1. Leonard J.M. Githinji, PhD Dep. of Agriculture and Environmental Sciences & Cooperative Extension Program Tuskegee University, AL Email: lgithinji@mytu.tuskegee.edu Phone: 334-724-4955 Building Healthy Soils for Organic Production

2.  What is soil health?  Soil health refers to the condition of the soil and its potential to:  sustain biological functioning,  maintain environmental quality, &  promote plant and animal health. Building Healthy Soils for Organic Production

3.  What are the characteristics of a healthy soil?  Has proper soil composition  Soil fertility is balanced  Water entry, storage & supply are optimized  Soil biological function is enhanced  Enhances environmental & community health and well-being Building Healthy Soils for Organic Production

4.  Proper s oil composition  A good soil for growing most plants should have about:  45% mineral (sand, silt and clay),  5% organic matter,  25% air, and  25% water. Building Healthy Soils for Organic Production

5.  Balanced soil fertility  Nutrient additions should match removals and losses  Plants take up nutrients and mobilize them.  Export of nutrients such as N and K off-farm.  Nutrient storage capacity is maintained  Manage soils to maintain soil organic matter.  Minimize nutrient loss off-site  Poor soil condition and loss of structure can result in losses of soil nutrients. Building Healthy Soils for Organic Production

6.  Optimized water entry, storage & supply  Poor soil structure can lead to compaction and surface sealing leading to:  reduced infiltration: water entry into the profile  reduced storage in the root zone.  Additional of organic matter will help maintain soil structure. Building Healthy Soils for Organic Production

7.  Enhanced soil biological function  Organisms in soil perform beneficial functions such as:  Transforming raw elements from one form to another.  Important nutrients in the soil are released by microbial activity including N, P, S, Fe and others.  Breaking down SOM into a form useful to plants.  Degradation of pesticides and other chemicals.  Suppression of pathogenic microorganisms. Building Healthy Soils for Organic Production

8.  Enhanced environmental well-being  A healthy soil provides adequate nutrients to produce healthy plant growth and produce, without the risk of contamination.  The soil resource must support productive land use without the risk of environmental damage.  A healthy soil does not limit production beyond the inherent limitations of the soil properties and climate. Building Healthy Soils for Organic Production

9.  Strategies for maintaining or improving the soil health:  Building up of organic matter  Use crop rotation practice  Good tillage practices  Use of cover crops Building Healthy Soils for Organic Production

10.  Building up of soil organic matter  Building up of soil organic matter into the soil provide the following benefits:  Provides food for beneficial organisms  Increase nutrient retention capacity  Improve water retention capacity  Improve soil structure Building Healthy Soils for Organic Production

11.  Strategies for building the soil organic matter  Use of compost  Use of green manure / cover crops  Eliminate unnecessary cultivation:  zero tillage (no-till)  minimum tillage Building Healthy Soils for Organic Production

12.  Composting  Refers to the decomposition of organic waste or material into organic fertilizer which can be utilized by plants on farms or gardens.  Involves spontaneous biological decomposition process of organic material in predominantly aerobic (oxygen rich) conditions.  "Team Compost" consists of microorganisms and macroorganisms choreographed to take advantage of changing temperatures, moisture, oxygen and pH. Building Healthy Soils for Organic Production

13.  Microorganisms involved are:  Bacteria  Fungi  Actinomycetes  Protozoa  Macroorganisms involved are:  Earthworms Building Healthy Soils for Organic Production

14.  Materials for composting  For efficient decomposition, a compost pile needs a good balance of these basic four ingredients: o Greens o Browns o Moisture o Air Building Healthy Soils for Organic Production

15.  Evaluating materials for composting  What's Brown? What's Green? o Every piece of organic material contains carbon and nitrogen in differing ratios. o Some materials are very high in carbon, such as sawdust and straw. o Others contain a relatively high amount of nitrogen compared to carbon, such as grass clippings, garden weeds, and chicken manure.  Understanding which materials are high in carbon, and which are high in nitrogen will help you build a pile with a good balance of ingredients for decomposition. Building Healthy Soils for Organic Production

16.  Making a compost pile  Loosen soil under area where pile will be built.  Layer 40% green to 60% brown by volume. Good balance leads to faster decomposition, more heat generation, and very slight odor. o Too little nitrogen: pile won't get very hot and won't decompose quickly. o Too much nitrogen: get too hot and release ammonia  To speed it up, turn the pile and layer in high nitrogen materials to aerate it, and layer in some carbon materials as the pile is rebuilt. Building Healthy Soils for Organic Production

