Abstract: ¹⁵N-labelled rice straw was used to feed three goats to study the digestion, assimilation, excretion and transformation patterns of Nand Ccompounds in it by goats. The results show that in two slaughtered goats, the digested, assimilated and transformed amount of ¹⁵Nis respectively 38.54 and 23.78% of ¹⁵Namount in diet, on an average of 31.16%. The ¹⁵Nin feces and urine excreted by three goats is respectively 34.78,33.88 and 33.18% of that in diet, on an average of 33.94%. For two slaughtered goats, their ¹⁵Nrecovery is 73.32 and 56.96%, and loss rate is 26.68 and 43.04% respectively. The ¹⁵Nrecovery of diet is coincided with amino acid digestion rate of it by goats. The digestion rate of carbohydrates in diet by three goats are respectively 76.40, 68. 66 and 65.19%, on an average of 66.93%.

Key words: ¹⁵N-labelled rice straw, Transformation of N and C compounds, Utilization rate, coal-mining area, ammonia oxidizer., soil property, nitrification, biochar