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The beneficial effects of climate change on rice in Madagascar(Taken from website of CIRAD)

In the highlands of Madagascar, upland rice growing has developed in recent years thanks to the availability of varieties suited to the prevailing low temperatures in this mountainous region. However, what repercussions is climate change likely to have on this crop, on which a large proportion of the island’s inhabitants depend? By simulating rice production over a century, depending on the extent of climate change and the cropping practices adopted, a team from CIRAD and FOFIFA came up with a surprising result: it was the most pessimistic climate scenario that enabled the best yields.

Global warming could have serious consequences for rice production, and as a result for food security. Precise data on the effects of global warming are few and far between, and primarily concern irrigated rice. Upland rice, on the other hand, has never been studied before.

A team of researchers from CIRAD and the Malagasy National Institute of Agricultural Research (FOFIFA) looked into the impact of global warming on upland rice productivity in the highlands of Madagascar, where the crop has developed recently. Their study covered a ninety-year period, from 2010 to 2099, depending on the cropping system adopted.

Two climate change scenarios

Rice yields were simulated using the CERES-Rice model, which was calibrated and then validated using the FOFIFA 161 rice cultivar, for which a set of experimental data was compiled over a six-year period. The cropping systems comprised two soil tillage systems – hand ploughing and no-tillage – and two nitrogen fertilizer rates – high and low.

In relation to the control, without climate change, two scenarios were tested. In the first, carbon dioxide emissions increased gradually up to 750 ppm and the temperature rose by 0.15 °C per decade. This was the optimistic scenario, in which the increase in carbon dioxide levels and the relatively moderate increase in temperature were supposed to foster rice growth.

In the second scenario, carbon dioxide emissions also rose gradually, but the temperature rose by 0.5 °C per decade and rainfall fell by 0.2 mm a day between December and February. This was the pessimistic scenario, in which the combination of a marked rise in temperature and a reduction in rainfall could have led to severe water stress in rice.

Surprising results

The analysis did not reveal any differences in yields between the soil tillage systems, irrespective of the degree of climate change and fertilizer rate. No-tillage did not improve yields compared to tillage, or the efficacy of water use or nitrogen uptake by the plant. It is likely that in order to significantly improve soil properties, no-tillage requires substantial dry matter production, which is impossible to achieve at the prevailing low temperatures in the region.

However, fertilization did have a significant effect on yields, with a gain of 1500 kg/ha of grain for nitrogen applications of 45 kg/ha. Nitrogen is a major constraint in this type of soil, in which its availability is reduced due to the soil’s poor anion exchange capacity and to leaching.

Rice yields, which were 5478 kg/ha on average, were markedly higher in the pessimistic scenario, with a gain of 576 kg/ha compared to the control. In that scenario, the increase in temperature speeded up flowering and grain maturity, in such a way that the demand for water and nutrients from the plant tallied better with their availability in the soil. Yield variability was lower, and the gap between this scenario and the others continued to grow over the years.

A positive effect on rice productivity

Although the initial hypotheses – crops without biotic constraints or marked weather events – limit the import of the results, global warming could have a positive effect on rice productivity in this cold region, where rice is grown at the lower limit of its temperature tolerance.

Unlike what it likely to happen in southern Asia, where rice is grown at the upper limit of its temperature tolerance and yields are likely to fall overall, the most “pessimistic” forecasts in terms of temperature could lead to a marked increase in yields in the highlands of Madagascar.

I acknowledge that the source of the important article ,’The beneficial effects of climate change on rice in Madagascar’ is the website of CIRAD which may be accessed at the following link:

http://www.cirad.fr/en/research-operations/research-results/2012/the-beneficial-effects-of-climate-change-on-rice-in-madagascar

The article has been published in this website to share and disseminate the research findings.All readers are invited to read and share their feelings about this article.

Cold Wave Hits Bangladesh:Is it An Indication of Climate Change?

The winter in Bangladesh was generally considered as pleasant.Usually lifestyle change in this season and many activities like,visiting countryside with family and friends, picnic,travels,sightseeing,festivals,fairs,ceremonies take place in this season.Many exotic and indigenous vegetables and fruits give the markets a colorful look and consumers make delicious  food items.One special activity in the winter of Bangladesh is making of various types of country cakes(locally called pitha) with rice,coconut,molasses made from the sap of  date palm,spices and many other ingredients.People generally relish these traditional food items when the invasion of imported foreign and locally machine made  packaged food items flood the market.

Foreign tourists also enjoy the pleasant winter weather of Bangladesh as it is almost similar to the summer of the west.This is why many foreigners from  the whole world and the migrant Bangladeshi people visit Bangladesh during winter.Cool temperature without any trouble of mud making rain give  delightful experience.

But,this winter that has started in December,2012 and rolled to January,2013 is different.Several cold waves have crippled the life of common people.They are struggling frantically to protect themselves from the bite of the shivering cold.Most people lack  sufficient warm clothing and this they are helpless in the foggy and wintry weather.Many children and old people have fallen victims of biting cold weather.News media reported 22 cases of death of humans up to 10 January.2013 .

The temperature in this winter has been recorded as the lowest in 58 years.Though the variation of temperature in different areas of the country may present a wrong picture about the severity of cold wave in particular places.The lowest temperature recorded in Dinajpur on 9 January,2013 was 3.2 degree Celsius while the highest was recorded in Cox’s Bazaar which was 11.8 degree Celsius.

Historically,the lowest temperature was recorded in Bangladesh in Srimangal, Moulvibazaar.The temperature was 2.8 degree Celsius and the day was 4 February,1968.The cold  temperature is mostly influenced by  various phenomena of weather.It has been observed that the adverse effects are many.Many kinds of diseases affect people in cold weather,domestic animals suffer badly in such weather.Crops like paddy  and potato production are badly affected by cold weather.The seedlings of winter paddy,called Boro rice get stunted by severe cold while potato may be damaged by fungal diseases like early and late blight.Mustard is another major crop of Bangladesh of winter which adds beauty to the nature by  its vast expanses of yellow flowers.This crop may be devastated by the attack of an insect pest called Aphid in the foggy weather.

The winter is one of six   vital  seasons of  Bangladesh.It would be a blessing unless the the people is devastated by cold waves.

This year the cold waves are biting hard causing great sufferings to peoples.Should we view the current winter as any indication

of climate change?I welcome the opinion of  experts in this discipline.

I will continue to update this article on the basis of real situation and opinion of experts.