Effect of Dairy Compost Application and Plant Maturity on Forage Kenaf Cultivar Fiber Concentration and In Sacco Disappearance.

Abstract

The forage potential of kenaf (Hibiscus cannabinus L.) grown for silage has not been fully realized, in part, because of lack of understanding of its quality dynamics. This study was conducted for 2 yr to compare fiber components and in sacco dry matter (DM) disappearance (ISD) differences among cultivars, dairy manure compost application rates, and plant maturity. The application of compost increased (P = 0.05) neutral detergent fiber (NDF) values only. Fiber components were affected by cultivar x plant maturity x year interactions [P < 0.05 for NDF, acid detergent fiber (ADF) and acid detergent lignin (ADL)] with cultivar EV41, late-season rainfall, and low maturity combining for the lowest values. Cultivar India, however, had as high or higher ISD values compared with the other two cultivars at any given plant maturity both years (cultivar x plant maturity x year ISD interaction, P < 0.05). Cultivar ISD residue fiber concentrations differed (P < 0.05) independently of year or plant maturity; ISD residue ADL and P concentrations also changed (P < 0.05) with plant maturity independently of year and cultivar. Changes in ISD residue NDF and ADF depended on both plant maturity and yearly rainfall patterns (NDF and ADF plant maturity x year interaction, P < 0.05). The proportion of N and P that disappeared in sacco was over 90% for all cultivars, maturities, and years. The proportions of NDF, ADF and ADL that disappeared in sacco, however, decreased with plant maturity and were generally higher for India. In this study, kenaf showed promise as a forage silage in semiarid regions. Differences in fiber concentrations and ISD among cultivars and plant maturity can be manipulated to increase kenaf's feed value to herbivores.