总是存在的

• That of available potassium showed the interruption of human activities with the highest value ( 81 . 2 % ) , and of cec , total potassium , available copper showed that spatial auto - correlation was master with the value less than 25 % . there was no relationship between spatial variability and distance , but with the nugget of 0 . 2 , therefore , the distance
  Kropng插值结果进一步表明土壤表层养分含量具有高度的空间异质性，决定了空间格局的存在，养分含量的斑块（ patch ）的大小、形状及空间分布等具有显著的差异，但是不论在什么方向，养分含量由低到高的分布梯度规律总是存在的。