About one quarter of all pesticides for the global crop system are going to cotton. In my mind the choice of agriculture for Africa should be based on biological and not chemical inputs. Many rice systems are very chemical dependent but System Rice Intensification offers a better approach in that regard. I believe the nature of the agriculture system needs to focus on mixed farming which animal and cropping phases are integrated and a diverse crop rotation has a major emphasis on legumes and forage. In temperate areas the Rodale Institute has demonstrated this amply so organic systems can be fully competitive with chemical input systems. The same needs to done in Africa with a systems approach rather than input and commodity approach. I very good start would be using the push pull crop pest management which needs to concentrate on Desmodium seed access and demonstrate and teaching the technique through sub Saharan Africa. This system addresses witch weed parasite and the stem borer complex. Another bright spot is the increase in the utilization of pigeon pea which is able to provide Nitrogen rotation and improve the dietary insufficiency associated with maize rice and wheat. A lot of improvement can be made by focusing on the soil improvement needs since the sub Saharan area is notably poor in fertility. Continuing teaching of improved compost techniques is essential to make headway solely needed. 

Thank you very much for your contribution. Waiting for other answers...

I think food security should be the first priority

I appreciate the question of Mr. Houngbo. As mentioned by other colleagues, the food security needs priority over commercial interests. Cereal crops like rice and maize need assured rainfall or good irrigation facilities. They also need sufficiently high inputs of plant nutrients.They can be supplied through fertilizers or fertilizers and manures(integrated).In rice, plant protection, the control of pests and diseases is also  needs good attention.Of course ,selecting and getting appropriate rice varieties  is equally important .IRRI or other rice producing countries like India and China may help.Delineation of area available/suitable for rice is  again important .Also equally important is whether some success was already achieved in some parts of Africa  in rice growing which can taken as success story and rice area in similar situations can be expanded without much risk.Of course training of manpower  like agricultural officers and progressive farmers also assumes importance.If Governments give priority to rice,it can be grown in Africa even without replacing cotton.

I appreciate the important points given by colleagues, I add few more considerations to look into for comparison between cotton and rice

1. Suitability classification of crops (on spatial basis)

2. Factor productivity of major inputs  (water, nutrients, pesticides)

3. Yield gap analysis on basis of research farm / farmers' field trials (attainable yield and actual yield)

4. Cost benefit analysis 

5. Resources and inputs availability

6. Short- and long- term consequences of adoption of specific land use types

Thanks to all the contributors of this imp discussion, which is important not only to Africa but to all regions over the globe for sustainable and profitable agriculture

regards

two more points to be indicated for choice of land use type (crop choice)

1. Bio-physical and socio-economic constraint analysis for adoption of rice or cotton, where even with low productivity of cotton farmers are going for this choice.

2. Second point is public/corporate interventions for replacing cotton with rice (logic and feasibility analysis)

regards

Based on my experience in Zambia, I can say it is possible. By using locally available resources (rainwater harvesting, by use efficient irrigation methods, choice of appropriate varieties) and change in crop management system (like SRI and direct seeded method) African farmers will be able to harvest good yield from rice and it will be very helpful to improve nutrition, food and financial security of African farmers. 

Thank you for your contribution.

Dr.Uprety,good information from from your practical experience in African country.

Many of the problems in developing and developed economies can be put to the foot step of non optimized diets.

While a white rice diet would certainly be a clear example the remedy is not rocket science.

 The supplementation of rice with a minor portion of pulses is clearly a way forward. The development of better legume use is not convincing however.

In addition the beri beri disease first discovered in white rice eaters was remediad by including bran in the diet.

In both the developed and developing world the use of whole foods is part of the education process we need. In both zones the knowledge and application of dietary principles falls way short of where we need it.

Our best health program is to stay healthy by our diet exercise and hygiene which needs to include our concentration on high goals in our lives. 

Dr.Hepperly ,good suggestion.It is better to fit in a pulse crop in rice based cropping system to provide/supplementnt protein diet to rice eaters.

It is important to do a socio-economic study and fit crops like rice, cotton and other food and commercial crops in cropping systems. It has to be noted that eco-system requirements for these crops would vary!

