Nutrient Uptake of Cassava
Cassava prefers good soil but also grows in poor soils.
- It can tolerate low pH.
- It can tolerate higher level of soluble aluminum and low available phosphorous.
- It grows in soil where other crops fails.
The crop removes considerable amounts of nutrients from the soil (see Table below). The degree of nutrient removal depends on the yield level. Hence, continuous production without replacement of the nutrient loss in the soil will reduce the soil productivity.
How to maintain adequate amounts of nutrients in the soil.
- Return the residues of healthy harvested plants to the soil by gathering them in one area to let them decompose and later apply it as organic fertilizer or by applying it as mulching material in the next cropping.
- Apply fertilizer. Fertilizers supply the essential nutrients that are lacking in the soil. Fertilizers are classified either as inorganic (i.e. complete, muriate of potash, solophos, etc.) or organic (manure, compost, etc.).
Fertilizer Application
Fertilizers are generally classified into either Inorganic or Organic. It is important to analyze the soil prior to planting to determine the amount and kind of fertilizer needed.
Inorganic Fertilizer
The general recommendation for soil, which have not been analyzed, is eight (8) sacks of complete (14-14-14) fertilizer per hectare. Apply fertilizer 2-6 weeks after planting at 5-10 cm depth and 15-20 cm away from the plant. The use of compost or organic fertilizer is highly recommended.
The table below shows the recommended methods of inorganic fertilizer application.
Dos and Donts in fertilizer application.
To apply fertilizers, make a small canal 15-20 cm away from the base of the plant using a plow. Cover the fertilizer immediately after application.
On sloping areas, dibble the fertilizer 3-5 cm away from the base of the plant, then cover with soil.
Do not apply fertilizer if soil fertility is high.
Do not apply fertilizer during rainy days or when rain is eminent right after fertilizer application.
Do not over fertilize the plant especially nitrogen. Excessive nitrogen promotes vegetative growth at the expense of root development and susceptible to diseases and insect pests.
Proper application of organic fertilizer on cassava.
- Apply organic fertilizer before land preparation for proper incorporation into the soi if abundant. The volume will depend on the availability of organic fertilizer.
- Apply organic fertilizer before land preparation for proper incorporation into the soi if abundant. The volume will depend on the availability of organic fertilizer.
- Supply at least 30 percent of recommended fertilizer rate with organic fertilizer.
Weeding and Cultivation
Weeds are plants growing where they are not wanted. Many different types of weeds like the images below occur in cassava plantations and can cause considerable losses for farmers. This is because weeds compete with the cassava crop for nutrients, sunlight and space. Weeds may harbor pests and diseases or physically injure cassava plants and storage roots. For these reasons, close attention should be paid to weed control in the farmer's effort to grow healthy crops and obtain high yeilds of cassava.
How do Weeds Spread?
Whenever an area is cleared for farming, weeds are among the first plants you see growing on the land. Because they grow and reproduce very quickly, they are able to establish themselves on farms within a short time. Weeds reproduce and spread through seeds and vegetative structures.
Type of weed reproduction.
Spread by Seeds
A number of weeds which live for only one year (annual weeds) reproduce and spread mainly by seeds. These weeds shed their seeds mostly in the dry season and die soon afterwards. The seeds survive in the soil and germinate the following season, or can remain in thesoil for many years until disturbed when the soil is tilled for planting. In order to effectively control annual weeds, you need to remove them early before they start flowering. This prevents the weeds from seeding and increasing the quantity of seeds in the soil.
Spread by Vegetative Structures
Some weeds spread through vegetative parts like stem cuttings. If these types of weeds are cut up into pieces, each piece is capable of growing into a new plant. You are therefore very likely to spread bermuda grass in this way during land and seedbed preparation for planting cassava.
How to Control Spread of Weed:
- Off-bar the plants at 3-4 weeks after planting to loosen the soil and kill the weeds.
- Hill-up the plants just after side-dressing not later than three months after planting (MAP).
- For the remaining weeds, handweed within the rows at 4-5 weeks.
0 Comments