Reinventing plows. Zimbabwe farmers are not always right

Revised 19 June 2009 at 0606 hours Manila time

ZIMBABWE! THE LAST COUNTRY in my list. Today, to the Christians, the Republic of Zimbabwe is a colossal, colonial challenge to faith and works and science. Yet, despite everything, they have to give honor to God, the origin of their life; they have to give honor to men, the origin of their everything else – and they have to work the soil, the origin of their food.

You give your soul to God; you give your best smile to men – and you give your best science to the soil. Can you do that? You have to. Even as you have done it to the worst of your brethren, you have done it unto your God. Even as you have done it to the worst of the soils, you have done it for your own good.

I don't understand the disheartening civil performance in Zimbabwe, but I do understand the depressing soil performance in that country: over-grazed, over-cultivated, lacking in irrigation, lacking in fertility, lacking in crop diversity. A farmer's son, I am an agriculturist by training (BSA '65, University of the Philippines College of Agriculture, UPCA), a writer by choice, a landless farmer at heart. At UPCA, we were taught in the old agriculture what to do – sow seeds on bed, plow, harrow, transplant, furrow, irrigate. And we were taught in the new agriculture what more to do – fertilize, spray against weeds & insects & diseases. Lessons learned, eventually, as it took me 5.5 years to finish a 4-year course.

After graduation, employed at UPCA as a Substitute Instructor (Horticulture, Lab), I had all the time in the world to read, and I had the best library in the world – that library had the largest collection of books, journals and magazines about agriculture and related fields, and they were all at the fingertips of any voracious reader like me. Those were my salad days of reading and learning on my own.

Now I'm in Manila; I have the whole world via the Internet as my library. I thank God for the Internet. If you tell me Zimbabwe is suffering, among other things, from desertification, land degradation, declining soil productivity, infertile soils, low organic matter content, poor water-holding capacity of sites – I know where you're coming from. You too are describing my country, the Philippines.

If you neglect the land, it will become a desert; if you abuse the soil, it will deteriorate; if you starve the soil, you will get a sick crop; if you don't build the soil, it will not keep the water for your crops; if you don't return to the soil what you take from it, it will repay you in kind.

Water is almost everything to the farmers, especially in the drylands of Africa and Asia. Without science, they depend mostly on the rain and, so, the behavior of the rain determines the behavior of their yields: erratic.

Not exactly in those words, but I've been thinking those thoughts and been reading for years on alternative agriculture. Thus I was excited when I read ICRISAT's Happenings 1363 (22 May 2009) about Walter Mupangwa of ICRISAT Bulawayo being awarded November 2008 a PhD by the University of Free State at South Africa for his thesis work on water and nitrogen management in farmers' fields in Zimbabwe. It's not as daunting as it looks. His study covers small farmers within 3 growing seasons, from 2005 to 2008, comparing on-sight (farmers' fields) and on-station (experimental areas) the outputs of plowing, planting basin and ripper systems in the dry soils of Zimbabwe. I was familiar with plowing of course, but it was the first time I encountered the basin and the ripper. I wanted to know more.

I had forgotten. In the book ICRISAT At 35: Triumphant Journey With The Poor In The Drylands (November 2007), it is reported that ICRISAT is working with NGO partners in Zimbabwe on a conservation agriculture, CA package for small farmers, supported by the Department for International Development (DfID), UK. The key component of the package is the planting basin; this is described as a small pit that is 15 cm across and 15 cm deep, where the rainwater collects, the seed is planted, the N fertilizer is applied and manure likewise. Crop rotation is also practiced. I had read that and forgotten.

I surfed the Internet and found that basins and rippers are parts of conservation agriculture. Why haven't I learned of CA in the Philippines? I also learned that CA was successfully introduced in Zimbabwe in 2004 by a task force led by the Food and Agriculture Organization, FAO Emergency Office in that country, indicating that relief and development can go hand in hand (S Twomlow, JC Urolov, M Jenrich & B Oldrieve, 2008, ejournal.icrisat.org). I understand that, because under relief conditions, you must think of the minimum, not necessarily the optimum, certainly not the maximum. Under extremely scarce farm resources, the better economists will hardly teach you to save, while the better agronomists and horticulturists will teach you to conserve. In this essay, I will talk about save and conserve.

