MAIDEN EDITION OF ENGINEERING LECTURE SERIES
IN FACULTY OF ENGINEERING,
NNAMDI AZIKIWE UNIVERSITY, AWKA, NIGERIA

ON

ROLE OF ENGINEERING IN SUSTAINABLE AGRICULTURE

PRESENTED BY

ENGR. BENJAMIN OKAH
(MD, GREEN…..FARMS AND MACHINES LTD)

JUNE, 2021

THE ROLE OF ENGINEERING IN SUSTAINABLE AGRICULTURE
Firstly I want to thank the Faculty of Engineering for finding me worthy to present this paper.
The objective of this paper as implied by the title is to look at the roles of engineering in sustainable agriculture. The word “sustainable” is very important because the drudgery associated with local farming has made it so unattractive, unprofitable, and indeed so unfulfilling. About 80 % of the world’s population live in the developing countries; therefore, there is an urgent need to increase food production in order to guarantee food availability for the ever-growing population in these areas. The constant innovation and application of “Engineering” to Agriculture becomes so important that emphasis must be placed on it if we are to survive as a people. The South-eastern part of Nigeria has not yet accepted farming as a profitable business venture; and due to this, ample research efforts and investments have not been put in this area. The East therefore is highly dependent on food products from other parts of Nigeria. In the South-west, youths have embraced agriculture using modern technology such as drip irrigation, greenhouses, and improved varieties of crops. This makes them more self-sufficient in food production; particularly root crops, vegetables and fruits. Most tomatoes, pepper, and other crops sold in Lagos and Ibadan are largely produced in the South-Western part of Nigeria. Of course, farmers in the Northern part of Nigeria have been empowered over the years by deliberate government policies to produce food abundantly and to export to the south.
If I may quote an excerpt from one of our lecturers in School, he said “FOOD IS THE INSTRUMENT OF PEACE”. We cannot get enough food using the big manual hoes in our farms. Without food, you will understand the real meaning of “the hungry man is an angry man”. Ertharin Cousin also said that “THERE IS NO FOOD SECURITY WITHOUT PEACE, AND NO PEACE WITHOUT FOOD”. So when I refer to food I want to be modern about it. The era of the big hoe is over and we must embrace modern technology in farming.
As countries advance in education, wealth, and technology, you will notice that they move away from root crops to vegetables, fruits, nuts, and healthy meat. I expect that the majority of people in this audience no longer consume “garri” and “pounded yam” every day! If you still do, please begin to shift.
In Nigeria, the only legally allowed business for civil and public servants is farming, and we can all help to achieve food sufficiency if each person can have a minimum of one hectare of farmland. If you just use half a hectare of land and sow 14,000 tomato plants using good agronomical practice, you can make a million naira every cycle of three month from that farm. In fact, in your one plot of land, you can make more money farming in it than what you will get from the rent of a two storey house you may be tempted to build.
Therefore, you can feed the entire university community from your produce, if you can move closer to nature and produce your own food using available new farming techniques. Our people complain of lack of farm land, but intensive farming will not require much land as modern engineering has provided methods of growing crops, both laterally and horizontally, thus making use of even the air. I believe you all know about aquaponics or hydroponics method of farming. I therefore call on our people, both in the diaspora and within, to embrace modern farming methods to create self-sufficiency and dignity. I say that the day the “Igbo people” or should I say “Anambra people” embrace agriculture as a business, Nigeria will become a net exporter of food!
Now my confidence is because technology has made agriculture very easy, pleasurable, fulfilling, and automatic. If you can drive and enjoy your air-conditioned car, you can also enjoy your air-conditioned tractor.

The role of Engineering in sustainable Agriculture is such a versatile topic, but I will talk on two to three simple areas; such as DRIP IRRIGATION, GREENHOUSE TECHNOLOGY, and FARM WASTE MANAGEMENT in the production of electricity. I will leave other very important areas like storage for another day. I am going to take on the first two areas where I believe that Engineering has been of immense benefit to agriculture; taking cognizance of my earlier assertion that eating habit has changed or ought to change.
1. DRIP IRRIGATION IN AGRICULTURE
With rapidly expanding population, diverse professions, unpredictable weather due to climate change, it becomes imperative to devise a way to cultivate food throughout the year, not minding the constantly changing weather. The designing of the Drip Irrigation seems to have solved this problem so that farmers can easily plant their crops all year round. Drip irrigation involves dripping water onto the soil at very low rates and low pressure (2-20 litres/hour) from a system of small diameter plastic pipes fitted with outlets called emitters or drippers. Water is applied close to plants so that only the part of the soil in which the roots grow is wetted; unlike surface and sprinkler irrigation which involves wetting the whole soil profile and plant.
Below is a simple diagram


