Table 16 gives the general fertilizer recommendations for crops grown in communal areas.
The recommendations in Table 17 are blanket recommendations that need to be adapted to local conditions. The recommendations are for normal rather than low yields, on soils of medium fertility. Table 17 shows recommended rates according to the yield level in different AEZs.
Maize is the main staple food in Zimbabwe. The crop is cultivated in all five NRs, NRs II and III accounting for about 84 percent of total maize production. NR IV has the largest area under maize but its yields are lower than those in NRs II and III. Under Zimbabwean conditions, maize generally requires 67 kg N/ha, 30 kg P2O5/ha and 11 kg Ca/ha. Compound D fertilizers and AN are the most commonly used fertilizers on maize. Prior to 2000, maize accounted for one-third of the fertilizer applied in the large-scale commercial subsector and 90 percent of fertilizer use in the smallholder subsector.
Soybeans require a deep, fertile soil with high Ca content. They thrive on light soils, provided these contain sufficient nutrients. Soybeans absorb considerable quantities of nutrients from the soil. It is advisable to apply a light dressing of Rhizobium inoculant at sowing. The inoculant is produced at Morondera. Liberal application of phosphate accelerates ripening. Soybean removes nutrients from the soil at a rate of 60 kg N/ha, 35 kg P2O5/ha and 80 kg K2O/ha. The crop needs 250 kg/ha of Compound L at planting (AGRITEX, 1982).
TABLE 16
Fertilizer recommendations, application rates
and timing
| |
At planting |
Top-dressing |
Timing |
Remarks |
|
| |
Compound |
Rate |
Rate
|
|
|
|
Cabbage |
L |
500 kg/ha |
AN: 200 kg/ha |
Split at 3 and 6 wap1 |
Best top-dress is (kg/ha): 100 AN 100 J |
|
Citrus |
Z |
400 g/tree |
J: 800 g/tree |
According to age |
Fertilizer according to yield |
|
Cotton |
L |
300 kg/ha |
AN: 200 kg/ha |
At 8 wae2 or flowering |
Extra 50-100 kg/ ha AN for irrigation |
|
Cowpea (nyemba) |
D |
150 kg/ha |
Nil |
or 100 J at 6 wap1 |
J on poor sandy soils |
|
Finger millet |
D |
150 kg/ha |
AN: 100 kg/ha |
4-6 wae2 |
|
|
Fruit trees |
Z |
400 g/tree |
J: 300 g/tree |
In split applications |
Increase fertilizer according to age and yield |
|
Groundnuts |
L |
300 kg/ha |
Gypsum: 150 kg/ha |
Over plants at pegging |
|
|
Maize |
D or Z |
300 kg/ha |
AN: 250 kg/ha |
Split at 3 and 6 wae2 |
Z one year in three |
|
Onions |
C |
1 000 kg/ha |
AN: 150 kg/ha |
3-4 wap1 |
|
|
Pearl millet |
D or Z |
200 kg/ha |
AN: 150 kg/ha |
At 6 wae2 |
|
|
Potatoes |
S |
1 000 kg/ha |
AN: 150 kg/ha |
2-3 wae2 |
|
|
Rape |
C |
500 kg/ha |
AN: 200 kg/ha |
|
Extra 100 kg/ha C and AN after 6 months |
|
Sorghum |
D or Z |
250 kg/ha |
AN: 200 kg/ha |
4-6 wae2 |
Best on clay soils |
|
Soybean |
L |
250 kg/ha |
Nil |
|
Inoculants needed |
|
Sugar beet |
Z |
300 kg/ha |
AN: 200 kg/ha |
at 4 wae2 |
Lime 3 weeks before planting. Do not apply boron |
|
Sunflower |
L |
250 kg/ha |
AN: 150 kg/ha |
at 6 wae2 |
Boron essential |
|
Tobacco (barley) |
B |
700 kg/ha |
AN: 300-400 kg/ha |
Half at 3 and 5 wap1 |
|
|
Tobacco (flue cured) |
B, V or C |
600-700 kg/ha |
AN: 100-150 kg/ha |
at 3 wap1 |
|
|
Tobacco (seed beds) |
S |
150 g/m2 |
Sodium nitrate: 10-20 g/m2 |
At 4 wae2 |
|
|
Tomatoes |
B |
1 200 kg/ha |
AN: 150 kg/ha |
Every 2 weeks after first fruit |
J is good for top-dressing |
|
Vegetables |
C |
600 kg/ha |
AN: 200 kg/ha |
Half at 3 and 6 wap1 |
J is good for top-dressing |
1 wap = weeks after planting.