17.  Environment needed for compost pile Aeration  Microbes require oxygen to decompose organic wastes.  Mixing the pile 1-2 times a month will provide the necessary oxygen and hasten the composting process. Moisture  Microbes require adequate moisture to function properly.  Recommended moisture is 50 to 55% w/w. The compost should give a few drops of water when squeezed from a handful of material. Building Healthy Soils for Organic Production

18.  Environment needed for compost pile Temperature  Decomposition generate large amounts of heat, which raises the temperature inside the pile.  A "hot" pile will produce temperatures between 140 and 160 degrees Fahrenheit. Particle size  The smaller the size, the faster the decomposition.  Materials should be shredded before adding them to the pile. Building Healthy Soils for Organic Production

19.  Some parameters for judging if compost is ready:  Temperature - After you turn the pile, measure the temperature. If it is below 100 F, then it is probably done.  Appearance – If you do not recognize anything as it was when you put in.  Size - If the volume of the compost is reduced by 50 to 75%.  Color - If it is dark brown or black.  Texture - If it is smooth or crumbly.  Smell – If it smell earthy like soil. Building Healthy Soils for Organic Production

20.  Crop rotation and nutrient relationship:  Crop rotation is one of the oldest and most effective cultural control strategies.  It means the planned order of specific crops planted on the same field.  It also means that the succeeding crop belongs to a different family than the previous one.  The planned rotation may vary from 2 or 3 year or longer period. Building Healthy Soils for Organic Production

21.  Crop Rotation and nutrient relationship:  How does crop rotation affect the soil?  Each crop has different nutrient requirements.  By changing the location of your crops you can avoid the risk of depleting the soil of specific nutrients.  Some crops will actually add essential elements to the soil.  By using crop rotation, you can actually build up the soil over the years. Building Healthy Soils for Organic Production

22.  Crop Rotation and nutrient relationship:  How should rotation be done?  Plants are often grouped by families that share similar growth habits and cultural requirements.  By knowing your plant families you can create a plan for your own garden rotation. Building Healthy Soils for Organic Production

23.  Crop Rotation and nutrient relationship:  Example of a three year rotation Building Healthy Soils for Organic Production bestgardening.com

24.  Cover crops and green manures  A cover crop is a temporary planting, usually done in the fall, that protects the soil from wind and water erosion and adds organic matter.  Crops grown for soil improvement are called green manure crops and are left in place for six months to a year.  Legumes are especially efficient because they "fix" nitrogen from the air into the soil. Building Healthy Soils for Organic Production

25.  Cover crops and green manures  After the summer garden crops have been harvested, and stalks and vines removed, lightly till the garden to prepare a seed bed  Broadcast the cover crop seed, rake lightly to cover it, and then irrigate.  Where you have fall crops growing, you can sow cover crop seed between rows a month or less before expected harvest.  If you plant a hardy species that survives the winter, it will resume growth as the weather begins to warm, but be careful not to let the crop go to seed. Building Healthy Soils for Organic Production

26.  Benefits of Cover Crops  Reduce weed pressure  Cover the soil to prevent erosion  Reduce soil compaction  Add organic matter  Increase water infiltration  Improve biodiversity  Increase the population of beneficial soil microorganisms Building Healthy Soils for Organic Production

27.  Types of Cover Crops Winter Cover Crop  Planted in late summer or fall to provide soil cover during the winter.  Often a legume is chosen for the added benefit of nitrogen fixation.  These cool-season legumes include clovers, vetches, and field peas.  They are sometimes planted in a mix with winter cereal grains such as oats, rye, or wheat. Building Healthy Soils for Organic Production

28.  Types of Cover Crops Summer Green Manure Crop  Occupies the land for a portion of the summer growing season.  These warm-season cover crops can be used to fill a niche in crop rotations, and to improve the conditions of poor soils.  Legumes such as cowpeas, soybeans, sweetclover, or velvet beans may be grown as summer green manure crops to add nitrogen and organic matter.  Non-legumes such as sorghum-sudangrass, millet, forage sorghum, or buckwheat are grown to provide biomass, smother weeds, and improve soil tilth. Building Healthy Soils for Organic Production