Corn Hybrids Response to Nitrogen Rates at Multiple Locations in Brazilian Amazon

Ricardo Shigueru Okumura ,Yweenns T Ferraz ,Cândido Ferreira De Oliveira Neto ,Ismael De Jesus Matos Viégas ,André Luís Macedo Vieira ,Daiane De Cinque Mariano ,Antonio Carlos Franco ,Ana Ecídia De Araújo Brito ,Francisco Fábio Albuquerque Mota ,Augusto José Silva Pedroso

doi:10.5539/jas.v10n12p233

Abstract

Among the nutritional requirements of corn crop, nitrogen (N) is the element required in greater quantity and, directly responsible for increase or decrease in grain production. The aims of study were to evaluate the effects of applied N rates in topdressing in development and production of corn in Brazilian Amazon. The experiments were installed on 20 January 2014 (Capit&atilde;o Po&ccedil;o city) and 24 January 2014 (Paragominas city). The experimental design was a randomized block design in a 5 &times; 2 factorial scheme, consisting of five N rates of topdressing applications (0; 40; 80; 120; and 160 kg ha-1 of N) and two corn double hybrids (AL-Avar&eacute;; and AL-Bandeirante), with four replicates. The evaluations of vegetative development components (plant height, height of ear insertion, and leaf area index) were carried out at time of male flowering stage, while evaluations of grain yield components (number of grains per row, grain yield, and harvest index) carried out during the harvest period. The corn hybrids, AL-Avar&eacute; and AL-Bandeirante, independent of experimental site, showed the highest technical efficiency between the rates of 80 to 120 kg ha-1 of N. Based on the information obtained in regression analysis verified that Paragominas experiment showed greater vegetative development (plant height, LAI, ear height, number of grains per row, ear length) and higher grain yield compared to corn developed in Capit&atilde;o Po&ccedil;o experiment.

Highlights

Corn is of great importance for world agribusiness because it is considered the main constituent in production of animal feed
The importance of obtaining high LAI values is due to leaves with an adequate N content present an increase in capacity to assimilate CO2 and to synthesize carbohydrates during photosynthesis, resulting in higher growth and duration of leaf area (Repke, Cruz, Silva, Figueiredo, & Bicudo, 2013)
It is considered as important component of grain yield the duration of leaf area, which remains physiologically active after the emergence of ears (Castro, Kluge & Sestari, 2008), called "stay green", since it provides the occurrence of photosynthesis for a longer period, resulting in greater availability of carbohydrates for plants (Jiang, He, Xu, Li, & Zhang, 2004; Carmo, Santos, Hagiwara, & Ferreira, 2007)

Summary

Introduction

Corn is of great importance for world agribusiness because it is considered the main constituent in production of animal feed. Its production is increasing, for use in ethanol manufacture (Hage, 2013). Corn production has basically followed the growth of pigs and chickens productions, both in Brazil and in the World (Belusso & Hespanhol, 2010). Brazil is the 3rd largest producer of corn, with an approximate production of 85.5 million tons of grains, in 15.8 million hectares of planted area and grain yield of 5.4 t ha-1, in which Pará state is the main producer in Brazilian Amazon (Conab, 2015). Among the nutritional requirements of corn crop, nitrogen (N) is the element required in greater quantity and, directly responsible for increase or decrease in grain production. According to Santos, Silva, Carvalho, and Caione (2010), most of Brazilian Amazon soils have insufficient nitrogen contents, requiring fertilizer supply

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Results

Conclusion