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Enzyme activities in a limed agricultural soil 总被引：11，自引：2，他引：9
This study assessed the effect of eight lime application rates, with four field replications, on the activities of 14 enzymes
involved in C, N, P, and S cycling in soils. The enzymes were assayed at their optimal pH values. The soil used was a Kenyon
loam located at the Northeast Research Center in Nashua, Iowa. Lime was applied in 1984 at rates ranging from 0 to 17,920 kg
effective calcium carbonate equivalent (ha–1), and surface samples (0–15 cm) were taken after 7 years. Results showed that organic C and N were not significantly affected
by lime application, whereas the soil pH was increased from 4.9 to 6.9. The activities of the following enzymes were assayed:
α- and β-glucosidases, α- and β-galactosidases, amidase, arylamidase, urease, l-glutaminase, l-asparaginase, l-aspartase, acid and alkaline phosphatases, phosphodiesterase, and arylsulfatase. With the exception of acid phosphatase,
which was significantly (P<0.001) but negatively correlated with soil pH (r=–0.69), the activities of all the other enzymes were significantly (P<0.001)and positively correlated with soil pH, with r values ranging from 0.53 for the activity of α-galactosidase to 0.89 for alkaline phosphatase and phosphodiesterase. The
Δ activity/Δ pH values ranged from 4.4 to 38.5 for the activities of the glycosidases, from 1.0 to 107 for amidohydrolases
and arylamidase, 97 for alkaline phosphatase, 39.4 for phosphodiesterase, and 11.2 for arylsulfatase. This value for acid
phosphatase was –35.0. The results support the view that soil pH is an important indicator of soil health and quality.
Received: 3 May 1999 相似文献
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This study investigated the long-term effect of lime application and tillage systems (no-till, ridge-till and chisel plow) on the activities of arylamidase and amidohydrolases involved in N cycling in soils at four long-term research sites in Iowa, USA. The activities of the following enzymes were assayed: arylamidase,
-asparaginase,
-glutaminase, amidase, urease, and
-aspartase at their optimal pH values. The activities of the enzymes were significantly (P<0.001) and positively correlated with soil pH, with r values ranging from 0.42* to 0.99*** for arylamidase, 0.81*** to 0.97*** for
-asparaginase, 0.62*** to 0.97*** for
-glutaminase, 0.61*** to 0.98*** for amidase, 0.66** to 0.96*** for urease, and 0.80*** to 0.99*** for
-aspartase. The Δactivity/ΔpH values were calculated to assess the sensitivity of the enzymes to changes in soil pH. The order of the sensitivity of enzymes was as follows:
-
-aspartase. The enzyme activities were greater in the samples of the 0–5 cm depth than those of the 0–15 cm samples under no-till treatment. Most of the enzyme activities were significantly (P<0.001) and positively correlated with microbial biomass C (Cmic) and N (Nmic). Lime application significantly affected the specific activities of the six enzymes studied. Results showed that soil management practices, including liming and type of tillage significantly affect soil biological and biochemical properties, which may lead to changes in nitrogen cycling, including N mineralization in soils. 相似文献
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Tillage impacts on soil biological activity and aggregation in a Brazilian Cerrado Oxisol 总被引：3，自引：1，他引：3
Mechanized agriculture is increasing rapidly in the Cerrado region of Brazil, causing concerns about water quality, off-site impacts, and sustainability. Our objective was to determine the impact of tillage on soil biological activity and aggregate stability in an Oxisol typical to the region. Three different tillage practices common to the Cerrado region (no-till, disk harrow, and disk plow) and an area under native vegetation were examined. Five different soil enzyme activities, C- and N-mineralization, organic C, total N, and aggregate distribution were determined. Total N, acid phosphatase, arylamidase, and C- and N-mineralization were the most sensitive to changes in tillage management. For each of these analyses, the no-till system had greater concentrations or activities (18–186%) than disk plow in the 0–5 cm layer. Significant differences observed in the 0–5 cm depth did not necessarily translate into total profile differences to a depth of 30 cm. No-till had significantly greater levels of total N, and C- and N-mineralization (20–127%) than the disk harrow system. Total N ranged from 1.8 to 2.2 kg m−3; C- and N-mineralization (24-day incubation) ranged from 2.8 to 6.8 and 0.04 to 0.10 kg m−3, respectively, among tillage systems and soil depths. Enzyme activities in all treatments were more strongly correlated with total soil N than with soil organic C (SOC), contrary to the norm in temperate soils where the stronger correlation is with SOC. Mean weight diameter of water stable aggregates was related to SOC (r = 0.73) and total N (r = 0.92), indicating that soil organic matter does play a significant role in stabilizing aggregates in Oxisols. Results indicated the importance of reducing tillage as a means of increasing soil biological activity of the topsoil in the Cerrado region of Brazil. By understanding the effects of tillage on soil biological properties, management systems can be implemented that improve natural nutrient cycling processes and soil structure, resulting in increased agricultural sustainability of tropical ecosystems. 相似文献
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土壤蛋白酶和芳香氨基酶的研究进展 总被引：9，自引：0，他引：9
蛋白酶和芳香氨基酶是影响土壤有机氮矿化的两种重要酶,其在参与土壤有机质释放氨基酸的过程中起重要作用,控制着氮循环的关键步骤。本文对土壤中蛋白酶和芳香氨基酶的命名、分类、来源、分布、影响因素及测定方法进行了综合评述,以期为开展土壤蛋白酶和芳香氨基酶的相关研究提供理论参考。 相似文献
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