Effects of Soil Amendment Application Rates on the Soil pH and Nutrient Contents in Castanea henryi orchards

In order to explore the effects of soil amendment application rates on the improvement of acidic soil environment and soil nutrient contents in Castanea henryi orchard, the Castanea henryi orchard in Jian'ou City of Fujian Province was taken as the research object, and five concentration gradients of soil amendment, including 0 kg·hm⁻²(CK), 373.13 kg·hm⁻²(A), 746.27 kg·hm⁻²(B), 1119.40 kg·hm⁻²(C), 1492.54 kg·hm⁻²(D) were set up to study the effects of different application rates of soil amendment on the soil pH and nutrient contents (organic matter, total nitrogen, total phosphorus, calcium, magnesium, potassium, silicon) in the orchard of Castanea henryi. The results showed that compared with CK, the contents of magnesium and silicon in the 0−20cm soil layer were significantly increased under the D treatment, with an increase of 35.3% and 33.6%, respectively. The contents of organic matter, total nitrogen, total phosphorus and silicon in the 21−40 cm soil layer were significantly increased under the B treatment, with an increase of 171.9%, 52.4%, 41.4% and 23.1%, respectively. The contents of organic matter, potassium and silicon in the 21−40 cm soil layer were significantly increased under the D treatment, with an increase of 203.1%, 54.8%, and 35.9%, respectively. At the same time, the pH value increased, which effectively improved the soil acidic environment. The contents of total nitrogen, total phosphorus and organic matter in the 41−60cm soil layer were significantly increased under the B treatment, with an increase of 93.5%, 41.7% and 440.5%, respectively. The contents of organic matter and total phosphorus in the 41−60 cm soil layer were significantly increased under the D treatment, with an increase of 297.3% and 200%, respectively. Different concentrations of acidic amendments had a certain improvement effect on the soil nutrient contents of Castanea henryi, and it was considered that the optimum application amount of soil amendment was 1492.54 kg·hm⁻².