Effects of nitrogen and phosphorus fertilization on the ratio of activities of carbon-acquiring to nitrogen-acquiring enzymes in a primary lowland tropical rainforest in Borneo, Malaysia

Figures & data

Table 1. Soil chemical properties of the study site.

Treatment	Bray-P (μg P g soil^−1)^a	pH(H2O)^a	Total C (%)^b	Total N (%)^b	Total P (%)^b
Control	1.5 (0.4)	4.3 (0.1)	3.6(0.55)	0.23(0.02)	0.027(0.002)
N-addition	1.1 (2.3)	4.2 (0.1)
P-addition	16.1 (10.0)	4.5 (0.1)
NP-addition	15.8 (6.6)	4.3 (0.1)

^aData from Yokoyama et al. (2017). Soil samples (0–5 cm) were taken from the same study plots as the present study. Values are means with standard errors in parentheses (n = 3). Bray-I-method was used to extract P from soil.

^bData from Imai et al. (2010). Soil samples (0–5 cm) were taken from a 2-ha permanent plot, which was established in the same forest as the present study plots were established. Values are means with standard deviations in parentheses (n = 9).

Figure 1. Effects of N and P fertilization on (a) BG, (b) NAG, and (c) LAP activities a primary lowland tropical rainforest in Borneo. Data are illustrated as box plots (n = 3 per treatment). BG, β-1,4-glucosidase; NAG, β-1,4-acetylglucosaminidase; LAP, leucine aminopeptidase. Results of two-way analysis of variance are shown. The band near the middle of the box indicates the median value. The top and bottom of the box are the first and third quartiles, respectively. The whiskers show the maximum and minimum values.

Figure 2. Effects of N and P fertilization on ratios of (a) BG to NAG and (b) BG to NAG + LAP. Data are illustrated as box plots (n = 3 per treatment). BG, β-1,4-glucosidase; NAG, β-1,4-acetylglucosaminidase; LAP, leucine aminopeptidase. Results of two-way analysis of variance are shown. The band near the middle of the box indicates the median value. The top and bottom of the box are the first and third quartiles, respectively. The whiskers show the maximum and minimum values.

Yokoyama D, Imai N, Kitayama K 2017: Effects of nitrogen and phosphorus fertilization on the activities of four different classes of fine-root and soil phosphatases in Bornean tropical rain forests. Plant Soil, 416 463–476. http://link.springer.com/10.1007/s11104-017-3225-x.

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Imai N, Kitayama K, Titin J 2010: Distribution of phosphorus in an above-to-below-ground profile in a Bornean tropical rain forest. J. Trop. Ecol., 26, 627–636. Available from: http://www.journals.cambridge.org/abstract_S0266467410000350 (November 2013).

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