ABSTRACT.- Long-term agricultural experiments (LTE) are essential to detect cumulative treatment effects on soil properties and to design sustainable production systems. However, to ensure high quality of long-term soil data and their correct interpretation, several analytical issues regarding the accuracy and analytical laboratory bias need to be considered.

ABSTRACT.- Long-term agricultural experiments (LTE) are essential to detect cumulative treatment effects on soil properties and to design sustainable production systems. However, to ensure high quality of long-term soil data and their correct interpretation, several analytical issues regarding the accuracy and analytical laboratory bias need to be considered.

The objective of the present paper is to review and update the experimental results and the model predictions about soil erosion and SOC content changes in Argiudolls of Uruguay.

Rice (Oryza sativa L.) systems rotated with perennial pastures have intensified in South America to increase annual grain productivity, but the effects on rice yield and soil quality remain poorly understood. We evaluated rice grain yield, crop and pasture biomass production, and soil organic carbon (SOC) and total nitrogen stocks (0?15-cm depth) in three rice-based rotations over 8 yr in Uruguay.

ABSTRACT.- The aim was to evaluate the association between growth, carcass and visual scores traits with precocious calving in Nellore cattle. Birth weight (BW), weight at 120, 210, 365 and 450 days of age, pre and post-weaning average daily gain, rib eye area, backfat thickness (BF), rump fat thickness and visual scores obtained at 18 months were used for the analysis. Records from 700 females born between 2009 and 2015, exposed to mating starting at 11 months of age were analyzed. Discriminant analyzes were performed with the software Statistica.

CONTENIDO. 1.- I+D+i en genética de eficiencia de conversión:apuesta a la sostenibilidad ganadera. Ing. Agr. Elly Ana A. Navajas (INIA). 2.- La eficiencia de conversión como vector de mejora productiva y económica de la ganadería. Ing. Agr. Juan Manuel Soares de Lima, Elly A. Navajas, Olga Ravagnolo, Mario Lema (INIA). 3.- Cuantificación de metano entérico en Kiyú:la bolilla que faltaba. Ing. Agr. José Ignacio Velazco (INIA).