Technical Yearbook 2023

25

5

Nitrogen extracted (kg/ha)

Phosphorus extracted (kg/ha)

20 25

4 5

Nitrogen extracted (kg/ha)

Phosphorus extracted (kg/ha)

15 20 25

3 4 5

to sandy clay loam soil. Ten different fodder producing catch crops were compared to a control where no catch crop was cultivated. Vetiver grass, Dolichos beans and Chicory performed best in terms of dry matter production (DMP) as summer catch crops. Additionally, Vetiver grass produced enough DMP to make bales which could potentially be sold. If element uptake from the soil is considered, then the Dolichos beans and Chicory were the best catch crops. Unfortunately, the summer catch crops only absorbed a low percentage of the elements applied via the diluted winery wastewater. In conclusion, the study showed that catch crops can be established using winery wastewater, but they are probably not the only solution, because they did not remove substantial amounts of the salts. Catch and cover crop responses in the vineyard will be presented in the next article. Acknowledgements • The project was funded by Winetech and the Agricultural Research Council (ARC). • ARC for infrastructure and resources. • Staff of the Soil and Water

Nitrogen extracted (kg/ha)

Phosphorus extracted (kg/ha)

10 15 20

2 3 4

5 10 15

1 2 3

0 5 10

0 1 2

Bottle brush grass

Bottle brush grass

Pearl millet

Pearl millet

Vetiver grass

Vetiver grass

Weeping love grass

Weeping love grass

Barsweet sorghum

Fodder radish

Cow peas

Chicory Dolichos beans

Barsweet sorghum

Fodder radish

Chicory Dolichos beans

E. teff

E. teff Cow peas

0 5

0 1

Bottle brush grass

Bottle brush grass

Pearl millet

Pearl millet

Vetiver grass

Vetiver grass

Weeping love grass

Weeping love grass

Barsweet sorghum

Fodder radish

Cow peas

Chicory Dolichos beans

Barsweet sorghum

Fodder radish

Chicory Dolichos beans

E. teff

E. teff Cow peas

5 0

2,0 0

Potassium extracted (kg/ha) Fodder radish E. teff Cow peas Chicory Dolichos beans Vetiver grass

Calcium extracted (kg/ha) Fodder radish E. teff Cow peas Chicory Dolichos beans Vetiver grass

Bottle brush grass

Bottle brush grass

Pearl millet

Pearl millet

Weeping love grass

Weeping love grass

Barsweet sorghum

Barsweet sorghum

4 5

0,0 0,5 0,5 1,0 0,5 1,0 1,5 1,0 1,5 2,0 1,5 2,0 0,0

Potassium extracted (kg/ha)

Calcium extracted (kg/ha)

3 4 5

Potassium extracted (kg/ha)

Calcium extracted (kg/ha)

2 3 4

1 2 3

0 1 2

Bottle brush grass

Bottle brush grass

Pearl millet

Pearl millet

Vetiver grass

Vetiver grass

Weeping love grass

Weeping love grass

Barsweet sorghum

Fodder radish

Cow peas

Chicory Dolichos beans

Barsweet sorghum

Fodder radish

Chicory Dolichos beans

E. teff

E. teff Cow peas

0 1

Bottle brush grass

Bottle brush grass

Pearl millet

Pearl millet

Vetiver grass

Vetiver grass

Weeping love grass

Weeping love grass

Barsweet sorghum

Fodder radish

Cow peas

Chicory Dolichos beans

Barsweet sorghum

Fodder radish

Chicory Dolichos beans

E. teff

E. teff Cow peas

5 0

5 0,0

Bottle brush grass

Bottle brush grass

Magnesium extracted (kg/ha) Fodder radish E. teff Cow peas Chicory Dolichos beans Vetiver grass

Pearl millet

Pearl millet

Sodium extracted (kg/ha) Fodder radish E. teff Cow peas Chicory Dolichos beans Vetiver grass

Weeping love grass

Weeping love grass

Barsweet sorghum

Barsweet sorghum

4 5

4 5

Magnesium extracted (kg/ha)

Sodium extracted (kg/ha)

3 4 5

3 4 5

Magnesium extracted (kg/ha)

Sodium extracted (kg/ha)

2 3 4

2 3 4

1 2 3

1 2 3

0 1 2

0 1 2

Bottle brush grass

Bottle brush grass

Pearl millet

Pearl millet

Vetiver grass

Vetiver grass

Weeping love grass

Weeping love grass

Barsweet sorghum

Fodder radish

Cow peas

Chicory Dolichos beans

Barsweet sorghum

Fodder radish

Chicory Dolichos beans

E. teff

E. teff Cow peas

0 1

0 1

FIGURE 2. The average amount of macro-elements extracted from the open land soil by the catch crops which were irrigated with diluted winery wastewater for four years. Pearl millet Barsweet sorghum Fodder radish E. teff Cow peas Chicory Dolichos beans Vetiver grass Bottle brush grass Weeping love grass Pearl millet Barsweet sorghum Fodder radish E. teff Cow peas Chicory Dolichos beans Vetiver grass Bottle brush grass Weeping love grass

0

0

Bottle brush grass

Bottle brush grass

Pearl millet

Pearl millet

Vetiver grass

Vetiver grass

Weeping love grass

Weeping love grass

Barsweet sorghum

Fodder radish

Cow peas

Chicory Dolichos beans

Barsweet sorghum

Fodder radish

Chicory Dolichos beans

E. teff

E. teff Cow peas

Abstract Wineries in South Africa are estimated to generate between 2 190 - 15 330 million litres of wastewater per year. Using this water for irrigation adds substantial amounts of elements to the soil. Maximising element removal by means of a catch crop is therefore important. Consequently, the objective of this study was to identify fodder producing crops that would intercept sufficient K (and Na) applied via irrigation with diluted winery wastewater on open land with loamy sand

considered, then the Dolichos beans and Chicory were the best catch crops. However, it should be noted that unfortunately the summer catch crops only absorbed a low percentage of the elements applied via the diluted winery wastewater. This indicates that it may not be sustainable to plant catch crops and that they are probably not the only solution. However, the negative effects of using winery wastewater for irrigation is a serious concern and these effects could potentially be negated, to a certain extent, by using catch crops.

Science division at ARC Infruitec-Nietvoorbij for technical support. 

References https://www.wineland.co.za/ winery-wastewater-for irrigation-part-2/

For more information, contact Carolyn Howell at howellc@arc.agric.za.

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TECHNICAL YEARBOOK 2023