26 mg kg−1 of dry soil in the autumn of 2009 (Fig. 2L). The NO3− concentrations at the 5–10 cm and 10–15 cm depths exhibited minor variations between seasons. Different yr-old ginseng exhibited similar seasonal trends for NO3− concentrations. The soil moisture at the 10–15 cm depth remained constant; however, in the 0–5 cm and 5–10 cm this website depths it decreased in summer and autumn and increased the following spring for all of the ginseng bed soils (Fig. 2K–O). Soil bulk density was always < 1 g cm−3 and increased by 30–40% during a 1-yr cycle for the different aged

ginseng fields (Fig. 2P–T). Although the soil bulk density in the 3-yr-old ginseng beds was kept relatively constant, a value of approximately 0.85 g cm−3 was higher than all of the other data, consistent

with the proposal that ginseng planting resulted in soil compaction and loss of air and water. Soil pH fluctuated from 3.8 to 5.2 throughout the three depths and tended to decrease within seasons in the different aged ginseng beds (Fig. 3A–E). Correlation analysis showed a soil pH that was significantly correlated with concentrations of NH4+ (r = 0.465, p < 0.01, n = 60) and Ex-Ca2+ (r = 0.325, p < 0.01, n = 60). The Ex-Al3+ concentrations fluctuated from 0.10 mg g−1 to 0.50 mg g−1 for dry soils and showed significant correlation with NO3− (r = 0.401, n = 60, p < 0.01). The Ex-Al3+ concentrations increased in the summer and further increased Docetaxel research buy in the autumn; then, there was a decrease in the different aged ginseng beds the following spring ( Fig. 3F–I). The Ex-Al3+ concentrations at the three depths of the ginseng bed planted 2 yrs previously were higher compared to those in the same depths of the different-aged ginseng bed ( Fig. 3L). The ginseng bed soils contained higher TOC concentrations that fluctuated from 50.1 mg kg−1 to 94.8 mg kg−1 of dry soil (Fig. 3K–O), which was positively correlated with the

pH (r = 0.293, p < 0.05, n = 60) and negatively correlated with the Ex-Al3+ (r = −0.329, n = 60, p < 0.05) content. The TOC concentrations had no obvious spatial variation, tended to decrease within a 1-yr cycle and reached their lowest levels in the 3-yr-old and transplanted 2-yr ginseng bed ( Fig. 3M,O). This was consistent with the view that ginseng growth will decrease the organic matter content Meloxicam of bed soils [1]. Al that is extracted with Na-pyrophosphate (Alp) is used as a proxy for Al in organic complexes. The Alp tended to decrease within a 1-yr cycle and was positively correlated with TOC concentrations (r   = 0.425, p   < 0.01, n   = 60), NH4+ concentrations (r = 0.34, p < 0.01, n = 60) and pH (r = 0.370, p < 0.01, n = 60; Fig. 3P–T). For the transplanted 2-yr-old ginseng beds, the Alp was constant, but the values were the lowest of all of the soil samples ( Fig. 3T). The Al saturation was calculated in the present study as an indicator of soil acidification and Al toxicity levels (Table 1).