Let me concentrate on Mupangwa's thesis work on comparing 3 tillage systems: plowing, planting basin and ripper. The first is conventional – you have seen a field plowed, you have seen them all. The last 2 are minimum-tillage techniques, not well-known. Let me describe them briefly.

Planting furrows (plowing system). This is the conventional system and should be familiar to most people in the tropics: in plowing, you create furrows for planting. In his study, Mupangwa compares the effects of single plowing and double plowing.

Planting basins (basin system). To make the planting basins, the farmer digs out the soil with a hoe, and the resulting hole turns into a basin for catching and holding rainwater; later, the basin is the site for planting and fertilizing. The problem is that in southern Africa, hoeing is difficult because the soil is hard, very hard. To encourage the farmers, the UN's World Food Programme, WFP provides food assistance while the farmers create the basins on their fields (IRIN, 2007, reliefweb.int).

Planting lines (ripper system). To make the planting lines (my term), pulled by a pair of ox, the plow-like ripper with its single tine opens a very narrow furrow in every pass. The idea that the tool 'rips the soil' is apt because the field is rock-hard. As with the planting basin, ripping is done before the rains come in order to harvest the rainwater. In Zambia in the mid-1990s, researchers of the Golden Valley Agricultural Research Trust, GART introduced the Magoye Ripper to farmers (see image), which it claims to be 'a Zambian original' (aec.msu.edu).

We might call double plowing maximum tillage and ripper plowing minimum tillage. The moldboard plow is designed to open up the land and turn over a wide path of soil with each passing, disturbing the whole field. In contrast, with the ripper, the rest of the field is not disturbed, soil and vegetation included. The ripper is essentially a soil chisel, and can be attached to an off-the-shelf plow frame. Thus, from where I sit, whoever invented the ripper literally reinvented the plow.

How does the ripper improve on the plow? It is claimed that John Deere 'invented a better plow' in 1837 yet (inventorsabout.com), but tell that to the farmers of Zambia and Zimbabwe! The ripper is for planting; since much of the field is not disturbed, whatever water is there is retained with the vegetation; the undisturbed vegetation covers the field and the soil underneath it does not run off with the rainwater. The vegetation also builds organic matter, especially if you apply a vegetative mulch. The plow is for disturbing the soil structure, disrupting soil buildup, preventing organic matter accumulation, and opening up the site for the soil water to evaporate. We need all the water we can save!

The ripper is a revolution in thinking such as it is. Now, will other farmers in other lands adopt the ripper and abandon the plow? I should think so, because the ripper is not too new; it is itself an adaptation of the plow, which has long been an accepted technology to the farmers all over the world. The plow was invented in China in 3 BC yet (Encyclopedia Britannica, quoted by computersmiths.com).

CA is a method of farming that minimizes soil disturbance, applies more precise timing for planting, and utilizes crop residue to retain moisture and enrich the soil' (IRIN as cited). In Mupangwa's study, the crop residue is used as mulch, which among other things, not only supplies water to crops all the time, but also enriches the soil, reduces soil runoff and evaporation of water from the field. The mulch is a natural collector and conserver of rainwater.

The results of Mupangwa's study include the following:

(1) Planting basins reduce soil water runoff, basins cropped or uncropped.
(2) Cowpea yields decrease with delayed planting.
(3) Sorghum yields decrease with the planting basin due to rodent attack.
(4) Sorghum and cowpea can be grown well on planting basins at 0.9 m x 0.6 m.
(5) Regardless of tillage system, nitrogen fertilizer increases maize yields.
(6) Mulching increases maize grain yield significantly.
(7) Double plowing gives the highest yields to farmers.

Giving them the highest yields, as expected Mupangwa reports that his study farmers rank double plowing as the most appropriate tillage system for them given local Zimbabwe conditions. Mupangwa himself cites SJ Twomlow & PMC Bruneau (2000) as reporting that studies in Botswana and Zimbabwe 'have demonstrated that double spring plowing can increase crop yields in a wide range of soil types under semi-arid conditions.' Double plowing is good for almost any kind of soil. Be that as it may, note that the farmers are, it seems to me, using yield as the single most or the only important factor in deciding whether to call a technology appropriate or not. This is of course conventional thinking, and a dangerous idea, because it makes you remember only the returns and forget the costs.

