Influence of organic-mineral fertilization of an oxisol on soil chemical properties and Bracharia brizantha production

The use of organic-mineral fertilizer produced by the manufacturing industry of lysine and threonine amino acids can improve the fertility of tropical soils. The objective of this study was to evaluate the influence of different doses of the organic-mineral fertilizer named Ajifer L-14 on chemical properties and on the response with increased production of a forage on a Red Latosol in the northwestern region of São Paulo State, Brazil. A randomized block design was used with seven treatments and four replications. The treatments consisted of: T1- control (without application of Ajifer L-14); T2- control (natural vegetation); T3- mineral fertilization according to crop requirements and soil analysis (application of 1.35 kg plot-1 of urea, 2.20 single superphosphate, and 0.51 KCl, corresponding to 60 of N, 40 P2O5 and 30 kg ha-1 of K2O); T4- fertilization with Ajifer L-14 according to the recommendation resulting from the soil chemical analysis (40 L plot-1, corresponding to 60 kg ha-1 N); T5- fertilization with Ajifer L-14, at a rate of 150 % of the recommended values (60 L plot-1, corresponding to 90 kg ha-1 N); T6- fertilization with Ajifer L-14 at a rate of 50 % of the recommended values (20 L plot-1, corresponding to 30 kg ha-1 N); T7- fertilization with Ajifer L-14 at a rate of 125 % of the recommended values (50 L plot-1, corresponding to 75 kg ha-1 N); T8- fertilization with Ajifer L-14 at a rate of 75 % of the recommended values (30 L plot-1, corresponding to 45 kg ha-1 N). The following soil chemical properties were evaluated (layers 0.0-0.1 and 0.1-0.2 m): P, organic matter, pH, K+, Ca2+, Mg2+, cation exchange capacity, potential acidity, and base saturation. The application of this organic-mineral fertilizer does not influence the soil chemical properties. Regression analysis indicated a polynomial relationship between the application rates of organic-mineral fertilizer and the production of dry matter and crude protein of Bracharia Brizantha.

Comparison of digestion methods to determine heavy metals in fertilizers

The lack of a standard method to regulate heavy metal determination in Brazilian fertilizers and the subsequent use of several digestion methods have produced variations in the results, hampering interpretation. Thus, the aim of this study was to compare the effectiveness of three digestion methods for determination of metals such as Cd, Ni, Pb, and Cr in fertilizers. Samples of 45 fertilizers marketed in northeastern Brazil were used. A fertilizer sample with heavy metal contents certified by the US National Institute of Standards and Technology (NIST) was used as control. The following fertilizers were tested: rock phosphate; organo-mineral fertilizer with rock phosphate; single superphosphate; triple superphosphate; mixed N-P-K fertilizer; and fertilizer with micronutrients. The substances were digested according to the method recommended by the Ministry for Agriculture, Livestock and Supply of Brazil (MAPA) and by the two methods 3051A and 3052 of the United States Environmental Protection Agency (USEPA). By the USEPA method 3052, higher portions of the less soluble metals such as Ni and Pb were recovered, indicating that the conventional digestion methods for fertilizers underestimate the total amount of these elements. The results of the USEPA method 3051A were very similar to those of the method currently used in Brazil (Brasil, 2006). The latter is preferable, in view of the lower cost requirement for acids, a shorter digestion period and greater reproducibility.

SUBSTRATE, LIME, PHOSPHORUS AND TOPDRESS FERTILIZATION IN MACAW PALM SEEDLING PRODUCTION

ABSTRACT The macaw palm [Acrocomia aculeata (Jacq.) Lood. ex Mart] has been domesticated to subsidize biodiesel production programs in Brazil. However, little is known about the seedling production of this species. This study aimed to evaluate substrate mixtures, limestone and phosphorus rates for substrate amendment and topdressing frequency in macaw palm seedlings. Three trials were conducted in a greenhouse up to six months of nursery cultivation. Trial 1: determination of percent mineral and organic fractions of seven substrate mixtures. Trial 2: evaluation of four limerates for soil amendment versus four phosphorus rates. Trial 3: evaluation of N, K and Mg topdressing frequency. Significant differences were found in the three trials for most of the variables (plant height, leaf number, shoot dry mass, root dry mass, vigor and bulb diameter). The main results obtained were as follow: Trial1 - the best seedling growth was observed in substrates with at least 25% organic matter. Trial2 -lime rates ranging from 0.50 to 1.25 kg associated with 3 to 4 kg of single superphosphate per m3 of substrate provided the best seedling growth. Trial 3 - topdressing fertilization provided better development of seedlings regardless of frequency.

