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December 2015

IN THIS ISSUE:

President’s message

International Visit by ASABE

SAIAE/Industry Gauteng Breakfast 2015

SAIAE/UKZN Industry Breakfast 2015

Summary of the 2015 Agricultural Engineering Final Year Design Projects in the School

of Engineering at the University of KwaZulu Natal

Agricultural Tour of Suffolk & Norfolk Farming Practices SAIAE at Career Fairs

Field visit to ZZ2 Field Visit to the Northern Cape

Membership matters

President’s message

As the year draws to a close, amidst soaring temperature and plummeting rainfall figures, we can look back on a year full of activities that brought us as agricultural engineers closer together. The two successful business breakfasts and two stimulating field visits that took place in the last two months again reminded us of the extent and complexity of agricultural engineering while the UKZN final year function showed that there are still young people full of optimism and innovation to take on the future.

There are also two very special birthdays in December – firstly, on 8 December, our dear Mr Charles Crosby celebrated his 90th birthday. On behalf of all our members I would to congratulate him on his birthday and good health for the future. As a community we have really been blessed by having him with us for so many years. Secondly, SAIAE honorary secretary/treasurer, and now also honorary fellow, Felix Reinders is celebrating his 60th birthday on the 21st of December. We would like to congratulate him on reaching this milestone, and thank him for his commitment to SAIAE since his appointment to the SAILI Council in 1985. On behalf of the SAIAE Council I would like to wish all our members a joyous festive season during which to relax with family and friends, and return safely in 2016. _______________________________________________________________________________________

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International visit by ASABE

By Richard van der Merwe

It was a momentous occasion on the 28th of May 2015 when the South African Institute for Agricultural

Engineers (SAIAE) met a delegation from the American Society of Agricultural and Biological Engineers (ASABE).

The delegation consisted of five members namely Dorota Haman (University of Florida), Lalit Verma, Immediate

Past President (University of Arkansas), Mark Zielke (ASABE Marketing/financial manager), Mary Leigh Wolfe,

Incoming President (Virginia Tech) and Ajit Srivastava, Chair of the Global Engagement Task Team (Michigan

State University). The visitors were guided by Umezuruike Linus Opara of Stellenbosch University, a life member

of ASABE and member of the Global Engagement Task Team.

One of ASABE’s chief aims for the meeting was to promote and encourage collaboration, with SAIAE, for the

“Global Food Security Conference” which will be held in October 2016 in Stellenbosch.

The ASABE delegation with SAIAE members, Mr Justin Mutenje, Mr Petrus Britz, Mr Richard van der Merwe, Ms

Boeboe Neethling and Mr Pieter de Witt

The meeting was mutually beneficial with both parties gaining an insight into and understanding of each

other’s activities. The ASABE team also expressed interest to develop ongoing cooperation with SAIAE to

advance the agricultural engineering profession in South Africa and Africa in general.

SAIAE/Gauteng Industry Breakfast 2015

By Felix Reinders

SAIAE’s business breakfast in Gauteng took place in Pretoria on 7 October 2015 and the event strengthened ties between SAIAE and businesses serving the agricultural engineering sector. Felix Reinders provided the commercial entities and other interested parties with an overview of agricultural engineering and the contributions that agricultural engineers are making in industry after which the President of SAIAE, Isobel van der Stoep led the discussions and possible ways of co-operation. A mutually beneficial network was established between the companies and agricultural engineers for future collaboration. The companies that attended were Barloworld, Citrus academy, New Holland, Westfalia fruit estate, Fruit SA, Luriware Consulting, ARC-IAE, Terratill implements, Valtrac, Dormas, Senter 360, Grundfos, Lemken, ProAgri, Turf – Ag products and Unisa

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Companies attending the SAIAE Business breakfast which was hosted at ARC-Institute for Agricultural Engineering

SAIAE/KZN Industry Breakfast 2015

By Felix Reinders

The 2nd KZN Annual Interactive Business Breakfast took place at Ascot Conference Venue, Pietermaritzburg on

22 October 2015. Keynote speakers in the persons of Kevin Meier, Peter Lyne and Felix Reinders gave

excellent presentations on “Water Resources Planning in Umgeni Water’s Operational Area”, “Vehicle

Scheduling System in the Sugarcane Industry” and “Water, Energy and Food Triology” that created a good

platform for discussions on strategic pathways to create employment and empower people in rural South

Africa with various interventions by agricultural engineers. The President of SAIAE, Isobel van der Stoep also

led the discussions and possible ways of co-operation between the companies and agricultural engineers.

Beyond the presentations and the discussions, the business breakfast also served as a networking platform.

Companies attending the SAIAE Business breakfast

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Summary of the 2015 Agricultural Engineering Final Year Design Projects in the School

of Engineering at the University of KwaZulu Natal

By Professors Jeff Smithers and Tilahun Workneh

Five design projects were undertaken by the 2015 Final Year Agricultural Engineering students from the discipline of Bioresources Engineering in the School of Engineering at the University of KwaZulu-Natal. These are summarized below.

