论文部分内容阅读
采用室内恒温培养法,研究了在乌沙土上添加15N标记秸秆后,秸秆15N在矿质氮、微生物氮和土壤不同组分中的分配情况,并应用氮同位素库稀释法测定了秸秆在乌沙土上的氮总矿化速率。结果表明:将秸秆添加到土壤后,微生物氮量显著增加,而土壤矿质氮量在14天时迅速下降。随着秸秆的分解,秸秆15N进入矿质氮库和微生物氮库,矿质15N在第7 d时最高,占到添加秸秆15N的6.7%,微生物15N在第14 d最高,占到添加秸秆15N的18.1%,随后矿质15N和微生物15N量都下降。56 d时,仍有50.8%的秸秆氮没有分解掉,5.4%的秸秆15N进入土壤53μm~2 mm组分,15.5%进入2~53μm组分,14.6%进入小于2μm组分,有13.6%的秸秆氮损失掉。在培养开始时,乌沙土的氮总矿化速率为2.81 mg kg-1d-1,秸秆在乌沙土上的氮总矿化速率分别为2.50 mg kg-1d-1。
With the method of indoor incubation, the distribution of 15N in different fractions of mineral nitrogen, microbial nitrogen and soil was researched after 15N labeled straw was added to the sandy soil. The nitrogen isotope dilution method was used to determine the distribution of straw on the sandy soil Of the total nitrogen mineralization rate. The results showed that after the straw was added to the soil, the amount of microbial nitrogen increased significantly, while the amount of mineral nitrogen in the soil decreased rapidly after 14 days. With the decomposition of straw, 15N of straw entered into the mineral nitrogen pool and microbial nitrogen pool, and the mineral 15N was the highest on the 7th day, accounting for 6.7% of the 15N addition of straw, and the 15N microorganism was the highest on the 14th day, accounting for 18.1 %, Then mineral 15N and microbial 15N decreased. At 56 days, 50.8% of straw nitrogen was still not decomposed. 5.4% of straw 15N entered soil 53μm ~ 2mm, 15.5% entered 2 ~ 53μm, 14.6% entered less than 2μm, 13.6% Nitrogen loss of straw. At the beginning of cultivation, total nitrogen mineralization rate was 2.81 mg kg-1d-1 in Uisha soil and total nitrogen mineralization rate was 2.50 mg kg-1d-1 in Uisha soil.