Though we are recommending the application of complex fertilizers at basal dose only but most of the farmers are applying the complex fertilizers during different growth stages also (Top dressing also). During different growth phases plants uptake the nutrients from the complex fertilizers or not.
Along with N , application of K in 2 to 3 splits is recommended or practiced in some crops like rice and sugarcane especially in soils low in K, light textured soils and late maturing varieties to get better tillering.Split application of K is also recommended in horticultural and plantation crops like tea, banana and grapes.
Generally Nitrogen fertilizers are top dressed and not complex fertilizers though there will be uptake of nutrients from complex fertilizers too at different stages of the crop. It is mainly due to the factors like -
1. Mobility of the nutrient in the soil
2. Availability of the nutrient for absorption by the plants.
Better use of nutrient is seen if complex fertilizers are applied as basal.
Complex fertilizers are preferred for basal application because at planting we apply N, P and K and using a complex fertilizer makes the job easier and economical. But when the crop is already growing, we generally apply N as top dress. Then using a complex fertilizer, which contains other nutrients along with N, does not remain an economical proposition.
Very clearly explained sir @Debasish Bohra and @Bijay Singh sir...
Complex fertilizers should not be recommended as top dressing because
1. Not economical
2. Decrease FUE
3. May increase soil and water contamination
Along with N , application of K in 2 to 3 splits is recommended or practiced in some crops like rice and sugarcane especially in soils low in K, light textured soils and late maturing varieties to get better tillering.Split application of K is also recommended in horticultural and plantation crops like tea, banana and grapes.
Generally water soluble fertilizers top dressed in drip fertigation of high value commercial crops.
Phosphorus and potash degrade at slow rate and micro element requirement in small quantity so meaning to apply as top dress, it reduce the use efficiency
As Complex fertilizers are slow releasing fertilizer i.e. they take longer time to become available forms for the plants, so they are applied to the soil during field preparation such as Phosphatic fertilizers like TSP, SSP etc. In contrast, the fertilizers those are used as top dressing become available forms for the plants very quickly after application to the soil such as urea, potash etc. If complex fertilizers are applied to the soil/crop as top dressing in that case they will not be fully available form during the rest span of that standing crop. However, maximum content of complex fertilizers will be lost if used as top dressing as these fertilizers remained unavailable in the soil, or not become available for the last span of that crop.
Complex fertilizers are not recommended as a top dress for those slow degrade elements because the application, in this case considered as uneconomical method.
- Badges
- Science topic
- Similar topics
- Clinical Pharmacology
- Dosing