Regenerative Agriculture – RA for small scale farmers in the sub-humid tropicsTools and techniques to maximize profits and build resilient farming systems and improve natural resources management in Zambia Sebastian Scott – Grassroots Trust

What’s the goal? To achieve improved livelihoods for the

rural population through a balance of social, economic and environmental factors to ensure sustainable growth.

Soil – the basis for growth

Organic Matter- the heart of the soil Increased organic matter leads to: - Increased infiltration and water holding capacity- Increased nutrient content and holding capacity- Improved soil structure which leads to reduced

erosion and less labour when the soil is cultivated

- Increased biological function in the soil which leads to nutrient release and disease suppression

How do we increase soil organic matter in tropical soils? No burning of crop residues – as this leads to the

carbon on the surface of the soil being released as carbon dioxide and monoxide.

No soil inversion – as this leads to the introduction of excessive oxygen into the soil which leads to rapid decomposition of soil organic mater by micro-organisms.

Reduce heavy applications of nitrogen fertilizer – as this directly kills micro organisms, leads to rapid bacterial growth and loss of carbon as CO2 and also leads to acidic soil conditions which limit nutrient availability.

Grow more organic matter in the field and cycle organic matter through animals in the form of manure.

Fire!

Why do people burn residue? To allow the plough to pass in the field To avoid the hindrance of residue during post

emergence weed control To avoid the risk of late season ‘hot’ fires near

their homes By accident when people – not necessarily the

farmers - burn bush around their farms To enable the hunting of field mice. To reduce disease/pest pressure from residue

Why do people plough? Ploughing is usually a method of early weed control and

allows a period of calm before weeding starts Ploughing with a mould-board plough allows a farmer to

plant seed and apply fertilizer in the furrow behind the plough

The plough is thought to loosen the soil – but in reality does the opposite through the action of smearing and by allowing particle separation to occur over time – both lead to ‘hard pan’ effects which limit root growth and soil drainage

In summary – ploughing is predominantly a labour saving technique

Why do people use fertilizer? Fertilizer gives good yield responses on soils

which have high organic matter – this has been the case for many virgin soils that have had organic matter built up over many years in our savannah eco-system, with few fires and abundant wildlife to aid decomposition and cycling of nutrients

Fertilizer is subsidized by the government Maize- our main crop- requires a lot of nutrients,

especially Nitrogen and Phosphorous for good growth and yields

So – how do we establish crops without burning and ploughing without increasing the labour burden, at low cost? For very dry areas – some form of dry season,

minimum tillage land preparation that concentrates water near the seed, e.g. basins, ripping.

Minimum/no tillage direct seeding. E.g. Mechanical/draft power drawn or hand seeders or dibble stick, possibly on slight contour ridges in very humid conditions or on poorly drained sites.

Ripping with oxen between established pigeon pea

Using a dibble stick to make holes for planting maize/soya/cover crops etc.

How do we provide crops with nutrients without fertilizer? Build soil organic matter, reduce soil disturbance and promote

soil biology that can release nutrients for plants over the season. Intercropping cash crops (grains, pulses or oil crops) with various

legumes has proven to be a sustainable method providing nutrients to subsequent maize crops if the nitrogen is releases at the correct time to correspond with cash crop demand.

Pigeon pea is one such legume that currently has a cash market in Zambia and is a very high protein food source for humans and livestock. It also has the ability to produce large amounts of biomass for building SOM.

Improved Manure Handling (IMH) techniques for ruminant and non-ruminant manure can boost crop yields and add valuable organic matter to the soil.

Fertilizer should not be ruled out and can play an important role in very sandy soils and soils which are in transition to increased SOM and improved soil biology. Furthermore, small additions of fertilizer (less than 100kg/Ha) may produce good economic returns once the soil has been returned to health (more than 2% organic matter)

If available, calcitic and dolomitic lime can be used in a strip applications in the field or through IMH manure in acid soils and as a source of calcium for soil biology.

Intercropping guidelines Should provide immediate benefit to farmers:

food, fodder, firewood, timber Seed should be cheap and easy to establish The system as a whole should be able to

produce large quantities of biomass (more than 6t/Ha dry or 25t/Ha wet above ground organic matter) in order to increase long term organic matter

In the case of legumes, should be able to fix sufficient N for grain crops

Cont.. In the case of legumes, should have the

ability to release N at the time that grain crops require it (little understood but extremely important for effective use of gm/cc’s)

Should do most of its growing before the main crop canopies (very fast maturing cowpea), after the main crop has matured (pigeon pea) or be shade tolerant (sweet potato, pumpkin)

6.6t/Ha maize, no fert, no manure after 2 years pigeon pea intercropping.

