Dry Gardening: A Modified Soil Sedimentation Method for a Garden with Gravelly Sandy Loam Soil

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As part of overall goal to establish simple methods for dry gardening in Sustainable Agriculture, our goal this winter year 2021-2022 is the establishment a garden that is resilient to climate change (i.e retains moitsure from winter rains to be used in the 2022 growing season without additional watering or irrigation during summer). As a first step, we have determined the profile of soil texture (i.e.% gravel, sand, silt and clay) at multiple sites throughout the garden. For each site, we determine % gravel, sand, silt and clay in two soil horizons ( topsoil and subsoil). We used a modified method of soil sedimentation using mason glass jars to allow determination of gravel, sand, silt and clay separately. The modified method is illustrated in the Figure below:
The results are shown in the table below:
These results show that the soil throughout the garden is gravelly sandy loam and are consistent with public soil records for our area- due to glacial till. The percent clay and gravel is higher slightly in the subsoil compared to topsoil. Thus, silt is higher slightly in the topsoil than subsoil. In the abscence of gravel, most areas of the garden are still composed of sandy loam. However, some areas of the garden are primarily loam or silt loam. This is good news, in that, except for gravel, the soil has a some capacity to hold moisture. Our goal in this case is to add organic matter to fill in between the large particles of sand and gravel- as a strategy for retaining both moisture and fertility. It requires as little tilling as possible.

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