木屑几乎不含氮，细菌分解木质素时，需要大量的氮，与植物争氮。如果用新鲜木屑改土，要同时多加氮肥。
Balance the carbon–nitrogen ratio
Fresh sawdust is very high in carbon (C:N ratio often >200:1) and low in nitrogen biologyinsights.com. To speed decomposition, mix it with nitrogen?rich “green” materials like grass clippings, fresh leaves, or kitchen scraps greenupside. A good starting ratio is about 3 parts sawdust to 1 part greens