The Design, Construction and Performance Evaluation of a Soya Milk Extractor

This project was undertaken by Zukile Xelelo, Siphiwe Mdlalose and Rebecca Nkhata. The objectives of the project were: (i) to design and construct a small scale soya milk extractor and (ii) to evaluate the performance of soya milk extractor with respect to extraction rate and efficiency. The basic processes to extract milk from soya beans include soaking, grinding, cooking and filtration and the project focused on the cooking of ground soya beans and expression processes. The design specifications for the batch system were to achieve a cooking temperature of 121°C, a cooking pressure of 110 kPa and 75 litres of milk should be produced per day. A double boiler using glycerine and a biomass thermal stove, shown in Figure 1(a), was designed and constructed for cooking and a mechanical screw press, shown in Figure 1(b) was designed and constructed for extraction of soya milk. The assessment of the system indicated that a cooking temperature of 116˚C and a cooking pressure of 100 kPa was achieved and the production rate exceeded the specification. Hence, it was concluded that the prototype is suitable for the production of soya milk for small scale farmers. The project demonstrated that soya milk extraction using biomass thermal energy could be used on a larger scale for soya milk production, which has potential for application in sub-Saharan Africa.

Figure 1(a) Double boiler and a biomass thermal stove

Figure 1(b) Mechanical screw press

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The Design, Construction and Evaluation of a Mechanical Winch for Timber Extraction The Institute for Commercial Forestry Research at UKZN requested the design of a mechanical winch for timber extraction by small scale farmers. The winch should be safe and easy to operate, robust and rugged, easy to repair with locally available skills and resources, and should be affordable. Namisani Nduli and Thankslord Hadebe undertook this project with following design specification: (i) lightweight and portable (< 50 kg), (ii) an extraction cable length of at least 150 m long, (iii) an extraction rate greater than 3 tons/day, (iv) the ability to pull 120 kg of logs simultaneously with a safe working load of 1000 kg and with a cost of less than R 6000. Given that the farmers own chain saws, a chain saw motor was used to power the system, as shown in Figure 2. The assessment of the system indicated that limitations of the motor used and inappropriate gearing resulted in not all of the design specifications being met.

Figure 2 Release and trigger mechanism for net launcher

Design, Construction and Performance Evaluation of a Solar and Pedal Powered Small Grain Cleaner

Thandekile Sibisi and Siphesihle Ntuli undertook the above project to improve the grain cleaning capacity and efficiency of small scale farmers. Design considerations included a simple and mobile system using a variable speed fan and exchangeable sieves with the system powered by renewable energy sources. The specifications for the design were a cleaning efficiency of 90 %, cleaning losses of less than 3 %, and a cleaning capacity of 150 kg.h−1. As shown in Figure 3, human pedal power was used to drive the vibrating sieves and solar energy stored in a battery was used to power the fan. The assessment of the system indicated that the system exceeded both the cleaning efficiency and cleaning loss specifications but did not meet the cleaning capacity specification. Hence it was recommended that the sieve dimensions and slope, the vibration stroke and gear ratios showed be reviewed to improve the cleaning capacity of the system.

Net housing

and activation

mechanism

Net launcher

base plate

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Figure 3 Schematic and constructed small grain cleaner

Design, Construction and Performance Evaluation of a Sprinkler Irrigation Demonstrator In order to demonstrate to farmers the consequences of improper management practices and poor design of irrigation systems, Jonathan Kirkman and Thokozile Siyaya designed, constructed and evaluated a portable sprinkler system to demonstrate the effect of: (i) pipes that are incorrectly sized or too long, (ii) incorrectly sized or worn nozzles, (iii) pressure variations above and below the design pressure, (iv) sprinkler spacings that are too large or too small, (v) stand times that are too long or short, and (vi) operating too many sprinklers simultaneously. A dragline system with a layflat main line was selected and designed to meet the above specifications and evaluated, as shown in Figure 4. Software was also developed to illustrate the impacts of variation from the correct design on the performance of the irrigation system. From the performance assessment it was concluded that the consequences of poor management and design and the advantages of correct system management practices were demonstrated.

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Figure 4 Evaluation of sprinkler irrigation demonstrator

Design, Construction and Performance Evaluation of an Alternate Technology for Use of Excess Biomass for Charcoal Production and Briquetting

Illovo suggested the use of excess bagasse from sugar mills could be used as a source of energy by rural communities. Vuyisa Gugushe and Piwe Piliso undertook a project to upgrade the performance of the existing kiln at Ukulinga and to design and construct a briquetting machine to produce briquettes from the biochar and to evaluate the performance of the charcoal kiln and the briquetting machine. A design was done to convert the kiln to have a primary combustion chamber, a carbonisation chamber and a secondary combustion chamber, as shown in Figure 5. A screw press was selected and designed to produce the briquettes (Figure 6). The performance of the kiln exceeded the design specifications and successfully produced biochar but problems with the manufacture of the screw press resulted in briquettes not being properly extruded.

Figure 5 Three-chamber kiln

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Figure 6 Feed hopper, motor and barrel for screw press

Awards Made to Agricultural Engineering Students in the School of Engineering at the

University of KwaZulu-Natal

The SAIAE made awards to the following students based on their academic performance in 2014:

Award Student

Best 1st year Agricultural Engineering student at UKZN in 2014

Thumbani Thapelo

Best 2nd year Agricultural Engineering student at UKZN in 2014

Roanne Sutcliffe

Best 3rd year Agricultural Engineering student at UKZN in 2014

Jonathan Kirkman

Best final year Agricultural Engineering student at UKZN in 2014

Nathan Bernstein

MBB also made an award to Jonathan Kirkman for the best final year design project student. Congratulations to all these students!

