Wednesday, May 23, 2012

Soil: The Heart of a Farm

Having land that is 'in good heart' is an English expression that means the soil is healthy. I think it's pretty obvious that in order to have a successful growing operation you need soil that will provide a good growing medium for your crops, giving them moisture and nutrients as they develop.

All soil can be improved by addition of humus, drainage, adding lime etc. but the better the soil you have to start with, and knowing what you've got, the easier it is. The soils on our new place are classified as 2f and 3m. So basically, we are starting with pretty good land, especially for this area. And through adding manure and composts we hope to continually improve the fertility and moisture retaining ability of our soil, and we'll have to lime as well to raise the pH of our acidic soil. On the bright side, raising the acidity to nearer neutral makes other nutrients available, thereby increasing fertility, and it only has to be done once every 7 years according to the local farmers and fertilizer salesmen. I'm hoping to do it once and then go on from there, testing periodically to see how we're doing and maybe using wood ash on the garden to raise the level naturally.

There are plenty of farms for sale with supposedly fantastic soil, and you'll pay a premium for them too. So is it worth the extra money for better soil? In our case we decided that we were willing to take something that was reasonable and could be easily improved over time (as described above) and pay less for it. We basically have 5 acres of good soil, that needs some improvement and irrigation for year-round growing, and 37 acres of tree covered hillside that will remain as a mix of forest, mushroom habitat, summer pasture (that's a project for another year) and maybe a cabin or two. For the $35 thousand we paid, I think we're doing pretty well right out of the gate. It's going to be a lot of work, but at least we have an idea of what we're in for both work and expense wise.

So let me tell you about soil classification in Nova Scotia, and infact in Canada in general. Soils are divided into 7 different numbered categories as follows:

Class 1 - Soils in this class have no significant limitations in use for crops.

Soils in Class 1 are level to nearly level, deep, well to imperfectly drained and have good nutrient and water holding capacity. They can be managed and cropped without difficulty. Under good management they are moderately high to high in productivity for the full range of common field crops

Class 2 - Soils in this class have moderate limitations that reduce the choice of crops, or require moderate conservation practices.

These soils are deep and may not hold moisture and nutrients as well as Class 1 soils. The limitations are moderate and the soils can be managed and cropped with little difficulty. Under good management they are moderately high to high in productivity for a wide range of common field crops.

Class 3 - Soils in this class have moderately severe limitations that reduce the choice of crops or require special conservation practices.

The limitations are more severe than for Class 2 soils. They affect one or more of the following practices: timing and ease of tillage; planting and harvesting; choice of crops; and methods of conservation. Under good management these soils are fair to moderately high in productivity for a wide range of common field crops.

Class 4 - Soils in this class have severe limitations that restrict the choice of crops, or require special conservation practices and very careful management, or both.

The severe limitations seriously affect one or more of the following practices: timing and ease of tillage; planting and harvesting; choice of crops; and methods of conservation. These soils are low to medium in productivity for a narrow to wide range of common field crops, but may have higher productivity for a specially adapted crop.

Class 5 - Soils in this class have very severe limitations that restrict their capability to producing perennial forage crops, and improvement practices are feasible.

The limitations are so severe that the soils are not capable of use for sustained production of annual field crops. The soils are capable of producing native or tame species of perennial forage plants and may be improved through the use of farm machinery. Feasible improvement practices may include clearing of bush, cultivation, seeding, fertilizing or water control.

Class 6 - Soils in this class are unsuited for cultivation, but are capable of use for unimproved permanent pasture.

These soils may provide some sustained grazing for farm animals, but the limitations are so severe that improvement through the use of farm machinery is impractical. The terrain may be unsuitable for the use of farm machinery, or the soils may not respond to improvement, or the grazing season may be very short.

Class 7 - Soils in this class have no capability for arable culture or permanent pasture.

This class includes marsh, rocky land and soil on very steep slopes.


And soils are further sub-classed based on local variations such as lightness (sand) or lack of nutrients, potential for flooding and other things a grower could experience.

Subclass C - Adverse climate: This subclass denotes a significant adverse climate for crop production as compared to the "median" climate which is defined as one with sufficiently high growing-season temperatures to bring common field crops to maturity, and with sufficient precipitation to permit crops to be grown each year on the same land without a serious risk of partial or total crop failures. In Ontario this subclass is applied to land averaging less than 2300 Crop Heat Units.

Subclass D - Undesirable soil structure and/or low permeability: This subclass is used for soils which are difficult to till, or which absorb or release water very slowly, or in which the depth of rooting zone is restricted by conditions other than a high water table or consolidated bedrock. In Ontario this subclass is based on the existence of critical clay contents in the upper soil profile.

Subclass E - Erosion: Loss of topsoil and subsoil by erosion has reduced productivity and may in some cases cause difficulties in farming the land e.g. land with gullies.

Subclass F - Low natural fertility: This subclass is made up of soils having low fertility that is either correctable with careful management in the use of fertilizers and soil amendments or is difficult to correct in a feasible way. The limitation may be due to a lack of available plant nutrients, high acidity, low exchange capacity, or presence of toxic compounds.

Subclass I - Inundation by streams or lakes: Flooding by streams and lakes causes crop damage or restricts agricultural use.

Subclass M – Moisture deficiency: Soils in this subclass have lower moisture holding capacities and are more prone to drought.

Subclass P - Stoniness: This subclass indicates soils sufficiently stony to hinder tillage, planting, and harvesting operations.

Subclass R - Consolidated bedrock: The occurrence of consolidated bedrock within 100 cm of the surface restricts rooting depth and limits moisture holding capacity. Conversely, in poorly drained soils the presence of the bedrock may, depending on depth, make artificial drainage impossible.

Subclass S - Adverse soil characteristics: This subclass denotes a combination of limitations of equal severity. In Ontario it has often been used to denote a combination of F and M when these are present with a third limitation such as T, E or P.

Subclass T - Topography: This subclass denotes limitations due to slope steepness and length. Such limitations may hinder machinery use, decrease the uniformity of crop growth and maturity, and increase water erosion potential.

Subclass W - Excess water: This subclass indicates the presence of excess soil moisture due to poor or very poor soil drainage. It is distinguished from Subclass I - water inundation which indicates risk of flooding from adjacent lakes or streams.

So there you have it, the basics of understanding soil. If you're new to growing and really want to get off to a good start, I recommend having your soil tested for nutrient levels so that you can plan your additions like cover crops and manures with that in mind. Happy Growing!

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