Crop rotation British Agricultural Revolution. The rotation between arable and ley is sometimes called ley farming. George Washington Carver (1860s–1943) studied crop-rotation methods in the United States, teaching southern farmers to rotate soil-depleting crops like cotton with soil-enriching crops like peanuts and peas. In the Green Revolution of the mid-20th century the traditional practice of crop rotation gave way in some parts of the world to the practice of supplementing the chemical inputs to the soil through topdressing with fertilizers, adding (for example) ammonium nitrate or urea and restoring soil pH with lime. Such practices aimed to increase yields, to prepare soil
Quantum yield <math>\Phi = \Phi_\mathrm{R}\times\frac{\mathit{Int}}{\mathit{Int}_\mathrm{R}}\frac{1-10^{-A_\mathrm{R}}}{1-10^{-A}}\frac Quantum yield The quantum yield (Φ) of a radiation-induced process is the number of times a specific event occurs per photon absorbed by the system. The "event" is typically a kind of chemical reaction. The quantum yield for the decomposition of a reactant molecule in a decomposition reaction is defined as: Quantum yield can also be defined for other events, such as fluorescence: Here, quantum yield is the emission efficiency of a given fluorophore. Quantum yield is used in modeling photosynthesis: In a chemical photodegradation process, when a molecule dissociates after absorbing a light quantum, the quantum