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The awards for the best final year design project in 2015 were made to:

Award Students Project

MBB prize for best final year design project

Thandekile Sibisi and

Siphesihle Ntuli

Design, Construction and Performance Evaluation of a Solar and Pedal Powered Small Grain Cleaner SAIAE shield for best final

year design project

Agricultural Tour of Suffolk & Norfolk Farming Practices By Alasdair Harris

Geoff Freed, of Chief Industries UK, long-time member of SAIAE and IAGRE (UK) generously put together a

mini-tour of various farming operations in Suffolk and Norfolk on request of SAIAE member Alasdair Harris,

who was in the UK for his part time studies. Geoff linked up with his college friend Stephen Collett who

utilised his vast network of farming compatriots to put together a thoroughly enjoyable tour. Below is an

account of the some of the highlights.

Stubbings Entry Farm – Botesdale, Suffolk

Chris Townsend is a young, “new generation” farmer in the UK.

He fully utilises the ±1000 acres (±400ha) of the Stubbings Entry

Farm. He traditionally rotates three crops, including rape, winter

wheat and barley but now with recently imposed laws relating to

compulsory legume cropping has also been farming beans. He

makes use of GPS guidance technology in some of his land prep

activities but relies on his 24m spaced tramlines (Figure 1) or

infield roads as guidance for his herbicide and topdressing

operations. Rows are planted diagonally apposed each year

(Figure 1) to reduce the effects of compaction and extending the

period between subsoiling/ripping operations. In addition to his

Figure 1 - Tramline every 24m for herbicide

application

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crop farming operations, Chris also has two 32000 bird chicken houses. These are powered by both wind

turbines (2x 5kW units) and solar panels (5 x 10kW clusters). A heat exchanger is also utilised to reduce his

energy requirements. Chris estimates the payback period for this unit to be within 3 years.

Church Farm, Wortham, Suffolk

They also visited Church Farm, farmed by Stephen Rash. Contractors are used to mechanically harvest and

haul the beet crop to the mill. The harvester’s header consists of a four rows oscillating extended “arms”

which run through the soil and lift the beat unto a series of horizontally rotating spoked disks.

These discs rotate and move the beet under the harvester and allow excess soil to fall off before a conveyor

lifts the beet into the on-board storage bin on the harvester. The infield tractor and trailer runs next to the

harvester and offloads the beet at two stock piles, known as clamps, at either end of the field to reduce infield

transport and compaction damage. Despite these efforts, compaction was evident and a ripping operation

was likely to be required to be conducted prior to replanting. The beet tops can either be spread on the

surface as a source of animal feed or incorporated back into the soil. The latter is preferred by Stephen Rash.

John Orfford Contracting and Recycling

The contracting business of John and Pam Orfford was also visited. This is a truly family run business with their

two daughters Sheila, running the fertiliser operation, and Alison running the Agri.Cycle recycling operation.

They are involved in the harvesting, haulage and storage of a most crops grown in the district.

There was a long discussion about the various constraints and

restrictions imposed on UK farmers relating to herbicide and

fertiliser application, labour, and of course, health and safety. In

general, the South African farming industry is subject to exactly

the same external pressures.

The Orfford’s run a franchise of the Agri.Cycle business

conducting collection, separation and compaction services for

the regional Agri.Cycle recycling facility. Farmers were issued

with certificates to prove the safe disposal of their plastic

waste. Figure 4 – Combine harvesting “tick” beans

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Grange Farm, Snetterton, Norfolk

The grange farm, owned and run by Ann and her son Johnny Whatt, consists of a diverse mix of operations

including diary, cereals and sugar beet. In addition, they supply power into the national grid from 20 acres of

solar panels and are due to commission a 0.5MW anaerobic digester in Mid-November 2016, fuelled

predominately from diary waste. This progressive and diverse approach is centred around the long term

financial and ecological sustainability of the farm.

Chief Industries UK

The tour was rounded off with a factory tour of the Chief grain dryer factor in Maldon, Essex. The factory was

in full swing during the visit, operated by only a few highly skilled operators combined with computer

controlled machines of various types and sizes. Construction was underway to extend their factory premises

to include a storage facility for their finished goods inventory; currently outsourced. This was a fascinating

end to the packed tour program.

Figure 5 - Geoff Freed at Maldon harbour

Thanks

Thanks go to Geoff Freed for giving of his time and for arranging the tour. Stephen Collett is also to be

thanked for giving of his time and utilising his network of agricultural contacts to put together a diverse and

comprehensive tour of the farming practices of Suffolk and Norfolk counties. And last but not least, thanks

must go to the Orffords for their generous hosting of lunch on the 28th September.

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SAIAE at Career Fairs By Isobel van der Stoep

The Produce Marketing Association (PMA) Fairs, of which three are held in South Africa every year, is organised

by an international trade association based in the United States of America (USA) which boasts member

companies around the world, whom it exists to serve in various ways in the fresh produce industry. The

response from the industry to address this challenge is remarkable, and a number of participant companies

exhibited at the fairs. SAIAE was one of them that attended the Pretoria and Pietermaritzburg fairs, and a huge

number of potential students visited the exhibition. Boeboe Neethling our Business Manager with the help of

SAIAE members put up the stands and promoted the agricultural engineering career.

SAIAE was also represented at three career fairs arranged by UNISA, following the first introduction of a career

fair in Pretoria in 2014. In 2015, a total of 6 fairs were arranged across the country, and a stand was kindly made

available to SAIAE free of charge at the fairs held in Pretoria, Polokwane and Nelspruit. This increased SAIAE’s

marketing footprint considerably and hopefully we will see the affect thereof in the student numbers in years

to come.