Physiological potential of Brachiaria brizantha cv. Marandu seeds kept in contact with phosphatic fertilizers

The effect of mixture of seeds of Brachiaria brizantha, cv. Marandu, with different sources, granulometry, and phosphatic fertilizer doses during various periods of exposure on the physiological potential of the seeds has been assessed. The treatments consisted in seed exposure during periods of 0, 3, 6, 12, 24, 36, 48, 72, 96, and 120 h to the following fertilizers: ground granulated single superphosphate (SS), and powdered (SSp); and ground granulated ammonium monophosphate (AMP), at doses of 40 and 80 kg P2O5 ha-1. Tests of germination, tetrazolium, moisture content, and vigor (first count, electrical conductivity, emergence, emergence speed, and fresh mass of seedlings) were performed. It has been concluded that seed physiological potential of B. brizantha cv. Marandu is reduced with increase on the exposure period to phosphatic fertilizer. Such effect, however, is dependent on the product source, granulometry, and dose. SSp was the most harmful to seeds, followed by SSp and AMP, respectively. Moreover, considering a 60% germination rate as acceptable, it may be inferred that seeds can be kept in contact with AMP and SSp, in dose of 80 kg of P2O5 ha-1, respectively, for periods of 71.2 and 16.2 hours.

Effects of fertility management strategies on phosphorus bioavailability in four West African soils

Low phosphorus (P) in acid sandy soils of the West African Sudano-Sahelian zone is a major limitation to crop growth. To compare treatment effects on total dry matter (TDM) of crops and plant available P (P-Bray and isotopically exchangeable P), field experiments were carried out for 2 years at four sites where annual rainfall ranged from 560 to 850 mm and topsoil pH varied between 4.2 and 5.6. Main treatments were: (i) crop residue (CR) mulch at 500 and 2000 kg ha^-1, (ii) eight different rates and sources of P and (iii) cereal/legume rotations including millet (Pennisetum glaucum L.), sorhum [Sorghum bicolor (L.) Moench], cowpea (Vigna unguiculata Walp.) and groundnut (Arachis hypogaea L.). For the two Sahelian sites with large CR-induced differences in TDM, mulching did not modify significantly the soils' buffering capacity for phosphate ions but led to large increases in the intensity factor (C_p) and quantity of directly available soil P (E_1min). In the wetter Sudanian zone lacking effects of CR mulching on TDM mirrored a decline of E_1min with CR. Broadcast application of soluble single superphosphate (SSP) at 13 kg P ha^-1 led to large increases in C_p and quantity of E_1min at all sites which translated in respective TDM increases. The high agronomic efficiency of SSP placement (4 kg P ha^-1) across sites could be explained by consistent increases in the quantity factor which confirms the power of the isotopic exchange method in explaining management effects on crop growth across the region.

Efficient phosphorus application strategies for increased crop production in sub-Saharan West Africa

