Foliar Fertilization by Tank-mixing with Organic Amendment on Creeping Bentgrass

Abstract

Foliar application of fertilizers on turfgrass via overhead fertigation or spray can improve nutrient absorption efficiency and uniformity. Foliar fertilizers can also be combined with other chemical applications to save labor and energy. However, foliar application of nitrogen may result in root growth reduction. The objective of this study was to evaluate if a liquid organic amendment can be tank-mixed with liquid fertilizer to improve creeping bentgrass (Agrostis stolonifera) performance. This greenhouse study was conducted on ‘Penncross’ creeping bentgrass grown in sand or 90 sand:10 peat (v/v) root zones. Three fertilizer packages (4N–0P–0.8K, 29N–0.9P–2.5K, and 20N–8.8P–16.6K) with or without the organic amendment, a liquid suspension derived from naturally mined humic materials, were tested in the study. Tank-mixing organic amendment resulted in better or same turfgrass visual quality and lower clipping yield compared with foliar fertilization alone. Tank-mixing organic amendment in liquid fertilizers resulted in an average increase of root/shoot biomass ratio from 0.62 to 0.65 grown in the sand-based root zones. The effect of organic amendment was shown in all liquid fertilizers tested except 20N–8.8P–16.6K. The results showed tank-mixing organic amendment with the right liquid fertilizer can reduce mowing frequency without reducing the turf quality. Field work is needed to test if the increased root/shoot biomass ratio by tank-mixing organic amendment with liquid fertilizer can contribute to drought tolerance in creeping bentgrass maintained at fairway height in sand-based root zones.