SAIAE would like to thank both the PMA and UNISA for inviting SAIAE to attend the career fairs and thereby

supporting the development of agricultural engineering.

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Field visit to ZZ2 By T Dube and Mr Sibuye ZZ2 aims to set the benchmark and provide sustainable value for all stakeholders. The main crops grown are

tomatoes, onions, avocados, mangoes and other deciduous fruit while some livestock is also produced.

Production is in both open fields and under net houses, and takes place in various areas of Southern Africa.

Open field tomatoes ZZ2 plant between 200 and 250ha of tomatoes per annum, divided into 4 units of 50ha in order to spread out the risks for hail. Products are regularly tested in the laboratory and checked for ecoli and bacteria. Typical yields are 95 tons per ha. Soils are managed on a rotational basis, with tomatoes planted in the same fields every 6 years, rotated with onion, sorghum or natural grass. Elephant grass is used to stop dust and wind damage at roads, while plants are regularly inspected for mites that hide under dust; at the end of the tomato rows, there is an indicator plant and catch crop for insects. Nematodes (eelworm) are controlled by natural farming practices, consisting of fermented plant extracts from lantana, applied through the drip system to the soil. No chemicals are use in the soil. Water scarcity forced ZZ2 to modernize irrigation in the following sequence: flood, sprinkler, centre pivot and drip. Drip with mulching saves them 30-35%, while pumps are optimised with variable speed drives. The systems consists of water being stored in a settlement dam, before being pumped through a filter station to the fields. Sub mainlines supply 2 blocks at a time, with 17 m3 being applied per hour for 4 hours per ha. The valves in the open field are operated by radio control. Soil conservation practices include contour banks. Road direction and block lay-out is determined by the drainage, sun and wind direction. Emitters of 2.3 L/hr drip is used on open field blocks which are 300m x 100m in size. Life expectancy of the drippers is typically 6-8 years. Chemicals and ultrasonic methods are used to clean dripper lines. Although probes used to measure water content, the preferred method is manually digging pits and inspecting root development to determine what to do the next day in terms of irrigation scheduling.

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Harvesting: Picking system consists of 6 crates fitting into a special design wheel barrow which is offloaded into a tractor trailer at the end of the row. When the tomatoes are ready, picking takes place 3 times a week.

Compost Compost manufacturing and biological farming are practiced for nutrition and control of diseases. Compost tea is prepared for the crops on the farm in sterilized tanks. Citric acid is used to stabilize the pH of water to 4. Organisms are used to break down the organic compost. 40 kg of compost is aerated for 36 hours together with other ingredients. The end results must be used within 6 hours after aeration. The process is aerobic, and 100 L per ha applied every 2 weeks. Compost material is sourced locally, and consists mainly of chicken and cow manure, grass, wood chips, and sawdust from local farmers. Activity of microbes breaks down the material during composting, taking about 110 days to produce compost. They aim to maintain 50% moisture throughout. The compost is turned regularly with 13 years old compost turner built in Tzaneen, at least 3 times a week during first two weeks. Gypsum or lime is applied over manure, and grading is done after composting - fine, medium and coarse. EM: Effective Microorganism (similar to brewing) is an anaerobic process. The product can be used for cattle to speed up digestion, or it can also be used for treating sewage smell. On the farm it is used for treating nematodes in the field by applying 70L per ha over the cycle.

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Shade net Some of the tomatoes are produced under net, using Insect Net 50 micron, which keeps White fly and other insects out. The structure consists of permanent steel poles and anchors which are concreted, with cabling in one direction and netting tied in valleys to allow for weakest point during hail. Under the net, the trellising height is 3.2m and workers walk on stilts to manage the top ties. All plants have been grafted on good root stock to fight soil diseases and also to give a long season. Plastic helps for weed control, with the white colour on surface radiating direct light. Plants last about 40 weeks and no crop rotation is used. The same amount of water is used as per open field, but yield under Shade net is 2 to 3 times higher. Cost is cheaper to build than greenhouse. Wind pollination (and self-pollination) is used. Bumble bees are not yet allowed in the country. On a hot day, they irrigate 28 m3 for 2 hours. The lay-out is 5 to 6 ha per house. 5 houses are irrigated from 1 pump, while fertigation is done at the pump house.

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Seedlings and greenhouse Hishtil from ISRAEL produced 120 million seedlings for tomatoes, papaya, watermelon and other vegetables last year. This takes place on site at ZZ2 and planting of the trays is mechanized. Germination takes place at the specific temperature for that crop. Best quality growing material and sterile conditions are used. Grafting is done by cutting at a certain angle and joining them with plastic half-pipe. It is expensive, (R3 to R9 per seedling) but give strong resistant roots and a good producing grower.

A big word of thanks to Johannes Grobler and the team at ZZ2 who made this field trip possible! And

as can be seen below, saving everyone….

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Field Visit to the Northern Cape Vaalharts Irrigation scheme By Mkhanyiseni Zimu: Candidate Engineer

The South African institute of Agricultural Engineers (SAIAE) embarked on an Agricultural Engineering study tour

to the area around Kimberley in the Northern Cape. The purpose of the study tour was to provide an opportunity

for the members to view typical agricultural engineering activities in action especially for young candidate

engineers and engineering technicians.

The tour commenced on Monday the 26th of October with a visit to the Vaalharts Irrigation Scheme located at

the confluence of the Vaal and Harts River. This historic irrigation scheme was constructed in the 1930s and

provided a perfect opportunity for engineers to be introduced to the intricate engineering aspects associated

with operating such a large irrigation scheme. It remains the largest irrigation scheme in the country with a

scheduled area of about 29181ha and a total length of 1120km main, feeder, community and drainage canals.

