Why do nematodes affect plants in sandy soil more than clay or loam?

Drainage is a reason why nematodes affect plants is sandy soil more than in clay or loam. Clay or loam may end up retaining too much water for the roundworms in question. Infiltration and percolation of water tends to be faster and non-saturating in sandy soils, which offer a drier environment, which adult nematodes prefer for ensuring the next generation's sustainability.