use of portable chlorophyll meter is a viable alternative for nitrogen monitoring and management in common bean. Management with chlorophyll meter reduced the need for chemical fertilizer application, saving 105 kg ha-1 of urea. Further studies are needed to better understand this technology under conditions with different genotypes, soils and production systems

COBERTURA NITROGENADA EM DIFERENTES ESTÁDIOS FENOLÓGICOS DO FEIJOEIRO COMUM ALTERA PRODUTIVIDADE E QUALIDADE DE GRÃOS

A necessidade de conhecer a marcha de absorção do nitrogênio (N) pelo feijoeiro é importante para compreender os desempenhos produtivo e qualitativo dessa cultura.  O objetivo deste estudo foi avaliar a influência da cobertura nitrogenada em função de diferentes estádios fenológicos no desempenho morfoagronômico e produtivo e nas características tecnológicas dos grãos do feijoeiro em sistema de plantio convencional. Utilizou-se o delineamento de blocos casualizados, com quatro repetições. Os tratamentos foram constituídos por doze combinações de fornecimento de N (FN) em cobertura (dose total = 90 kg ha-1 de N) aplicadas nos estádios fenológicos V3, V4 e R5 (V3+V4+R5) do feijoeiro de inverno irrigado: 00+00+00; 30+30+30; 30+60+00; 30+00+60; 60+30+00; 00+60+30; 45+45+00; 00+45+45; 45+00+45; 90+00+00; 00+90+00; e 00+00+90. A fonte de N utilizada foi ureia convencional. Os FN 30+00+60, 00+45+45 e 45+00+45 incrementam a produtividade de grãos e a eficiência agronômica em relação à ausência de N e à aplicação de dose única no estádio fenológico V4. do feijoeiro comum. As maiores produtividades de proteína bruta e o menor tempo para cozimento foram proporcionadas pelos FN 00+45+45, 45+00+45, 90+00+00, 00+90+00 e 00+00+90.Palavras-chave: Phaseolus vulgaris; parcelamento do N; eficiência agronômica; tecnologia dos grãos. NITROGEN TOPDRESSING AT DIFFERENT PHENOLOGICAL STAGES ON COMMON BEAN CHANGES GRAIN YIELD AND QUALITY ABSTRACT: The need to know the nitrogen uptake (N) by common bean is important to understand the productive and qualitative performance of this crop. The objective of this study was to evaluate the influence of nitrogen topdressing as a function of different phenological stages on the morphometric and productive performance, and on the technological characteristics of the bean grains grown under conventional soil preparation. A randomized block design with four replications was used. The treatments were constituted by twelve topdressing N supply combinations (NS) (total dose = 90 kg ha-1 N) applied in the phenological stages V3, V4 and R5 (V3+V4+R5) of irrigated winter bean: 00+00+00; 30+30 +30; 30+60+00; 30+00+60; 60 + 30 + 00; 00+60+30; 45+45+00; 00+45+45; 45+00+45; 90+00+00; 00+90+00; and 00+00+90. The source of N used was conventional urea. NS 30 + 00 + 60, 00 + 45 + 45 and 45 + 00 + 45 increase grain yield and agronomic efficiency in relation to the absence of N and single dose application at V4 phenological stage of common bean. The highest crude protein yields and the shortest cooking time were provided by FN 00+45+45, 45+00+45, 90+00+00, 00+90+00 and 00+00+90.Keywords: Phaseolus vulgaris; N splitting; agronomic efficiency; grains technology.

Grain quality of common bean (Phaseolus vulgaris L.) cultivars under low and high nitrogen dose

