The extent of mineral fertilizer use on different crops in the various regions of Uzbekistan is determined by a combination of complex factors. The most important are soil and climatic conditions in Uzbekistan, the soil nutrient content, the crop yields, the use of organic fertilizers, the relationship between the prices for the fertilizers and those of agricultural products. The average rates recommended by the scientists of Uzbekistan for the main crops are given in Table 9.
The quantities and rates of application of mineral fertilizers in Uzbekistan are shown in Tables 10 and 11. The rates of application of mineral fertilizer to cotton have been declining in recent years in relation to recommendations. In the case of cereals it is the other way round and rates have been increasing.
Table 9
Average standard rates of fertilizer application for the main agricultural crops
(kg nutrient/ha)
|
Crops |
Nitrogen (N) |
Phosphorus (P2O5) |
Potash (K2O) |
|
Cereals |
|||
|
- Irrigated land |
150 to 200 |
100 to 120 |
50 |
|
- Arid land |
50 to 60 |
40 to 50 |
- |
|
Cereals for seed |
180 to 220 |
120 to 140 |
85 to 90 |
|
Rice |
200 to 220 |
140 to 145 |
150 to 180 |
|
Cotton |
|||
|
- Average fibres |
215 to 240 |
145 to 165 |
95 to 110 |
|
- Fine fibres |
230 to 250 |
155 to 165 |
100 to 110 |
|
Kenaff |
160 to 180 |
130 to 140 |
80 to 90 |
|
Tobacco |
120 to 150 |
80 to 100 |
40 to 45 |
|
Potatoes |
120 to 150 |
85 to 100 |
60 to 75 |
|
Vegetables |
145 to 200 |
100 to 110 |
70 to 75 |
|
Gourds |
50 to 75 |
100 to 110 |
45 to 80 |
|
Fodder roots |
220 |
90 |
60 |
|
Maize for silage |
200 |
90 |
60 |
|
Established alfalfa |
100 |
90 to 100 |
50 to 60 |
|
Orchards and vineyards |
120 to 130 |
85 to 90 |
65 |
Table 10
Main crops: use of mineral fertilizers and yields
|
Crop/year |
Use of mineral fertilizers, thousand tonnes |
Yield |
|||
|
Total |
N |
P2O5 |
K2O |
||
|
Cotton |
|||||
|
1998 |
385 |
290 |
69 |
26 |
2.1 |
|
1999 |
411 |
299 |
83 |
30 |
2.4 |
|
2000 |
355 |
291 |
62 |
2 |
2.2 |
|
Cereals |
|||||
|
1998 |
266 |
214 |
30 |
22 |
2.3 |
|
1999 |
259 |
221 |
36 |
2 |
2.3 |
|
2000 |
247 |
201 |
35 |
11 |
2.7 |
Source: MAWRRUz, 2002.
Table 11
Main crops: rates of fertilization
|
Crop/year |
Rates, (kg/ha) |
|||
|
Total |
N |
P2O5 |
K2O |
|
|
Cotton |
||||
|
1998 |
253 |
191 |
45 |
17 |
|
1999 |
270 |
197 |
54 |
19 |
|
2000 |
256 |
210 |
45 |
1.2 |
|
Cereals |
||||
|
1998 |
203 |
164 |
23 |
16 |
|
1999 |
197 |
169 |
27 |
1.3 |
|
2000 |
182 |
148 |
26 |
8 |
Source: MAWRRUz, 2002.
In Uzbekistan, the rate of application of fertilizers per hectare on grain crops in the past reached nearly 250 kg/ha; today it is about 180 kg/ha. Farm managers as a rule consider that it is unprofitable to apply the average recommended rates of fertilizer application if the ratio between the expenditure and the profit is not at least 1:2 to 1:3. It should also be noted that part of the cereal crop is grown under partial irrigation in zones with insufficient moisture, where the usage of larger quantities of fertilizers is less effective.
According to the assessments of the Institute of Soil Science and Agro Chemistry of the State Committee of the Land Resources of the Republic of Uzbekistan, at the present time in Uzbekistan the overall use of mineral fertilizers has become 20 percent to 30 percent less than is recommended by the scientific institutions. This is confirmed by data provided by the Ministry of Agriculture and Water Resources of the Republic of Uzbekistan (MAWRRUz), which show that in all the regions studied, fertilizers are applied on cotton, cereals and potatoes at lower rates than those recommended by scientific establishments.
According to the calculations of the Central Scientific Institute Agrochemical Service (CSIASUz), in Uzbekistan, on average 1 kg of nitrogen provides, gives 3.8 to 7.2 depending on the rate, from 4.2 to 7.5 kg of wheat; 1 kg P2O5 kg of wheat and 1 kg K2O from 2.0 to 3.5 kg/ha of wheat. The simultaneous use of nitrogen, phosphate and potassium significantly increases their efficiency.
