Wednesday, April 20, 2011

Soil diagnosis

The health of one's soil determines the health of one's plants.

Our farm plan contains an extensive review of how to improve soil health. The soil's pH, macro- and micronutrient contents, and cation exchange capacity, among others, are critical indicators of the land's ability to nourish vegetation. We've been adding organic material - such as horse manure, compost, humus and decaying leaves - to our hard, rocky soil. But these efforts have all been temporary as we waited for the results of our soil test...

... And finally! They've arrived.

First, the bad news:
(1) As expected in the Hudson Highlands, our soil is strongly acidic (pH=4.95; ideal range is 6.2-6.8). This means we should be adding an organic material (i.e., lime) to raise the pH. Avoiding a complex chemistry lesson, a higher pH will allow plants to access important nutrients (e.g., nitrogen, phosphorus, potassium) in the soil that are otherwise locked up in the soil particles at low pHs. We should be adding approximately 7 pounds of lime per 100 sq. ft. to raise our pH to an appropriate level.
(2) Our cation exchange capacity (CEC) and basic cation saturation (BCS) are both low. Simply, these indicators tell us how quickly our soil will be amended once we begin to add lime and other fertilizers. A higher CEC and BCS means that any fertilizers or other amendments we add to our soil are more likely to get the job done.
(3) We've got below optimum levels of two important macronutrients (i.e., magnesium and calcium), which can be remedied by applying lime and the egg shells we received from our local bakery.

Now, some good news:
(1) We have optimum levels of the two other important macronutrients (i.e., phosphorus and potassium). We also have relatively adequate levels of micronutrients (e.g., zinc, copper, manganese and iron). Once the pH is increased, these nutrients will be accessible in our soil and will help our plants grow.
(2) And... what will surely be a surprise to any of you who have dug into our soil... we have Sandy Loam! Loam is a soil that has 40-40-20 proportions of sand-silt-clay. Loam is a good thing because it is relatively well-balanced. We almost fell out of our chairs when we read this, because we assumed our soil was pure clay. And to top this good news off, we also have very high organic matter content (3.5%) for sandy loam.

There are lots of other factors that go into diagnosing and helping your soil. We are taking very seriously the health of our soil - and also the health of our environment as a result of fertilizing and amending it. That's why we will use only organic soil amendments and we won't use more than the levels recommended by our county extension office. Inorganic or excess organic fertilizers can be detrimental to our environment when they runoff and pollute our water and land. Some states (e.g., New Jersey) have implemented laws to monitor and manage fertilizer runoff. Farmers and households can all do their part by getting their soil tested annually and applying only the recommended amount of organic fertilizer to their soil.

Now... to get to work. We've got to till some lime into our topsoil.

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