This study aimed to evaluate the effects of low and high topdressing doses of nitrogen (N) on the qualitative attributes of common beans (Phaseolus vulgaris L.) cultivars and indicate cultivars with better grain technological characteristics. The experimental design was randomized blocks in split plots, with four replicates. Plots comprised 16 common bean cultivars of the commercial grain ‘Carioca’, while subplots comprised two N doses: 20 and 120 kg ha-1 applied as topdressing. The following evaluations were carried out: sieve yield (SY), relative grain production on sieves (RGPS), crude protein content (PROT), final water volume absorbed (FVabs), time for maximum hydration (TMH), hydration ratio (HR), cooking time (CT) and resistance to cooking (RC). The results were subjected to analysis of variance by F test and means were grouped by the Scott-Knott test. Multivariate principal component analysis was used to identify processes. Grain quality of common bean resulted to be more dependent on the genotype studied than on the agricultural management, such as nitrogen fertilization. Increasing N dose applied as topdressing increased grain size and protein content, but had little influence on grain hydration. FVabs and CT depended on the interaction between cultivar and N doses. Although low value, CT had an inverse correlation with PROT. The cultivars BRSMG Uai, IAC Alvorada, TAA Dama and TAA Bola Cheia showed the best grain quality characteristics

Eficiencia de la urea con inhibidores de ureasa y nitrificación en la producción de forraje de pasto bermuda

The adoption of strategies aimed at a more efficient use of nitrogen (N) and ontaining hig yields are important to satisfy the demand for food for animals and humans. The Tifton 85 Bermuda grass (Cynodon spp.) is a crop with high productive potential and may be used to create hay, but its culture requires elevated doses of nitrogen. In this sense, the objective of this experiment was to evaluate, in field conditions, the growth and production of Tifton 85 Bermuda grass according to nitrogen doses with urea containing urease and nitrification inhibitors for two agricultural years — eight cycles of forage growth. The treatments were evaluated in a randomized complete block design with three repetitions in a 3x5 factorial scheme. Treatments were: I) urea; II) urea + triamide N-(n-Butyl) thophosphoric (NBPT) urease inhibitor; and III) urea + nitrification inhibitor 3,4-Dimethylpyrazole phosphate (DMPP) with N rates (0, 40, 80, 120 and 160 kg ha-1 of N) applied after each growth period. Then, the study proceeded to estimate forage dry mass and N concentrations in dry mass for each of the growth cycles and their sum, as well as the apparent N recovery. N critical levels were set when relative production reached 90%. The use of urease (NBPT) or nitrification (DMPP) inhibitors did not improve the efficiency of urea regarding growth and production of Tifton 85 Bermuda grass. The appropriate dose of nitrogen for Tifton 85 Bermuda grass in a hay production system is 40 kg per ton of dry mass produced in each growth period.La adopción de estrategias destinadas a un uso más eficiente del nitrógeno (N) y la obtención de altos rendimientos son importantes para satisfacer la demanda de alimentos para los animales y seres humanos. El pasto bermuda Tifton 85 (Cynodon spp.) es un cultivo con un alto potencial productivo, que puede utilizarse para la producción de heno, pero es un cultivo que requiere  altas dosis de N. En este sentido, el objetivo de este experimento fue evaluar en condiciones de campo, el crecimiento y la producción del pasto bermuda Tifton 85 en función de las dosis de nitrógeno con urea que contiene ureasa e inhibidor de la nitrificación durante dos años agrícolas, totalizando ocho ciclos de crecimiento de forraje. Los tratamientos fueron evaluados en un diseño de bloques completos al azar con tres repeticiones en un esquema factorial de 3 x 5. Los tratamientos consistiéron en: I) urea; II) urea + triamida N-(n-butil)tiofosfórica (NBPT), inhibidor de la ureasa  y III) urea + inhibidor de la nitrificación (DMPP - 3,4-dimetilpirazol fosfato) y dosis de N (0, 40, 80, 120 y 160 kg ha-1 de N aplicado después de cada período de crecimiento). Posteriormente, se estimo la mass seca de forraje y las concentraciones de N en masa seca (para cada ciclo de crecimiento y suma de los ciclos de crecimiento), así como la recuperación aparente de N. El nivel crítico de N se estableció cuando la producción relativa fue del 90%. El uso del inhibidor de la ureasa (NBPT) o la nitrificación (DMPP) no mejoró la eficiencia de la urea con respecto al crecimiento y la producción de pasto bermuda Tifton 85. La dosis adecuada de nitrógeno para el Tifton 85 en un sistema de producción de heno es de 40 kg por tonelada de masa seca producida en cada período de crecimiento

Desempenho agronômico, qualitativo e retorno econômico relativo do feijoeiro sob fontes e doses de nitrogênio

