Environmental impact of winery effluent in the Western and Northern Cape Provinces

Please read the abstract in the section 00front of this documentDissertation (M Inst Agrar (Land Use Planning))--University of Pretoria, 2001.Agricultural Economics, Extension and Rural Developmentunrestricte

Effect of Irrigation with Diluted Winery Wastewater on Enzyme Activity in Four Western Cape Soils

Irrigating vineyards with winery wastewater is an established practice. However, the effect of this water on soil enzyme activity is unknown. Soils from four vineyard areas were irrigated, in pots, over four simulated seasons with municipal water, and with winery wastewater diluted to a chemical oxygen demand of 3000 ml/L. Urease, ?-glucosidase and phosphatase activities were determined after each season. The experimental soils were: an alluvial vineyard soil from Rawsonville (RS), an aeolian veld soil from Lutzville (LS), and shale (SS)—and granite (SG)—derived soils from Stellenbosch. Comparedwith municipal water, irrigating with winery wastewater significantly (p = 0.05) increased urease activity in all four soils, and promoted ?-glucosidase activity in SS and SG. Conversely, winery wastewater suppressed phosphatase activity in the RS, SH and SG soils. Averaged over all soils, winery wastewater promoted the activity of ?-glucosidase and urease, but suppressed that of phosphatase. All-treatment enzyme activities increased in the sequence: LS<RS<SG<SS for urease, LS<RS<SS<SG for phosphatase and LS<RS<SG<SS for ?-glucosidase. Winery wastewater and municipal water therefore affect soil enzyme activity differently. The extent of this activity varies inconsistently between soils. Whether similar results would be obtained under vineyard conditions have yet to be determined

Growth and yield parameters of three cowpea (Vigna unguiculata L. Walp) lines as affected by planting date and zinc application rate

Cowpea is one of the most important food legumes in most African countries. Cowpea is a valuable source of dietary protein for both humans and their livestock. There is limited information available on cowpea production and suitable agronomic practices, such as planting date, to best suit different environmental conditions in South Africa. Therefore, the objective of this study was to evaluate the effect of two locations on cowpea production and the effect of planting date as affected by zinc application rate. Field experiments were conducted at two locations (Bien Donne’ and Nietvoorbij) in the Western Cape Province of South Africa, using two planting dates (2 October and 2 November), three cowpea lines (Veg1, M217 and Qukawa) and three zinc (Zn) fertiliser application levels (0 kg/ha, 15 kg/ha and 30 kg/ha) during the 2015 growing season. The experimental design was a randomised complete block with five replicates. The results showed that Veg1 and Qukawa lines performed significantly better in both vegetative and reproductive parameters when compared to M217 at both locations. Application of zinc fertiliser significantly (p<0.05) affected seed iron content in Veg1 and M217 at Bien Donne’ and seed iron content in M217 and zinc content in Veg1 at Nietvoorbij. Significance: • Cowpea lines Veg1 and Qukawa were the best performing lines in all parameters measured, making these two lines suitable for dual purpose cultivation. • Planting cowpea in November, rather than October, increased the crop production efficiency. • Cowpea showed a better overall total yield in the sandy soil of Bien Donne’ than in the sandy loam clay soil of Nietvoorbij. Open data set:  https://osf.io/u4veb/?view_only=45d90f5cd93949fb90cd0ee45055f92

Micromineral Content of Swiss Chard (Beta vulgaris L. var. cicla) Leaves Grown on Zeolite-Amended Sandy Soil

Swiss chard (Beta vulgaris L. var. cicla), a popular leafy vegetable grown mainly for its ease of production and nutritional content, is normally used as a good source of microminerals iron (Fe) and zinc (Zn). Improving plant uptake of Fe and Zn could assist in reducing micromineral deficiencies in humans, which are a global problem. A greenhouse pot experiment was conducted at the Agricultural Research Council, Stellenbosch to assess the response in micromineral and soil trace elements uptake in Swiss chard grown under zeolite and sandy soil. The experiment consisted of four treatments, with six replicates arranged in a randomized complete block design. Zeolite was applied at 0%; 10%; 20% and 30% in combination with sandy soil. Swiss chard was harvested for micromineral analysis 143 days after transplanting. Soil samples were also collected at the end of each growing season. Swiss chard leaves were analysed for Fe, Zn, Mn, and Cu content with soil samples also analysed for the same elements. The study found that zeolite did not improve Swiss chard uptake of Fe, Zn and Mn. Soil Fe also had an inverse relationship to zeolite application while the residual effect of zeolite showed the same trend, but only in the second season. This study indicated that zeolite cannot be used to improve micromineral uptake by Swiss chard but can be used to rectify heavy metal-infested soils

The effect of winery wastewater irrigation on the properties of selected soils from the South African wine region