Comparable data are lacking from the range of environments found in sub-Saharan West Africa to draw more general conclusions about the relative merits of locally available rockphosphate (RockP) in alleviating phosphorus (P) constraints to crop growth. To fill this gap, a multi-factorial field experiment was conducted over 4 years at eight locations in Niger, Burkina Faso and Togo. These ranged in annual rainfall from 510 to 1300 mm. Crops grown were pearl millet (Pennisetum glaucum L.), sorghum (Sorghum bicolor (L.) Moench) and maize (Zea mays L.) either continuously or in rotation with cowpea (Vigna unguiculata Walp.) and groundnut (Arachis hypogaea L.). Crops were subjected to six P fertiliser treatments comprising RockP and soluble P at different rates and combined with 0 and 60 kg N ha^-1. For legumes, time trend analyses showed P-induced total dry matter (TDM) increases between 28 and 72% only with groundnut. Similarly, rotation-induced raises in cereal TDM compared to cereal monoculture were only observed with groundnut. For cereals, at the same rate of application, RockP was comparable to single superphosphate (SSP) only at two millet sites with topsoil pH-KCl <4.2 and annual average rainfall >600 mm. Across the eight sites NPK placement at 0.4 g P per hill raised average cereal yields between 26 and 220%. This was confirmed in 119 on-farm trials revealing P placement as a promising strategy to overcome P deficiency as the regionally most growth limiting nutrient constraint to cereals.

Phosphorus placement an acid arenosols of the West African Sahel

Phosphorus (P) deficiency is a major constraint to pearl millet (Pennisetum glaucum L.) growth on acid sandy soils of the West African Sahel. To develop cost-effective fertilization strategies for cash poor farmers, experiments with pearl millet were conducted in southwestern Niger. Treatments comprised single superphosphate hill-placed at rates of 1, 3, 5 or 7 kg P ha^−1 factorially combined with broadcast P at a rate of 13 kg ha^−1. Nitrogen was applied as calcium ammonium nitrate at rates of 30 and 45 kg ha^−1. At low soil moisture, placement of single superphosphate in immediate proximity to the seed reduced seedling emergence. Despite these negative effects on germination, P placement resulted in much faster growth of millet seedlings than did broadcast P. With P application, potassium nutrition of millet was improved and seedling nitrogen uptake increased two- to three-fold, indicating that nitrogen was not limiting early millet growth. Averaged over the 1995 and 1996 cropping seasons, placed applications of 3, 5 and 7 kg P ha^−1 led to 72%, 81% and 88% respectively, of the grain yield produced by broadcasting 13 kg P ha^−1. Nitrogen application did not show major effects on grain yield unless P requirements were met. A simple economic analysis revealed that the profitability of P application, defined as additional income per unit of fertilizer, was highest for P placement at 3 and 5 kg ha^−1.

Teores de nutrientes da folha bandeira e grãos de aveia-preta em função da adubação fosfatada e postássica

The black oat (Avena strigosa Schreber) has been commonly used as green manure, in crop rotation systems under no-tillage, fall-winter crop, and for cattle grazing, hay, and silage. The objective of this work was to evaluate the nutrient concentrations in the flag leaf and grains of black-oat affect by phosphate and potassium fertilization. The experiment was carried Out under field conditions on a Rhodic Nitosol, in Botucatu, São Paulo State, Brazil. Three doses of single superphosphate (0, 40 and 80 kg.ha(-1) of P(2)O(5)) and three of potassium chloride (0, 20 and 40 kg ha(-1) of K(2)O) were tested as a factorial (3 x 3), in a randomized complete block design, with four replicates. The fertilizers were applied in the sowing row. Ammonium sulphate was supplied for all plots (20 kg ha(-1) of N applied at sowing and 30 kg.ha(-1) after tillering stage). The concentrations of Ca, Mg, S, Fe, Mn, Cu and Zn in the flag leaf and the P and K concentrations in the grain were increased by phosphate fertilizer application. The potassic fertilization had no effect on the concentrations of nutrients in the flag leaf and grains of black-oat.

Efeitos de fontes de nitrogênio e de modos de aplicação do adubo fosfatado (32P) sobre a porcentagem de utilização do fósforo do superfosfato simples pelo trigo (Triticum aestivum L.)