Um dos fatores responsáveis pela baixa produtividade do feijoeiro é o manejo inadequado da adubação nitrogenada. Objetivou-se avaliar o efeito de fontes e doses de nitrogênio no desempenho agronômico e qualitativo e no retorno econômico relativo do feijoeiro. O experimento foi desenvolvido na safra de inverno na região de Guaíra, SP (20º 22’ 20’’ S, 48º 22’ 10’’ W), utilizando a cultivar Pérola. O solo da área experimental foi classificado como Latossolo Vermelho distrófico (590 g kg-1 de argila). Utilizou-se o delineamento experimental de blocos casualizados, em esquema fatorial 2 x 5, constituído por duas fontes de N (ureia e sulfato de amônio) e cinco doses de N (0, 40, 80, 120 e 160 kg ha-1), em quatro repetições. As variáveis analisadas foram o teor de N foliar, número de vagens por planta, número de grãos por vagem, massa de 100 grãos, produtividade, retorno econômico relativo, teor de proteína dos grãos, tempo de cozimento, relação de hidratação e tempo para máxima hidratação. A massa de 100 grãos, produtividade, teor de proteína bruta dos grãos e relação de hidratação apresentaram diferenças entre as doses de N estudadas. A adubação nitrogenada de cobertura aumenta o desempenho agronômico e qualitativo do feijoeiro, incrementando a produtividade e o teor de proteína bruta dos grãos até as doses de N de 139 e 136 kg ha-1, respectivamente. A fonte de nitrogênio utilizada não altera o desempenho agronômico e qualitativo do feijoeiro, entretanto, a fonte de nitrogênio ureia apresenta maior retorno econômico relativo

Agronomic and qualitative performance of common bean cultivars of carioca and special commercial groups in the winter season

No Brasil, existe uma ampla disponibilidade de cultivares de feijoeiro de vários grupos comerciais. Nesse sentido, estudos para avaliar o potencial produtivo dos genótipos são necessários para a indicação das melhores cultivares aos produtores. Objetivou-se avaliar o desempenho agronômico e qualitativo de cultivares de feijoeiro dos grupos comerciais carioca e especial e indicar os melhores genótipos dentro de cada grupo. O experimento de campo foi conduzido na Unesp, Jaboticabal, SP, na safra de inverno de 2017. Foram utilizadas dez cultivares de feijoeiro comum, sendo cinco do grupo comercial carioca: BRS Estilo, BRS MG Majestoso, BRS Ametista, BRS Notável e BRS Cometa e cinco do grupo comercial especial: BRS MG Realce, BRS Embaixador, BRS FC 305, BRS Executivo e BRS Ártico. O delineamento experimental foi o de blocos casualizados, com quatro repetições. Os resultados foram submetidos à análise de variância (Teste F) e as médias comparadas pelo teste de agrupamento de Scott-Knott a 5% de probabilidade. Para as características de desempenho agronômico, a cultivar BRS MG Majestoso se destacou dentro do grupo comercial carioca e as cultivares BRS Embaixador e BRS Executivo dentro do grupo comercial especial. Na qualidade dos grãos, se destacaram as cultivares BRS Estilo no grupo comercial carioca e a BRS Embaixador no grupo comercial especial.In Brazil, there is a wide availability of bean cultivars of various commercial groups. In this sense, studies to evaluate the productive potential of genotypes are necessary to indicate of the best cultivars to the producers. The objective was to evaluate the agronomic and qualitative performance of bean cultivars of the carioca and special commercial groups and indicate the best genotypes within each group. The field experiment was conducted at Unesp, Jaboticabal, SP, in 2017 winter crop season. Ten common bean cultivars were used, five of them from the carioca commercial group: BRS Estilo, BRS MG Majestoso, BRS Ametista, BRS Notável e BRS Cometa and five from the special business group: BRS MG Realce, BRS Embaixador, BRS FC 305, BRS Executivo e BRS Ártico. The experimental design was randomized blocks with four replications. Results were subjected to analysis of variance (F-Test) and the means compared by Scott-Knott cluster test at 5% probability. For the agronomic performance characteristics, the cultivar BRSMG Majestoso stood out within the carioca commercial group and the BRS Embaixador and BRS Executivo cultivars within the special commercial group. In terms of grain quality, the cultivars BRS Estilo stood out in the commercial group and BRS Embaixador in the special commercial group.Facultad de Ciencias Agrarias y Forestale

