World update

  In 1973, sunflowers grew in my father's vegetable garden. They appeared to sprout spontaneously in a few rows he'd lent to new California neighbors that year. At the moment, just six years old, these garish plants first set me off. Such odd and colorful flowers seemed out of place amid the respectable beans, peppers, spinach, and other vegetables that we've all grown. Yet eventually, sunflowers' beauty won me over. Their fiery halos relieved the lush monotonous garden dominated by late summer. I marveled at birds clinging to shaggy, gold balls, wings fluttering, seed plundering. That summer, Sunflowers identified flowers for me and changed my outlook. Flowers have a way to do so. They started transforming the way the planet looked nearly as soon as they arrived on Earth about 130 million years ago, during the Cretaceous period. That's comparatively recent in geological time: if all Earth's past were squeezed into an hour, just the last 90 seconds would b

  Soil: its nature and needs Soil is the basic element in plant cultivation, but soilless water growth, with or without gravel or sand, enriched with suitable chemicals (hydroponics) can be quite effective. Soil consists of particles, primarily calcium, extracted from rock dissolution along with organic matter. In particle pore spaces, all water (containing dissolved salts) and air circulate. The atmosphere contains more carbon dioxide and less oxygen. Minute living organisms are also found in immense quantities of soil , making it viable. Plants must cross this area to access most of their fuel. The soil must be maintained for fertility (supplying plant nutrients) and physical health. Nutrients must be supplied and published in plant-available ways. Plant growth requires sixteen elements. Three of these, fuel, oxygen, and hydrogen, are supplied by water and air; the other 13 by soil. The elements required in relatively large quantities are called major elements: nitrogen, phosph