Thesis (PhD)--Stellenbosch University, 2016.ENGLISH ABSTRACT: Due to an increase in wine production as well as an intensification of environmental legislation in South Africa, the need for guidelines for sustainable management of winery wastewater has increased. To address this, the first part of the study focused on the seasonal dynamics of the volumes and quality of undiluted winery wastewater. The soil chemical dynamics were monitored in two different soils that were irrigated with undiluted winery wastewater for three years. Over-irrigation with undiluted winery wastewater in combination with winter rainfall caused large amounts of cations, particularly K+ and Na+, to leach beyond 90 cm soil depth. Consequently, the leached elements are bound to end up in natural water resources over time. Irrigation with undiluted winery wastewater did not have a pronounced effect on soil pH(KCl). This was probably due to the decomposition of organic matter and the fact that the applied salts as well as dissolved organic or mineral acids leached beyond 90 cm depth. The practical application of irrigation with diluted winery wastewater was assessed in a pot experiment. Irrigations were applied under a rain shelter over four simulated irrigation seasons. Four soils varying in texture were irrigated with winery wastewater that was diluted to 3000 mg/L chemical oxygen demand (COD). The four soils were irrigated with municipal water as a control. The rate of K+ increase in the soil containing 20% clay was higher than in soils containing 13% clay, or less. This suggested that heavy soils will aggravate the risk of high K+ levels. The risk of Na+ accumulation increased linearly with the clay content in the soil. Low Ca2+ and Mg2+ concentrations in the diluted wastewater had no effect on the soil, irrespective of clay content. Irrigation with diluted winery wastewater increased soil pH(KCl) substantially in all soils over four simulated seasons. The soil pH increase was attributed to the addition of organic and mineral salts via the diluted winery wastewater to the soil. The effect of simulated rainfall on soils irrigated with winery wastewater was also assessed in a pot experiment. Six soils with different clay content were irrigated with winery wastewater diluted to 3000 mg/L over one simulated irrigation season. Thereafter, good quality river water simulating winter rainfall was added to the pots. The rainfall was simulated according to the long term averages of the regions were the soils originated. Leaching of cations, particularly K+ and Na+ occurred only from four of the six soils when winter rainfall was simulated. In one of the sandy soils, the simulated rainfall was too low to allow leaching. In the case of other soil where there was no leaching, high clay content of 35% in combination with low rainfall prevented leaching. Where three soils received the same amount of rainfall, more cations leached from the sandy soils compared to the two heavier soils. These trends indicated that leaching of cations was a function of soil texture and rainfall.AFRIKAANS OPSOMMING: As gevolg van die toename in wynproduksie, asook ‘n verskerping in omgewingswetgewing in Suid-Afrika, het die behoefte vir riglyne vir volhoubare bestuur van kelderafvalwater ‘n belangrike aspek van wynproduksie geword. Om dit aan te spreek, het die eerste deel van die studie op die seisoenale dinamika van die volumes en gehalte van onverdunde kelderafvalwater gefokus. Die grondchemiese dinamika in twee verskillende gronde wat met onverdunde kelderwater besproei is,by twee verskillende kommersiële kelders oor drie seisoene gemonitor. Oorbesproeiing met die onverdunde kelderafvalwater, in kombinasie met winterreënval, het veroorsaak dat groot hoeveelhede katione, veral K+ en Na+, dieper as 90 cm gronddiepte geloog het. Die nagevolg hiervan is dat die geloogde elemente oor tyd in natuurlike water hulpbronne sal beland. Besproeiing met onverdunde kelderafvalwater het nie ‘n noemenswaardige effek op grond pH(KCl) gehad nie. Dis was heel waarskynlik te wyte aan die feit dat die organiese materiaal ontbind het, en dat die toegediende katione as opgeloste organiese of mineraal soute verby 90 cm diepte geloog het. Die praktiese toepasbaarheid van besproeiing met verdunde kelderafvalwater is in ‘n potproef ondersoek. Besproeiings is onder ‘n reënskuiling oor vier gesimuleerde seisoene toegedien. Vier gronde met verskillende teksture is besproei met kelderafvalwater wat tot 3000 mg/L chemiese suurstof aanvraag (Eng. = chemical oxygen demand, of kortweg COD). As ‘n kontrole is die vier gronde met munisipale water besproei. Die K+ toename in die grond wat 20% klei bevat het, was hoër as in gronde wat 13% of minder klei bevat het. Dit het aangedui dat die risiko van K+ aansameling hoër is in swaarder gronde. Die risiko van Na+ toename het reglynig toegeneem met klei inhoud in die grond. Lae Ca2+ en Mg2+ konsentrasies in die verdunde afvalwater het geen effek in die gronde gehad nie, ongeag die klei-inhoud. Besproeiing met verdunde kelderafvalwater het die grond pH(KCl) in al die gronde oor die vier gesimuleerde seisoene betekenisvol laat toeneem. Die pH toename in die gronde kon aan die toediening van organiese en mineraal soute deur middel van die verdunde kelderwater toegeskryf word. Die effek van gesimuleerde winterreënval op gronde wat eers met verdunde kelderafvalwater besproei is, is ook met behulp van ‘n potproef ondersoek. Ses gronde met verskillende kleiinhoude is vir een gesimuleerde besproeingseisoen met kelderafvalwater wat tot 3000 mg/L COD verdun is, besproei. Daarna is gesimuleerde winterreënval in die vorm van hoe kwaliteit rivierwater op die gronde toegedien. Die reënval is volgens die langtermyn gemiddeldes van die streke waar die gronde voorgekom het, gesimuleer. Loging van katione, veral K+ en Na+ het slegs by vier van die ses gronde tydens die gesimuleerde winterreënval voorgekom. In die geval van een van die sanderige gronde, was die gesimuleerde reënval te min om loging te veroorsaak. In die geval van die ander grond waar geen loging voorgekom het nie, het die hoë-klei inhoud van 35%, in kombinasie met lae winterreënval, loging verhoed. Waar drie gronde dieselfde hoeveelheid reënval ontvang het, het meer katione uit die sanderige grond in vergelyking met die twee swaarder gronde geloog. Hierdie tendense het aangedui dat loging van katione ‘n funksie van grondtekstuur en reënval is