2 wae = weeks after emergence.
Source: Zimbabwe Fertilizer Company Limited.
TABLE 17
Fertilizer rates for crop yield in various
agro-ecological zones
|
Crop |
Expected yield level |
Product |
Recommended rate |
| |
(tonnes/ha) |
|
(kg/ha) |
|
Maize NR I, IIA, IIB |
3.0 |
Compound D |
250 |
| |
|
AN |
100 |
|
Maize NR III, IV |
2.0 |
Compound A |
200 |
| |
|
AN |
100 |
|
Cotton NR IIA, IIB |
1.5 |
Compound L |
300 |
| |
|
AN |
100 |
|
Cotton NR III, IV |
0.8 |
Compound L |
200 |
| |
|
AN |
100 |
|
Sunflower NR IIA, IIB |
0.8 |
Compound L |
100 |
| |
|
AN |
50 |
|
Sunflower NR III, IV, V |
1.0 |
Compound L |
50 |
| |
|
AN |
50 |
|
Groundnuts NR I/IIA, IIB/III & III |
0.8 |
SSP |
200 |
| |
|
Gypsum |
200 |
|
Sorghum (white) NR III, IV, V |
0.8 |
Compound D |
50 |
|
Rapoko NR III, IV, V |
0.8 |
Compound D |
50 |
|
Pearl millet |
0.8 |
Compound D |
50 |
|
Soybeans in NR I/IIA, IIB |
1.0 |
Compound D |
50 |
Source: Piha, 1995.
Groundnuts are produced mostly by small-scale farmers in communal areas. As an N-fixing crop, groundnuts supply N to the soil. Groundnuts need 300 kg/ha of Compound L at planting and a top-dressing of gypsum fertilizer at a rate of 150 kg/ha. Groundnuts take up nutrients at the following rates: 105 kg N/ha, 15 kg P2O5/ha, 27 kg Ca/ha, 18 kg Mg/ha and 42 kg K2O/ha (AGRITEX, 1982).
Wheat requires a relatively large supply of readily available nutrients because the vegetative period is shorter under tropical conditions than in temperate regions. The amount of available N has the greatest effect on yield. The most commonly used fertilizers for wheat are Compound D and AN. Phosphate stimulates early root development and hastens maturity. Wheat is grown mainly under irrigated conditions in the dry winter period. Where rotated with soybeans, the wheat benefits from residual N from the soybeans. The required fertilizer rates vary with soil type, land history, variety and climate. Wheat removes nutrients from the soil at the following rates: 94.5 kg N/ha, 75.5 kg P2O5/ha and 66.5 kg K2O/ha (AGRITEX, 1982).
TABLE 18
Cotton fertilizer rates for various yield
levels
|
Expected yield |
Optimal nitrogen application |
|
1 000 |
15 |
|
1 500 |
30 |
|
2 000 |
45 |
|
2 500 |
60 |
|
3 000 |
75 |
|
3 500 |
90 |
Source: AGRITEX, 1982.
The most commonly used fertilizers for cotton are Compound L and AN. Smallholders apply 8 percent of their fertilizer on cotton. The ratio of Compound L to AN on cotton is about 1:1. Table 18 gives the average fertilizer N requirements at different expected yield levels for seed cotton.
Tobacco is a major cash crop, grown by both smallholders and large-scale farmers. Smallholders grow the crop under dryland conditions, while it is both a dryland and an irrigated crop in the large-scale farming systems. Tobacco grows best on sandy soils. Fertilizers used for tobacco include Compounds A, B and C. The P2O5 and K2O contents in the three fertilizers are the same. National application rates in the large-scale commercial sector averaged 764 kg/ha, while smallholders applied 1 percent of their fertilizers on tobacco.
The main fertilizers for sugar cane are AN (which accounts for 65 percent of the fertilizers used on the crop), SSP (20 percent), muriate of potash (MOP) (9 percent), and Compounds D (4 percent) and M (2 percent). NR V produces the bulk of Zimbabwe's sugar cane, under irrigation. Fertilizer application rates in NR V are relatively high.
