The prolonged drought in the Western Cape province of South Africa in recent years has been particularly detrimental to the wine industry. Water restrictions imposed by authorities and the limited supply of fresh water that can be stored, have emphasisedthe need for alternative water sources for vineyard irrigation. Treated municipal wastewater has been used successfully as an alternative source of irrigation water in other countries. A long-term trial was conducted in commercial vineyards in the Coastal region of South Africa to assess the impact of treated municipal wastewater irrigation on vineyards. Cabernet Sauvignon and Sauvignon blanc grapevines were irrigated using treated municipal wastewater from the Potsdam wastewater treatment works for 11 years. Grapevines were either rainfed (RF), irrigated with treated municipal wastewater via a single dripper line (SLD), or received twice the volume of wastewater via a double dripper line (DLD). Irrigation using treated municipal wastewater increased soil pH(KCl), the electrical conductivity of the saturated extract (ECe) and Cl-. Substantial amounts of Na+ and K+ accumulated in the topsoil due to irrigation with treated municipal wastewater. These soil K+ increases could have a negative effect on wine colour stability should the levels of soil K+ be such that they are absorbed excessively by grapevines. The near-saturation hydraulic conductivity (Kns) at the surface of the soil could be related to the ECe in the topsoil. The results represent specific in-field situations in three commercial vineyards under one set of climatic conditions.

A long-term trial was conducted in commercial vineyards in the Coastal region of South Africa to assess the impact of treated municipal wastewater irrigation on vineyards. Cabernet Sauvignon and Sauvignon blanc grapevines were irrigated using treated municipal wastewater from the Potsdam wastewater treatment works for 11 years. Grapevines were either rainfed (RF), irrigated with treated municipal wastewater via a single dripper line (SLD) or received twice the volume of wastewater via a double dripper line (DLD). Grapevine responses were measured from the 2013/14 to 2017/18 seasons. Although high amounts of K+, Na+ and Cl- were applied via wastewater irrigation, it did not result in excessive uptake by plants and did not affect vegetative growth or yield negatively. Irrigation reduced water constraints throughout the growing season compared to RF conditions, particularly for Cabernet Sauvignon. Consequently, SLD and DLD grapevines produced stronger vegetative growth and higher yields compared to RF. Results showed that the availability of irrigation water (albeit of relatively low quality) in regions where grapevines are usually grown under dryland conditions can increase grapevine productivity whilst maintaining good fruit quality. However, the water can vary in its availability as well as its quality over a short period of time. Plant and soil water status should be monitored regularly to avoid over-irrigation. Implementing low frequency irrigation scheduling with a sufficient leaching fraction will allow adequate time between irrigation applications for soils to aerate and organic material to decompose. Irrigation water, soils and grapevine leaves should be analysed to ensure that chemical parameters conform to recommended thresholds and norms.

Sustainable viticulture is important for socio-economic prosperity in the Western and Northern Cape provinces of South Africa. Limited natural water resources, as well as periodic droughts in these regions necessitate the need to find alternative sources of irrigation water to sustain yield and quality. The large volumes of treated municipal wastewater generated annually holds promise as an alternative water source. Despite various treatment procedures, municipal wastewater may contain high levels of Na+, B3+, Cl- and SO42-, as well as trace elements and heavy metals. However, it often contains essential plant nutrients, e.g. N, P and K+. If treated properly, municipal wastewater may be beneficial when reused for irrigating agricultural crops. Possible benefits include recycling of nutrients, fertiliser savings, the addition of organic material, a reduced pressure on fresh water sources and reduced environmental contamination. However, high salt loads, in particular Na+, can have detrimental effects on soil physical and chemical properties, as well as crop sustainability. Therefore, it is essential to implement measures that will limit damage caused by salinity and/or sodicity. The attenuation and accumulation of toxic substances should also be managed to a minimum. Most of the information regarding treated municipal wastewater has been generated through laboratory studies using simulated wastewater, or in some cases actual wastewater. No studies have yet investigated the impact of irrigation with treated municipal wastewater under the conditions that prevail in South African grape growing regions.

