Technical Yearbook 2023

TABLE 1. The macro-element status in the petioles of the Shiraz/110 Richter vines irrigated full surface with micro-sprinklers at Nietvoorbij research farm near Stellenbosch at full bloom (November 2017). Treatment no. Catch crop/cover crop combination N (%) P (%) K (%) Ca (%) Mg (%) Na (mg /kg) 1 Pearl millet/Oats 0.97 0.12 1.57 1.19 0.58 752 2 Pearl millet/N-fixing mixture 0.93 0.11 1.48 1.21 0.58 668 3 Dolichos beans/Oats 0.91 0.10 1.69 1.25 0.51 723 4 Dolichos beans/N-fixing mixture 0.97 0.12 1.77 1.13 0.55 743 5 Chicory/Oats 0.91 0.13 1.48 1.15 0.53 678 6 Chicory/N-fixing mixture 0.93 0.10 1.43 1.16 0.57 736 7 None/Oats 0.88 0.11 1.33 1.20 0.62 760 8 None/N-fixing mixture 0.99 0.10 1.43 1.08 0.54 685 LSD (p=0.05) NS NS NS NS NS NS TABLE 2. The macro-element status in the leaf blades of the Shiraz/110 Richter vines irrigated full surface with micro-sprinklers at Nietvoorbij research farm near Stellenbosch at full bloom (November 2017). Treatment no. Catch crop/cover crop combination N (%) P (%) K (%) Ca (%) Mg (%) Na (mg/ kg) 1 Pearl millet/Oats 2.73 0.18 0.82 1.30 0.31 506 2 Pearl millet/N-fixing mixture 2.79 0.21 0.80 1.43 0.35 532 3 Dolichos beans/Oats 2.59 0.17 0.83 1.30 0.29 517 4 Dolichos beans/N-fixing mixture 2.75 0.18 0.82 1.23 0.29 516 5 Chicory/Oats 2.68 0.19 0.77 1.20 0.29 483 6 Chicory/N-fixing mixture 2.65 0.18 0.77 1.30 0.30 517 7 None/Oats 2.56 0.18 0.74 1.38 0.31 516 8 None/N-fixing mixture 2.67 0.19 0.79 1.20 0.31 488 LSD (p=0.05) NS NS NS NS NS NS TABLE 3. Yield and berry mass, as well as cane mass, of the Shiraz/110 Richter vines irrigated full surface with micro-sprinklers at Nietvoorbij research farm near Stellenbosch as determined in the 2017/18 season. Treatment no. Catch crop/cover crop combination Yield (t/ha) Berry mass (g/berry) Cane mass (t/ha) 1 Pearl millet/Oats 9.97 1.59 3.93 2 Pearl millet/N-fixing mixture 11.47 1.63 4.43 3 Dolichos beans/Oats 9.05 1.56 3.64 4 Dolichos beans/N-fixing mixture 11.33 1.69 4.89 5 Chicory/Oats 11.28 1.61 4.21 6 Chicory/N-fixing mixture 9.82 1.64 3.83 7 None/Oats 11.34 1.62 4.42 8 None/N-fixing mixture 8.65 1.74 4.00 LSD (p=0.05) NS NS NS

Results and discussion In the 2017/18 season, the macro-element content of the leaf petioles and blades did not differ between treatments (tables 1 and 2). According to norms for grapevine nutrient levels in leaf petioles, i.e. 0.60% to 0.98% for N, 0.11% to 0.62% for P, 1% to 2.9% for K, 0.6% to 2.2% for Ca, and 0.16% to 0.55% for Mg, analyses of the leaf petioles were well within these norms (table 1). According to norms for

grapevine nutrient levels in leaf blades, i.e. 1.6% to 2.7% for N, 0.14% to 0.55% for P, 0.65% to 1.3% for K, 1.2% to 2.2% for Ca, and 0.16% to 0.55% for Mg, analyses of the leaf blades were well within these norms (table 2). With a few exceptions, similar trends were observed for the petioles and blades in the 2018/19 and 2019/20 seasons. Yield, berry mass at harvest and cane mass did not differ between treatments in the 2017/18 season (table

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TECHNICAL YEARBOOK 2023