ABSTRACT

Intercropping is commonly used in low-input systems but could also be a strategy for higher input systems. Three ratios of substitutive oat–pea intercrops were tested on a fertile soil in eastern Austria with application of a low nitrogen (N) fertiliser rate (6 g N m⁻²) versus an unfertilised control to assess the effect of intercropping and low N fertilisation on dinitrogen fixation (N_FIX). The above-ground dry matter (AGDM) and N yield of intercrops increased with N fertilisation, but the increase occurred only in oat, while pea was not affected by N fertilisation. Pure pea stands and intercrops with high pea share resulted in N sparing in the soil at harvest, as the soil mineral N was higher than in pure oat. Half of the applied amount of N was recovered by the AGDM of crops and half remained in the soil at harvest. The N_FIX per unit area was highest in pure pea. Intercropping considerably reduced N_FIX, especially in intercrops with low pea share. N_FIX per unit of AGDM of pea, however, was neither affected by intercropping nor by N fertilisation. Consequently, a low amount of N fertilisation of oat–pea intercrops on a fertile soil can increase overall performance of the system through increasing the performance of oat without impairing that of pea.

摘要

间作通常在低输入系统中使用，但也可能是高输入系统的一种策略。在奥地利东部的肥沃土壤上，以低氮（N）施肥量（6 g N m ^-2）和未施肥的对照试验了三种替代燕麦-豌豆间作的比例，以评估间作和低氮施肥的效果固氮（N _FIX）。间作作物的地上干物质（AGDM）和氮素产量随着施氮量的增加而增加，但这种增加仅发生在燕麦上，而豌豆不受施氮量的影响。纯豌豆林和高豌豆间作的农作物在收获时会导致土壤中氮的节省，因为土壤中的矿物质氮高于纯燕麦中的氮。施用的氮的一半通过农作物的AGDM回收，另一半在收获时保留在土壤中。在纯豌豆中，每单位面积的N _FIX最高。间作大大降低了N _FIX，特别是在豌豆占有率低的间作中。ñ _FIX但是，每单位豌豆AGDM的单位量不受间作和氮肥的影响。因此，在肥沃的土壤上少量施用燕麦-豌豆间作的氮肥可以通过增加燕麦的性能而不损害豌豆的性能来提高系统的整体性能。