Plant Development, Stage of Maturity and Nutrient Composition

Abstract

Declining nutrient content of native and seeded pasture plants with advancing growing stages are discussed. All plant types display this regression in nutritive value but to different degrees, different rates, and varying patterns. The situation is further aggravated by the concomitant increase in lignin and other fibrous properties which precludes maximum digestibility of an already declining nutrient level in the plant. Countless observations by generations of people through research measurements, performance trials, and producer experience have contributed to the almost irrefutable recognition and acceptance of the fact that the nutrient composition of early plant growth exceeds that of the same plants with advancing maturity. We need to be reminded of this on occasion as we streak along in a world of accelerating automation and technological change. In the face of this turmoil we should review and reflect on some of the basic knowledge that we have come to take for granted. Influencing Factors A multiplicity of factors affects the rate of change in nutrient composition with advancing plant development and maturity stages. These factors may include any one or a combination of the following: plant type, climate, season, weather, soil type and fertility, soil moisture, leaf stem ratio, physiological and morphological characteristics and others, and may vary with annuals vs. perennials, grasses vs. legumes, etc. By themselves, nutrient composition levels are not necessarily the only criterion in evaluating the nutritive value of plants (Cook

Productivity, chemical composition and ruminal degradability of irrigated Napier grass leaves harvested at three stages of maturity

“…These factors include plant type, climate, season, weather, soil type and fertility, soil moisture, leaf stem ratio, physiological and morphological characteristics, and may vary with annuals versus perennials, grasses versus legumes, etc. (Kilcher, 1981).…”

Impacts of dugong foraging on seagrass habitats:observational and experimental evidence for cultivation grazing

“…The shoot nitrogen concentration of terrestrial plants (Kilcher 1981, Coppock et al 1983) and seagrasses (Harrison & Mann 1975) generally declines a s the plants a g e a n d mature. However, in grasses, heavy or prolonged grazing often increases the shoot nitrogen content (Bakker et al 1983, Coppock e t al.…”

Composição químico-bromatológica do feno de cipó-de-escada (Bauhinia glabra Jacq.) em cinco estádios de corte

“…Isto pode ser considerado aspecto positivo, uma vez que vários autores verificaram que o teor de proteína diminui com o avanço do estádio vegetativo da planta (KILKER, 1981;AZEVEDO, 1983;MINSON, 1990;BATISTA, 1995;e NASCIMENTO et al, 1996a), podendo favorecer melhor manejo desta forrageira, por permitir maior opção quanto à adoção de intervalos de corte que garantam maior produtividade de MS, desde que a qualidade da fibra não comprometa o valor nutritivo.…”

“…O valor nutritivo das plantas forrageiras está relacionado com o estádio de maturação, o qual depende do aumento da relação caule/folha, em decorrência da intensificação do processo de alongamento dos caules (LAVEZZO, 1988). À medida que a planta se desenvolve, ocorre diminuição do seu valor nutritivo, representado pelo menor teor protéico e aumento da fração fibrosa e lignina (KILKER, 1981).…”