Technical Yearbook 2023

TABLE 1. Treatments applied on the open land at Nietvoorbij research farm. Treatment no. Species Management practice applied 1 Pearl millet

Allowed to complete life cycle, harvest and bale. 1

2 3 4 5 6 7 8 9

Barsweet sorghum Allowed to complete life cycle, harvest and bale. 1

Fodder radish Eragrostis teff

Allowed to complete life cycle, harvest (can be used for fodder immediately).

Allowed to complete life cycle, harvest and bale. 1 Allowed to complete life cycle, harvest and bale. 1 Allowed to complete life cycle, harvest and bale. 1 Allowed to reach maturity, harvest and bale. 2 Allowed to reach maturity, harvest and bale. 2 Allowed to reach maturity, harvest and bale. 2

Cow peas Chicory

Allowed to reach maturity (cut with slasher to simulate grazing and measure harvest).

Dolichos beans Vetiver grass Bottle brush grass Weeping lovegrass

10 11

Bare soil, no catch crop 1 Bales may be sold for winter fodder or bio-fuel. 2 Bales may be sold for mulching of crop rows.

TABLE 2. Treatments applied in the micro-sprinkler irrigated Shiraz/110 Richter vineyard irrigated full surface at Nietvoorbij research farm. Treatment no. Summer catch crop (baled/harvested) Winter cover crop for summer mulch Irrigation 1 Pearl millet Saia oats or Pallinup oats Diluted winery wastewater/raw water 1 2 Pearl millet Mixture of N-fixing species Diluted winery wastewater/raw water 3 Dolichos beans (N-fixing) Saia oats or Pallinup oats Diluted winery wastewater/raw water 4 Dolichos beans (N-fixing) Mixture of N-fixing species Diluted winery wastewater/raw water 5 Chicory Saia oats or Pallinup oats Diluted winery wastewater/raw water 6 Chicory Mixture of N-fixing species Diluted winery wastewater/raw water 7 No cover crop Saia oats or Pallinup oats Raw water 8 No cover crop Mixture of N-fixing species Raw water 1 Water from the Nietvoorbij farm dam.

02/04/2019. The average COD and EC of the irrigation water applied to the open land were 1 212 mg/L and 151 mS/m, respectively. The average COD and EC of the irrigation water applied to the vineyard were 1 533 mg/L and 214 mS/m, respectively. The average Na, K, Ca and Mg content of the irrigation water applied to the open land was 107 mg/L, 318 mg/L, 66 mg/L and 18 mg/L, respectively. The average Na, K, Ca and Mg content of the diluted winery wastewater applied to the vineyard was 148 mg/L, 519 mg/L, 94 mg/L and 23 mg/L, respectively. Irrigation of the open land and vineyard commenced in mid-March 2020. Irrigations were applied to the open land and vineyard on 19/03/20, 11/05/20, 20/05/20 and 26/05/20. The average COD and EC of the irrigation water applied was 2 570 mg/L and 186 mS/m, respectively. The average Na, K, Ca and Mg content of the irrigation water applied was 83 mg/L, 332 mg/L, 98 mg/L and 15.9 mg/L, respectively. The concentrations of each element applied via the diluted

winery wastewater in the vineyard were used to calculate the amount of each element applied. In the 2017/18 season, 190 kg/ha, 133 kg/ha, 21 kg/ha and 115 kg/ha of K, Ca, Mg and Na, respectively, were applied. In the 2018/19 season, 238 kg/ha, 43 kg/ha, 10 kg/ha and 68 kg/ha of K, Ca, Mg and Na, respectively, were applied via the diluted winery wastewater to the vineyard. In the 2019/20 season, 325 kg/ha, 95 kg/ha, 15 kg/ha and 79 kg/ha of K, Ca, Mg and Na, respectively, were applied. Conclusions The diluted winery wastewater used for irrigation of the open land and vineyard contained high levels of K. Consequently, substantial amounts of K were applied via the irrigation with diluted winery wastewater. This could supply more than adequate K to the vineyard if grape yield amounts to 10 t/ha. The winery wastewater also contained high levels of Ca and Na and substantial amounts of these elements were also applied to the open land and vineyard via the diluted winery wastewater irrigation.

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TECHNICAL YEARBOOK 2023