No programa de pesquisa a respeito da adubação da cultura de trigo, utilizando isotopos (32P e 15N), o plano do ano 1971/1972 tinha, entre outros objetivos, a finalidade de determinar a porcentagem de aproveitamento do fósforo pelo trigo, em função do modo de aplicação e interação com fontes de nitrogênio. Oexperimento foi instalado em solo pertencente a ordem Ultisol e grande grupo Podzólico Vermelho-Amarelo (Pelotas-RS), contendo 9 ppm de P. Os adubos nitrogenados: sulfato de amônio, uréia e nitrato de amônio, na dose de 120 kg/ha, foram aplicados metade no plantio (ao lado e abaixo das sementes) e metade em cobertura, na fase do perfilhamento. O fósforo radioativo, na forma de superfosfato simples, foi aplicado na dose de 30 kg P2O5/ha de duas maneiras: junto com as sementes ou junto com o adubo nitrogenado aplicado no plantio. Amostras de plantas de trigo foram coletadas entre perfilhamento e espigamento e determinaram-se os pesos de matéria verde e seca, as porcentagens de P total e de P proveniente do fertilizante contidos na matéria seca e a porcentagem de utilização do fósforo aplicado (% UP). Pode-se concluir que a aplicação de nitrogênio é necessário para se obter maio res % UP, mas não há diferenças entre as fontes. Os modos de aplicação do fósforo não diferiram entre si quanto a % UP.

Influence of organic-mineral fertilization of an oxisol on soil chemical properties and Bracharia brizantha production

A utilização de fertilizante organomineral da indústria produtora dos aminoácidos lisina e treonina pode melhorar a fertilidade de solos tropicais. O presente trabalho teve como objetivo avaliar a influência de diferentes dosagens do fertilizante organomineral denominado Ajifer L-14 nos atributos químicos e no aumento de produção de forragem de um Latossolo Vermelho do noroeste paulista. O delineamento utilizado foi em blocos casualizados, com sete tratamentos e quatro repetições. Os tratamentos foram: T1- testemunha (sem aplicação de Ajifer L-14); T2- testemunha com vegetação natural; T3- adubação mineral de acordo com a necessidade da cultura e a análise do solo (usando 1,35 kg de ureia, 2,20 kg de superfosfato simples e 0,51 kg de KCl por parcela, o que corresponde a 60 kg de N, 40 kg de P2O5 e 30 kg ha-1 de K2O, respectivamente); T4- adubação com Ajifer L-14 de acordo com a recomendação da análise química do solo (40 L parcela-1, o que corresponde a 60 kg ha-1 N); T5- adubação com Ajifer L-14 em dosagem 50 % acima da recomendação (60 L parcela-1, o que corresponde a 90 kg ha-1 N; T6- adubação com Ajifer L-14 em dosagem 50 % abaixo da recomendação (20 L parcela-1, o que corresponde a 30 kg ha-1 N); T7- adubação com Ajifer L-14 em dosagem 25 % acima da recomendação (50 L parcela-1, o que corresponde a 75 kg ha-1 N); e T8- adubação com Ajifer L-14 em dosagem 25 % abaixo da recomendação (30 L parcela-1, o que corresponde a 45 kg ha-1 N). Nas profundidades de 0,0-0,1 e 0,1-0,2 m, avaliaram-se os seguintes atributos químicos do solo:, teor de matéria orgânica (MO), pH, K+, Ca2+, Mg2+, capacidade de troca catiônica (CTC), acidez potencial e saturação por bases. A aplicação do fertilizante organomineral não influenciou os atributos químicos do solo. Na análise de regressão, houve relação polinomial entre as doses de aplicação do fertilizante organomineral e a produção de massa seca e proteína bruta de Bracharia brizantha.

Aproveitamento de um fosfato natural parcialmente solubilizado pelas culturas do arroz, milho e soja: I. Resultados preliminares

Em solos pouco ácidos, pobres em P disponível, dois dos quais anteriormente com vegetação de cerrado, foram conduzidos ensaios destinados a comparar a eficiência de um fosfato natural parcialmente acidulado com ácido sulfúrico (FAPS) com a do super simples (SS) e a do fosfato de Araxá original. Usaram-se as culturas de arroz de sequeiro, milho e soja. Verificou-se que: (1) o FAPS deu produções que não diferiram estatísticamente das obtidas com o SS sendo maiores que as conseguidas com o FA; (2) os resultados das análises de solos e da diagnose foliar indicam que o FAPS funcionou como fonte de P, Ca e S.

