Increased Drought tolerance and Resistance to Salinity Through Fungi

Past articles have looked at evidence of mycorrhizal fungi helping plants tolerate salinity, heavy metals and arsenic, and have increased tolerance to acid rain. Here we look at two recent discoveries showing how mycorrhizal inoculation can help plants better survive drought and salinisation.

In one study (Marulanda, A, et al. Drought tolerance and antioxidant activities in lavender plants colonized by native drought-tolerant or drought-sensitive Glomus species. MICROBIAL ECOLOGY), researchers looked at drought-tolerant species of the mycorrhizal fungi Glomus (namely drought-tolerant strains of Glomus intraradices and Glomus mosseae ) and their effects on drought-tolerant Lavandula spica (lavender). Drought tolerant strains of Glomus intraradices showed 35% greater root mass growth in the lavender compared to the regular strains of G. intraradices. And the drought tolerant Glomus mosseae showed 100% greater root mass compared to regular strains of G. mosseae.

Other beneficial effects included an increase in water content in the plant and decreases in antioxidants which would hurt plant health in times of drought. Plants with the drought tolerant strain also had higher levels of nitrogen and potassium compared to the non-drought tolerant Glomus species.

I think one could reasonably expect that the less drought tolerant strains would still be better than an absence of any mycorrhizal fungi. Nevertheless, the drought resistant strains would be a very useful and welcome addition to arid and semi-arid systems.

The following is an excerpt from the study’s abstract:

This study compared the effectiveness of four arbuscular mycorrhizal (AM) fungal isolates (two autochthonous presumably drought-tolerant Glomus sp and two allochthonous presumably drought-sensitive strains) on a drought-adapted plant (Lavandula spica) growing under drought conditions. The autochthonous AM fungal strains produced a higher lavender biomass, specially root biomass, and a more efficient N and K absorption than with the inoculation of similar allochthonous strains under drought conditions. The autochthonous strains of Glomus intraradices and Glomus mosseae increased root growth by 35% and 100%, respectively, when compared to similar allochthonous strains. These effects were concomitant with an increase in water content and a decline in antioxidant compounds: 25% glutathione, 7% ascorbate and 15% H2O2 by G. intraradices, and 108% glutathione, 26% ascorbate and 43% H2O2 by G. mosseae. Glutathione and ascorbate have an important role in plant protection and metabolic function under water deficit; the low cell accumulation of these compounds in plants colonized by autochthonous AM fungal strains is an indication of high drought tolerance.

The second study on the effects of Glomus fasciculatum on the salt tolerance of Acacia nilotica (Giri, B, et al. 2007.Improved tolerance of Acacia nilotica to salt stress by arbuscular mycorrhiza, Glomus fasciculatum may be partly related to elevated K/Na ratios in root and shoot tissues. MICROBIAL ECOLOGY), higher nutrient levels were observed in trees inoculated with the mycorrhizal fungi Glomus fasciculatum where soil was salinated.

The United States Department of Agriculture considers soil over 4 dS/m to be “saline soil.”The study looked at uninoculated trees and inoculated trees at salt levels of 1.2, 4.0, 6.5, and 9.5 dS per metre. In the inoculated plants, higher biomass in root and shoot was observed, showing that fungi assisting in plant growth. Inoculated trees had higher levels of phosphorus, zinc and copper than their uninoculated counterparts. And interestingly, in the lower levels of salt, inoculated trees took up more sodium (1.2 and 4.0 dS/m) than the control trees. At higher levels (6.5 and 9.5 dS/m), the sodium levels decreased whereas the control trees took up more sodium. And as salinity increased, the absorption of potassium in the inoculated trees increased. These results show that Glomus fasciculatum fungi increases the health of Acacia nilotica in saline conditions when compared to uninoculated Acacia nilotica. It is reasonable that this species of Glomus and possibly others could benefit other species of trees in saline conditions as well.

They found that at the higher level of salt (9.5 dS/m), the mycorrhizae had a harder time being established. Designers might offset this somewhat with swales. This would allow fresh rainwater to hold in the soil, reducing the salt content over time. Where salty water tables are a problem, appropriate trees can be used to pump down the water table, thereby removing salt from the upper levels. Whether or not Glomus spp. could help tree species used in this way to pump down salty water tables remains to be seems; but it is very plausible.

