(Difference between revisions)
| Revision as of 14:47, 25 August 2006 Peter (Talk | contribs) (→Crops implemented in CM Box) ← Previous diff |
Revision as of 14:55, 25 August 2006 Peter (Talk | contribs) (→Crop coeficcients) Next diff → |
||
| Line 39: | Line 39: | ||
| The crops implemented in AgrometShell can be displayed with the ''Database-Configure-Crops'' function. | The crops implemented in AgrometShell can be displayed with the ''Database-Configure-Crops'' function. | ||
| - | ===Crop coeficcients=== | + | ===Crop coefficients=== |
| + | |||
| + | In the FAO water balance model, the water use of crops is based on weather factors aggregated in the ET<sub>0</sub>, the water availability through rain, soil and irrigation and the crop coefficients. Crop coefficients describe the relationship between ET<sub>0</sub> and water use at every stage of crop growth. Crop coefficients differ from crop to crop and even from crop variety to variety. Therefore more than one set of crop coefficients can be implemented in CM Box. | ||
| + | |||
| + | {|"class=prettytable" cellpadding="15" border="1" style="border-collapse:collapse" | ||
| + | |width="225"|To view and change crop coefficients, the Database-Configure-Crop Coefficients function is activated.||[[Image:graph64.jpg|500px|]] | ||
| + | |} | ||
| ===Defining new crops=== | ===Defining new crops=== | ||
Revision as of 14:55, 25 August 2006
Monitoring crops
Limiting factors for yield
Monitoring crops with a water balance calculation is possible as long as water is a limiting factor for the crop. In circumstances where water is not a limiting factor in any way, water balance output will not be strongly correlated to yields obtained. Limiting factors for crop growth can be grouped into four groups:
- Weather dependent, such temperature, solar raddiation, rainfall and CO2 content of the air.
- Crop dependent, such as genetic potential and crop canopy (LAI)
- Related to Pests and diseases (insects, weeds etc..)
- Related to cultivation techniques (irrigation, fertilizer etc..)
Basically, water balance calculations have predictive value for yield in arid and semi-arid areas. In areas where temperatures are high and water is not limited, solar radiation is loosely correlated to yields. In areas of abundant water and high solar radiation during the growing season, temperatures are often more limiting than other factors (e.g. Northern pats of Russia and Canada)
Limiting factors for yield
Monitoring crops with a water balance calculation is possible as long as water is a limiting factor for the crop. In circumstances where water is not a limiting factor in any way, water balance output will not be strongly correlated to yields obtained. Limiting factors for crop growth can be grouped into four groups:
- Weather dependent, such temperature, solar raddiation, rainfall and CO2 content of the air.
- Crop dependent, such as genetic potential and crop canopy (LAI)
- Related to Pests and diseases (insects, weeds etc..)
- Related to cultivation techniques (irrigation, fertilizer etc..)
Basically, water balance calculations have predictive value for yield in arid and semi-arid areas. In areas where temperatures are high and water is not limited, solar radiation is loosely correlated to yields. In areas of abundant water and high solar radiation during the growing season, temperatures are often more limiting than other factors (e.g. Northern pats of Russia and Canada).
Crops implemented in CM Box
AgroMetShell comes with a number of pre-defined crops. These crops have been selected as they are important in terms of crop forecasting for food security. The following crops are implemented:
- Maize
- Millet (bulrush)
- Tef
- Beans (haricot)
- Wheat
- Sorghum
- Finger millet
- Flooded rice
- Upland rice
The crops implemented in AgrometShell can be displayed with the Database-Configure-Crops function.
Crop coefficients
In the FAO water balance model, the water use of crops is based on weather factors aggregated in the ET0, the water availability through rain, soil and irrigation and the crop coefficients. Crop coefficients describe the relationship between ET0 and water use at every stage of crop growth. Crop coefficients differ from crop to crop and even from crop variety to variety. Therefore more than one set of crop coefficients can be implemented in CM Box.
To view and change crop coefficients, the Database-Configure-Crop Coefficients function is activated. 
Defining new crops
Development Stages
Clarence Sakamoto
At each stage of their development, from germination through to the formation of seeds, plants come under the influence of their environment and show external modifications (appearance of leaves, formation of inflorescence, etc.). These external modifications of the plants correspond to the different phases of their development. Each phase shows up in a different way. In the same cultivated field, plants do not reach the following stages of development simultaneously, it can take several days. On the other hand, certain stage of development are reached very quickly. Here again, in the same cultivated field, a particular stage of development will not be reached at the same time by the totality of the plants. In general, the start of a development stage will be the day when 10 % of the plants have reached that stage. The development stage will be reached when 50 % of the plants are showing the characteristics of the phase.
