Suggestions for improving high desert soil fertility

Hoping for some advice. I have a small (v small 300m squ) patch of land in the Highlands of peru. It's very dry (from my perspective anyway) with a max average of around 150mm of rain in the wet season, only around 4 months of rain a year and 5 months with only around 10mm of rain on average. To compound problems, sheep and goat graze the area. There are some pepper trees and eucalyptus growing in a gully at one end of the plot and I have seen prickly poppies growing in the area. The soil is fairly rocky clay, not terrible though.

What would be the best approach to getting the land more fertile? Organic matter will be the key in the long run I am guessing. Initial thoughts are to fence it off to keep animals out, maybe trying to get sawdust from sawmills in the area (likely to be eucalyptus) to cover the soil. Will that be any good for the soil? What would you recommend trying to plant to increase organic matter? Would broad beans manage with that level of rainfall? I am thinking of cutting down the eucalyptus and using the wood to block off the gully to catch rain washing down the valley, get rid of a water hungry tree and catch water.

Thanks for the advice.

Tough growing conditions. Water seems like the limiting factor, not minerals.

What currently grows in the ecosystem and nearby areas? I recommend planting more of that.

Hello,

First I would try to keep whatever trees or shrubs manage to grow on your land. I think they will give much more with their growth, fallen leaves, shadow, transpiration etc. than with a one-time logging. And control the grazing pressure with fencing.

For contouring, creating terraces, blocking the winds, I would try to assemble rock piles and dry walls first. They will condense dew and keep the moisture, accumulate run-off particles and water. Then on the more protected or less dry side, you could try to plant hedges with naturally occuring species, though I suppose you have more stones than plants to begin with.

Swales on contour lines and ephemeral ponds on flat areas can also help with moisture accumulation, and could be converted in sunken culture beds or inverted hugels thereafter.

Would your oldest eucalyptus trees be able to support tree guilds with some shadow and wind protection ? Not only are they water hungry - they also signal water where they stand.

When you study your land, there are chances you will find wild pioneer plants waiting for just a little more shadow or a few more drops of water to kick in and give their organic matter to the soil, including some wild nitrogen fixers. I would not try to import other species to start, and stick to what is usually grown in the area until you start to see more diversity in your "weeds", among the micro-climates you are creating.

Have a nice evening,
Oliver

Thanks for the advice, it's hard to tell what the natural environment was like as humans have substantially altered it. The plants that remain are both acclimated to the dry conditions and unpleasant for the grazing animals, either prickly or poisonous.

The trees are all found in the gully at one end, the land is in a valley so i believe all the water is chanelling down there. Once it's fenced off I will try and establish some more plants around the trees from plants that are surviving in the area.

I have already taken some of the actions to a degree, I have created rows of rocks about 15 to 20cm high, not much growth around them but if I move them there is insect life living there and it clearly is damper. I will try and add more rocks to those to act as windbreaks. I have also dug a mini 'pond' to try and catch/accumulate rain, it's dry but is clearly greener than everywhere else...barring the gully.

Thanks for the advice.

I would suggest trying to find wood chips and leaves other than eucalyptus.

Plant as suggested above what will grow on the property.

Make compost and chop and drop as much as you can.

Are there mushrooms that will grow in that climate?

Cris said, "He says basically that nature abhors a vacuum. If you leave a piece of "dead" landscape alone, nature itself will fill the space with whatever fills the
need from the local environment. The nutrient builders, the pioneer plants, the soil breaker-uppers, groundcovers,etc. already exist in the environment, who am I to fight
nature?, it has a lot more experience in this than I do.
Not to say I don't help a little by adding a bit of mulch here and there, spread seeds from the "weeds", cut out pine saplings,etc.

https://permies.com/t/19589/plants-improve-clay-soil-Mediterranean

Here are some threads that might be of interest to you or others:

https://permies.com/t/89965/dry-climate-leads-sustainability-mulch

https://permies.com/t/86600/Nutrient-Density-Plants

https://permies.com/wiki/89899/Advice-soil-building

I would encourage you to do what you can to try and slow and sink as much of the available seasonal water as you can into the landscape. Are you aware of the concept of a sand-dam, used widely through arid regions to trap seasonal water flows. They store and sink huge quantities of water in creekbeds, where plants and animals can later use it.



Similar results can be achieved using rock check dams, terracing etc...

I found this video as well, which was new to me, on using checkdams as water harvesting systems. I think it is worth it's own thread as well.

Thanks for all the advice, I think it will be a long haul, but sure I will make progress.

Not sure if it warrants a separate thread, thinking about the trees on the land, although they are both hardy species and their shade and foliage will be of benefit, I worry they may restrict other plants in the long run.

Eucalyptus are horrible in my opinion. They have been brought in because they are great at what they do, growing tall and straight in poor conditions, but from what I have seen they outcompete everything and in the plantations I have seen, nothing else grows.

Pepper trees (Schinus Molle, think most people would know them as Californian Pepper Trees) are native and I like them a lot, however I have read that they suppress other plants growing around them.

Does anyone have any knowledge about how these plants interact with others?

Greetings from Mexico.
I'm in a similar landscape--though likely lower elevation. We are just about 1600 meters above sea level. The practice of free grazing can be very detrimental to land, in my region there are many goats but there is a movement to keep the goats enclosed more, which can cause a lot of problems among communities. For example, we are in a reforestation program where the federal government is paying us to plant and take care of young trees, we have no grazing animals, but many neighbors do. Traditionally, once the seasonal corn crop was in, they've been allowed to free-graze their animals anywhere. But now they can't because they have to keep their goats away from our young trees so they see the reforestation program as taking away their animals' food. Keeping animals enclosed means there is a need for feed for the animals, but it also means it is easier to use their manure on crops.
As others have mentioned the need to slow, spread and sink water as it crosses the landscape is important.  As is adding more organic matter to the soil and keeping it covered as much as possible.

Hi Melissa, sounds very similar, down to the cultural challenges around grazing animals.

I have been doing some research on weather data from a weather station close to the land and think I may have hit on a solution. Even during the months where precipitation is low, humdity remains quite high. It typically stays at around 70-80% throughout the year with the driest months having humidity at 58% at the lowest, some years humidity has remained in the 70s and 80s throughout the dry season. What are some easy, low-tech solutions to collect moisture from the air that can be left in place to passively improve the land? Would fog nets work, on the coast nets are common to collect the sea fog.

Does the land lie in a lomas area? If yes, many species of plants exist that can subsist on fog.

Unfortunately not, I didn't know what one was until I googled. Fog isn't present where the land is, I imagine the lowest tech solution would be piles of rocks/rock walls to collect dew. I'm aiming to get the fence in place next weekend and will try and will try and build up the rock wall at its base.

Matthew Tebbit wrote:Hi Melissa, sounds very similar, down to the cultural challenges around grazing animals.

You can find a document here called MANUAL DE BUENAS PRÁCTICAS DE CABRINOS Y EL ENFOQUE ECOSISTÉMICO with which we've had some success at guiding people to less of a free grazing approach to small livestock.