12. Fertilizer extension work
As an extension agent, it is your obligation, but also the opportunity to helpfarmers. Thus you will demonstrate to them through conversation, articles,fieldwork and meetings how fertilizers will lead to higher yields of theircrops.
Furthermore, you will show them the benefits of improved farm managementpractices leading to better farm income and protection of the environment,and thus to sustainable agriculture.
Consequently, your work withfertilizers is not only very important for the farming community in yourregion, but also for your country.When introducing fertilizers to the local farmers you have to know whatyour objective is. Therefore, you need to prepare yourself clearly and well.
First you have to find out where you can get fertilizers, i.e. who are thefertilizer retailers in your region, what grades of fertilizers are available instock and what is the time required to order them.
Secondly, you will contactyour experimental station, agricultural school or agricultural university forappropriate fertilizer recommendations. Recommended amounts of fertilizersto be applied to the crops of your country may be inserted as an appendixto this booklet. Start your field demonstrations on the basis of these recommendationsand adapt them to the results you will get in your region.
Thirdly,you will invite the farmers to the demonstration plots, to see and discusswith them the effects of fertilizers on growth and yield of their crops. Thisshould be integrated in a programme of good agricultural practices.
Finally,you will hold field days or start a farmers’ field school and you will demonstratethe economic benefit from improved yields through fertilizer use.
CONDUCTING A FERTILIZER DEMONSTRATION
Before starting a fertilizer demonstration you should set up a plan and alayout:
What do I want to demonstrate to the farmer?
With which crop willthe demonstration be most convincing (most valuable or most grown in your area or most needed for food)?
With which farmers will I cooperate?
Whatwill be the best situated place or field for the demonstration?
What fertilizerdo I have available for use on the selected crop?
When and how do I have toapply the fertilizer?
What other measures do I need to take into account?
Therefore, in order to carry out a fertilizer demonstration you need toprepare and have ready the following:
1. A plan for the demonstration (two or more plots24, where and with whichcrop, size of each plot, demonstration on one field only or on severalfields).
2. A notebook for the demonstration plan, for plot records (amount of nutrientsapplied, date of application), location of plots, growth observations,weed and pest control during crop growth and the final yields.
3. One or more interested farmers who will work with you and help you toconduct the demonstration in his/their fields.
4. Fertilizer of the right grade or grades at the right time and a dry place tostore the fertilizers before use.
5. A scale or balance to weigh out the fertilizer quantity for each plot.
6. Have ready paper bags, preferably multilayered, in which you put thefertilizer for the different treatments clearly marked.
7. A measuring tape or device to determine the plot size/length and shape;stakes and strings to mark the plot boundaries, particularly the corners.
8. Harvesting equipment, including cutting tools, and scale or balance formeasuring crop yields.
9. Information on actual fertilizer and agricultural produce prices, and possiblya pocket calculator to calculate the economic outcome of the demonstration(value/cost-ratio VCR and/or the net profit).
As a general rule: Keep your fertilizer demonstrations simple!
a) Identify the fertilizer effect against a non-fertilized plot, with all otherfactors remaining equal. The simple design would be: no fertilizer – recommendedfertilizer.
b) If you want to convince farmers to use a higher rate of N and/or P2O5and/or K2O you have to adapt the design to compare two rates of nutrients.
The design then would be:
no fertilizer – lower rate of nutrient (e.g. 30kg/ha N) – higher rate of nutrient (e.g. 60 kg/ha N). The same design is used for P2O5 and K2O. The demonstration while testing a higher rate ofone nutrient, should always be done in the presence of the other twonutrients (balanced fertilization).
c) If you want to demonstrate to the farmers the importance of balancedfertilization you will have to use a three or four plot-design: no fertilizer- plot only with nitrogen (N) – plot with nitrogen and phosphate (NP) -plot with nitrogen, phosphate and potassium (NPK).
Variations of this design with three plots are:
no fertilizer - NP -NPK
or no fertilizer – P – NP
or no fertilizer – N – NP
or no fertilizer – N – NPK.
d) In addition to proving the benefits of fertilizer use you may also wantto demonstrate the benefits of improved agricultural practices, particularlythe system of integrated plant nutrition. Then you need a four plotdesign:
1. plot: no fertilizer with farmer’s practice.
2. plot: recommended fertilizer with farmer’s practice.
3. plot: no fertilizer with recommended improved practices (conservationtillage, organic matter supply, manure, green manure,improved seed variety, date and method of planting, weed anddisease control, etc.).
4. plot: recommended fertilizer with recommended improved practices(conservation tillage, organic matter supply, manure,green manure, improved seed variety, date and method of planting,weed and disease control, etc.).
Because of the gradual inclusion of “other” improved practices, and notonly fertilizer use, this last design calls for special emphasis. Therefore, it isrecommended to work primarily with simple demonstrations as describedunder a) and b), and to implement the other demonstrations or simple trialsas under c) and d) or with still more, i.e. six to ten treatments25 in cooperationwith your local experimental station.
DETERMINATION OF PLOT SIZE
The size of demonstration plots will depend on the field size of farms. Sincefarms and fields may often be small in your region, the demonstration plotsalso have to be small. However, they should be large enough to make convincingdemonstrations and to get accurate yield data to determine the effectof the treatments. Thus, the size of plots or strips may vary between 50 to400 square metres (5 m x10 m up to 10 m x 40 m).
In general, the plots used for the demonstration should be rectangularand laid out side by side. Paths of 0.5 to 1 m in width should be left betweenthe plots and around the site of the demonstration (see Figure 11). Keep inmind the topography of the field so that all plots look in the same direction.
It is recommended that the order of treatments should be at random forthe trials, not systematic. However, when you are running a demonstrationwith only three plots the order 0-1N-2N (or other nutrients) should be used.To avoid any confusion to the farmers regarding the plots, this should alsobe done if you lay out the same demonstration on several farmers’ fields26.
For row crops you have to adjust the width of the plot so as to include anexact number of rows: ten rows each spaced 1 m apart require a plot 10 mwide, but nine rows 1.20 m apart will need a plot which is 10.80 m wide. Ifthe treated plots are of the larger size it is not necessary to harvest the wholeplot, but only 20 to 50 square metres or 10 m of total length of row per plottreatment.
CALCULATION OF FERTILIZER RATES PER PLOT
If you wish to apply straight fertilizers to the demonstration plot, e.g. urea,triple superphosphate and muriate of potash, you calculate the quantities forthe different treatments according to the formula:
Example: the demonstration design isPlot treatment N and/or P2O5 and/or K2O(kg/ha)a) 0 0 0b) 30 30 30c) 60 60 60Please note that high fertilizer application rates should only be used forirrigated crops or in areas with high rainfall. With a nutrient rate of 30 kg/ha N, a plot area of 50 square metres and urea with 45% N as nitrogenfertilizer the calculation is as follows:
Fertilizers are one of the most important tools for agricultural developmentin support of food security and for maintaining soil productivity. Throughyour efforts, interest and enthusiasm, you can bring about a real changethrough introducing and expanding fertilizer use. It is your responsibilityand a challenge for you to help to improve the living conditions in yourregion, and to help to maintain sustainable agriculture.