Effects of plant density and nitrogen rate on lodging-related stalk traits of summer maize

Abstract

Stalk lodging is a major constraint to limit grain yield under increased planting density in modern maize (Zea mays L.) production. A 3-year field experiment was imposed to study the effects of plant density and nitrogen (N) rate on stalk lodging and lodging-related stalk traits of two maize hybrids of contrasting susceptibility to lodging. The results indicated that the stem diameter, rind penetration strength (RPS), bending strength (BS), rind thickness, vascular bundle sheath’s thickness (Vbs) and number of vascular bundle (Vb) of both hybrids all significantly decreased at the high density, while ear height and ear ratio clearly increased in Ludan981 (LD981; lodging-susceptible cultivar) with plant density increase. The lower plant height and ear height, stronger RPS and BS, and more Vb at high plant density might be reasons for Zhengdan958 (ZD958, lodging-resistant cultivar) had lower rate of stalk lodging. Meanwhile, N supply can significantly improve the stalk quality and decrease the risk of stalk lodging, however, little effects were observed in cv. LD981. Therefore, using lodging-resistant cultivar, planting at 82 500 plant/ha and supplying 180 kg N/ha can obtain high grain yield and low stalk lodging.