This may appear as simple as in other engineering feats, but it took a lot of time to perfect it by the engineers and farmers. Drip irrigation is a better alternative to sprinkler type or flood type of irrigation which causes soil leaching, crop infection, and wastes a lot of water. With drip irrigation, water and fertilizer applications are more frequent and accurately applied than with other methods. This provides a very favourable high moisture content for the soil in which plants can flourish. The emitters are placed in pre-determined distances along the pipe so as to ensure proper plant population, in order to achieve highest yield per hectare. Drip irrigation can be manual by turning on and off the tap or automated by sensors and timers in which irrigation occurs at preset times and conditions. Drip irrigation is most suitable for row crops like vegetables, soft fruits, trees, and vine crops where one or more emitters can be provided for each plant.
There are so many advantages of using this type of irrigation technology. It is very simple to install by farmers; and also helps in precise and controlled fertilizer, pesticide, and water application to crops. This reduces the possibility of infection in crops. Weeds can also easily be controlled in this type of irrigation.
The different types of crops that can be irrigated this way include but not limited to tomatoes, okro, corn, pepper, broccoli, green beans, onions, citrus, cabbage, lettuce, banana, anara, ugu, different local vegetables, spices and so on.
Drip systems are adaptable to oddly shaped fields or those with uneven topography or soil texture; these specific factors must be considered when designing the drip system. Drip systems also can work well where other irrigation systems are inefficient because parts of the field have excessive infiltration, water puddling, or runoff.
With Good Agronomic practices, a typical yield for drip irrigated farm can be around 300 % more than a farm without this type of irrigation. This engineering feat has revolutionalised the ways of Agriculture and made it very simple to achieve food sufficiency.
Of course, there are some disadvantages such as initial cost and clogging of pipes when not properly used.
2. GREENHOUSE TECHNOLOGY IN AGRICULTURE
The discussion here is on the utilization of greenhouse effect in food production. I will explain greenhouse effect in a general language as the role that the atmosphere plays in insulating and warming the earth's surface. The atmosphere is largely transparent to incoming solar radiation. When this radiation strikes the earth's surface, some of it is absorbed, thereby warming the earth's surface. The surface of the earth also emits some of this energy back in the form of infrared radiation. As this infrared radiation travels through the atmosphere, much of it is absorbed by atmospheric gases such as carbon dioxide, methane, nitrous oxide, and water vapor. These gases then re-emit the infrared radiation, some of which strikes and is absorbed by the earth. The absorption of infrared energy by the atmosphere and the earth, called the greenhouse effect, maintains a temperature range on earth that is hospitable to life. Without the greenhouse effect, the earth would be a frozen planet with an average temperature of about -18°C .
From above, it is clear that for the survival of living plants and animals on earth, there should be a favourable environment in the terrestrial region controlled by short wave length radiation that is transmitted by the atmosphere. When scientists, industrialist, and politicians quarrel on greenhouse effect, it is because the atmospheric gases are being depleted by the activities of heavy industries that continue to endanger the life of man.
Scientists and Engineers have used this concept to recreate a system which mimics a perfect atmosphere to grow food all year round.
Therefore, a micro climate can be created in an enclosure called GREENHOUSE for maximum crop production in a controlled environment all year round. It can be small enough to fit into the back of your house, or take a whole football field or more.
A typical greenhouse is a simple structure of wood or steel covered with transparent polythene film. Such material may also be glass, polyethylene or FRP. It could be of any size that can fit your purpose.

In order to meet the ever-increasing food requirement of a rapidly rising global population, it is extremely important to increase agricultural production. In this scenario, greenhouse cultivation has emerged as a viable solution for achieving enhanced production by facilitating cultivation even during the off-season; and protecting crops from all types of inhospitable outdoor conditions like high temperature, cold, rain, wind, insects and rodents, vermin diseases, etc.
The availability of land for cultivation has been decreasing all over the world because of indiscriminate industrialization and urbanization. This situation calls for increased productivity with the implementation of new alternative technologies to bridge the gap and hence, the introduction of greenhouse technology to food growth.
A typical greenhouse with good agronomic practice may yield up to 700 % when compared with a typical farm, especially if drip irrigation is also used.
As technology continues to evolve, it is extremely likely that greenhouses will continually become more sophisticated in the days to come and play mores in farming. It is also likely that urban greenhouses will become more popular and form the backbone of our food supply infrastructure.
3. FARM WASTE TO ENERGY AND GREAT WEALTH
It is a thing of joy for any Engineer to participate in new projects, especially those we have always thought were only theories and not practical. Over the decades, in Abakaliki Rice mill Cluster, there has been an accumulation of rice husk waste constituting a very big nuisance and danger to the environment. It has been an unquenchable fire for more than 50 years emitting smoke constantly! Many groups and institutions from Nigeria and abroad visit the site to study how best to convert the rice husk mountain into something useful.

When I was the Commissioner of public utilities in Ebonyi State, I worked hard with my team to find a useful purpose for the husk. When Ebonyi State Government built 3 units of 120 tons per day rice mills, the challenge was how to parboil the paddy. Local people were employed to parboil and dry the paddy in a most inefficient method before milling. The rice mills were mostly inactive because of lack of parboiled paddy. So we worked with an Indian Company to build a parboiling plant of 200 tons per day using the waste rice husk. The husk was used as fuel for the boiler and drier.