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THE VENUE

The Vaalharts Water User Association (VHWUA) hosted SAIAE at The Venue in

Hartswater to give an overview of the scheme infrastructure, the operation and

management, and ongoing rehabilitation activities. Due to the age of the canal, early

detection of problems and the timely fixing of the problem are of utmost importance

to the effective functioning of the scheme. The user association has in-house civil and

mechanical teams responsible for the repairs and maintenance. Canal operators log

the problems which are then investigated and taken further by the operations

manager. The escalating cost of maintenance is a major challenge within the scheme

and the user association has embarked on a rehabilitation programme to reduce the

high maintenance cost and to ensure the continued life of the scheme.

The major crops irrigated in the scheme are Lucerne, barley, maize, groundnuts, cotton and wheat. An

interesting turn in the evolution of crops in the scheme is the recent surge of pecan nuts orchards driven by

higher market profits. A considerable number of farmers are slowly switching parts of their farms to pecan-nuts

orchards.

The scheme uses the award winning Water Administration System (WAS) for the management of the water

which has led to considerable water savings. The water user association says the WAS system has considerably

increased its efficiency in the management and administration of the scheme. By ending the reliance on staff

making manual calculations the system has reduced errors and also made time available for the same staff to

focus on other tasks.

FIELD VISITS

After the presentations the officials of the VHWUA led the SAIAE contingent on a field visit to selected areas of

the scheme where discussions continued. The areas visited included the community canals, drainage canals,

commercial farm and to the construction site of the new canal.

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The Canals

Field visits started with the visit to the long-weir and measuring structure at the intersection of the feeder canal

and community canals. Viewing the status of the infrastructure also demonstrated the need for rehabilitation

and refurbishment of the infrastructure. Although in working condition, severe leaks from the canal were clearly

visible along the canal. The VHWUA noted that they are also looking at the option of piping the feeder and

community canals to reduce losses and maintenance costs.

Farm Visit

The visit to Burger Boerdery to view the farms development of a pecan nut orchard was enlightening. The

farmer is currently intercropping Lucerne in-between the pecan nut trees to address cash flow issues while the

pecan nut trees are still developing. This is a common trend within the scheme to ensure a smooth transition

from field crops to orchards.

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State-of-the-art construction

We also visited a new bulk water supply canal being constructed adjacent to the existing bulk water canal. The

existing canal being replaced was deemed to be in a critical condition of disrepair and required urgent

replacement. This is part of the ongoing rehabilitation programme to minimise interruptions due to breakages.

A paver machine is being used for the construction of the canal to speed up the construction process.

The new canal is expected to perform better over the long term due to modern engineering construction

methods being used. As standard the canal has a length-wise drainage pipe installed together with no-fines

concrete blinding base to curb the building up of water pore pressure underneath the concrete lining. A curing

compound is being used on the concrete to ensure the proper curing of the concrete and the prevention of

shrinkage cracking. The SAIAE engineers got to see first-hand the paver working on the canal. The contractor

said this paver constructed approximately 60m consisting of 2.5m panels, per 12hour shift. This will assist in

speeding up the construction of this 2.2km canal.

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THE HEADWATERS

The Vaalharts weir was visited to conclude the eventful day; constructed in the 1930s and raised in 1967 it has

a capacity of 48.7million m3. Although the weir receives its water from the Bloemhof dam upstream it is still

largely regarded as the heart of the scheme with its significance to the Harts river valley evident. The scheme

literally reshaped the landscape, as Lani van Vuuren puts it ‘A garden in the Desert’.

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A very big thank you to Gert Kruger and the team at the Vaalharts scheme for

a wonderful visit!

Visit to Wildeklawer farms

Pumpstation By Andiswa Sigwanda Background

From the 26-28 October 2015 SAIAE organized a study tour to the area

around Kimberley in Northern Cape. The main purpose of the tour was

to visit the Vaalharts Irrigation Scheme, where part of the main canal

is being reconstructed, however also it was to provide an opportunity

for SAIAE members to view typical agricultural engineering activities

in action and also for young candidate or professional engineers and

technicians to get exposure to different technologies as well as

interact with more experienced SAIAE members as part of their

professional development. A number of interesting visits were

arranged including onion harvesting and packaging at the Wildeklawer

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farming operations near Barkly-West, Vaalharts canal construction site and a pasta and biscuit factory amongst

others. Being of the mechanical background I was mostly interested in the pump station visit at Wildeklawer

farm.

In as much as the pump station is not complete yet, but the ideas surrounding the new design sound efficient.

From the pump station you will be able supply water wherever needed around the farm. The pump, which runs

on a 90KW motor is driven by a variable speed drive system which controls the pressure and flow required as

per the design of the center pivots. Currently the farm is making use of a temporal installation but the final

trailer housing the pump will have wheels running in the channel so as to be able to move the pump up and

down the river bank depending on the river level.

The pump house is equipped with two cyclone-type filters which can be easily cleaned/back flushed using a

valve at the bottom of each filter during normal operation. The suction hose will come in the channel, with the

hope that one person will be able to remove it and connect it to the next outlet within half an hour. Also the

cables are placed on top (at the expected maximum level of the river ) and connected at each pole so as to be

able to connect the pump anywhere on the channel should there be a need to move the pump up or down.

