Of the 26 Brazilian states, nine have semiarid areas, where rain is rare and
irregular. However, these states produce a variety of foods that range from
fruit, corn, beans and sorghum, to cattle, sheep and goat milk.
The years of drought that these regions face, some in which rain does not fall more than five days, have made Brazil into a specialist in producing in lands with a dearth of water. And now the country is also sending to other countries its experience in management of scarce water for planting and growing.
This year, the Brazilian Agricultural Research Corporation (Embrapa) is going to teach the citizens of Mozambique, in Africa, the technology of underground barrages. The solution is simple.
“You dig a ditch and put some waterproofing material in it,” explains the water resource researcher at the Embrapa Semiarid, Luiza Teixeira de Lima Brito. The ditch is vertical.
The waterproofing material, which may be a tarpaulin, is fixed into the earth with mortar. The hole is then covered with mortar. The work, similar to an underground wall, should be built beside the farmland and will hold rainwater for more time during the crop season.
According to a study by the Embrapa, There are around 200 underground barrages in the northeastern Brazilian states of Paraíba, Pernambuco and Bahia. One of them is in the interior of Afrânio, in the land of José dos Santos.
“It holds the water in the plantation area,” explained Santos. The barrage, 525 feet wide, benefits an area of two hectares. There, farmer Afrânio grows grass for his cattle, sheep and goats, as well as rice, passion fruit, watermelon, cassava, banana, guava and mangoes. The corn crop, which is not right next to the barrage, is also favored by the technology. “It worked out,” stated Santos.
In Mozambique, the Embrapa professionals are also going to talk about cisterns, a system through which rainwater is collected for household use in rural zones. The water falls on the roof of the house and runs into a reservoir from where it is later taken out by the family with a manual pump. In some cases, this water is also used to quench the thirst of the herds.
Rain, in the semiarid, is focussed few days a year, and both the underground barrage and the cisterns allow for it to be used over a longer period of time.
If it is not stored, it is lost, as the soil in the region is shallow and the water filters down to the rock layer and runs away. The technologies, according to Luiza, are not new, but were adapted and spread by institutions like the Embrapa.
Embrapa, incidentally, took these water conservation techniques to dry areas in Haiti, last year, and in previous years to countries like Guatemala, Peru, Honduras and Panama.
The transfer of information to other regions of the world is normally through agreements between the government of Brazil and the partner country.
“Embrapa is prominent in tropical agriculture and much of this knowledge is being used by other countries. Water management by Embrapa Semiarid is one of the areas that generates greatest international interest,” stated the general head of the unit, Pedro Carlos Gama da Silva, a doctor in Applied Economics.
The use of underground barrages should be spread around the semiarid in coming years. Organization Agriculture in the Semiarid (ASA) started executing a pilot project called Program One Land and Two Waters (P1+2) three months ago, to promote the use of water retention technologies for production in dry areas in Brazil.
It is the complementation of another program, One Million Cisterns (P1MC), which started being developed in 2003 and has helped build 195,441 cisterns in the semiarid, Maranhão (Northeast) and Espírito Santo (Southeast). In the P1+2, the use of mud-patches, small areas for retention of rainwater that will later be used in farming, should also be promoted.
Irrigation is also being used in the Brazilian semiarid, mainly in areas of fruit planting. However, it is not, according to researchers, the most adequate solution for dry areas.
“It is the shortest route to solve the problem of production in the semiarid, but it has its limitations, one of which is the availability of water. And not all soil may be irrigated. When we combine these factors, the areas appropriate for irrigation are very few,” said Gama.
The cost of irrigation, in the case of some cultures, like beans and corn, is too much, according to the head of the Embrapa Semiarid. This is so true that irrigated areas in the semiarid normally grow fruit, which have a greater added value. This is the case with the São Francisco River Valley, in which grapes are grown.
The semiarid is present in eight northeastern Brazilian states: Piauí, Ceará, Rio Grande do Norte, Paraíba, Pernambuco, Alagoas, Sergipe and Bahia, as well as the north of the southeastern state of Minas Gerais.
The region is formed of 100 million hectares and has its geographic center in the cities of Petrolina, in Pernambuco, and Juazeiro, in Bahia. The Brazilian semiarid has a population of around 30 million people.
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