the atmosphere is 78% dinitrogen so there should be plenty, right? but the problem is that most organisms don't have access to that dinitrogen in the atmosphere. they can't use it. they can't get at it. narrator: while certain bacteria can convert this nitrogen into forms that other organisms can use, for many crops more nitrogen is still required. and nitrogen fertilizer allows plants to receive the much-needed nutrient that they lack. the use of fertilizer dramatically increased during the green revolution, where, from the 1940s through the 1960s, new seed varieties were introduced in many developing nations helping avoid widespread famine. dr. naylor: the green revolution is just adapting crop varieties to have much higher yields on a limited land base. and the key factor was new seeds for plant types, and these plant types were dependent on fertilizer inputs to get those higher yields. narrator: the green revolution began in the yaqui valley of cimmyt, which is the spanish acronym for the international maize and wheat improvement center. dr. ivan

the atmosphere is 78% dinitrogen, so there should be plenty, right?ilizer dramatically increased during the green revolution, where, from the 1940s through the 1960s, new seed varieties were introduced in many developing nations, helping avoid widespread famine. dr. naylor: the green revolution is just adapting crop varieties to have much higher yields on a limited land base. and the key factor was new seeds for plant types, and these plant types were dependent on fertilizer inputs to get those higher yields. narrator: the green revolution began in the yaqui valley of cimmyt, which is the spanish acronym for the international maize and wheat improvement center. dr. ivan ortiz-monasterio is a senior scientist in the wheat program. in cimmyt's experimental plots, he examines the effects of a wide range of growing conditions, such as nitrogen levels. dr. ortiz-monasterio: what you can see here we have grown without applying any nitrogen fertilizer. it's a wheat crop with very severe nitrogen deficiency. the older leaves, which are at the bottom, start tu