## 2 Materials and Methods
### Experimental Design  
This experiment focused on the typical chernozem soil cultivation area of Nong'an County, Changchun City, Jilin Province. The research used the nylon mesh belt landfill method to investigate the effects of adding different materials on the decomposition degree of straw and its impact on soil active organic carbon content. The findings aim to provide a scientific basis for the efficient utilization of straw and the recycling of agricultural waste. The experiment commenced in April 2020 using chernozem soil and maize variety Qifeng 568. Four treatments were established based on the random block principle: (T1) corn stalk; (T2) Corn stalk + chicken manure; (T3) Corn stalk + cow manure; (T4) corn straw + maturing agent. Maturing agent is a biological agent specially used for straw decomposition. The main component is a highly active compound strain that can decompose organic materials. Each treatment was replicated three times, resulting in a total of twelve test plots. Each plot covered an area of 20 m\({}^{2}\) (4 m \(\times\) 5 m) where six rows of corn were planted, totaling eighteen rows from west to east across three plots with a row width of approximately 0.65 m. The previous year's corn straw was uniformly mixed with various materials, formed into strips, compacted to a thickness of about 2 cm, and then subjected to the plot test. Strips were placed in the east-west direction between corn plantings every two rows, with six rows and three strips in each plot, and a strip width of about 50-80 cm. Aisles in the north-south directions were 1 m wide, with no straw strips between them. The straw decomposition test was conducted using the nylon mesh belt method. In October 2019, corn stalks (including stems and leaves) were collected from the field during the harvest period. These were then cut into 1-2 cm pieces, thoroughly mixed, and dried at 65 \({}^{\circ}\)C until a constant weight was achieved. Subsequently, 5 g of straw was weighed and placed into a decomposition sample bag measuring 15 cm \(\times\) 25 cm with a diameter of 0.01 mm. Each treatment test site had these bags sealed and buried between the straw strip and the soil surface. In total, 144 decomposition sample bags were buried, with four bags buried in each strip. Given that the majority of local farmers predominantly raised livestock and poultry, the organic materials examined in this study were sourced from the local agricultural safety test site, with the maturing agent chosen as the Gabor organic material maturing agent. All fertilizers and materials in each treatment are applied once as a base fertilizer. Except for the test fertilizers and fertilization methods, field management practices such as sowing, irrigation, and weeding are consistent with the practices of local farmers. The specific nutrient properties and contents of the organic materials utilized in the 2020 test are detailed \begin{table}
\begin{tabular}{c c c c c c c} \hline
**Soil Layer** & **Organic Carbon** & **Total N** & **Alkaline N** & **Olsen-P** & **Available K** & **pH** \\
**(cm)** & **(g/kg)** & **(g/kg)** & **(mg/kg)** & **(mg/kg)** & **(mg/kg)** & **(mg/kg)** & **pH** \\ \hline
0–20 & 12.73 & 1.26 & 103.53 & 19.26 & 127.02 & 7.70 \\ \hline \end{tabular}
\end{table} 
Table 1: Basic physical and chemical properties of soil. in Table 2. This test evaluates the carbon and nitrogen balance, utilizing equal amounts of both elements. A total of 10,000 kg/hm\({}^{2}\) of straw is returned to the field. The total carbon content from the added livestock and poultry manure is 486 kg. Specifically, the application rate for chicken manure is 1860 kg/hm\({}^{2}\), while the application rate for cow manure is 1595 kg/hm\({}^{2}\). Urea, containing 46% nitrogen, is used to adjust the carbon-to-nitrogen (C/N) ratio, achieving a final ratio of 25:1 after mixing the livestock and poultry manure with straw.