Pigeon pea intercropping guidelines Plant at the same time as maize in the same

planting hole For Zambia, use medium maturity varieties

like Zamseed ‘Early Bulk’ and ICEAP 015/14 Plant high seed rates to avoid brittle stems

which lead to damage during browsing and make cutting back easier

High plant density also increases yield potential and biomass production

Three or more crops from one field in one year! Harvest maize – May/June Harvest Pigeon pea – July/August Allow ruminants or pigs to browse pigeon pea - August

to Nov Pigeon pea is strip harvested Pigeon pea is ratooned for two years after the year of

establishment Pumpkins, climbing beans and cowpea can also be

planted together with maize in this system in the second and third season(not in the first as these crops may interfere with the growth of the pigeon pea

The potential for immediate benefit Establishment cost 1 man-day to plant 1Ha (in the

same hole as maize at the same time). Planting once every 3 years.

15kg seed/Ha 20USD(in Zambia) from seed companies, 10USD from farmers once at the beginning of the cycle.

Yield of pigeon pea in maize intercrop 200-700kg/Ha for 3 years (16-24% protein)

Cash return from Pigeon pea/Ha: 100-300USD/year Also dry season browsing for livestock and

firewood.

IMH guidelines Use local/cheap material to cover and

protect manure for the drying effect of the sun and leaching effects of rain to increase to nitrogen content in manure by up to 10 times = 10 times less hauling

Strip apply manure in crop row only and combine with weeding to cover manure

Apply manure twice in a season if possible – most of the N in manure is used up in 3-4week after application.

Unlike traditional compost making - IMH is a low-labour technology and requires no added organic matter, water or mixing

Mrs Tembo, Chongwe, Zambia. Reducing inputs, increasing yields…

2011/12 100kg D 100kg Urea

2012/13 5 t IMH + 100kg D 100kg urea

2013/14 5 t IMH + 40 kg Urea

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Maize yield kg/HaProfit K/ha - no hired labour

Mechanical weed control Light mechanical weed control can be

used to bury manure/compost/residues to preserve nutrients, encourage decomposition and the release of nutrients.

Mechanical weed control using animal draft power (ADP) and hand hoe are made more difficult where abundant residues are present on the soil surface.

Excessive soil disturbance reduces SOM and can lead to moisture loss and erosion.

Herbicides Can allow farmers with access to herbicides

and appropriate training to control weeds effectively in low/no-tillage systems.

For farmers that do not employ labour for weed control (most farmers in Africa) it usually increases variable costs.

Can be toxic to soil organisms, water borne organisms, people and livestock. Some selective herbicides have long term residual action, reducing potential for crop rotation.

Makes intercropping (the basis for resilient, productive, low cost cropping systems) very difficult.

Slashing – you’ll be surprised!

Allows a farmer to suppress weeds during the growth of the cash crop.

Can be very fast compared to mechanical weed control(7-14days/Ha compared to 25-45). This allows farmers to cover large areas at critical times in the growing season.

Allows weeds to grow back after the cash crop has matured, increasing soil fertility and providing soil cover and livestock fodder in the dry season.

Works best with higher plant densities/bigger plants that can effectively compete with weeds through canopy closure.

Needs sharp tools to work effectively and can takes longer if done when weeds are big.

Cannot bury manure/compost/fertilizer, which can promote nutrient losses.

Pasture management and improved livestock production Planned/rotational grazing to reduce internal

and external parasites and improve grassland species diversity and re-growth.

Selecting indigenous cattle and goat breeds with disease resistance and improved performance under dry-land conditions.

Value adding grain by producing farm-made feed for mono-gastric animals. This can double, triple or even quadruple the value of farm produced grain and provide a valuable source of manure for crop production.

Planned grazing‘Bunching’ animals together in a herd to graze in strips simulates large herbivore behavior in the wild and leads to many grassland and livestock health benefits.

Free-range swine production

Free-range broilersBroilers are housed in a movable cage which is moved to a new position every day and effectively weed and fertilize the soil – in this case for bananas.

Free-range eggsLaying hens are kept in simple housing with an outside run. Manure from the house these chickens is used as a fertilizer for crops.

Community dynamics Some RA technologies can be applied

independently by farmers to improve management practices, but..

The success of many of these technologies depends upon community decisions as a whole and…

Without community awareness and common consensus about what can be achieved and how it can be achieved….

Regenerating soils, trees, grasslands, livestock numbers, wildlife and fish stocks and improving rural livelihoods can be very difficult

Grassroots Trust We provide training for farmers at our farm

in Kafue to give farmers hands on experience with these technologies

We work with communities to enhance awareness about natural resource management and give specific guidance where needed

We facilitate/enhance relationships with communities and other stakeholders to facilitate a conducive development environment

We link communities to appropriate private sector partners to aid in marketing and finance opportunities