Title : Overall benefits of biochar, fed to dairy cows, for the farming system
Abstract:
Biochar has been used as a feed supplement for dairy cattle to improve both livestock and soil health. The co-application of animal manure mixed with a porous biochar into soil also offers multiple agronomic and economic benefits by providing plant essential nutrients and reducing nutrient release from the soil. This study was conducted on a dairy with 250 cows in South Australia (SA), where the cows received biochar through a feed supplement over 9 months. The biochar was produced from a mixture of 50% eucalyptus wood chips, 25% soybean residue and 25% tea tree mulch at a pyrolysis temperature of 450 ºC. The biochar was then mixed with a supplement at a rate of 0.006% of the total dry matter (DM). The changes in milk yield and quality, manure, soil and plant properties were investigated over 9 months, both before the biochar was fed (in January) and after feeding the biochar (in September). The farmer’s income was also assessed. The average milk yield was marginally higher (2.2%) compared to yield prior to this trial (P > 0.05). There were increases in N, C, Na, Si, Ca, P and K in the manure after feeding biochar to the cows. In addition, the biochar in the manure contributed to binding with organic C and N that were not water soluble. The results also revealed lower proportions of Na (3.6%), K (10.3%), Si (0.14%), Ca (0.52%) and Fe (0.21%), but higher proportions of Mg (5.9%) and P (2.7%) released from the manure collected in September. Increases in the concentrations of soil Ca, K and P, and plant available N, P and K were also observed following the burial of biochar-infused-manure. Investigating the financial benefits revealed that the overall income increased by 10% compared to the previous year, over 9 months. This study showed that additions of small quantities of biochar, as a feed supplement, can assist in improvements in animal health and productivity of a farm.