Efeito de condicionadores químicos sobre a qualidade da cama de frango

Avaliou-se a qualidade química da cama de frango submetida, por três lotes consecutivos de criação, a diferentes condicionadores químicos. Foram utilizadas 1320 aves, 440 por lote, em delineamento experimental em blocos ao acaso, com cinco tratamentos (Trat. 1 - cama sem tratamento; Trat. 2 - cama tratada com sulfato de alumínio; Trat. 3 - cama tratada com gesso agrícola; Trat. 4 - cama tratada com superfosfato simples e Trat. 5 - cama tratada com cal hidratada) e quatro repetições. As amostras de cama foram coletadas no 42º dia de utilização. Não houve influência dos condicionadores (P>0,05) sobre a matéria seca. O sulfato de alumínio reduziu (P<0,002) o valor de pH (7,42; 7,07 e 6,00, respectivamente no primeiro, segundo e terceiro lotes) e reduziu (P<0,05) a quantidade de amônia volatilizada (3,14; 1,36 e 1,79mg/100g, respectivamente no primeiro, segundo e terceiro lotes), quando comparado aos outros tratamentos. Concluiu-se que o sulfato de alumínio pode ser adicionado à cama de frango para manter o pH baixo e inibir a volatilização da amônia.

Efeito de condicionadores químicos na cama de frango sobre o desempenho de frangos de corte

Estudou-se o efeito de condicionadores químicos na cama de frango sobre o desempenho de frangos de corte criados em três lotes consecutivos. Foram utilizadas 1320 aves, 440 em cada lote, em delineamento experimental em blocos ao acaso, com cinco tratamentos (Trat. 1 - cama sem tratamento; Trat. 2 - cama tratada com sulfato de alumínio; Trat. 3 - cama tratada com gesso agrícola; Trat. 4 - cama tratada com superfosfato simples e Trat. 5 - cama tratada com cal hidratada) e quatro repetições. As aves e as rações foram pesadas no início e no final do período experimental para obtenção do peso final, do consumo de ração, da conversão alimentar e da viabilidade. O uso dos condicionadores não influenciou (P>0,05) o peso final, o consumo de ração e a conversão alimentar. A adição do sulfato de alumínio e do superfosfato simples reduziu (P<0,05) a viabilidade das aves. Não é necessário o uso dos condicionadores na cama de frango reutilizada até o terceiro lote.

Millet seeds mixed with phosphate fertilizers

O tamanho reduzido das sementes de milheto dificulta sua semeadura uniforme, principalmente para os produtores que não possuem semeadoras apropriadas. Assim, a mistura das sementes com os fertilizantes fosfatados vem sendo utilizada para facilitar a semeadura. Entretanto, o período de contato pode provocar prejuízos na germinação e no vigor. Avaliou-se a qualidade fisiológica das sementes de milheto submetidas a diferentes períodos de contato (0, 6, 12, 24, 48, 72, 96 e 120h) com os fertilizantes superfosfato simples (SFS) e superfosfato triplo (SFT), em um experimento em delineamento inteiramente casualizado em esquema fatorial 8x2 (n=4). Os atributos químicos e físicos dos fertilizantes foram previamente determinados. Foi utilizada a proporção de 1 kg de sementes para 2,5 kg de fertilizante. Após manutenção da mistura em saco plástico no laboratório, as sementes foram separadas dos fertilizantes e submetidas à determinação de umidade, germinação, primeira contagem e condutividade elétrica. Paralelamente, na casa de vegetação, em caixas plásticas contendo terra, determinou-se a emergência e o índice de velocidade de emergência, sem e com a manutenção dos fertilizantes. Porque apresentam resíduos ácidos, tanto SFS como SFT afetaram de maneira semelhante e negativamente a germinação e o vigor das sementes de milheto em mistura, na medida em que se aumentou o período de contato.

Eficiência agronômica de fontes de manganês, disponibilidade para a soja e distribuição nas frações do solo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)