The farmers are not always right!

Mupangwa says that long-term (69-year) simulation modeling reveals that crop failures can be expected in the use of either basin or plowing systems 'due largely to uneven distribution of rain events during the growing season.' Translation: You can't rely on the rain because the weather is unpredictable. Implication: Harvesting and storing the rainwater is critical to the growing of crops. Another lesson I learned from ICRISAT.

On that matter, aside from ICRISAT's holistic watershed approach for a whole village to harvest rain (see my 'Water Lessons of Adarsha,' 02 November 2008, americanchronicle.com), mulching for a farmer's field can be used. In his study, Mupangwa finds that mulching maize, cowpea and sorghum fields improves the soil water supply and increases yield even in a season with below-average rainfall. I can explain it. The mulch becomes humus (organic matter), and in turn the humus, being spongy, increases the water-holding capacity of the soil. If there is no rain, the soil gets its water from the humus itself; as well, the humus absorbs capillary water rising through the layers of soil. Thus, all things being equal, water being life to the crop, with a mulch applied, one can expect much better yields. Bare soils, and therefore hungry and thirsty, can only give bare yields.

Mupangwa's study is based on the grand concept of Conservation Agriculture; that is looking at it from the point of view of scientists. I believe in conservation agriculture; I'm just looking at the term itself. And having been learning from ICRISAT science in the last 2 years since February 2007 (for the beginning, see my 'The Yankee Dawdle. On Discovery Sorghum, The Great Climate Crop,' 04 February 2007, americanchronicle.com), I want now to look at it from the point of view of the farmers and call it Saving Agriculture, and it comprises the following:

(1) Saving the soil. Soil erosion is stopped or reduced by minimum tillage. 'We're losing 400 million tons of soil every year,' says James Breen, an agronomist of the Food and Agriculture Organization, FAO (IRIN as cited). I say if you're losing soil, you're losing food – you're losing the nutrients that can become cereal, vegetable, nut or fruit.

(2) Saving on fertilizer, 1. Fertilizer is applied as ICRISAT micro-dose, 1 bottle cap of fertilizer to a planting basin. No over-fertilization, hardly any fertilizer leached to the underground.

(3) Saving on fertilizer, 2. Mulch applied turns into organic matter rich in plant nutrients. Crop rotation with a legume enriches the soil with nitrogen.

(4) Saving on water. Rainwater is harvested by the planting basin, also absorbed by the undisturbed soil. In the Adarsha approach, as mentioned above, the rainwater is saved so that a whole watershed is rehabilitated and the underground water is replenished. Drip irrigation – ICRISAT's African Market Garden package – is another option.

(5) Saving on weed control. Crop residue is applied as mulch, an excellent technique for weed control. Planting a cover crop is also effective against weeds.

(6) Saving on pest control. Planting on time, that is, simultaneously with other farmers or fields, prevents a specific crop from becoming the feeding and, therefore, the breeding ground for pests. Planting trap crops is another option to save on pest control. These techniques minimize the use of pesticides that are expensive.

(7) Saving on cost of sad experience. Since inter-cropping is a hedge against a single crop failure, multiple cropping is a multiple hedge.

Saving Agriculture is not saving on farm labor, no. Not the Conservation Agriculture I'm thinking of. 'Labor-intensive' is a term to describe Conservation Agriculture, as there is a need to do all these manually: prepare planting basins with a hoe, rip the field with planting lines, mulch field with crop residue, apply fertilizer, and plant the seeds. At any rate, small farming is always labor-intensive. Thus, I might say CA in the Philippines is perfect, as our President Gloria Macapagal Arroyo currently is encouraging job creation – the more brains and brawns employed, the better for the economy.

Saving Agriculture is not reinventing Conservation Agriculture; it is only calling for a paradigm shift in thinking about Climate Change globally and acting on Agriculture locally. From Australia to Zimbabwe, the small farmers will understand.