The following is the abstract from the study:

A pot experiment was conducted to examine the effect of arbuscular mycorrhizal fungus, Glomus fasciculatum, and salinity on the growth of Acacia nilotica. Plants were grown in soil under different salinity levels (1.2, 4.0, 6.5, and 9.5 dS m(-1)). In saline soil, mycorrhizal colonization was higher at 1.2, 4.0, and 6.5 dS m(-1) salinity levels in AM-inoculated plants, which decreased as salinity levels further increased (9.5 dS m(-1)). Mycorrhizal plants maintained greater root and shoot biomass at all salinity levels compared to nonmycorrhizal plants. AM-inoculated plants had higher P, Zn, and Cu concentrations than uninoculated plants. In mycorrhizal plants, nutrient concentrations decreased with the increasing levels of salinity, but were higher than those of the nonmycorrhizal plants. Mycorrhizal plants had greater Na concentration at low salinity levels (1.2, 4.0 dS m(-1)), which lowered as salinity levels increased (6.5, 9.5 dS m(-1)), whereas Na concentration increased in control plants. Mycorrhizal plants accumulated a higher concentration of K at all salinity levels. Unlike Na, the uptake of K increased in shoot tissues of mycorrhizal plants with the increasing levels of salinity. Our results indicate that mycorrhizal fungus alleviates deleterious effects of saline soils on plant growth that could be primarily related to improved P nutrition. The improved K/Na ratios in root and shoot tissues of mycorrhizal plants may help in protecting disruption of K-mediated enzymatic processes under salt stress conditions.

The moral of the story reaffirms what we already know: Healthy soils with mycorrhizal fungi allow for healthier plants, particularly in difficult situations.

Click for information on Acacia nilotica subsp nilotica.

The Green Tree Foundation

Writing this blog first from Japan then from Canada, it is all too easy to forget that there are regions of the world that are faced with environments that are severely damaged. One such region is Andhra Pradesh, India. Once a lush, sub-tropical environment, it has been reduced by inappropriate land use to drylands with evapotranspiration (evaporation combined with transpiration of vegetation) exceeding rainfall. These dryland environments are the final act before full desertification takes hold.

Luckily for the people of the Anantpur District of Andhra Pradesh there is the Green Tree Foundation. Their goal is the re-greening of the district to provide more food and fiber for the local residents. Their additional aims are to establish more water harvesting infrastructure in the area and, on a global scale, do their part to combat global warming through carbon sequestration.

The Green Tree Foundation has surveyed the local situation to identify the problems faced by the public and used that knowledge to work out strategic solutions to those problems. The most visible strategy employed is the establishment of vegetation in and around villages.

The simple act of planting trees can increase food supply, provide shade, harvest rainfall, repair soil hydrology, increase soil health, and increase precipitation both through capture of condensation and through increased transpiration, leading to increased downwind precipitation.

The man who started this effort is Gangi Setty, a local teacher. Growing up in Andhra Pradesh, Gangi Setty is no stranger to hunger and has seen the local environment grown increasingly arid and impoverished over his lifetime. Since the founding in 2004, he has managed to put together a team of two nursery technicians, two program officers, one civil engineer, one computer operator and about 200 volunteers from locals, who help out in the field with the difficult work of land assessing and planting, to people overseas such as myself who provide technical advice and assist in grant requests.

So far the Foundation has been operating on a budget of approximately 120,000 Rupees, which has come entirely from local donation. That such fantastic results can come out of such a small budget is testament to the sensibility of the Foundation’s strategy of partnering with nature to achieve its goals.

What follows are images of the Green Tree Foundations recent tangible achievements:

Young volunteers getting an almond tree into the ground.

Nursery stock of Arjoon sadura (A.K.A. Terminalia glabra, A.K.A. Terminalia arjuna, edible seeds and the bark is mixed with milk to make a beverage), one of the Bauhinia species (depending on the species, the edible parts can include the nectar, leaves shoots flowers and flower buds, seeds and sap), almond and a plant Gangi Setty identifies as tachoma.

A village leader plants bamboo, excellent for providing food and fiber.

Shade and food are provided for this outdoor kitchen thanks to a bean-covered trellis. The Green Tree Foundation has planted more than 20,000 plants in residential kitchen gardens.

The founder, Gangi Setty, and some volunteers find a strategic microclimate for Cassia fistula (edible flowers, leaves and fruit, also a mild laxative) and Jujupus luluba. Planting on hillsides such as this helps control erosion, goes a long way towards reestablishing the local water table, provides shelter and food for wildlife, and supplies a commons area with food to help provide for the whole village.

A villager walks away with a free Bauhinia tree.

In a very clever strategy to distribute plants, this taxi driver was given saplings to give to his customers.

The foot of this hill has been planted with of Arjoon sadura (A.K.A. Terminalia glabra, A.K.A. Terminalia arjuna).

Kitchen gardens planted providing food and shade.

A Leucaena species going into a strategic microclimate. (These species have edible seeds, leaves and flowers.)

