本試驗以傳統廚餘堆肥(General, G)，食品肉類堆肥(Meat, M)，傳統廚餘堆肥與已堆肥7個月肉類堆肥做1:1(v:v)混合(General+Meat, GM)，肉類堆肥於堆肥初期添加水分(Water, W)，共4種特性堆肥共堆肥化261天。以市場常見之小白菜作為盆栽試驗，共栽種三期，分別為第1期栽種時間為2012/6/5至2012/6/27，第2期為2012/7/18至2012/8/9，第3期為2012/9/4至2012/10/4號。
As the local culture and daily food vary among areas, the features of kitchen waste for different areas also vary. Cooking oil and salt are used in significant quantity in Chinese cuisine, resulting in the high oil (around 15%) and salt (around 1%) in kitchen waste. Through four types of onsite composting, this study tried to understand the effects on crops from composting kitchen waste with a high level of oil and salt and discussed about the features and application of the compost.
The four types of compost observed in this study were traditional kitchen waste compost (General, G), meat compost (Meat, M), the 1:1 (v:v) mix of traditional kitchen waste compost and 7-month-old meat compost (General+Meat, GM), and meat compost with the addition of water at early stage (Water, W). The four types of compost were composted for a total of 261 days. The experiment was conducted on potted plants of Brassica chinensis, a common vegetable at markets, during three periods of time in 2012. The first period was from June 5thto 27th, the second period was from July 18th to August 9thand the third one was from September 4th to October 4th.
The results showed the lipid in the four types of compost decomposed significantly within the first seven days, the early composting stage, with an average decomposition rate of 70% while the levels of sodium ion in the compost gradually increased. Final compost maturity was determined by the levels of TOC, DOC, Phenol, NO3-and NH4+. Although the final levels in our study were stable, the compost was still determined immature because it hadn’t been turned for a long time. The survival rate was poor in the experiment on potted plants of Brassica chinensis L. in the first period (less than 40%) and the rates for the other two periods were 100%. The later the period was, the higher levels of Na+,K+ and TOC were observed in the soil while the levels of Na+ and K+ in Brassica chinensis didn’t increase in this way. TOC protected Brassica chinensis L. from Na+, continued to support it with nutrition, and regulated pH level and EC change in the soil.
The ratio of Na+/K+ in Brassica chinensis in our study was around 0.48, similar to that (0.5) in Brassica chinensis sold on the market. Therefore, the growth and Na+/K+ ratio were similar for Brassica chinensis grown with the mixed compost in our study and that sold on the market. The accumulation of Na+ didn’t bring damage to the plant in our study, and proper accumulation of Na+ and K+ could assist the growth of plant. Therefore,
kitchen waste compost can be used on crop if mixed at the right proportion (Soil: Compost=7:3, 1:1) and after a period of time to reach a balance with the soil.