KARACHI, Dec 27: A study shows that an inexpensive biological solution with multiple benefits is available to reclaim thousands of acres going unproductive in Sindh due to water-logging and salinity.
Avicennia marina, a mangrove species, has the potential of not only reducing the impact of water-logging and salinity, it also increases soil's productivity, says the research conducted at the botany department of the Federal Urdu University of Arts, Science and Technology.
The research titled 'An assessment of the use of Avicennia marina Forsk Vierh to reclaim waterlogged and saline agricultural land' was published in the Pakistan Journal of Botany last year.
The research results showed that the plant rapidly adapted to the soil conditions and made it productive for vegetable cultivation.
The seeds of the specific mangrove species were collected in the Sandspit area and planted in a green house. And, then, seedlings were planted on the university campus, a highly saline and water-logged piece of land. Tomatoes were sown before and after the plantation of mangroves on the same land.
According to the study, the mangroves grew and adapted fast to the changed soil conditions and did not develop the aerial roots, a basic feature of the plant, due to the availability of oxygen in the soil. Tomato seeds planted before mangrove plantation did not germinate while swift germination was observed after a 15-month trial of mangrove plantation.
“Though mangroves have been studied from different aspects, it's the first time that its impact on water-logged and saline land has been scientifically determined,” said Dr Kanwal Nazim, a key researcher who was helped by Dr Mohammad Uzair Khan and Dr Syed Shahid Shaukat at the university.
The planted mangroves, she said, could also be used as fuel wood or fodder for livestock, if resources were available, as previous studies had already established the plant's potential in that regard.
“Mangroves have remarkable capability to cope with saline environments. There may be no other group of plants with such highly developed morphological and physiological adaptations to extreme conditions,” she said.
Highlighting the study's significance, Dr Nazim said that agriculture, which played a central role in the country's economy, had been badly hit by water-logging and salinity and there was a dire need for an inexpensive biological solution to reclaim unproductive land.
“In Pakistan, about 6.30 million hectares of land is salt-affected and of this 94,000 hectares land exist in Sindh. While more land is going saline and water-logged at a fast rate every year. The devastation has occurred mainly because of the obsolete irrigation system,” she said.
Explaining the flaws in the irrigation system introduced in the British period, Dr Moinuddin Ahmed, head of the dendrochronology laboratory at the university and research supervisor, said it was not scientifically prepared.
“Crops are generally irrigated with huge quantities of water, often 100 times more than the plant's needs, with the help of unlined canals. In area with hot climatic conditions, 60 per cent of the water evaporates, leaving large quantities of salts in the soil.
“The water left standing gradually increases the level of water table as there is no drainage mechanism. Consequently, the soil becomes water-logged and unfavourable for most crops over the years,” he said.
Dr Ahmed regretted that the country had no concept of water management and no technology had so far been used on a large-scale to find a solution to the problem.
The university, he said, wanted to expand the project and was looking for affected farmers who could offer their land for experimental purpose.
“The trial has shown positive results and could be successful on a large area. The university is willing to provide technical assistance free of cost. All the provinces share the problem of water-logging and salinity, but mangroves could be planted only in areas that do not get frost,” he said.