ISHS Acta Horticulturae 689: VII International Symposium on Grapevine Physiology and Biotechnology
RESPONSE OF ´FLAME SEEDLESS´ GRAPEVINES TO SOME NITRIFICATION INHIBITORS |
| Author: | S.M. El-Shazly |
| Keywords: | ´Flame Seedless´, mineral nutrition, nitrification, nitrate, ammonia |
| Abstract:
A field study was conducted to determine the effects of three nitrification inhibitors on ‘Flame Seedless’ grapevines grown in a sandy loam soil. The nitrification inhibitors (NIs) were: nitrapyrin at rates of 2.5, 5 and 10 mg L-1; 8-Hydroxyquinolin (8-HQ) and carbon disulphide (CS2) at rates of 10, 20 and 40 mg L-1. The data indicated that, nitrapyrin at all rates tested and CS2 at 20 or 40 mgL-1 significantly increased vegetative growth (shoot length, leaf area and pruning weight) as compared to the control. Furthermore, 8-HQ at 20 or 40 mg L-1 markedly increased shoot length but only slightly increased leaf area and pruning weight. Nitrapyrin at 5 or 10 mg L-1 and CS2 at 40 mg L-1 caused a significant increase in the number of clusters vine-1 and yield, meanwhile 8-HQ at all rates caused a slight increase in yield and number of clusters vine-1. Nitrapyrin and CS2 at the medium and high rates and 8-HQ at 20 mg L-1 markedly increased cluster weight, juice volume of 100 berries, total soluble solids and vitamin C contents. None of the NI rates significantly affected juice acidity. Leaf N, Fe, Mn, Zn and Cu contents significantly increased as a result of the NI applications. Leaf P, K and Ca contents decreased, especially with high NI rates. Generally, the addition of NIs significantly increased soil NH4+-N and decreased both soil NO3--N and soluble N. Moreover, the nitrification rate (NR) markedly decreased due to NI applications. The inhibition of nitrification expressed as a percent of the control and ammonium recovery ratio increased with increasing NI rates with the effect of nitrapyrin more superior compared with the other nitrification inhibitors. | |
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