How the type of dairy production system affects the nutrient balance from an environmental and economic perspective.

The knowledge of nutrient flow in dairy farms has to be explored to find optimized strategies for efficient nutrient conversion to milk. This study aims to improve the understanding of variances in nitrogen and phosphorus balance and efficiency indicators between dairy farm systems. The study analyzed 67 dairy cattle farms located in the watershed Lajeado Tacongava, Rio Grande do Sul State, Brazil. Selected dairy farms represented three production systems: confined (3 farms); semi-confined (7 farms); pasture-based (57 farms). Input-output nutrient balances were calculated at the dairy system level for nitrogen and phosphorus over a year. Inputs are feed and fertilizer and outputs are milk and meat. The main nitrogen and phosphorus input on the all farms resulted from the feed. The average N and P surplus on pasture-based farms were 352 and 49 kg ha-1 year-1, respectively. In semi-confined systems were 508 and 63 kg ha-1 year-1 and in confined systems were 786 and 70 kg ha-1 year-1. When considering the monetary value of the total N surplus, the averages were US$ 2.615, 4.950, and 12.171 for pasture-based, semi-confined and confined systems respectively. Monetary values of P surplus were US$ 346, 588, and 1119 for pasture-based, semi-confined and confined. The productive aspects that most determined the values of N and P surplus were the total number of lactating cows and the farm area. Results indicate that surplus can partially replace chemical nitrogen fertilizer, except in the confined system, and fully replace phosphorus fertilizer. Confined farms presented values to use surplus as fertilizer greater than the crop demand. For the other production systems, it happens only for phosphorus. Large variability between dairy farms of the same production system and between different production systems was observed. It reflects the inherent productive, economic, and environmental conditions of each farm and system.

Water productivity of milk produced in three different dairy production systems in Southern Brazil.

Water is a crucial resource to produce dairy milk and studies are required to identify opportunities for improvements in water management. This study evaluates the water productivity of milk (WPMilk) produced on 67 farms located in southern Brazil and the influence of dairy cattle production systems (pasture-based, 57 farms; semi-confined, 7 farms; confinement, 3 farms) on water productivity. Indirect and direct water flows were taken into account and the dairy milk was the output. Pasture yield was estimated based on a weighted average. Indirect water represented >98 % of water consumption for milk production on farms assessed. In the pasture-based system, the WPMilk ranged from 0.27 to 1.46 kg FPCM (Fat Protein Corrected Milk) m-3 of water; in the semi-confined system it ranged from 0.59 to 1.1 kg FPCM m-3; in the confined system, it ranged from 0.89 to 1.09 kg FPCM m-3. Results show that 20 farms in the pasture-based system presented higher WPMilk than the maximum WPMilk of farms in the semi-confined system. Comparing outcomes of farms in the confined system with pasture-based system, similar results were observed with higher WPMilk on 22 farms in the pasture-based system. Results indicate that, regardless of the type of production system, water productivity is influenced by the dairy productivity indicators of the farm, such as milk yield and feed components. The large variability in the WPMilk was expected and reflects the inherent attributes and conditions affecting this indicator, which underlines the importance of assessing it on a farm scale. Consequently, achieving high dairy productivity indicators should be encouraged in the pasture-based system due to the environmental, economic and social advantages for the farmer. Results advance the knowledge about water flows and WPMilk in different dairy cattle production systems besides defining the first benchmarks for WPMilk produced on farms in Brazil.

Eficiência energética de um trator agrícola utilizando duas configurações de tomada de potência / Energy efficiency of a tractor using two configurations of power take-off

A tomada de potência (TDP) de um trator agrícola tem por principal finalidade transmitir a potência gerada no motor, para acionamento de órgãos ativos das máquinas agrícolas. Tendo em vista a necessidade de se aumentar a eficiência energética na agricultura, alguns fabricantes disponibilizam para os agricultores uma configuração de TDP que proporciona o acionamento dessas máquinas a um regime de rotação menor do motor do trator. Assim, a rotação da TDP é mantida podendo-se obter uma redução do consumo de combustível. Este trabalho objetivou quantificar o consumo de combustível de um trator agrícola, operando com duas configurações de TDP (normal e econômica) em duas áreas agrícolas de relevo distinto. Como resultado, evidencia-se que, com a utilização da TDP econômica, tanto o consumo horário quanto o consumo operacional de combustível, em ambas as áreas trabalhadas, foi menor quando comparado à TDP normal.(AU)

The agricultural tractor power take-off main purpose is to transmit the power generated in the engine to drive the active organs of farm machinery. In view of the need to increase the energy efficiency in agriculture, some manufacturers provide for farmers a power take-off with economy mode, which provides to the drive these machines at a reduced engine rpm. Thus, the PTO speed is maintained and can obtain a reduction in fuel consumption. This research aimed to quantify the fuel consumption of a tractor with two power take-off configurations in two agricultural areas with different reliefs. As result, it is evident that the use of economy mode, both hourly fuel consumption and operational fuel consumption in both areas worked less when compared to standard power take-off.(AU)

Eficiência energética de um trator agrícola utilizando duas configurações de tomada de potência / Energy efficiency of a tractor using two configurations of power take-off

A tomada de potência (TDP) de um trator agrícola tem por principal finalidade transmitir a potência gerada no motor, para acionamento de órgãos ativos das máquinas agrícolas. Tendo em vista a necessidade de se aumentar a eficiência energética na agricultura, alguns fabricantes disponibilizam para os agricultores uma configuração de TDP que proporciona o acionamento dessas máquinas a um regime de rotação menor do motor do trator. Assim, a rotação da TDP é mantida podendo-se obter uma redução do consumo de combustível. Este trabalho objetivou quantificar o consumo de combustível de um trator agrícola, operando com duas configurações de TDP (normal e econômica) em duas áreas agrícolas de relevo distinto. Como resultado, evidencia-se que, com a utilização da TDP econômica, tanto o consumo horário quanto o consumo operacional de combustível, em ambas as áreas trabalhadas, foi menor quando comparado à TDP normal.

The agricultural tractor power take-off main purpose is to transmit the power generated in the engine to drive the active organs of farm machinery. In view of the need to increase the energy efficiency in agriculture, some manufacturers provide for farmers a power take-off with economy mode, which provides to the drive these machines at a reduced engine rpm. Thus, the PTO speed is maintained and can obtain a reduction in fuel consumption. This research aimed to quantify the fuel consumption of a tractor with two power take-off configurations in two agricultural areas with different reliefs. As result, it is evident that the use of economy mode, both hourly fuel consumption and operational fuel consumption in both areas worked less when compared to standard power take-off.