One of the most fascinating things to learn was that on the outlet from the pump, as there was a reducer; it

was not only reducing but changes direction as well which was very interesting. I cannot wait to visit the pump

station once it has been complete as it promises to be an efficiently running system.

Laserwerk by Spilpunt 62 Deur Johan Grobler Die strewe na eenvormigheid is ‘n jarelange doelwit, die voordele is baie maar die pad om daar uit te kom vat

lank, kos ‘n paar rand en is ‘n langtermyn belegging.

Dit is onder andere te danke aan ‘n paar onbeheerbare probleme soos dreinering na donderstorms en verskille

onder spilpunte dat Wildeklawer ‘n klompie jaar gelede besluit het om juis dié jarelange projek aan te pak. So

wat behels die jarelange projek?

Grond eenvormigheid (grondtipe, tekstuur en infiltrasie vermoë) en ‘n eweredige (gelyke) helling oor ‘n 20ha

spilpunt. Dit is wel nie waar dit stop nie. Daar kan wel nie net na een individuele spilpunt gekyk word nie, die

aangrensende spilpunte moet ook in ag neem word as daar na dié tipe verandering gekyk word. Dus moet al

die spilpunte saam ook ‘n eenheid vorm.

Met dié doel in oog is daar 25jaar terug begin met ‘n ongekende grondverskuiwings oefening in die landbou

bedryf. Daar is jaar na jaar, spilpunt vir spilpunt met die plan voort gegaan en tans is daar enkele spilpunte oor

wat nog nie op die streng standaard is nie.

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Om te begin word daar ‘n opmeting van ‘n spilpunt gedoen om ‘n uitsny en terugvul te bepaal. Saam met dit

word daar 3m diep profielgate gegrou op ‘n matriks van 50m x 50m om die grond eenvormigheid te bepaal. Die

mikpunt is om ‘n val oor die spilpunt te kry van tussen 0.4-1.4% saam met ‘n 700mm diep laag “goeie grond”

(was aanvanklik 1m diep gewees). Dus as daar met die grou van die profielgate klei in die boonste 700mm laag

grond gevind word, sal die klei verwyder word en “goeie grond” sal terug gery word om eenvormigheid te

bewerkstellig.

Nadat al die inligting verwerk is word die taak aangepak met trekkers en damskroppe. Daar word gebruikgemaak

van laserbeheer op die skroppe om akkuraatheid te verseker. Die trekkers en skroppe werk tydens so projek

24h per dag om die taak te voltooi.

Die proses vat maar tyd en kan tot 9 maande duur om 1 spilpunt af te handel. Die lang tydskaal begin meer sin

maak as daar besef word dat die uitsny soms 3m is en die terugvul tot 5m. Per spilpunt kan daar enige iets

tussen 4000 en 40 000m³ grond geskuif word. Vandat daar met die projek begin is, word daar geraam dat daar

al ‘n totaal van ±18mil m³ grond verskuif is.

Soos wat die grond teruggevul word, word die grond ook die heeltyd losgemaak sodat die grond wat onder is

nie vasgetrap en verdig is nie. Nadat die land gelyk gemaak is en die uitsny en terugvul is afgehandel, kry elke

spilpunt 35 ton mis wat met ‘n skotteleg ingewerk word om die “lewe” terug te sit in die grond.

Al hierdie werk wat gedoen word het baie voordele waarvan een van die groot voordele die gemaklike bestuur

van die spilpunte is. Van die ander voordele is:

Waterafloop word baie goed beheer

Minder plant en oes bestuur nodig

Fabriek bestuurs styl kan toegepas word oor al die spilpunte

Verhoogde wins

Kan gebruik maak van semi geskoolde mense vir die bestuur omdat dieselfde beginsels(resep) op al die spilpunte toegepas kan word - herhaling

Grondvog op die land is orals dieselfde so daar kan met swaar masjiene gewerk word, trekkers sit nie vas nie, daar is nie nat kolle nie

Reën afloop is baie goed en beinvloed nie jou beplanning nie, land droog vinnig af en dan kan jy weer met jou beplanning aangaan.

Goeie dreinering en wortelontwikkeling in “goeie grondlaag”

Met die gelykmaak van die lande raak dit moontlik om 3 rye gelyk te lig instede van 1 op ‘n slag.

En daar is nog vele meer

Afsny areas word gebruik as bufferdamme vir afloop water. Daar word in die areas ook lusern geplant wat deur

die afloopwater natgemaak word. Lusern help dan ook vir die stof en dis ‘n ekstra inkomste. Blaaspootjies hou

ook meer van lusern so dan word die lusern meer gespuit en op die land minder.

Voor uie aanplantings word lande weer gediens om weer by die ontwerp uit te kom sodat mens seker maak

alles is nog reg. Dit gaan vinnig en daar kan so 7ha per skof gedoen word.

Dit is ‘n werkswyse en ‘n lang termyn belegging. Die realiteit is dat die opbrengs wel laer kan wees vir die eerste

6 jaar. So dit is ‘n baie duur proses maar as jy eers so gewerk het wil jy nie op ‘n ander manier werk nie. So aan

die einde van die dag is daar geen uitdaging wat te groot ge-ag word om dit reg te kry nie. Die doel is vas en

daar word nie afgewyk nie.

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Successful harvesting of onions at Wilderklawer Paul Makwela

ARC-Institute for Agricultural Engineering

Onions are popular cool season vegetables that can be cultivated from seeds, sets or transplant. They are easy

to grow and manageable crop that when properly harvested, can provide good yields. The use of onions for

food goes back over 4000 years.

