Crop residue return is an effective and low-cost agricultural approach for soil organic carbon (SOC) sequestration. Yet, it is largely unknown to what extent the soil fertility and residue type affect the mineralization of maize (Zea mays L.) residue carbon (C) and the decomposition of native SOC. Therefore, a better understanding of the mineralization of C derived from residues and its priming on native SOC is crucial to accurate assessment of the benefits of crop residue returning in agricultural systems. A 360-day laboratory incubation experiment was carried out with a Cambisol of low and high fertilities amended with three types of 13C-labeled maize residues (root, stem, leaf). The abundance of 13C (δ13C) in the soil samples was measured during different incubation stages. The results showed that the total mineralization of residue C was significantly higher in the low fertility soil than in the high fertility soil, but there were no significant differences among residue types. For the high fertility soil, all the residue types induced a negative priming on native SOC mineralization during the early incubation stage, but a significant total positive priming by the end of incubation, whereas for the low fertility soil, there was no significant effect of residue return on SOC mineralization. The accumulated priming by the end of incubation did not vary across residue types. Moreover, the sum of mineralization of residue C and native SOC in the high fertility soil was 1.4 times as large as that in the low fertility soil. We conclude that mineralization of crop residue C and native SOC is affected by soil fertility rather than residue type.

Mineralization of plant residues and native soil carbon as affected by soil fertility and residue type

Below ground residues were more conducive to soil organic carbon accumulation than above ground ones

Biotechnology for lignocellulose conversion is developed with its research and application. During this process, the research method plays an important role in discovering, exploring, and establishing theories. The research method for lignocellulose conversion is also necessary for industrialization testing and control. In this chapter, research methods for the biotechnology of lignocellulose are presented. According to the biological conversion process of lignocelluloses, research methods are classified into three types: research methods for primary refining, research methods for hydrolysis with microorganisms, and research methods for fermentation engineering. Finally, research methods for the whole biotransformation process are also summarized. In each part, the related research advances of my group are also given.

Research Methods for the Biotechnology of Lignocellulose

Based on the literature on the degradation mechanism and the change of micro-functional groups in the fermentation process of modified rice straw, this study aimed to solve the problems of low biogas production rate and poor stability of the biogas production system. In this work, mathematical equations were developed and combined with duck dung and rice straw mixed raw material to perform a fermentation test. The molecular micro-functional group changes of cellulose, hemicellulose, and lignin were studied to obtain the optimal ratio of mixed raw materials for fermentation and to explore the optimization mechanism of its fermentation biogas production. Experimental results showed that the optimal ratio of mixed raw materials was 2.8:1, and the inclusion of a suitable amount of Mn2+(concentration of 2 mol × L-1) was able to strengthen MnP activity and improve the ability of white-rot fungi to rupture β-O-4 bonds. A modification pre-treatment via activated carbon-based solid acid was performed, and the experimental group generated 15.8% more cumulative biogas than the control group. The biogas yield reached its peak when 300 g of inoculum was added to the pre-treatment at a concentration of 30%.

Biodegradation Mechanism of Biogas Production by Modified Rice Straw Fermentation

The distribution and dynamic of residue-derived carbon after incorporation into soil at different fertility levels have been well documented. However, the distribution of maize residue–derived C in particulate organic C (POC) from different types of organic residues in soils of different fertility levels is poorly understood. A 540-day in situ field experiment was carried out. In 2016, three types of 13C-labeled maize residues (root, stem, leaf) were added to brown earth of different fertility levels in Northeast China. 13C-POC content in the soil samples was measured on the 60th, 90th, 180th, and 540th days after in situ incubation. The results showed that 13C-POC content was significantly higher in high-fertility soil than in low-fertility soil during the whole incubation time. There were significant differences among different types of maize residues at the beginning of 180 days, with stem (0.13 g kg−1) and root (0.11 g kg−1) residues higher than leaf residue (0.08 g kg−1), and sequestration of residue in POC was similar between the roots, stems, and leaves after the 540-day field incubation. The mean residence time and residue POC in soils at each fertility level increased (P < 0.05) with increasing incubation time, with a range from 1.52 to 128.72 years in the high-fertility soil and 1.07 to 60.52 years in the low-fertility soil, but showed no significant differences among different types of maize residue. The results revealed that high-fertility soil was more conducive for new POC accumulation than low-fertility soil, and its sequestration was similar among the roots, stems, and leaves after 540 days.

Incorporated maize residues will induce more accumulation of new POC in HF compared with that in LF soils: a comparison of different residue types

This paper describes several different types of peanut shells in the determination of cellulose and lignin content approachIt selects concentrated sulphuric acid hydrolysis,oxidation of potassium dichromate peanut shell in celluloseIt separates the acetic acid,sulfuric acid hydrolysis of peanut shells in the lignin

Qiu Hui-dong

Papers

On the Determination of Cellulose and Lignin of Peanut Shells