 Earth 's biosphere produces many useful biological products for humans , including food , wood , pharmaceuticals , oxygen , and the recycling of many organic wastes . The land @-@ based ecosystem depends upon topsoil and fresh water , and the oceanic ecosystem depends upon dissolved nutrients washed down from the land . In 1980 , 5 @,@ 053 Mha ( 50 @.@ 53 million km2 ) of Earth 's land surface consisted of forest and woodlands , 6 @,@ 788 Mha ( 67 @.@ 88 million km2 ) was grasslands and pasture , and 1 @,@ 501 Mha ( 15 @.@ 01 million km2 ) was cultivated as croplands . The estimated amount of irrigated land in 1993 was 2 @,@ 481 @,@ 250 square kilometres ( 958 @,@ 020 sq mi ) . Humans also live on the land by using building materials to construct shelters . 