As part of a technical tour, members of the South African Institute of Agricultural Engineers (SAILI) visited an

onion farm in the Northern Cape (Kimberley) by the name of Wilderklawer on the 27 October 2015. Wildeklawer

is one of the South African leading onion producers under the leadership of SAILI member Louis and Cora de

Kock. They produce 50 000 tons of onions per annum and in the peak harvesting time the harvest 900 tons of

onions per day

Successful harvesting of onions at Wilderklawer depend on proper planting and care throughout the growing

season. There are three varieties of onions that are produced at Wildeklawer namely Brown, Red and Sweet

onions. All under pivot irrigation system. Onions are planted as soon as the soil is properly prepared. Rich soil,

consistent moisture and cool temperatures help bulb development. In addition to good planting, they know

when to harvest the onions for the best flavour. Green onions are harvested as soon as the tops reach a height

of 150mm. The longer they wait to harvest the green tops the stronger they become. The best time for onion

harvesting is early in the morning when temperatures are not too hot. The bulb onion harvest time begin when

the onion tops naturally fall over. With the brown onions it is normally 100 – 120 days after planting.

For the SAILI group this was a learning experience and everybody learned a lot about the harvesting of onions.

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The harvested onions ready to be picked up and transported to the drying bins

Two different planting stages with onions tops that fell over as an indication that it is ready for harvesting

Container depot and pack house By Jaco Homann The container depot at Wildeklawer houses approximately 268 containers and is divided into several rooms,

consisting of 24 containers each. All of the rooms are temperature controlled, in order to nurse the produce

and achieve the best results. The containers are placed in four rows, two containers per row and stacked 3

layers high. The produce from the fields is transported to the pack house in large containers, each weighing

approximately 20 tons. Each container has chalk writing on it, which describes the (i) field location, (ii) date, (iii)

time, (iv) produce condition and (v) risk. Depending on description, each container is hoisted up by a 24 ton

overhead crane, operated by trained personnel, and transferred to the desired location. In future, the crane

will be completely computerised, automatically placing the container in the correct area. The containers have

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a rectangular sponge material to seal the two neighbouring containers in each row, fitted with double floors

with holes in to force the air upwards and provide sufficient air circulation. On the open side of the rectangular

section, stoppers are inserted to prevent air flowing through. Bread bags are used to indicate that the motors

are still running, in addition to the computerised system that displays motor status, as well as a small light next

to the containers. Each set of two containers has its own computerised fan system. The system also has a heat

exchanger and water cooler to vary the moisture and temperature of the inlet air. As the onions enter the

container depot, they are stabilised, dried, cured and then stored. During peak times, the onions are dried

within 2-3 weeks and transported to the market. The onions can be stored for 3-5 months to stretch the season,

but the produce will then be treated in a different manner. There are two pack house managers on site to

ensure that everything runs smoothly. During the onion season, the depot is filled 2-3 times to supply

consumers all over South Africa A tipper is used to empty the containers onto a conveyor belt, which goes to

the packaging sector. The tipper was designed by Louis de Kock and Fritz Teseling. In future, a faster motor will

be inserted and expanded to a double tipper. Once on the onions fall onto the conveyor belt, they go through

several grading and sorting processes, before it reached the packaging line. Once all of the onions are packed,

it is transported to the desired locations throughout South Africa.

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Workshop By Andre van der Walt The highlight of the trip was surely to meet Mr Louis De Kock; ‘’Megaboer’’, Agricultural Engineer and owner

and founder of the farm Wildeklawer. This farm is both South Africa’s biggest single producer of onions and a

significant exporter. They boast with a record-breaking life span on their tractors and says that Maintenance is

one of the key elements in ensuring that everything runs smoothly with as little as possible down time.

The level of mechanisation and automation on the field and in the pack-house is astounding. There are over 70

tractors at service of the more than 80 laser-levelled centre pivots. The oldest functional tractor, which also

holds the record, has 30 000 hours on the clock. Every 250 or 500 hours, it is the responsibility of the driver to

take the tractor to the workshop for a service. At the workshop, professional personnel take care of servicing

the tractor, using only genuine quality parts.

Many problems require a unique solution, which is why the workshop is fitted with equipment like welding

machines, a bending machine, a lathe, a plate press and a plate punch, to make almost anything that can’t

readily be bought. For everything else, there is a large amount of spare parts in the store room where they go

through approximately R500 000 worth of John Deere parts every month.

Thank you to Louis and Charles de Kock for a very special visit! And a very special thanks to Cora de Kock who treated everyone to a delicious lunch! PS; Cora, we are still waiting for the pudding recipe…

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GWK Wheatmill and cookie factory By Mervyn Hansen The visit to these factories complimented the study tour.

The wheat, pasta and biscuit factory was impressive although not fully operational. GWK focuses on adding

value to agriculture products grown in the Northern Cape. The SAIAE delegates were shown every facet of the

processes involved in wheat milling and biscuit making. The complexities of producing consistent quality wheat

flour was enlightening and indeed an art for the millers. Rather like making wine! To this end, each stage of the

wheat milling and rehydration utilized state of the art machinery and computer controls with numerous quality

checks. The wheat mill is strategically placed next to wheat silos of which they have access by an underground

conveyor. This helps hugely with safe and economic wheat transfer to the mill. For the observant delegate the

tour of the factory highlighted food processing operations and food health safety standards that are so part of

Agricultural Engineering.

