FOLIAR AMINO ACID-BASED FERTILIZER IMPACT ON CREEPING BENTGRASS DROUGHT RESISTANCE

摘要

Nitrogen (N) nutrition is closely associated with turfgrass performance,especially during summer stress in the U.S.transition zone.This study was designed to evaluate effects of a liquid,glutamate-based amino acid-based fertilizer (hereafter referred to as AAF) (GreenNcrease,6-0-0) on creeping bentgrass (Agrostis stolonifera L.) quality,growth,and N metabolism under greenhouse and field conditions.Greenhouse treatments were AAF at low (1.5 kg N ha-1),medium (3.0 kg N ha-1),and high (4.5 kg N ha-1) rates compared to ammonium sulfate fertilizer control (3.0 kg N ha- 1),and an unfertilized control.Treatments were applied every 10 d in the greenhouse and 14 d in the field.The AAF at the medium rate (3.0 kg N ha-1) was compared to the ammonium sulfate fertilizer control and an unfertilized control in the field study.In the greenhouse,drought stress reduced creeping bentgrass quality,but the AAF at medium and high rates offset these reductions significantly better than ammonium sulfate at 55 days after initial treatment (DAIT).The AAF at the medium and high rate increased tiller density,but did not impact root biomass when compared to the controls.Medium and high rates of AAF increased leaf soluble protein content and superoxide dismutase (SOD) activity relative to the controls at 45 DAIT.In a putting green trial,AAF provided equivalent quality to ammonium sulfate under reduced and well-watered conditions.The AAF treatment did stand out by resulting in greater tiller density relative to the other two treatments under well-watered conditions.Small,but significant increases in quality,chlorophyll content,and SOD activity at the end of the greenhouse drought cycle (45 or 55 DAIT) for the medium AAF treatment relative to the equivalent amount of N from ammonium sulfate,indicate a positive role for foliar amino acids in a summer creeping bentgrass N fertilization program.