Agronomic performance and sweet corn quality as a function of inoculant doses (Azospirillum brasilense) and nitrogen fertilization management in summer harvest

ABSTRACT The inoculation of sweet corn seeds with Azospirillum brasilense in association to nitrogen fertilizer may be an agronomic alternative for increasing the crop yield and net income of plant growers. Therefore, the aim of this study was to investigate the effect of the different doses of inoculant (Azospirillum brasilense) associated to the nitrogen fertilization management on the phenotypic traits of one sweet corn hybrid in summer growing periods, under supplemental irrigation, in the Northwestern Paraná state, Brazil. The experiment followed the complete randomized block design with four replications. The treatments were: i) five inoculant doses (0.0, 50, 100, 150 and200 mL∙ha–1) containing Azospirillum brasilense; ii) two N doses (0.0 and 30.0 kg∙ha–1) applied at sowing time; and iii) two topdressing doses of N (0.0 and 110.0 kg∙ha–1) applied at the V4 stage. The sweet corn hybrid RB 6324 was evaluated in 2012/2013, 2013/2014 and 2014/2015. The traits plant height (ranged from 2.11 to 2.26 m), leaf area index (3.33 to 4.32), crop yield (7.21 to 10.43 Mg.ha–1), and the sugar kernel contents (38.46 to 43.31%) and protein (12 to 12.81%) were positively influenced by the seed inoculation with A. brasilense, and the nitrogen fertilizer increased all the traits except the kernel total sugars. The dose of inoculant that provided the best agronomic result was 100 mL∙ha–1 in conjunction with the application of N either at sowing or topdressing.

摘要：将巴西固氮螺菌（Azospirillum brasilense）接种至甜玉米种子并配合氮肥施用，或可成为提升作物产量与种植户净收益的农艺备选方案。为此，本研究旨在探究巴西巴拉那州西北部补充灌溉条件下，夏季种植季中，不同剂量的巴西固氮螺菌接种剂配合氮肥管理模式，对某甜玉米杂交品种表型性状的影响。本试验采用完全随机区组设计，设置4次重复。试验处理包括：i）5种接种剂剂量（0.0、50、100、150及200 mL·ha⁻¹），均含有巴西固氮螺菌；ii）2种播种时施用的氮肥剂量（0.0与30.0 kg·ha⁻¹）；iii）2种于V4生长期追施的氮肥剂量（0.0与110.0 kg·ha⁻¹）。本研究于2012/2013、2013/2014及2014/2015三个种植季对甜玉米杂交品种RB 6324开展评价。测定的性状包括株高（范围2.11~2.26 m）、叶面积指数（3.33~4.32）、作物产量（7.21~10.43 Mg·ha⁻¹）、籽粒含糖量（38.46%~43.31%）及蛋白质含量（12%~12.81%）；上述性状均受到巴西固氮螺菌种子接种的正向影响，而氮肥施用可提升除籽粒总糖外的所有性状表现。综合农艺效果最优的接种剂剂量为100 mL·ha⁻¹，配合播种期或V4生长期追施氮肥均可获得最佳效果。