<Tr> <Th> Topsoil Type </Th> <Th> HM% </Th> <Th> BS% </Th> <Th> pH </Th> <Th> P-I </Th> <Th> K-I </Th> <Th> Ca% </Th> <Th> Mg% </Th> </Tr> <Tr> <Td> Bulk </Td> <Td> 0.3 </Td> <Td> 69 </Td> <Td> 5.2 </Td> <Td> 009 </Td> <Td> 026 </Td> <Td> 45 </Td> <Td> 10 </Td> </Tr> <Tr> <Td> Bagged </Td> <Td> 0.7 </Td> <Td> 78 </Td> <Td> 5.8 </Td> <Td> 166 + </Td> <Td> 178 </Td> <Td> 56 </Td> <Td> 12.3 </Td> </Tr> <P> Alternatively the British Standard relates to other working values: </P>

What are two ways that nutrients are lost from the top layers of soil