Comparison of Ochroma lagopus Swartz Growth and Soil Ecological Effects under Different Cultivation Modes

The manufacture of modern large-scale wind turbine blades generally uses composite sandwich panels with balsa wood as the base materials, and with no alternative materials. The balsa wood in China is completely dependent on imports, and with the increasing demand of balsa wood and the uncertainty of Sino-foreign trade, the supply of balsa wood raw materials has become a “stuck neck” problem for wind power equipment manufacturing industry in China. In this study, the composite cultivation experiment was carried out with the balsa wood plantations constructed in May 2017, and the following cultivation models were constructed by using the cultivation techniques of ridge, furrow and film mulching with important cash crops in Xishuangbanna: balsa wood plantation (Q), balsa-soybean plantation (QD), balsa-soybean with plastic film plantation (QDF). Balsa wood plantation (CK), balsa-soybean/coriander plantation (QDX), balsa-soybean/coriander with plastic film plantation (QDXF). Through the measurement of soil nutrients, soil moisture content, balsa wood DBH growth and volume volume, the sustainable cultivation mode of balsa wood in Xishuangbanna was explored to provide theoretical basis and technical support for the localization of balsa wood raw materials. The results showed that the diameter at breast height (DBH) of balsa wood could reach 23 cm after growing for 2 years and 8 months, which can meet the requirements of manufacturers (DBH > 20 cm). After 3 years and 8 months, the DBH could reach 26 cm, and the increase of volume was over 30%. In order to obtain high income, balsa wood trees could be harvested after 4-5 years of planting. From April to November, the total soil water storage in QDX, QDXFQD, QDF increased 29.11 mm and 21.74 mm, respectively, however, CKQ decreased 13.19 mm. In the rainy season, CKQ increased the soil water consumption in 20-40 cm soil layers, and QHB, QDXFQDF increased soil water content in 20-40 cm soil layers. Film mulching practices in balsa plantations increased soil available P and NO³-N content. From January to August 2020, soil P in QDX, QDXFQD, QDF increased 5.54 mg kg⁻¹ and 10.72 mg kg⁻¹. From January to August in 2020, soil nitrate nitrogen content under QDXFQDF treatment increased by 126.32 mg kg⁻¹. Cultivation of soybean with plastic film under light wood forest could significantly increase soil available phosphorus and nitrate nitrogen content, increase soil water storage and promote the sustainable growth of light wood..