Question

Productivity of land is how many billion tons​

Answer 1

Answer:

The loss of soil from land surfaces by erosion is widespread and reduces the productivity of all natural ecosystems as well as agricultural, forest, and pasture ecosystems [1,2,3]. Concurrently with the growing human population, soil erosion, water availability, climate change due to fossil fuel consumption, eutrophication of inland and coastal marine bodies of water, and loss of biodiversity rank as the prime environmental problems throughout the world.

Currently nearly 66% of the world population is malnourished [4,5], the largest number of malnourished people ever (malnutrition: faulty nutrition due to inadequate or unbalanced intake of nutrients or their impaired assimilation or utilization) [6]. With the world population now over seven billion and expected to reach 9.3 billion by 2050, more food will be needed [7]. Consider at present that more than 99.7% of human food (calories) comes from the land [8], while less than 0.3% comes from the marine and aquatic ecosystems. Maintaining and augmenting the world food-supply basically depends on the productivity and quality of all agricultural soils.

Human induced soil erosion and associated damage to all agricultural land over many years have resulted in the loss of valuable agricultural land due to abandonment and reduced productivity of the remaining land which is partly made up for by the addition of nitrogen and phosphate fertilizers [2,9,10,11]. This loss of cropland to the effects of soil erosion often