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An analysis of some components of the nitrogen cycle as affected by land use adjacent to the riparian zone of a southern Ontario stream.

机译：分析了安大略南部南部河岸带附近土地利用对氮循环某些成分的影响。

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To assess components of the N cycle such as ammonification, nitrification and net nitrogen mineralization, as well as extractable nitrate and ammonium (NH4+-N) pools, a study was conducted at Washington Creek, southwestern Ontario. Four different land use systems were studied: natural forest (NF), agricultural land + grass buffer (AP), livestock land (LS), and agriculture + rehabilitated buffer (RA).;Soil net N-mineralization rates were calculated from ammonification and nitrification rates using the buried polyethylene bag method. Extractable nitrate and ammonium concentrations were obtained from samples taken as part of the sampling protocol for N-mineralization fluxes. Groundwater was also sampled from wells installed in the four land systems, and periphyton was sampled in stream waters associated with each land use system.;Net soil N-mineralization rates were generally significantly higher (p≤0.05) in the RA (81 mg m-2 d-1) and AP (40 mg m -2 d-1) systems compared to the NF (24 mg m -2 d-1) and LS (18 mg m-2 d-1 ) systems, particularly in the fall. The same pattern was observed for extractable NO3--N over all seasons. However, for extractable NH4+-N, higher concentrations were found in the NF system in the fall of both 2003 and 2004; no differences were noted between land uses in other seasons. Chlorophyll a and ash free dry mass (AFDM) of periphyton were significantly higher (p≤0.05) in the LS system. Chlorophyll a and AFDM was poorly correlated with aqueous concentrations of nutrients, but was positively correlated with canopy openness. The groundwater flux (Q) was highest in the NF and LS systems. In contrast, nitrate flux was highest in the AP system.;This study showed that rates of N mineralization, nitrification and ammonification varied seasonally in each land use system. The RA and NF land use systems yielded different processing rates for the N species studied, when it was expected that these systems would have similar values after 25 years of rehabilitation. Future studies should focus on studying long-term N cycling recovery in rehabilitated riparian areas, such Washington Creek, and the relationship between buffer strip width, total buffered area, and stream basin hydrology.
机译：为了评估氮循环的组成部分，例如氨化，硝化和净氮矿化，以及可提取的硝酸盐和铵盐（NH4 + -N）库，在安大略省西南部的华盛顿河进行了一项研究。研究了四种不同的土地利用系统：天然林（NF），农业用地+草地缓冲带（AP），牲畜用地（LS）和农业+修复后的缓冲带（RA）。土壤净氮矿化率是通过氨化和硝化率采用埋聚乙烯袋法。从N矿化通量采样规程的一部分中获取的样品中可提取的硝酸盐和铵盐浓度较高。还从安装在这四个土地系统中的水井中抽取了地下水，并在与每个土地利用系统相关的溪流中抽取了浮游植物。RA中的净土壤氮矿化率通常显着更高（p≤0.05）（81 mg m -2 d-1）和AP（40 mg m -2 d-1）系统与NF（24 mg m -2 d-1）和LS（18 mg m-2 d-1）系统相比，特别是在秋季。在所有季节中，可提取的NO3--N观察到相同的模式。但是，对于可萃取的NH4 + -N，2003年和2004年秋季在NF系统中发现了更高的浓度。其他季节的土地利用之间没有差异。在LS系统中，附生植物的叶绿素a和无灰干质量（AFDM）显着更高（p≤0.05）。叶绿素a和AFDM与营养液中水的浓度相关性很弱，但与冠层的开放度呈正相关。在NF和LS系统中，地下水通量（Q）最高。相比之下，AP系统中硝酸盐通量最高。该研究表明，每种土地利用系统中氮矿化，硝化和氨化的速率随季节变化。 RA和NF土地利用系统对所研究的N个物种产生不同的处理率，当时预计这些系统在经过25年的恢复后将具有相似的价值。未来的研究应集中于研究恢复的河岸地区（如华盛顿河）的长期氮循环恢复，以及缓冲带宽度，总缓冲面积和流域水文学之间的关系。

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