All people of all religions are welcome. Here Muslims take Bauhinia to plant at a Mosque.

Fruit trees stand on what was once barren earth.

Gangi Setty on a street that he has helped to regreen. Shade, food, erosion control and soil rehabilitation are all in place thanks to the efforts of the Green Tree Foundation’s volunteers.

This pharmacist handed out 100 productive trees to people in one day. Such strategies make the regreening effort much easier and more wide-spread.

As a birthday gift, this boy receives a food and fiber source that, with proper care, will provide for his descendants many generations down the line.

Sesbania (a nitrogen-fixing forage tree that also providing edible flowers, leaves and young fruit, and it makes an anti-tumor, anti-helminthic tea) and papaya growing in this kitchen garden.

This teacher took 50 trees to plant at the school.

A group of about 40 volunteers from the Green Tree Foundation dug pits to assist in water harvesting for 700 trees which were planted at the Yogi Vemana channel.

I greatly admire Gangi Setty and his dedicated and knowledgeable team and hope that one day I may travel to Andhra Pradesh to assist in their efforts. But with North America rapidly becoming hotter and drier (parts of the Great Lakes have fallen over 4 feet due to decreased rainfall), and our energy-hungry society facing a future with diminishing energy reserves, the day may come when we may need experienced people like Gangi Setty and his team to come and repair our damaged landscapes.

If you would like to contact the Green Tree Foundation or donate to their cause, they can be contacted at

Gangi Setty, Green Tree Foundation,Poola Bazaar,

Talupula (Post and Village) ,Anantapur Dist,

Andra Pradesh,

India, PIN: 515581

gangisettygtf(at)gmail.com

http://greentreefnd.org/

Read about my project with the Green Tree Foundation HERE

Jordan: The Kafrin Site, Part 2

In Part 1, we saw that the Kafrin site was very arid and extremely salty. In this part, we will look at some of the steps taken by Geoff Lawton and his team to repair the devastated land on the site.

To tackle the problems of extreme salinity and “absolute scarcity” of water present at the Kafrin site, the capture and storage of water was of the utmost importance. As deserts are regions were evaporation exceeds rainfall, reducing evaporation was also of great concern.

To capture every drop of rainfall possible, the site was surveyed to provide a detailed map of the site contours. Once the contour lines were identified, swales (water-harvesting ditches placed on contour) were planned for the site to capture as much of the runoff rain to allow it to sink into the ground where it is most easily stored for the benefit of soil life and vegetation.

There were 8 swales dug into the site with a total length of 1.5 km, and ranging from 2 to 3 metres wide and made 50 cm deep. Additionally, the top swales catch water runoff from the road. The downhill sides of the swales were uncompacted to facilitate water absorption; and they were heavily mulched with organic waste from local farms help combat evaporation. Along the south end of the site, there is an erosion gully. Each swale connects to the erosion gully via pipes to collect the rainfall from them during large rain events, which occur a few times a year.

On the upper side of the swale, fast-growing, pioneering support trees were planted to improve soil conditions. Among the species planted were nitrogen-fixing wattles (also good as poultry fodder), leucaena species (saline-tolerant and good for fodder and fuel), Cercidium microphyllum, AKA palo verde, which is a nitrogen-fixer (also producing edible seeds), nitrogen-fixing casurinas (which can be coppiced for fuel), and nitrogen-fixing Sesbania sesban (which can be used for fodder or fuel and the leaves can be used to make an anti-tumor, anti-helminthic [i.e. anti-parasite] tea).

On the lower side of the swales fruit trees were planted. Among these trees were fig, olive, guava, dates palm, citrus, mulberry, pomegranate, carob, tuna cactus, and grapes. Bananas, the world’s largest herbaceous plant, were also planted on site.

When starting any project, the initial stages require extra care. In this case, the young trees required additional irrigation (apart from rainfall) to get them established on the site. A mulch-covered drip irrigation system was set up to supply each tree with water. The water for the drip system is supplied by a raised goose pond. Nutrient-rich water from the pond supplies “fertigation” for the trees. And as the pond is raised, the water can be moved to the trees without the aid of pumps. Also, the pond itself is shaded to reduce evaporation and provide better shelter for the geese.

The area between the swales is planted with vegetables and grains. The grains include barley for fodder and nitrogen-fixing alfalfa . Organic material from plant production, leaves, stems, etc, is used as mulch to improve soil conditions and help retain moisture in the soil.

As mentioned, there are geese on site, but also chickens, pigeons, turkeys, ducks and rabbits. As the site matured and was able to produce enough forage, sheep and a dairy cow were added.

