Physiology, Productivity and Utilisation of Warm Season (C4) Grasses in a Short Growing Season Area

Download or read book Physiology, Productivity and Utilisation of Warm Season (C4) Grasses in a Short Growing Season Area written by Ignacio Casper Madakadze and published by . This book was released on 1997 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Warm season grasses are increasingly being cultivated in North America for summer forage, soil conservation, and biomass production. In more northern environments, temperature and length of growing season have an overriding effect on the productivity of warm season grasses. There is limited information on the adaptability and production potential of warm season grasses in these short season areas. A study was conducted in south-western Quebec from 1993 to 1996 to evaluate the productivity of five species of warm season grasses. Phenological development, canopy leaf area development and architecture, radiation-use efficiency (RUE), yield and chemical composition were determined. In terms of phenology, there was a diversity of developmental patterns and the genotypes of greatest potential were characterised by early spring growth and late onset of dormancy in fall. Most of the genotypes that were early in spring growth were also early maturing and low yielding. Late maturing genotypes were generally late in spring growth, high yielding and generally of southern origin. Differences in developmental patterns were partly explained by differences in base temperatures for germination and growth, and growth rates. Seed osmoconditioning and/or matriconditioning alleviated effects of low temperatures on switchgrass seed germination and potential establishment. Maximum leaf area index ranged from 6.1 to 8 and the vertical leaf area distributions and light interception levels varied among genotypes. Average end of season biomass yields ranged from 8.5 to 14.4 Mg ha-1. Switchgrass rates of DM accumulation ranged from 175 to 191 kg ha-1 day-1 and RUE 0.89 to 1.1 g MJ-1 of incoming solar radiation. Moderate amounts of N fertilisation increased yield and quality of switchgrass, which could be harvested in a 2-cut system. NDF and ADF ranged from 77--88 and 46--57% respectively, and showed a rapid increase to a mid season plateau. Nitrogen concentrations declined curvilinearly wit" --