Ikwo rice mill parboiling sector
This effectively solved the parboiling problem. On our own, we have scaled the machine down for the use of local rice millers who now build their own parboiling plants with their rice husk as a source of fuel.
However, this process did not solve all the problems as the rice heaps continued to increase, causing more environmental hazards of pollution and fire outbreaks in Abakaliki and its environs. The Rice milling machines continued to work smoothly but at a cost that was affecting the final price of the rice.
Take note that the biggest cost in producing rice for the market is the cost of milling, mostly due to the cost of diesel as the grid electricity will provide unreliable and unsteady power which leads to the burning of electric motors and long downtime experienced always. This disrupted the work as well as added to the cost of rice in the market.
Then, we approached the Unido to assist us in using the rice husk as fuel to generate electric power for the factories. Unido was in agreement but opted for combustion method of steam turbine-powered electric generator but my team favoured gasifier method of providing fuel. This might have been because India didn’t have the technology to use rice husk for a gasifier then. They could only do with pellets or diced wood. My fear then was the capacity to run a steam turbine with its complexities and also the advantages of running a low speed internal combustion engine. You can run the engines and turn off as often as you want, whereas it is best to run the turbines continuously. Stopping the turbines frequently reduces its life rapidly. So I was able to convince the executive council to use the biomass gasifier method to produce synthetic gas for internal combustion engine to produce electricity. This proved very simple and workable. Today, Ebonyi State has made full use of their rice mill wastes to power their parboiling machines, as well as generate enough electricity for their use. Excess power can be deployed to small businesses by the rice mills for a fee. Each of the clusters has 500kw generator installed. One has been tested successfully while the Covid-19 pandemic has temporarily delayed the rolling out of the others. We employed the services of the Chinese people to assist in the project, and our active participation gave us the ability to actually build a gasifier reactor.
I also want you to note that our association with the Technical University of Bangalore in India, yielded us a 37kw gasification power plant which used diced wooden sticks cut uniformly. Based on this, the Power Plant Team fully built an upgraded biomass generator of 125 KW from materials sourced locally. These plants now provide power for a rice mill cluster, a Health Centre and street lights in Ngbo, Ebonyi State. The plants are wholly managed by the cluster owners. In fact, that was the first Gasifier plant ever built locally in Nigeria. The NERC graciously approved the plants we built.

It will be good and interesting to understand the engineering technique used to achieve this feat.


Biomass Storage 2. Biomass Conveyor 3. Biomass Buffer Bin 4. Biomass Gasifier 5. Cyclone Dust Collector 6. Gas Filter 7. ESP 8. Gas Scrubber 9. Gas Dryer 10. Blower 11. Buffer Tank 12. Gas Flare 13. Gas Generator Sets.

500MW Biomass gasifier in Ikwo Rice mill during construction
Gasification is the use of heat to transform solid biomass or other carbonaceous solids into a synthetic 'natural gas like' flammable fuel. Through gasification, we can convert nearly any dry organic matter into a clean burning fuel that can replace fossil fuel in most situations. Mixed with air, the producer gas can be used in gasoline or diesel engine with little modifications. It is a much cleaner process than direct combustion.
Gasification is a century old technology which flourished quite well, before and during the Second World War. The technology disappeared soon after the Second World War when liquid fuel became easily available. Today, because of increased fuel prices and environmental concern, there is renewed interest in this old technology. Gasification has become a more modern and quite sophisticated technology.
Examples of biomass materials include any kind of agro-waste/forestry waste and animal waste. In India and indeed China, it is a no waste system. Farmers sell all waste including stalks, leaves, and whatever remains after harvesting to power generating companies or to compost makers, raking enough financial returns equaling the prices of their farm produce. Based on the design of gasifiers and type of fuels used, there exists different kinds of gasifiers. Portable gasifiers can be used for running vehicles while stationary gasifiers combined with engines are widely used in rural areas of developing countries for many purpose including generation of electricity and running irrigation pumps and so on.
Technologies such as biomass gasification which allow utilization of biomass fuel should be of great importance to agro-related factories in rural set ups to minimize the cost of food production.
Finally, I believe this presentation should spur our universities, business people, and leaders to invest even more in agriculture with available technology to provide enough food for the people; and most importantly, to invest in manufacturing of these simplified equipment that will make life easier for our farmers. Thank you all for your attention, and I say “may God bless you all”.

Much useful information shared here, very capable of lifting us from these energy crisis instantly.
I made a coconut shell gasifier from scrape metal also in Lagos, here is the youtube link of it at work.

https://youtube.com/shorts/xXC5XGAd2Zs?feature=share

Currently modifying the unit for conversion of municipal waste to syngas.
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Once again great work.