In-field assessment of soil pH and mineralization of phosphorus and potassium following the application of composted winery solid waste in sandy loam Ferric Luvisol

Special attention on the plant nutrients mineralization rates is often required when organic fertilizers are used on croplands. This study described the patterns of phosphorus (P) and exchangeable potassium (K) released from winery solid waste (WSW) compost in sandy loam soil. Treatments consisted of equivalent rates of 0, 5, 10, 20 and 40 t ha-1 of compost-soil mixture in Ziplock bags buried on the field at 30 cm soil depth. Destructive sampling of treatments was conducted at 0, 7, 21, 42, 63, 84, 105 and 126 days after incubation (DAI) for laboratory analysis. The 40 t ha-1rate resulted in up to a 9.5% increase in soil pH while the contents of net mineralized P and K measured were significantly affected by compost rate and incubation period interaction. Over the 126 days of the incubation period that runs across summer and winter seasons, mineralized P ranged from -62 to 86 mg kg-1 whereas mineralized K varied between 41 and  2047 mg kg-1. Cumulative mineralized P and K contents ranged from 62 to 207 mg kg-1 and 1272 to 9206 mg kg-1, respectively with the highest amount obtained at the 40 t ha-1 compost rate. The high net P and K mineralized contents suggest that WSW compost may act as a P and K source. However, cautious use of WSW compost as a soil amendment is recommended to mitigate the potential risks of soil pH increases and other unintended consequences such as toxicity, nutrient imbalance, and possible P and K antagonistic effects.Keywords: Compost; Nutrient mineralization; Phyto-toxicity; Soil amendment

In-field assessment of soil pH and mineralization of phosphorus and potassium following the application of composted winery solid waste in sandy loam Ferric Luvisol

Special attention on the plant nutrients mineralization rates is often required when organic fertilizers are used on croplands. This study described the patterns of phosphorus (P) and exchangeable potassium (K) released from winery solid waste (WSW) compost in sandy loam soil. Treatments consisted of equivalent rates of 0, 5, 10, 20 and 40 t ha-1 of compost-soil mixture in Ziplock bags buried on the field at 30 cm soil depth. Destructive sampling of treatments was conducted at 0, 7, 21, 42, 63, 84, 105 and 126 days after incubation (DAI) for laboratory analysis. The 40 t ha-1rate resulted in up to a 9.5% increase in soil pH while the contents of net mineralized P and K measured were significantly affected by compost rate and incubation period interaction. Over the 126 days of the incubation period that runs across summer and winter seasons, mineralized P ranged from -62 to 86 mg kg-1 whereas mineralized K varied between 41 and  2047 mg kg-1. Cumulative mineralized P and K contents ranged from 62 to 207 mg kg-1 and 1272 to 9206 mg kg-1, respectively with the highest amount obtained at the 40 t ha-1 compost rate. The high net P and K mineralized contents suggest that WSW compost may act as a P and K source. However, cautious use of WSW compost as a soil amendment is recommended to mitigate the potential risks of soil pH increases and other unintended consequences such as toxicity, nutrient imbalance, and possible P and K antagonistic effects.Keywords: Compost; Nutrient mineralization; Phyto-toxicity; Soil amendment