Technical Yearbook 2023

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0,5

3,5

Phosphorus (%)

Nitrogen (%)

0,0 0,1 0,1 0,2 0,1 0,2 0,3 0,2 0,3 0,4 0,3 0,4 0,5 0,4 0,5 0,0 0,0 0,5 0,5 1,0 0,5 1,0 1,5 1,0 1,5 2,0 1,5 2,0 2,5 2,0 2,5 2,5 0,0 0,0

3,0 3,5

Phosphorus (%)

Nitrogen (%)

2,5 3,0 3,5

FIGURE 1. The average macro-elements content of the catch crops was determined in the vineyard in May for three years.

Phosphorus (%)

Nitrogen (%)

2,0 2,5 3,0

1,5 2,0 2,5

1,0 1,5 2,0

0,5 1,0 1,5

0,0 0,5 1,0

Pearl millet Dolichos beans Chicory

by a commercial laboratory for macro- and micro-elements. The amounts of the different macro- and micro-elements intercepted by the catch and cover crops were estimated by multiplying the DMP of the species with the concentration of the different The DMP, which is commonly used as an indication of how well a catch/cover crop grows under prescribed conditions is shown in table 1. Over the three years of using the catch crops, only the Dolichos beans (T3 & T4) performed consistently with the growth increasing over the duration of the trial. On average, Pearl millet (T1 & T2) produced a DMP of 0.2 t/ha, Chicory (T5 & T6) was 0.04 t/ha and Dolichos beans (T3 & T4) was 1.05 t/ha. The poor performance of the Pearl millet (T1 & T2) catch crop was opposite to the substantial DMP produced by a Pearl millet catch crop in a previous sandy soil trial. 5 It is possible that this was due to the heavier textured soil in the current study. The DMP of the winter cover crops is given in table 2. In particular, in September 2018 and 2019, the growth of the N-fixing winter (T2, T4, T6 & T8) cover crops was substantially more than that of the oats (T1, T3, T5 & T7). On average over the three seasons, the Chicory (T5 & T6) had the highest P, K, Ca, Mg and Na in its foliage (figure 1). Dolichos beans (T3 & T4) elements in the samples harvested for analyses. Results and discussion

0,0 0,5

Pearl millet Dolichos beans Chicory

3,5 0,0

Pearl millet Dolichos beans Chicory

Potassium (%)

Calcium (%)

3,0 3,5

Potassium (%)

Calcium (%)

2,5 3,0 3,5

Potassium (%)

Calcium (%)

2,0 2,5 3,0

1,5 2,0 2,5

1,0 1,5 2,0

0,5 1,0 1,5

0,0 0,5 1,0

Pearl millet Dolichos beans Chicory

0,0 0,5

Pearl millet Dolichos beans Chicory

0,7 0,0

0,0

Pearl millet Dolichos beans Chicory

Sodium (g/kg)

Magnesium (%)

0 1 2 1 2 3 2 3 4 3 4 5 4 5 6 5 6 0 1

0,6 0,7

Sodium (g/kg)

Magnesium (%)

0,5 0,6 0,7

Sodium (g/kg)

Magnesium (%)

0,4 0,5 0,6

0,3 0,4 0,5

0,2 0,3 0,4

0,1 0,2 0,3

0,0 0,1 0,2

Pearl millet Dolichos beans Chicory

0,0 0,1

Pearl millet Dolichos beans Chicory

0,0

Pearl millet Dolichos beans Chicory

Pearl millet Dolichos beans Chicory The aim of this study was: 1. to determine whether irrigation of a vineyard with diluted winery wastewater affected the performance and nutrient content of selected catch crops in a vineyard on loamy sand to sandy clay loam soil, 2. to determine the ability of the selected catch crops to intercept sufficient amounts of Na and K from the soil, and 3. to determine whether a further benefit of winter cover crops could be element interception and to what extent? Methods Diluted winery wastewater was applied to a Shiraz vineyard on the Nietvoorbij

research farm where combinations of three different fodder-producing summer catch crops and two winter cover crop treatments were compared to a control. Catch crops were not cultivated in the control treatment during the summer, but there were still two winter cover crop treatments. Details of the irrigation application and water quality have been given previously. 7 The dry matter production (DMP) of the catch and cover crops was estimated by sampling the above-ground vegetative growth in a 0.5 m 2 sub-plot randomly chosen in each plot. Samples were oven-dried for 48 hours at 105 ° C. A sample was collected from the sub-plot and analysed

TECHNICAL YEARBOOK 2023

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