生物质炭制备过程中的养分调控及对土壤理化性质改善机制

In recent years, the studies of biochar returning to farmland are developed very quickly for responding to the problem of climate change, but these studies are mainly focused on the effectiveness of biochar returning. We note that the nutrients (N, P, S, K, etc.) are easy to lose in the process of biochar preparation by the usual pyrolyzation, which will greatly affect the quality of biochar and the effects of biochar returning. To this end, the new technology of nutrient regulation during the process of biochar preparation is proposed in this project, that is, under the premise of straw conversed into biochar, the nutrients (N, S, P, K) tracked for the mechanism of migration, transformation and distribution in the three-phase products of gas, liquid and solid, and then the nutrients are directionally regulated to prepare the high-quality biochars of rich nutrients (N, S, P, K), which will be applied into the process of returning farmland utilization. Through these studies, not only the entire technical process will be got through from the biochar preparation to returning to farmland so as to provide the technical support for the standardization, normalization and industrialization of biochar preparation; but also these scientific and technological issues will be clarified about the migrated and transformated mechanism of the nutrients (N, S, P, K) and the feedback mechanism of the physical and chemical properties of soils improved by the nutrient regulation; thus, the new technology and approach will be developed for the high-value utilization of straw prepared to biochar returning.

近年来为应对气候变化问题，生物质炭还田技术研究发展相当迅速,但这些研究主要围绕生物质炭还田功效展开。我们注意到通常的热解制备生物质炭过程中，养分元素(N、P、S、K等)很容易损失，这将大大影响到生物质炭品质及其还田功效。为此，本课题提出生物质炭热解制备过程中的养分调控新工艺，就是在保证秸秆热解转化为生物质炭的前提下，追踪养分元素（N、S、P、K）在气、液和固三相产物中的迁移转化和分布规律，并定向养分调控，从而制备出富含养分元素（N、S、P、K）的高品质生物质炭并尝试将它们应用于生物质炭还田利用中。通过这些研究不但能打通从秸秆制备生物质炭到还田的整个工艺流程，为生物质炭制备过程标准化、规范化和产业化提供技术支撑；而且能阐明养分元素（N、S、P、K）在秸秆自热热解过程中的迁移转化以及对土壤理化性质改善反馈机制等关键科学和技术问题；从而为秸秆制备生物质炭还田的高附加值利用技术开拓新方法和新思路。

我们注意到通常的热解制备生物炭过程中，养分元素很容易损失，这将大大影响到还田生物炭品质及其还田功效。为此，开展了以下研究：（1）秸秆热解基础研究，为自热热解过程中来自土壤的养分元素调控获得基本参考数据；（2）秸秆热解的养分元素气、液和固三相迁移转化过程的分配调控研究；（3）养分调控后制备的还田生物炭产品对土壤理化性质反馈效果研究；（4）从生物炭制备到还田过程中养分元素及其形态的迁移转化机制研究。通过这些研究，不但能打通从秸秆制备生物炭到还田的整个工艺流程，找到了秸秆制备还田生物炭的最佳工艺，而且阐明了养分元素从生物炭制备到还田过程中的迁移转化机制。从而为秸秆制备生物炭还田提供新方法和坚实的理论指导。