My thoughts on this is that there isnt a general fertilizer regime for all crops and there isnt one specific fertilizer that would produce optimum results in all crops. Depending on the crop type, the nutrient requirement at each stage would vary. for example, for poi plants the recommended rate of K2O application at 10 days after transplanting is 15 kg/ha while at 30 days it isnt required to apply K2O. If we are to apply potassium fertilizer for plantains then the requirement is much higher in the vegetative stage than the early establishment stage. In essence, i dont think there is a fertilizer that can be applied to cover the growth stage of all crops. The regime and type and quantity of nutrient required for each stage is crop specific.

Requirements for plant nutrition depend on the species under study, varietal characteristics and plant growth phase. The mineral nutrition of plants also depends on the soil and climatic characteristics of the growing region.

Answer in its simplest form is that plants show best response to fertilizer if we can ensure that enough amount of nutrients are available at critical growth stages of the crops. These stages differ from crop to crop. Having said this, we must also ensure that at any time during the crop growing season, nutrients supplied by fertilizers or soil itself are not too much than what plants can use. This will ensure that applied fertilizer nutrients are not lost from the soil-plant system. Losses of applied nutrients also influence response of plants - but in a negative way.

Simply this depend on plant species,age ,growth stage,and whereas the plant was annual,biennial or perennial plant and finally the purpose of fertilization is it to promote vegetative or flowering and fruiting.

Best regards

It depends on soil parameters, climate, and plant species. And your aim.

Every stage of the growing plant has specific nutrient requirement. For instance a fruiting vegetable, at the initial growth stage would need food nutrients that are good sources of nitrogen to encourage healthy development of foliage and root system. At the onset of flowering, say 40-50% of the plants, food nutrients with potassium, calcium and other micro-nutrients will enhance fruit development, improve quality, prevent fruit falls (e.g. in tomatoes) and attain desired level of sweetness in case of crops consumed for its sugar content. Soil analysis prior to planting is a must to give the right and proper amount of fertilizer based on the recommended rate required by the specific crop. I also recommend use of organic fertilizer materials if possible.

Hope I helped you.

As answered by most experts in here, it depends on the type of crop, area/location, growth stages, seasons including the climatic factors which all put together determines the recommended rates. The recommended rates are usually tagged with detailed information on when to apply, how much to apply, etc. However, sound knowledge on plant nutrient management and crop physiology would help one in better understanding the crop fertilizer requirement for optimum performance.

it will depend on plant response, environmental conditions. i think it difficult to define that plant need more fertilizer in what stay