On site, there is an education centre building made from local materials (sandstone and cob) with sustainability in mind. The character of the building is in keeping with the local aesthetic while having design features appropriate to the climate. The building employs a wind chimney which scoops up oncoming winds and channels them over trays of wet charcoal to create an evaporative cooling effect. From there, the air is drawn out the top of the building via a solar chimney. The stone walls of the building also have a thermal flywheel effect. They slowly draw up the heat of the day releasing it at night, warming the building at night. Then in the morning the stones are cooler than the surrounding air providing a cooler environment during the day. The overall effect is to moderate the extreme desert temperatures.

In Part 3, we will have a look at the results of the project.

Jordan: The Kafrin Site, Part 1

In the first part of this series, we looked at some of the larger problems facing Jordan. This installment focuses on the initial conditions of a site in Kafrin, Jordan, in which a permaculture pilot project was carried out.


Earlier, we looked at some of the problems facing Jordan. The greatest among the obstacles is an “absolute scarcity” of renewable fresh water available for use [“absolute scarcity” being less than 500 m³ per capita per year]; and the situation has been rapidly worsening. In 1946, there were 3400 m³ per person available each year. This has dropped to 155 m³ per person today, making Jordan one of the world’s poorest countries in terms of water resources. Of the water available to the nation, 62.5% goes to agriculture and 32.5% goes to household use. So, through the introduction of permaculture techniques, it is hoped that more efficient use can be made of water in Jordan.

In 2000, a project involving permaculture designer and teacher Geoff Lawton was initiated on behalf of Japan’s Nippon International Cooperation for Community Development (NICCO) and the Hashemite Fund for Human Development (JOHUD), which currently funds the management of the project.

A 5 hectare site in Kafrin, Jordan, 10 km from the Dead Sea and 6 km from the Israeli border, was selected for the pilot project. The aim was to show techniques of sound ecological management in a region with otherwise very low agricultural output, to improve local agriculture and livelihood, and to study the effect of permaculture on soils, plants, agriculture and the local environment.

Rainfall at the site comes in 2 or 3 large events and amounts to only 100 to 150 mm per year. Regular hot, desiccating winds contribute to severe evaporation on the site. The soil is very infertile with little organic matter and extremely high salinity. Soil to a depth of 30 cm was found to have 98.1 dS/m, and soil from 30 to 60 cm deep registered 101.7 dS/m, making it extremely salty. [dS/m, or decisiemens per metre, is a measure of electrical conductivity which can be used to measure soil salinity. The United States Department of Agriculture considers soil over 4 dS/m to be “saline soil.” The soils at the Kafrin site are above this level by more than an order of magnitude!] Only sparse, intermittent vegetation could exist on the site at the time the project started.


In the next article in the series, we will look at the steps taken to turn the site around.

An introductory look at the Jordan Valley.

This article is the first in a series of articles on past and present permaculture projects in the Jordan Valley.

Image by Юкатан

The Jordan Valley is one of the most devastated landscapes on the planet. Once home to productive forests with rich soils, today it is denuded of its natural splendor and has been reduced to a salinated landscape which is spiralling into a completely dead environment.

Archeological evidence shows that Jordan had once been a green land. It is known that during the time of the Roman Empire, water harvesting features had existed in Jordan for the purpose of agriculture.

Unfortunately as has been the history of agriculture in most regions of the world, the practices of deforestation and overgrazing have created desolation.

The removal of trees results in a reduced capacity for soils to retain water. Trees increase local precipitation through condensation - this is precipitation that will not register on a rain guage. For example, upland slopes in coastal rainforests can account for up to 80% of the total precipitation. Removing the trees means that this precipitation will not be intercepted and drawn into the soil.

Additionally, trees transpire water into the atmosphere providing moisture for downwind rains. Cut out a forest and you will reduce the rainfall downwind.
Plough agriculture damaged the delicate soils contibuting to erosion. Today the land is characterised by wadis washed out of the hillsides - a telltale sign of serious erosion problems. This problem is compounded by overgrazing. Goats are currently stripping the vegitation off the land dooming it to become a totally dead environment.

Fifty years ago, 1.3 billion cubic metres of water flowed through the Jordan river. Today, less than one tenth that amout flows through the river, and this flow is kept alive by sewage. The remainder has been diverted for agricultural purposes.

To make up for shortfalls in water, aquifers are tapped. And without any attempts to recharge them, they are being depleted, dooming the inhabitants to a waterless future. Compounding this problem, modern industrial agricultural techniques are contaminating the aquifers with pesticides and fertilisers.

Despite this seemingly bleak future, there is a working solution: one that has been employed in the Jordan Valley. The next article in this series will look at the solutions that have been employed and their surprising results.