| Forestry training manual for the Africa region |
Total time 2 hours
- To observe the results of the compost heap prepared the first week,
- To use compost as top dressing (mulch in nursery),
- To learn how a greenhouse is constructed and used,
- Presentation of the results of the germination project.
During this session, two unrelated technical forestry exercises are undertaken; the compost heap started in week one is now ready for use and the greenhouse constructed during the first week of training is explained.
1. The Compost Heap
2. Greenhouse Construction
3. Determining Percent Germination
Flip charts, marker pens, tape, compost heap (four weeks +), clear glees bottles (four ounces and under), alcohol, plastic bags (hand size), one greenhouse.
Exercise 1 Compost Heap
Total time 1 hour
Composting is any process which facilitates or increases the speed of the natural break-down process of decomposition. One of the trainees who has started a compost heap in the first days of training presents a lecture. me trainees go to the compost heap. Using compost as mulch for the seedlings, the trainees spread it on seed beds.
1. The trainee who has started the compost heap as a special project gives a lecture on starting compost heap. He/she answers questions from other trainees (See "The 30 Day Hot Compost System").
2. me trainees go to the compost heap and, if ready, use it as mulch for the seedlings that were planted during the first week.
THE 30 DAY "HOT" COMPOST SYSTEM
Composting is any process which facilitates or speeds up the natural breakdown process of decomposition. There are many forms of comporting; some involve combining many types of materials that require long periods of time to break down. Times vary from three weeks to several years. The method that will be covered here is a 30 day or "Hot Compost" method. This is a system using high temperatures (up to 170°F) and frequent turnings to achieve a fast, usable compost in 30 days. Several advantages to using Hot Compost include:
1. High temperatures eliminate weed seeds, disease and insect eggs,
2. Quick usable compost is available in just 30 days.
Many believe that composting is a complicated and time-consuming process. This belief can be overcome if a couple of basic principles are understood.
1. A hot compost has to be properly mixed with the correctly matched materials. While putting together a compost pile, a helpful guideline to remember is the "Carbon: Nitrogen" ratios. The Carbon: Nitrogen ratio is the amount of brown or dried stalky materials (carbon source) that are mixed to the amount of green leafy or fresh materials (nitrogen source). A well balanced compost pile usually has a Carbon: Nitrogen ratio of 1:12 (l part carbon to 12 parts nitrogen). It is important to maintain this ratio because a pile with too much carbon containing materials and not enough nitrogen will not achieve the 170°F temperature necessary for the compost. A pile with too large or a disproportionate amount of nitrogen means nitrogen lost needlessly to the atmosphere in the form of NO2 gas (ammonia). Organic materials high in nitrogen are any type of fresh green material (i.e., fresh grass clippings, fresh young weed cuttings, etc.) or any type of animal manure; the best or "hottest" is chicken manure. Another source is kitchen scraps: coffee grounds or waste seeds (i.e., grape seed are especially hot). Materials high in carbon are usually brown dried plant materials (i.e., leaves, dried grass or straw, dried weeds, saw dust or wood shavings, etc.).
2. Watch compost pile temperatures. Get a good soil thermometer to measure temperatures. One with a long stem is the most useful. A good pile will heat up to 110°F within 24 hours of being mixed. Within three days it should be 125°F. If it does not heat within the first three days, take it apart and start over. Each time the pile temperature begins to drop (every four to five days), it will be time to turn and mix the pile again. After a while the pile will not heat more than 100-110°F no matter how much you mix it. At this point the compost can be used as is or may be left until it achieves a fine and easily crumbled texture.
3. TURNING THE PILE. The first turning is the heaviest and most time-consuming. If it is done correctly, the rest will be easy. Once the pile is put together and has heated correctly to 120°F or so, it might maintain this temperature until day five or six then begin to drop. At this point, take a pitch fork and move the pile. While rebuilding it, mix all the materials that were on the outside into the center of the pile, so that they will heat. Also break large pieces of organic material with a machete so that they will be broken down quickly. After this first turning, the mixing should not involve anything more than half an hour of tossing the pile from one spot to another with a pitch fork and shovel.
4. Think about the amount of moisture percentage in the pile while you are putting it together. Sometimes a pile will not need any water other than the natural moisture contained in the compost material. Fresh green materials (grass clippings) are an example. A good rule of thumb for determining the correct moisture content in the pile is that the material should feel like a squeezed out sponge. It should not, however, release water if squeezed very tightly. If water is required, it should be judiciously applied to each layer as the pile is being built, rather than watering it from the top after the pile is put together. Remember: too much water can drown a pile and not enough water can retard bacterial growth so the pile will not heat.