Mancozeb spray deposition and the persistence thereof to rainfall are important factors influencing the efficacy of apple scab control caused by Venturia inaequalis. Fungicide deposition can be assessed through quantification of fungicide residue, or fluorescent pigment quantification. Fluorescent pigment quantification is a more cost effective and less labour intensive method, since it is assessed using only photomacrography and image analyses. The yellow fluorescent pigment used in this study was shown to be a suitable tracer for five different mancozeb formulations on apple leaves when evaluated at different concentrations (0.5, 1.0, 1.5 and 2.0). Pearson's correlation was significant (P < 0.001) and high (r = 0.896) between fluorescent particle coverage (FPC%) and mancozeb residue (mg/kgDry Weight) for all five formulations. The particle size ranges of two wettable powder (WP) formulations were significantly smaller than those of the other WP formulations, but this did not result in differences in mancozeb residue on apple leaves. The persistence of mancozeb to different rain volumes applied to apple leaves was determined for three mancozeb formulation treatments: Dithane M-45 800 WP NT, Ventum 800 WP, and Ventum 800 WP combined with the sticker-spreader adjuvant Nu-Film P. There were no significant differences (P > 0.495) between the three treatments based on FPC% and mancozeb residue quantity when simulated rain was applied to apple seedlings at a constant rainfall intensity of 5 mm/h at five different rainfall volumes (0, 1, 5, 10 and 15 mm). A fair to good correlation (r = 0.697 and 0.995) existed between FPC% and mancozeb residue, and their percentage loss at different rainfall volumes. However, the response of FPC% and mancozeb residue differed based on exponential regression curves. This was due to a markedly larger predicted loss by each model's asymptote, 51.67% for FPC% and 40.76% for mancozeb residue. Based on actual mancozeb residue values, a significant percentage loss in residue already occurred after applying 1 mm (32.90%) rain. When rain volumes were increased to 5 and 10 mm rain, the percentage losses (37.88 and 41.08%) did not differ significantly from 1 mm rain. The same was true for percentage loss in FPC%, except that a significant higher loss occurred at 10 mm (52.36%) than at 1 mm rain (41.13%).

The re-use of winery wastewater for irrigation was investigated in a field trial with micro-sprinkler-irrigated Cabernet Sauvignon/99 Richter in the Breede River Valley region of South Africa. Irrigation with winery wastewater diluted with river water to 100, 250, 500, 1 000, 1 500, 2 000, 2 500 and 3 000 mg/L chemical oxygen demand (COD) was compared to irrigation with river water. No trends were found in soil pH((KCl)) and electrical conductivity of the saturated soil extract (ECe) that were related to the different levels of dilution. However, ECe was considerably higher after the application of diluted winery wastewater irrigations compared to ECe at bud break. This suggests an accumulation of salts from the diluted winery wastewater. Under the prevailing conditions, soil K+ and Na+ increased with a decrease in the dilution of the winery wastewater. Increases in K+ could have a negative impact on wine colour stability should potassium be taken up by the grapevine in sufficient quantities, particularly if soil K+ accumulates to such an extent that it is luxuriously absorbed by grapevines. There were no consistent trends with regard to soil organic C, which indicates that there was too little organic material in the wastewater to have had a positive effect on soil fertility. Furthermore, organic material in the wastewater probably oxidised when the soil was aerated between irrigations. Although irrigation with diluted winery wastewater had almost no other effects, element accumulation, particularly with respect to K+ and Na+, might be more prominent in heavier soils or in regions with low winter rainfall.

The annual wastewater quality dynamics of a winery from which wastewater was sourced for a field experiment investigating the dilution of winery wastewater for vineyard irrigation were determined. Annual mean monthly pH ranged from 4.2 to 6.8 and was lower during grape harvest than in winter. Electrical conductivity (EC) increased from the start of harvest (February) and reached a maximum in May, followed by a decline to a minimum in August. The increase in EC probably originated from cleaning agents used in the winery, as well as K+. in the grape lees and spillage from the grape fermentation process. With the exception of August, EC exceeded the critical value of 0.75 dS/m, which is the salinity threshold for water used for grapevine irrigation. The mean monthly chemical oxygen demand (COD) level increased from January and was highest at peak harvest (March). The K+ and Na+ levels in the winery wastewater increased from February to May. The sodium adsorption ratio (SAR) ranged from 2.4 to 9.0 and increased from January to June. Although COD concentration in winery wastewater is the preferred indicator of water quality for the South African wine industry, it did not provide a reliable indication of suitability for irrigation. However, EC was strongly determined by the K+ concentration. This was to be expected, since K+ is usually the most abundant cation in winery wastewater. Therefore, EC would be a more reliable indicator of winery wastewater quality than COD concentration, particularly with regard to the concentrations of cations such as K+ and Na+.

Heuweltjies are unique landscape features putatively created by the termite Microhodotermes viator through their burrowing and nest-building activities. They have been closely examined in the natural veld of the Western Cape in the recent past and are the focus of many ecological studies, but their effect in cultivated landscapes (e.g. vineyards and orchards) has remained unexplored. This study addresses the vigour and physiology of vines growing on and off heuweltjies, as well as the wine emanating from these vines. This study was conducted on Cabernet Sauvignon and Shiraz in two climatic regions of the Western Cape, namely Stellenbosch (Mediterranean climate) and Robertson (semi-arid climate) respectively, to better understand how differences in heuweltjie characteristics correspond to differences in rainfall and temperature. Through the use of ANOVAs and Fisher’s LSD post hoc tests to indicate statistical significance, it was apparent that the soil on and off heuweltjies differed significantly in respect of several physical and chemical properties. Consequently, soil water content was more favourable on heuweltjies, especially in the Stellenbosch area, where only supplementary irrigation was applied. Heuweltjies induce substantial changes in grapevine vigour and grape composition. Differences in grapevine physiology between heuweltjie and non-heuweltjie plots were subtle, but vine vigour was severely altered on the heuweltjieassociated vines, exhibiting excessive vegetative growth in Stellenbosch and leading to variations in berry and wine characteristics on and off the heuweltjies. The opposite was observed in the semi-arid climate of Robertson. The presence of heuweltjies in vineyards presents an opportunity to produce and market wines with a difference in respect of their characteristics and unique origin.

