Generally,when the content of rapidly available potassium in the soils is more than 30mg k/100g soil or there is a huge amount of plant ash in the manure applied,the efficiency of chemical potassium fertilizers is not so obvious.

• 一般当土壤速效钾(K)大于30mg/100g±或所施农肥中含有大量草木灰时肥效就不明显。