Meloidogyne incognita suppression and changes of grapevine yield properties determined by waste residues from jojoba, black seed oil extraction and slow release of nitrogen fertilizer

Five different treatments i.e., cold-pressed jojoba residues (CPJR), screw-pressed jojoba residues (SPJR), cold-pressed black seed residues (CPBR), screw-pressed black seed residues (SPBR) and slow release nitrogen fertilizer (SRNF) namely "Enciabein" were applied as soil amendments for their efficacy in suppressing the root-knot nematode, Meloidogyne incognita infesting grapevine cv. Superior. This nematode was found infesting nine-year-old grapevines cv. Superior planted in newly reclaimed sandy soil under a drip irrigation system. The impact of the tested additives were also studied on plant growth variables and yield production when incorporated into the soil at three rates (on base lower rate, recommended rate and higher rate) during two successive seasons. The equatorial and longitudinal dimensions of the berries, leaves and soil contents of N, P, K and Fe were determined. All the tested substances significantly (P less than or equal to 0.01 or 0.05) suppressed M. incognita populations either in the soil or in roots through the two successive seasons as compared to the control vines. Statistical differences in the nematode populations were found within and between the tested treatments. In respect of percentage efficacy of such substances in reducing M. incognita populations in both soil and roots of Superior cv., the recommended rate of SRNF compound has surpassed the other compounds two times through two successive seasons however, at using all rates of SPJR, the lower rate of each of CPJR and SPBR treatments and the recommended rate of each of CPJR and CPBR substances were superior for one experimental periods in reducing M. incognita populations in both soil and roots of Superior cv. All the treatments had increased N, P, K and Fe concentrations in the soil and grapevine leaves compared to checks. All yield, physical, vegetative and chemical properties of berries were increased to some extent while, all treatments gave low total acidity (TA) in juice and high ratio of TSS / TA especially with the recommended rate of SPBR in the first season and the higher rate of CPJR compound in the second season. These data proved that some natural compounds may be effective as natural nematicides in the control of M. incognita and improve the growth and yield of grapevines.