Litter decomposition and CO2 emission on Xaraés-grass pasture submitted at rotational stocking intensity

• Grant number: 09/15708-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2009
• End date: October 31, 2010
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Pastures and Forage Crops
• Principal Investigator: Ana Cláudia Ruggieri
• Grantee: Elisamara Raposo
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil

Abstract

Litter decomposition and CO2 emission on Xaraés-grass pasture submitted at rotational stocking intensity. It is aiming quantify CO2 emission and the litter decomposition of Xaraés-grass pasture submitted at rotational stocking intensity in the environmental conditions in Jaboticabal, SP. The total area of xaraés-grass is 2795.9 m2, formed in December 2004 and will be divided into 12 paddocks for the allocation of treatments and replications. The experiment will be conducted by repeated measurements over time, and portions a completely randomized design with 4 intensities of grazing, repeated in 4 grazing cycles (time). The treatments will consist of four grazing intensities, defined by LAI (leaf area index) residual and four grazing cycles. The LAI residual will be estimated aid of a canopy analyzer - ACCUP Linear PAR / LAI - Decagon, before animal grazing, when the canopy reaches 95% LI (light interception) will be the calculation of forage intake for animals in the paddock and LAI residual is predetermined reached between 6-8 hours of grazing. For the issue of CO2 from the soil will be used unit of air flow LI-COR (LI-6400-09) to be installed on the picket 48 hours before to the entry of animals and measures of CO2 emissions will be made 24 hours before to grazing. After removal of animals from the unit will be re-installed and will be made measures of CO2 emissions in the post-grazing. The evaluation of the decomposition of litter will follow the technique of bags nylon (Dubeux Jr. et al. 2006). The bags used will mesh ¼ 75 m and measure 15 cm x 15 cm. It will be incubated the different fractions of the litter. Bags nylon will first be dried in an oven at 55 º C for 24 hours, weighed and placed in them will be the corresponding fractions of litter in each bag (15 g / bag). Then, the bags will be placed on the soil surface and covered with litter, and incubated for 0, 4, 8, 16, 32, days. After the end of each incubation time, the bags will be cleaned with a brush for the removal of waste impregnated and will dried 55 ° C for 72 hours. The results will be used to determine the dry matter (DM), organic matter (OM), nitrogen (N) and phosphorus (P) using the methodology described by Silva and Queiroz (2002) and carbon (C) using the methodology described by Bezerra Neto and Baker (2004). (AU)