The control of soil nutrient loss to lighten non-point source pollution to water body and improve soil fertility is a global problem. Biochar application to soil is widely considered as an effective method to improve soil fertility and reduce nutrient loss. However, the effect of biochar application to barren karst yellow soil in global karst regions on the loss of nitrogen (N) and phosphorous (P) and the growth of oil peony (an important woody oil crop) remains unclear. We conducted the indoor leaching experiments, in-site observation of the N and P loss with surface runoff under three types of rains and the comparative experiment of oil peony growth when the different amount of biochar was applied to karst yellow soil. The results indicated that soil pH, total nitrogen (TN), total phosphorous (TP), available N and available P contents in the soil increased with an increase of biochar application under indoor simulation but the loss of leaching solution decreased. 2 kg/m² biochar application caused the least loss of TP, TN, nitrate nitrogen (NN) and ammonia nitrogen (AN) with the leaching solution compared with 0, 4 and 6 kg/m² application. The rapid and slow attenuation of P and N concentrations, respectively, were observed in karst yellow soil with biochar application. The N/P change in leaching solution showed a parabolic form. Under natural rainfall, 4 kg/m² biochar application had the best effect on a reduction of TP, TN and AN loss in surface runoff. Rainstorm caused AN and TP large loss but rainstorm, heavy and moderate rains all easily caused NN large loss. 4 kg/m² biochar application had the best effect on the growth of plant height and base diameter, leaf SPAD and N and P content in organs in the fertilized area but 6 kg/m² in the unfertilized area. Biochar application effectively improved the fertility of karst yellow soil, reduced the loss of N and P with vertical leaching and surface runoff, and promoted the growth of oil peony. This study provides new knowledge for biochar application.

控制土壤养分流失，减轻水体面源污染，提高土壤肥力，是一个全球性问题。生物炭在土壤中的应用被广泛认为是提高土壤肥力和减少养分流失的有效方法。然而，生物炭在全球喀斯特地区贫瘠的喀斯特黄土上施用对氮（N）和磷（P）的损失以及油牡丹（一种重要的木本油料作物）生长的影响尚不清楚。我们进行了室内浸出试验、三种降雨下地表径流氮磷流失的现场观察以及不同用量生物炭施用于喀斯特黄土油牡丹生长的对比试验。结果表明，土壤 pH、总氮（TN）、总磷（TP）、在室内模拟下，随着生物炭施用量的增加，土壤中速效氮和速效磷含量增加，但浸出液损失减少。2公斤/平方米与施用 0、4 和 6 kg/m ²相比，施用²生物炭导致浸出液的 TP、TN、硝态氮 (NN) 和氨氮 (AN) 损失最少。在施用生物炭的喀斯特黄色土壤中分别观察到 P 和 N 浓度的快速和缓慢衰减。浸出液的 N/P 变化呈抛物线形式。在自然降雨条件下，施用4 kg/m ²生物炭对减少地表径流中TP、TN 和AN 损失的效果最好。暴雨造成AN和TP损失较大，但暴雨、大雨和中雨都容易造成NN大损失。4 公斤/米²施生物炭对施肥区株高、基径、叶片SPAD和各器官N、P含量的生长影响最好，未施肥区为6 kg/m ²。生物炭的施用有效地提高了喀斯特黄壤的肥力，减少了垂直淋失和地表径流对氮、磷的流失，促进了油牡丹的生长。该研究为生物炭的应用提供了新的知识。