Fosfato decantado e calagem no perfilhamento e produção de massa seca do capim-marandu

The decanted phosphate (DF), by-product of wastewater treatment of phosphoric acid production (H3PO4), is considered an environmental liability and resulting economic obligations to the phosphate fertilizer manufacturers. In this sense, this experiment was conducted in a greenhouse using pots filled with samples of a sandy clay loam Typic Haplustox with main objective to evaluate the effects of DF at tillering and shoot dry matter production of marandu grass (Brachiaria brizantha cv. Marandu) during three consecutive growths in the presence and absence of lime. The experiment was conducted in a completely randomized experimental design with three replications, according to a factorial 6 x 2 x 2 [six rates of P; two sources of P; presence (P/L) and absence of lime (A/L)]. The rates of P were 0, 30, 60, 90, 120 and 150 mg kg-1 of P. The sources of P were the DF and triple superphosphate (TS) (reference source). Lime was applied to the soil in an amount calculated to raise the soil base saturation to 60%. It was found that the phosphate fertilization caused a significant increase in tillers number and shoot dry matter of marandu grass, and the DF did not differ significantly from the TS in the absence of lime, but was significantly lower in the presence of this correction. P supply to the soil by FD was favored by soil acidity which was increased in the course of the experiment The critical levels of P in soil and the marandu grass shoot were 15 mg dm-3 and 1.2 g kg-1, respectivelyO fosfato decantado (FD), subproduto resultante do tratamento de efluentes da produção de ácido fosfórico (H3PO4), é considerado um passivo ambiental podendo acarretar obrigações econômicas aos fabricantes de fertilizantes fosfatados. Nesse sentido, conduziu-se esse experimento em casa de vegetação utilizando-se vasos preenchidos com amostras de um Latossolo Vermelho distrófico textura média (LVd) com objetivo principal de avaliar os efeitos do FD no perfilhamento e na produção de massa seca da parte aérea do capim-marandu (Brachiaria brizantha cv. Marandu) por três crescimentos consecutivos, na presença e ausência de calcário. O experimento foi conduzido em delineamento inteiramente casualizado com três repetições, obedecendo a um esquema fatorial 6 x 2 x 2 [seis doses de P; duas fontes de P; presença (C/C) e ausência de calcário (S/C)]. As doses de P foram 0, 30, 60, 90, 120 e 150 mg kg-1 de P. As fontes de P foram o FD e o superfosfato triplo (ST) (fonte de referência). O calcário foi aplicado ao solo em quantidade calculada a fim de elevar a saturação por bases do solo a 60%. Verificou-se que a adubação fosfatada promoveu incrementos significativos na produção de perfilhos e de massa seca da parte aérea do capim-marandu, sendo que o FD não diferiu significativamente do ST na ausência de calcário, porém foi significativamente inferior na presença desse corretivo. O fornecimento de P ao solo pelo FD foi favorecida pela acidez do solo que foi aumentada com o decorrer do experimento. Os níveis críticos de P no solo e na parte aérea do capim-marandu foram 15 mg dm-3 e 1,2 g kg-1, respectivament

Characterization of potential CO2 emissions in agricultural areas using magnetic susceptibility

ABSTRACTSoil CO2 emissions (fCO2) in agricultural areas have been widely studied in global climate change research, but its characterization and quantification are restricted to small areas. Because spatial and time variability affect emissions, tools need to be developed to predict fCO2 for large areas. This study aimed to investigate soil magnetic susceptibility (MS) and its correlation with fCO2 in an agricultural environment. The experiment was carried out on a Typic Eutrudox located in Guariba-SP, Brazil. Results showed that there was negative spatial correlation between fCO2 and the magnetic susceptibility of Air Dried Soil (MSADS) up to 34.3 m distant. However, the fCO2 had no significant correlation with MSADS, magnetic susceptibility of sand (MSSAND) nor clay (MSCLAY). However, MSADS could be a supplemental mean of identifying regions of high fCO2 potential over large areas