GWK Cotton Gin By Mervyn Hansen At the front yard of the cotton ginnery we were greeted by the evidence of a cotton fire that had broken out a few months earlier. This was a good lesson for us to witness, as it brought home the importance of health and safety in the work place. The financial loss must have been huge as the fire spread from bale to bale. Cotton is very difficult to extinguish as it keeps on shouldering.

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That being said, the processes involved in cleaning the cotton and the transfer thereof were very interesting and educational. The machines that removed the seed from the cotton were fascinating to watch. Although the machines seemed rather dated the final product was clean. A special thanks to GWK to show us around and answer all our questions.

SAIAE Pretoria branch meeting By Richard van der Merwe A very informative and successful Pretoria SAIAE Branch Meeting was held on the 10th September 2015 in the

Kopano Hall on the premises of the Agricultural Research Council in Silverton, Pretoria. The meeting was

attended by 26 members and it was a pleasure to welcome current members and visitors to the gathering. Two

very enlightening presentations were given on topics that are both current and of importance to the

sustainability of resources in our country. Mr Mark Tiepeldt, a civil engineer by profession, who is the current

chairman of the South African Biogas Industry Association gave a very passionate and educational talk on

“Agricultural Biogas in South Africa”. He gave a brief explanation of the chemical processes involved in bio-gas

production and outlined the state of the bio-gas industry, in particular bio-gas generation from agricultural

wastes, in South Africa.

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Mr Mark Tiepeldt – Chairman of the South African Biogas Industry Association

Following Mr Tiepeldts presentation, Mr Gareth Simpson, a technical director at a consulting firm Jones and

Wagener, gave in-depth insight into a current environmental engineering project he and his team are involved

in, namely the “Mafube Colliery Wetland Re-establishment Design”.

Mr Gareth Simpson – Technical Director: Jones and Wagenaar

The technical nature of the solution was astounding and it was stimulating to see how a sound knowledge of

the natural environment, in this case wetland hydrology, coupled with a comprehensive technical

understanding of the properties of engineering materials and displaced natural material led to an all

encompassing, workable solution.

After the meeting an enjoyable social function was held. The highlight was a superb potjiekos prepared by Pieter

Jacobs – our very own Master Chef! Our thanks go to him for his fabulous efforts.

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Mr Pieter Jacobs – Potjiekos Master Chef! Guests enjoying the social function

_____________________________________________________________________

Membership matters

Honorary fellowship for Felix Reinders

SAIAE’s Honorary Secretary/ Treasurer has been awarded Honorary Fellowship by the SAIAE Council. To

celebrate the achievement, a large surprise gathering of friends and colleagues was arranged in Pretoria to

make the presentation and also to celebrate Felix’s 60th Birthday which is taking place on 21 December.

Felix has up to and including October 2015 for 30 years in succession served as a Councillor to the SAIAE

Council. He has also served as Chairman of the Pretoria Branch, Vice President and has in fact served two

terms as President of the Institute. He has played an important role in the Institutional life of the agricultural

engineering discipline, as he has in the irrigation engineering field.

Also in the field of statutory registration of professional engineers in South Africa, Felix has played an

important role for several years. He was elected from 1991 as the assistant to the chief representative for

Agricultural Engineering at the Engineering Council of South Africa (ECSA), and held this position for 11 years

until 2002. In 2003, Felix became the chief representative for agricultural engineering at ECSA. Felix has

played an important role as a member of the Professional Advisory Council for ECSA, assisting in fulfilling a

huge task with the establishment and implementation of the system of Continuing Professional Education.

Because of his ongoing commitment and tireless effort to promote SAIAE, the Council also awarded a second

gold medal to Felix. We thank him and wish him well on the celebration of his birthday.

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Felix Reinders with his special birthday cake displaying all the features of Agricultural Engineering

New members

We would like to welcome the following new members to the Institute:

Mr F Swanepoel

Mr IR Chakanyuka

Mr P Jugdawooh

Mr M Chimbunde

Mr K Zungu

Ms ET Akinlabi

Mr OK Ogbutu

Ms C Tricoire

Mr TL Dirwai

Mr BU Egesimba

Mr GK Chitsiko

Mr J Mailosi

Mr TN Nkomozepi

Membership Upgrade

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Mr HG de Jager Fellow Pensioner

Mr HE du Plessis Fellow Pensioner

Mr SW Jacobsz Fellow Pensioner

Mr ABD Joubert Fellow Pensioner

Mr JS Lichtenstein Fellow Pensioner

Mr GJ Meikle Fellow Pensioner

Mr AN Murray Fellow Pensioner

Dr JM Rankin Fellow Pensioner

Mr BH Read Fellow Pensioner

Mr JCH van Niekerk Fellow Pensioner

Mr O Beyi Member

Resignations

Mr GW Ascough

Mr PD Drennan

Mr N Bestbier

Mr BH Read

Retirement

Mr AJ von Eckardstein

Deceased

Mr PD Hittersay 02/08/15

General

Members are reminded to send through proof of payment of membership fees. When making payments,

please use the invoice number, or the first three letters of your surname together with the number as shown

under “Rekening/Account” on the invoice, as reference for the transaction, as this makes it possible for the

secretariat to trace payments from the bank statement.

The secretariat wishes to remind members that when they reach retirement age, they are welcome to apply

to change their membership to the Pensioner category which has lower annual fees than the active member

and fellow categories.

For any administrative or financial queries, please contact Boeboe Neethling in the SAIAE office on (012) 842-

4043 (Mon - Fri 09:00-13:00), or email boeboe@saili.co.za