The re-use of winery wastewater for irrigation was investigated in a field trial with micro-sprinkler irrigated Cabernet Sauvignon/99Richter in the Breede River Valley region of South Africa. Irrigation with winery wastewater diluted with river water to 100, 250, 500, 1 000, 1 500, 2 000, 2 500 and 3 000 mg/L chemical oxygen demand (COD) was compared to irrigation with river water. Under the prevailing conditions, plant water status did not respond to irrigation using diluted winery wastewater. Leaf and shoot element contents did not respond consistently to irrigation using diluted winery wastewater. There were no differences in vegetative growth or yield or juice characteristics, with the exception of juice pH. Consequently, water use and water status of the grapevines also were not affected. The results indicate that a summer interception crop may increase the evapotranspiration of vineyards substantially. The irrigation of grapevines using diluted winery wastewater did not have detrimental effects on wine colour and sensory wine characteristics, and the grapevines did not respond to the COD level per se. This indicates that sufficient aeration occurred between irrigations, which allowed organic carbon breakdown. The low salinity and sodicity levels in the diluted winery wastewater could be a further explanation of why the grapevines did not respond to the wastewater irrigation. In heavier soils, regions with lower winter rainfall, situations where the winery wastewater contains more potassium or where no interception crop is cultivated during summer, grapevine responses may be more pronounced.

Possible re-use of winery wastewater for irrigation was investigated in a field trial with micro-sprinklerirrigated Cabernet Sauvignon/99 Richter in the Breede River Valley region of South Africa. Irrigation with winery wastewater diluted to 100, 250, 500, 1 000, 1 500, 2 000, 2 500 and 3 000 mg/L chemical oxygen demand (COD), respectively, was compared to irrigation with raw river water. Since the pH was lower than 6, the diluted wastewater could cause nutrient toxicity. The diluted winery wastewater did not pose any salinity hazard, as the electrical conductivity was well below 2 dS/m. For the given range of dilutions, the sodium adsorption ratio never exceeded 10, which indicates that the water posed no sodicity hazard. Sodium and Cl- never exceeded 115 and 150 mg/L, the respective upper thresholds for grapevines. With the exception of N, levels of H2PO4 -, K+, Na+, Ca2+, Mg2+, HCO3 -, SO4 2- and B3+ in the diluted wastewater increased with a decrease in dilution level. The N load in diluted winery wastewater appeared to be completely inadequate to supply the grapevine’s requirements. In contrast, the P load in the winery wastewater diluted to 2 500 mg/L COD and higher would supply more than adequate P if the grape yield amounts to 10 t/ha. Likewise, the dilution of winery wastewater to 250 mg/L COD and higher would supply more than adequate K+ if the grape yield amounts to 10 t/ha. However, K+ applied via the wastewater will only be beneficial if it is not leached from the root zone during winter.

This is the first book in 70 years on soils of South Africa and is a significant scientific contribution on the understanding of South African soils. As the title suggests, this book's main objective is to give the reader a comprehensive view on the unique soils of South Africa, their distribution, properties, classification, genesis and land use. The author has developed his own grouping system with which all the soils from the South African soil classification system are grouped into fourteen distinctive soil groups. This totally new concept for South African soils and the key on how to do this is well thought out. This book compares well with any book written in the U.S.A. or Europe and is quite unique in the way the author strikes a relationship between animals and soils. There have been no previous attempts in the literature to illustrate the contribution of animals to soil formation so clearly as this book.

Large areas of the soils under rainfed crop production in the semi-aridclimate regions Southern Africa are of Aeolian origin with a sandytexture. These soils are prone to wind erosion, soil compaction anddrought, which hamper sustainable crop production. Field experimentswere conducted over three years in which 3 tillage practices werecombined with 3 cropping practices. The tillage practices were: i)conventional mouldboard ploughing, ii) stubble mulch tillage, both incombination with deep ripping and controlled traffic, and iii)no-tillage with chemical weed control. Every tillage practice wascombined with three cropping practices viz. i) continuous maize, ii)wheat with a 5-month fallow, and iii) maize and wheat in rotationallowing a 10-month fallow. It was found that continuously grown maizeand wheat with conventional tillage gave the highest rainfall useefficiency. Conventionally grown maize and wheat in rotation with alonger fallow gave the highest yields, whereas no-tillage withcontinuous maize and wheat gave the lowest yields. The yields onstubble mulching were lower than those on conventional tillage.