Agora a coisa está andando.. outro artigo aqui: http://www.walterreeves.com/tools_chemicals/article.phtml?cat=22&id=996
"Even if we allow for potentially greater efficiency of nutrient use with foliar vs. soil applied fertilizer, it would still be impractical if not impossible to provide all the foliar applications needed to deliver enough nitrogen in a timely manner."
A adubação exclusivamente foliar deixaria muito a desejar, portanto ela deve ser considerada como auxiliar.
"A distinction needs to be made between foliar fertilization and the application of soluble nutrients in liquid form where the majority of the nutrients taken up by plants are absorbed by the roots from the soil. When liquid fertilizer is sprayed on foliage some nutrients are absorbed through the leaves and light, frequent applications would constitute true foliar fertilization. However, with heavier spraying there will be considerable runoff from the foliage and the liquid fertilizer will soak into the soil. In this case there would be some nutrient absorption through leaves, but the majority of the nutrients used by the plant would actually be taken up by roots. From the plant’s perspective, this is essentially the same process that occurs when dry fertilizer is added to the soil."
Como eu falei anteriormente, se o adubo cai no solo e é absorvido pelas raízes, a parte absorvida pelas folhas é uma fração mínima comparativamente.
Agora um pró!
"An appropriate time to consider foliar fertilization is when a specific nutrient shortage is evident based on visual symptoms or soil analysis."
É uma boa idéia utilizar o adubo foliar quando existe uma deficiência sintomática de certo nutriente, normalmente quando o Ph do solo limita sua concentração e absorção pelas raízes.
e por fim:
"The cuticle on leaves of most plants will cause water to bead up and prevent good penetration. So, for all foliar applied products, it is important to include a wetting agent or surfactant to allow for full coverage of the leaf. One or two drops of detergent per gallon of water will help to wet the leaf surface. If rain occurs shortly after an application, most of the spray will be washed off the leaves and reapplication will be necessary."
A cutícula é uma grande barreira para a absorção dos compostos, sugerem a aplicação de algumas gotas de detergente para facilitar a absorção, em caso de chuva, tem que aplicar denovo, pois lava toda a aplicação para o solo.... bom, considerando que regamos 1 ou 2 vezes por dia, é de se supor que o adubo pare todo no substrato...
"Important points about foliar fertilization:
1. Routine use of foliar fertilizers without a documented need is not recommended.
2. Foliar fertilization is unable to meet the total plant requirements for the major nutrients nitrogen, phosphorus, and potassium.
3. Foliar fertilizers are most effective when soil problems occur that restrict nutrient availability such as iron availability in high pH soils.
4. Foliar fertilization should not be used as a substitute for good soil fertility management. Have your soil tested and fertilize according to soil test recommendations."
"Even if we allow for potentially greater efficiency of nutrient use with foliar vs. soil applied fertilizer, it would still be impractical if not impossible to provide all the foliar applications needed to deliver enough nitrogen in a timely manner."
A adubação exclusivamente foliar deixaria muito a desejar, portanto ela deve ser considerada como auxiliar.
"A distinction needs to be made between foliar fertilization and the application of soluble nutrients in liquid form where the majority of the nutrients taken up by plants are absorbed by the roots from the soil. When liquid fertilizer is sprayed on foliage some nutrients are absorbed through the leaves and light, frequent applications would constitute true foliar fertilization. However, with heavier spraying there will be considerable runoff from the foliage and the liquid fertilizer will soak into the soil. In this case there would be some nutrient absorption through leaves, but the majority of the nutrients used by the plant would actually be taken up by roots. From the plant’s perspective, this is essentially the same process that occurs when dry fertilizer is added to the soil."
Como eu falei anteriormente, se o adubo cai no solo e é absorvido pelas raízes, a parte absorvida pelas folhas é uma fração mínima comparativamente.
Agora um pró!
"An appropriate time to consider foliar fertilization is when a specific nutrient shortage is evident based on visual symptoms or soil analysis."
É uma boa idéia utilizar o adubo foliar quando existe uma deficiência sintomática de certo nutriente, normalmente quando o Ph do solo limita sua concentração e absorção pelas raízes.
e por fim:
"The cuticle on leaves of most plants will cause water to bead up and prevent good penetration. So, for all foliar applied products, it is important to include a wetting agent or surfactant to allow for full coverage of the leaf. One or two drops of detergent per gallon of water will help to wet the leaf surface. If rain occurs shortly after an application, most of the spray will be washed off the leaves and reapplication will be necessary."
A cutícula é uma grande barreira para a absorção dos compostos, sugerem a aplicação de algumas gotas de detergente para facilitar a absorção, em caso de chuva, tem que aplicar denovo, pois lava toda a aplicação para o solo.... bom, considerando que regamos 1 ou 2 vezes por dia, é de se supor que o adubo pare todo no substrato...
"Important points about foliar fertilization:
1. Routine use of foliar fertilizers without a documented need is not recommended.
2. Foliar fertilization is unable to meet the total plant requirements for the major nutrients nitrogen, phosphorus, and potassium.
3. Foliar fertilizers are most effective when soil problems occur that restrict nutrient availability such as iron availability in high pH soils.
4. Foliar fertilization should not be used as a substitute for good soil fertility management. Have your soil tested and fertilize according to soil test recommendations."