土壤供氮能力测试方法的研究——Ⅲ.0-100cm土层可矿化氮对作物吸氮量的意义

Studies on Methods Determing Soil Nitrogen-supplying Capacities Ⅲ. The Contribution of Mineralizable Nitrogen from 0-100cm Soil Layers to Plant Uptake Nitrogen

研究表明,0～15cm矿化出来的氮素最多,但对作物吸氮量的贡献并非最大,贡献最大的出现在较深的层次。总体来看,对作物吸氮有重要意义的是上部土壤的可矿化氮:旱区为0～45cm土层;灌区为0～30cm土层。然而,即使是上部土壤的可矿化氮,由于测定方法不同,其反映土壤供氮能力的效果也明显不同。本研究再一次表明,通气培养法优于淹水培养法和碱解扩散法。

Field trials show that the amounts of nitrogen mineralized from 0～15cm soil layer are themost, but not the greatest in contribution to plant uptake nitrogen, the greatest contribution beingfrom deeper layers. As a whole, mineralizable nitrogen in upper layers(0～45cm for fields withno irrigation,and 0～30 cm for fields with irrigation) plays an important role in plant uptake nitrogen. However, mineralizable nitrogen determined by different methods from upper layers hasobviously different effects on reflecting soil nitrogen-supplying capacities. This research proves a-gain that aerobic incubation method is better than waterlogged incubation and NaOH-hydrolyza-tion diffusion methods.