二、温室栽培应使用硝态氮氮素有两种形态:一类是无机形态,如硝态氮(硝酸钾、硝酸钙)和铵态氮(硫酸铵、氯化铵和磷酸铵等),它们都呈离子状态,能被根系直接吸收,另一类是有机态氮(腐殖质),它们分子量大,难于直接进入植物体内。硝酸根离子带负电荷;铵根离子带正电荷。铵根正离子能被土壤粘粒负离子所吸附,自由移动能力低。少部分铵离子能被植物根系直接吸收,绝大部分铵被固 Second, greenhouse cultivation should use nitrate nitrogen has two forms: one is the inorganic form, such as nitrate (potassium nitrate, calcium nitrate) and ammonium nitrogen (ammonium sulfate, ammonium chloride and ammonium phosphate, etc.) They are all ionized and can be absorbed directly by the root system. The other is organic nitrogen (humus), which have large molecular weights and are difficult to access directly into plants. Nitrate ions are negatively charged; ammonium ions are positively charged. Ammonium ions can be adsorbed by soil clay particles, low free mobility. A small portion of ammonium ions can be directly absorbed by plant roots, most of the ammonium is solid