Nitrogen and potassium synergism influences the yield and quality of Dioscorea cayennensis / Sinergismo de nitrogênio e potássio influencia na produtividade e qualidade de Dioscorea cayennensis

This study aimed to evaluate yield, quality, nematode incidence, chlorophyll content, and primary foliar macronutrients of yam in response to nitrogen and potassium fertilization. A complete randomized block design was used in a factorial scheme (5 x 5), with five nitrogen (0; 60; 120; 180 and 240 kg ha-1 of N) and five potassium doses (0; 60; 120; 180 and 240 kg ha-1 of K2O), with four replicates. The mass, total and commercial productivity of tubers, starch content, ash, leaf N, P, and K content, chlorophyll, and nematode incidence were evaluated. The average mass of tubers obtained was 1.935 kg with doses of 133 kg ha-1 of N and 105 kg ha-1 of K2O. The dose of 178 kg ha-1 of N promoted maximum total tuber productivity (22.56 t ha-1). The doses of 132 kg ha-1 of N and 118 kg ha-1 of K2O resulted in maximum productivity of commercial tubers with 20.35 t ha-1. Leaf N and K, starch, and ash contents were within the standards for yam. The incidence of Meloidogyne, Scutellonema, and Pratylenchus reduced with the increasing simple effect doses of N and K2O. The maximum chlorophyll content was obtained at the dose of 240 kg ha-1 of N. The nitrogen and potassium interaction, despite the antagonistic effects on the accumulation of foliar P and starch, increased the productivity and average mass of commercial tubers, consequently ensuring the profitability of yam cultivation.

Objetivou-se avaliar a produtividade, qualidade, incidência de nematoides, teor de clorofila e macronutrientes primários foliares do inhame em função das doses de nitrogênio e potássio. O delineamento experimental de blocos casualizados foi utilizado em esquema fatorial (5 x 5), com cinco doses de nitrogênio (0; 60; 120; 180 e 240 kg ha-1 de N), e cinco doses de potássio (0; 60; 120; 180 e 240 kg ha-1 de K2O), com quatro repetições. As características avaliadas foram à massa média, produtividade total e comercial de túberas, teor de amido, cinzas, teor de N, P e K foliar, clorofila e a incidência de nematoides. A massa média de túberas foi de 1,935 kg com uso de 133 kg ha-1 de N e 105 kg ha-1 de K2O. A dose de 178 kg ha-1 de N proporcionou máxima produtividade total de túberas (22,56 t ha-1). As doses de 132 kg ha-1 de N e 118 kg ha-1 de K2O, foram responsáveis pela produtividade máxima de túberas comerciais de 20,35 t ha-1. Os teores de N e K foliar, amido e cinzas ficaram dentro padrão para o inhame. A incidência de Meloidogyne, Scutellonema e Pratylenchus foram reduzidas com aumento das doses de efeito simples de N e K2O. A clorofila máxima foi observada na dose de 240 kg ha-1 de N. A interação nitrogênio e potássio apesar dos efeitos antagônicos sobre o acúmulo de P foliar e amido, promove aumento da produtividade e massa média de túberas comerciais, consequentemente, garante a rentabilidade do cultivo de inhame.

Effect of litter substrates on the performance, carcass traits, and environmental comfort of red-winged tinamou (Rhynchotus rufescens)

The study aimed at evaluating the effect of litter substrates on the performance, carcass traits, and environmental comfort of red-winged tinamou (Rhynchotus rufescens). In this experiment, 160 birds, with 100 and 300 days of age, were housed into 20 pens, and distributed according to a completely randomized experimental design into five treatments with four replicates of eight birds each. Treatments consisted of five litter substrates: wood shavings, rice husks, peanut hulls, grass hay, or sand. Feed intake; weight gain; breast, hock, and footpad lesions; back feathering; total meat production; carcass and parts yield; and leukocyte counts were evaluated. Litter substrates were analyzed for dry matter content, standard microbial count, ammonia volatilization potential, water content, water holding capacity, temperature, and radiant heat load. The results showed that litter substrate did not influence the evaluated bird parameters, despite the higher microbial counts and released ammonia values determined in peanut hulls and sand, respectively. Sand also tended to have higher average temperature than the other litter substrates. It was concluded that litter substrate should be chosen at farmer discretion, taking into consideration its cost and utilization after use.

Effect of litter substrates on the performance, carcass traits, and environmental comfort of red-winged tinamou (Rhynchotus rufescens)

The study aimed at evaluating the effect of litter substrates on the performance, carcass traits, and environmental comfort of red-winged tinamou (Rhynchotus rufescens). In this experiment, 160 birds, with 100 and 300 days of age, were housed into 20 pens, and distributed according to a completely randomized experimental design into five treatments with four replicates of eight birds each. Treatments consisted of five litter substrates: wood shavings, rice husks, peanut hulls, grass hay, or sand. Feed intake; weight gain; breast, hock, and footpad lesions; back feathering; total meat production; carcass and parts yield; and leukocyte counts were evaluated. Litter substrates were analyzed for dry matter content, standard microbial count, ammonia volatilization potential, water content, water holding capacity, temperature, and radiant heat load. The results showed that litter substrate did not influence the evaluated bird parameters, despite the higher microbial counts and released ammonia values determined in peanut hulls and sand, respectively. Sand also tended to have higher average temperature than the other litter substrates. It was concluded that litter substrate should be chosen at farmer discretion, taking into consideration its cost and utilization after use.(AU)