Long-term trends in fertility of soils under continuous cultivation and cereal cropping in southern Queensland. VII. Dynamics of nitrogen mineralization potentials and microbial biomass
Long-term trends in fertility of soils under continuous cultivation and cereal cropping in southern Queensland. VII. Dynamics of nitrogen mineralization potentials and microbial biomass
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昆士兰州南部连续耕作和谷物种植土壤肥力的长期趋势。
DOI：
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发表时间：
1987
期刊：
影响因子：
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通讯作者：
R. Mayer
中科院分区：
文献类型：
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作者：
R. Dalal;R. Mayer
对6种主要粮食作物种植土壤的氮素矿化潜势(N0)和矿化速率常数(K)的动态变化进行了研究。在0.1m土层，N0的变化范围为110±22 mg·kg~(-1)(河景)到217±55 mg·kg~(-1)(朗兰兹-洛吉)，分别占土壤全氮的13%和11%。种植后，N0下降1.7±0.5 mg kg-1yr-1(河景)至4.8±2.0 mg kg-1(Billa Billa)。这表示40℃时粘土含量为40%，K为0.066周-1(25℃和35℃时分别为0.027周-1和0.054周-1)。在所研究的6种土壤中，稳定的微生物生物量(预培养30周后测定)中所含的有机碳和有机氮占总有机碳的1.7-38%和总氮的2.0-5.1%。土壤微生物生物量C、N随耕作时间的延长而下降，生物量N占N0年损失总量的10-23%。土壤微生物生物量、尿素酶活性和全N，以及其他一些土壤性质[如轻组分(<；2mgm-3)C、砂粒粒度C、CEC和ESP]与N0和K显著相关，这表明土壤中微生物生物量和潜在矿化N的活性、缔合和稳定性存在着无数的环境。
The dynamics of nitrogen mineralization potential (N0) and mineralization rate constant (k) were studied in six major soils which had been used for cereal cropping for up to 20-70 years. In the top 0.1 m layer of virgin soils, N0 varied from 110 ± 22 mg kg-1 soil (Riverview) to 217 ± 55 mg kg-1 soil (Langlands-Logie), representing about 13% and 11%, respectively, of total N in these soils. Upon cultivation and cropping, N0 declined by 1 7 ± 0.5 mg kg-1 yr-1 (Riverview) to 4.8 ± 2.0 mg kg -1 yr -1 (Billa Billa). This represented 40% clay and k as 0.066 week-1 at 40°C (0.027 week-1 and 0.054 week-1 at 25°C and 35°C, respectively). Organic C and N contained in the 'stabilized' microbial biomass (determined after 30 weeks' pre-incubation) accounted for 1.7-38% of total organic C and 2.0-5.1% of total N in the six soils studied. The microbial biomass C and N declined with cultivation in most soils, biomass N representing 10-23% of the total annual loss of N0. The microbial biomass, urease activity and total N, in addition to a number of other soil properties [e.g. light-fraction (<2 Mg m-3) C, sand-size C, CEC and ESP], were significantly correlated with N0 and k, thus indicating the existence of a myriad of environments for the activity, association and stability of microbial biomass and potentially mineralizable N in soil.