Effect of zinc fertilization on productivity and zinc uptake in chilli-finger millet-amaranthus system

Crops' response to zinc application may vary under different management systems. The objective of the current investigation was to study the effect of different levels of Zn fertilization on direct and residual availability of zinc in soil, crop yield and uptake of zinc in the chilli-finger millet-amaranthus system on an Alfisol. Field experiments were conducted during 2019-2020 in low zinc soil (0.88 mg kg-1) and treatments were as a one-time application of 5, 10, 15 and 20 kg Zn ha-1 through ZnSO4.7H2O as basal dose only for chilli; foliar application of 0.5% ZnSO4.7H2O (two times for each crop) and control (no Zn fertilization). Extractable Zn content of soil improved from 0.88 to 2.10 mg kg-1 by basal application of Zn. It also enhanced Zn concentration in crop produce resulting in higher Zn uptake. The direct effect of Zn fertilization significantly improved chilli yield in all the treatments over the control, however, the significant residual effect of yield enhancement in finger millet and amaranthus was recorded by basal application of Zn from 10 kg ha-1 onwards. By increasing the Zn doses from 10 kg to 20 kg per ha, no further significant improvement in yield was noticed with corresponding soil DTPA-Zn of more than 1.5 mg kg-1. From the results, it is obvious that onetime zinc fertilization of 10 kg ha-1 y-1 through soil could be the best option to correct Zn deficiency and improve the productivity of vegetable-based systems. If DTPA-Zn content of soil reaches 1.5 mg kg-1 and above, subsequent Zn application can be avoided.