| 摘要 |
<p>The feed effects the gradual addition of nutrients to the soil, adding a set quantity at a steady rate over a period of several weeks or more. The additive, in the form of a powder or hygroscopic granules or a liq. is incorporated in a package made of material which is permeable to water vapour. The container may be pierced by small holes which allow the gradual escape of the additive. It may be made of porous material, i.e. a sachet of porous plastics material.</p> |
