Response of corn silage (Zea mays L.) to zinc fertilization on a sandy soil under field and outdoor container conditions

The purpose of the experiments was to evaluate zinc (Zn) fertilization effect on growth, yield and yield components of corn silage grown on a sandy soil under field and outdoor container conditions. Six rates of Zn supply (0 or control; 1.5; 3; 5; 10 and 50 mg kg−1) were tested. They were split at three different times during the growing season: (i) 50% immediately after sowing, (ii) 25% at 4-5 leaf stage and (iii) 25% at 8-9 leaf stage. These Zn rates were applied to the soil surface as a solution of Zn sulfate (ZnSO4·7H2O). Zn deficiency symptoms appeared at an earlier stage (4-5 leaf stage) as white stripes between the midrib and the margin of leaves for a Zn rate below or equal to 5 mg kg−1. Severity of these symptoms manifested more in container than in field. For both experiments, Zn supply induced a significant increase in stem height and leaf area. Furthermore, in both experiments, control plants showed a notable delay in achieving anthesis, silking, pollination and kernels maturity. The maximum shoot dry weight at harvest was recorded with Zn supply of 5 mg kg−1 in field experiment and 10 mg kg−1 in containers experiment. The shoot dry weight was especially linked to kernels dry weight. This latter was mainly enhanced through two compounds: 1000 kernels dry weight and pollination rate. On the other hand, outdoor container results can be used to help predict field plant responses to Zn except for control treatment.