5. AIR. Composting is an aerobic process. Soil microbes need oxygen to develop. Try to avoid building the pile higher than four feet, otherwise poles layered horizontally in the pile will be required to aid air circulation. Care should also be taken while building the pile to ensure that fine materials (i.e., grass clippings) are not layered too thickly, to prevent matting which will form a barrier to air circulation.
6. PUTTING IT ALL TOGETHER. Start the pile with a five inch thick layer of leaves to provide good drainage. The next layer should be two inches of grass clippings, loosening it to keep it from matting. On top of this sprinkle a mixture of topsoil and organic material. This will increase the nitrogen content and innoculate the pile with soil microbes (the power house of the compost pile). If kitchen scraps are available, they can also be added here. Water each layer lightly - if needed. Now repeat the whole process until all your materials are used.
Composting is the backbone of my nursery and home garden. Once you begin to use it, it becomes invaluable. Be patient. I have yet to meet the person whose first pile heated properly. With time and practice, you can expect much in return for a small investment.
Exercise 2 Greenhouse
Total time 30 minutes
The trainee for whom this is a special project, shows the other trainees how a greenhouse is constructed and its use.
1. The trainee explains greenhouse construction and use.
This type of greenhouse has many advantages it is portable, retains heat during cold periods (only when lids are covered with clear plastic), and provides protection from animals.
Plywood or any scrap wood for sides and bottom will work, 2" X 4"(s) for frame, 1" X 2" for lids, and wood lath to add shade. Screens may also be used for more shade and protection from birds.
This type of greenhouse is easy to install. It is usually cooler in the summer. During the summer months if there is wood lath or screen, it will allow heat to escape and add more shade. During the cold seasons, plastic retains the heat.
This type is very simple - make a frame then put plastic on all sides and top leaving bottom opens place over pots, seed beds or wherever you want to grow plant(s).
Exercise 3 Determining percent Germination
Total time 30 minutes
The trainee for whom this is a special project shows the other trainees the results of the trainees' germination projects from week one.
DETERMINING PERCENT GERMINATION
When working with seeds from an unknown or little known source, a germination test is often a helpful guide in determining planting techniques and pretreatment methods. The percentage of germination will provide information for planning on the amount of seed needed to establish a particular species.
Two seed species were studied. Since this experiment was a general study of germination, scientific names were not necessary to differentiate between the two seed species. The "Big Seeds" were wrinkled, whitish and hard-coated. The "Little Seeds" were smooth, black and had a thin shell-like seed coat. Because the seed types were so varied, a variety of pre-treatments were used to find a most effective means of germination.
After pretreatment, the seeds were placed on moist paper towels in plastic bags for approximately five days. Average high temperature was about 90°F during the day and average low temperature about 75°F at night. Approximately 14 hours of indirect light were provided. Seeds were observed daily until no new germination occurred.
Germination percentage was calculated as follows:
germination = (# of seeds germinated) / (# of seeds treated)
Percent germination was determined for each particular pretreatment used. Results were then graphically displayed. ( See following page)
Analysis and Conclusions
From the graph, Percent Germination for "Big Seeds" the pretreatment or scarification with two hour soaking appeared to be the most effective. Without scarification, soaking alone reduced percent germination lower than that of control (untreated) seeds. Scarification increased percent germination even without soaking. Clipped seed coats and scarified seeds with a relatively short cold treatment also had a higher germination than untreated seeds.
Clipped seed coats treatment was also quite effective in increasing percent germination for the "little seeds". Unlike the "big seeds", fewer generalizations were possible in analyzing the results displayed on the graph, Percent Germination for "Little seeds". A two hour soaking and a soaking with short cold treatment increased percent germination over that of the control group. However, longer soakings and soakings with scarification reduced germination. Since clipped seed coats and seed coats rubbed together increased germination more than seeds scarified with emery paper, the exact method of scarification was detrimental in percent germination.
Although a study such as this one can provide the "researcher" with information on how to pretreat seeds and how many to plant, there are many other factors which must be considered before actual planting takes place. More specifically, in this particular study seven separate groups were conducting individual germination tests. As shown on the graphs, ranges of results for the same treatment were often quite great. An example is the control group of "big seeds" where percent germination ranged for 20 to 100%. Many variables could have caused such differences in germination: moistness of paper towelling, sealing or not sealing bags, duration of study, methods of counting, and definition of "a germinated seed". There were most likely other factors within a group which affected the outcome.
Improvements in the consistency of this study would aid application in the field. If conducted by a single person, methods can be pretty uniform. Ground rules as to counting, maintenance, pretreatment, duration, etc. must be made, however, regardless of the number of "researchers". Also, important to remember, actual environmental conditions in the field can vary germination test results might disagree significantly with field results.