Since the biggest ecological economic footprint in a Carbon sense and from the input standpoint is Nitrogen fertilizer the use of the cropping system to supply that need through a legume is very important.

In the case of crop like maize over 50% of the calories for the inputs can be put into the ammoniated fertilizer.

The input for a crop of cotton can be reduced by biological nitrogen fixation, no till planting, using amendments which sequester Carbon and Nitrogen into the soil long term reduction of the pesticide inputs by use of resistant varieties and biological pest controls.

In terms of the long sustainability and increase in overall productivity the building of the soil organic matter resources might be the most effective and should be employed in the overall system. .

Mixed animal and crop farming composting wastes and returning them,  tracking the soil resource are proven ways to open up yield and quality plateaus and the unsustainable nature of much of our past and current agricultural activity.

There have not been many concerted efforts to set goals and increase the soil resource in relation to our food system but it remains a powerful tool in humanity tool chest for dealing with run away greenhouse gases which most people are not fully aware of or engaging in any profound sense.  

Dr.Hepperly, I appreciate the last paragraph in your reply.Dr .Imran, both cotton and rice need more nutrients when we target high yields.Of course, we have to plan for reducing the fertilizer nutrient requirement and use more of biological inputs.

I too support the point given by our seniors. we can meet the cotton and rice needs through use of green manures or crop rotation.

definitely rice can meet the nutritional requirements, but as indicated we have to see the crops' capability classification of the region, and then we have to assess the resources available for meeting the nutritional requirement of rice to judge the possibility of alternate land use type.

The System of Rice Intensification uses 1) an earlier transplant date, 2) the use of more space per plant, 3) the inclusion of organic amendment and 3) rigorous mechanical aeration and  weeding to optimize rice root systems.

This approach might be more biologically sound and sustainable than trying to rely strictly on chemical inputs and having a system that concentrates strictly on upward growth and not focusing on the roots.

When roots are optimized the nutrition of the plant will also. When amendments dwarf the root system the nutrition will suffer. The use of high populations and heavy ammoniated fertilizer will have a negative consequence of disbalancing plant top heavy and root weat.

Nutriotn of the end product can be expected to suffer.

Since farmers are not reqrded for the nutrition of the crops they produce we might need to anticipate better ability to identify better nutrition to benefit the producer and consumer. 

In all of systems we need to optimize the soil condition to optimize the crop condition and this starts with in depth soil analysis and a plan to optimize t. 

Dr.Hepperly I agree with you that optimization of soil conditions/root environment and plant type with good root system will help to fully exploit the applied nutrients.  Managing good agronomy through population ,spacing,timely sowing, nutrient and water management practices,  weed and pest control measures will definitely help in better nutrient utilization by crops and reflct the same in yield.Efficient resource use and use of non-monetary technologies  (good agronomic practices with out purchasing from outside the farm) will not only save the resources but also the economies of farmers.

While scientists debate on this issue farmers have already started changing their cropping cycle. I witnessed this during the 1990s in Tanzania when farmers in former cotton zones switched to rice as a cash crop when the price for cotton declined during several years. Switches to other cash crops will take place in other African countries when the prices for cotton do not satisfy the farmers. Everybody should know that people need cash next to food. And for farmers that do not produce enough food themselves that cash is mainly used to buy food.

Back for a trip with African yam farmers in Guinea West Africa. There the farmers are selling their yams for rice. At the same time epidemic malnutrition has a root in the rice diet. Cheap food has a high cost and the emphasis on teaching about the importance of nutrition is lacking. Our nutrition starts with the farming systems and we need systematic appreciation that our nutrition is from the soil and Africa has huge issues related to deficient and toxic soil situations. 

Constituent   White Rice   Yam    % Advantage

Potassium               115     816          609.6

Fat                            0.66    0.17        -74.2

Vitamin C                     0     17.1       infinite

Vitamin B6             0.16     0.29          81.3

Vitamin A                     0      138         infinite

Vitamin E               0.11      0.39          254.5

Vitamin K                 0.1        2.6         2500.0

Beta Carotene        0 8           3          infinite

Glycemic Index                                     -46