Varying Nitrogen Fertigation for Cucumbers Grown in Greenhouses with Soil of Optimal or High Nutrient Status

The standard growth-stage-based fertigation schedule has provided the weekly supply amount of fertilizer considering the expecting yield with no regard of soil nutrient status. The study aimed to examine if fertigation with nitrogen applied at a standard rate results in the best cucumber yield in two greenhouses with different soil nutrient levels, i.e. optimal and high. We investigated the nitrogen (N) uptake pattern of cucumbers with the different nitrogen supply levels which included half the standard rate (N0.5), the standard rate (N1) and double the standard rate (N2). In year 2020, the N1 amendment resulted in highest yield in the soil with optimal nutrient level, however, lower N0.5 resulted in higher yield in the high-nutrient soil. In year 2021, there was no statistical difference in the yield by different nitrogen supply levels in both soils with optimal and high nutrient level. Soil NO 3 -N remained low in the low nutrient soil regardless of the amount of N supplied, but soil NO 3 -N was high in the high nutrient soil supplied with N2. The Partial Factor Productivity of Nitrogen (PFPN) was highest in the N0.5 and it decreased as N supply increased in the optimal and high nutrient soil. In conclusion, a precise fertigation schedule is needed to be set with the consideration of the soil nutrient status.