Reflections on Soil in Zambia

My family and I recently traveled to Zambia this last month to visit some friends in Lusaka. It was an amazing trip on many levels! While there, I saw a lot of different types of soil and soil management, both natural and manmade, and I felt such a deep sense of gratitude for the experience, the warm welcome of so many of the people we met, and the chance to see a variety of landscapes throughout the country. We were there during the dry, winter season. A lot of the soil we saw was light-colored or red and dusty (it was the dry season after all!), though there was also soil that was rich and dark, usually when it was near more consistent water, in dambos (spongy water-holding grasslands areas), or in gardens where they were watered more often or amended with manure/compost. I was fascinated to see where the soil was exposed and bare, and when it was covered. Here are some pictures that stood out to me.

Here's a dried grass seedling from a dry river bank with soil still clinging to its roots. The soil "sheath" is evidence of active soil biology where the plant leaked sugars through its roots to feed beneficial microbes in exchange for compounds it needed. These microbes also hold tiny amounts of water and can keep plants alive in very dry conditions! Neighboring grass seedlings that were a little bigger were still green and growing.

Burning back grass is one way to get nutrition or create fertilizer (from the ash) for new growth. It works and will give a new flush of growth. Small, controlled fires also can help prevent larger ones. It used to be a common land management practice in North America, too. Yet sometimes if these small fires get too hot or happen too often they can also damage the plants' roots and ultimately the soil structure over time. Notice the bright new green growth coming back through the burned old grass. Also notice the light soil color, indicating this soil is low in organic matter.

Elephants hanging out at a pool filled with a plant called "nile cabbage". The cabbage is food for many animals. It grows using nutrients from animal waste and also helps keep the water drinkable for wildlife. Notice the tree in the foreground and how its roots are above the soil level: an indicator that erosion is active here, and the soil level in that spot used to be 2-3 feet higher. I had great respect for the gardeners in the town nearby... we struggle with groundhogs and deer that eat our agricultural crops, but what do you do if an elephant visits your garden? Managing people/animal conflicts was a constant challenge from what I heard, especially near the National Parks.

A massive fig tree is fruiting near a road in South Luangwa National Park. Notice all the impalas under the tree eating the fallen figs. The tree was also filled with birds enjoying the figs. It's an example of abundance: in the midst of the dry season the tree produces fruit, and the animals come and leave waste and nutrient-rich droppings and trample it into the ground which in turn continues to feed the tree. Large trees like this anchor the soil in place, build nutrition over time, and create abundance for the entire ecosystem.

Notice how the zebras also are under a tree, both for shade and for nutrient pods. I think this was an acacia-type tree, possible winter thorn? Notice also how this landscape is covered in grass, despite the dry season. Everything but the road. Imagine what it would look like when the rains come!

At one point we were in a landscape called Mopane Woodlands named after the mopane trees that filled them. Families of elephants would go back and forth through these woods during the day and back to the river again at night. The tall trees in the background are older mopane trees, and the short, truncated shrubs in the foreground are actually also mopanes that have been pruned/eaten by elephants. It's interesting to notice how elephants maintained the grasslands by keeping forest trees small, and yet also it was interesting to consider whether or not the landscape had enough variety of ages of trees to be resilient and continue to provide enough food and fuel in the future for animals and people.