CCA Exam Nutrient Management Section Questions with Correct Answers What process causes a plant to fix nitrogen? - Correct Answer Rhizobium bacteria infects plant root and forms nodule Legumes and Rhizobium bacteria have what kind of relationship? - Correct Answer Symbiotic How much nitrogen does alfalfa fix? - Correct Answer 250 How much nitrogen does sweet clover fix? - Correct Answer 170 How much nitrogen does red clover fix? - Correct Answer 150 How much nitrogen does soybean fix? - Correct Answer 100 How much nitrogen does hairy vetch fix? - Correct Answer 70 How much nitrogen do field peas fix? - Correct Answer 50 After a field is planted with a legume, a grass species is planted such as corn, grain sorghum, or other small grains. How much nitrogen is needed for a credit from the legume species? - Correct Answer Half of what it fixes annually What factors limit nitrogen fixing of legumes? - Correct Answer Soil pH, Temp, soil aeration, photosynthetic rate, soil fertility, high nitrogen in soil What is the optimum range for soil pH to fix the most Nitrogen? - Correct Answer 5.5 to 7 What is the optimum range for temperature to fix the most Nitrogen? - Correct Answer 65 to 82 What are the temp limits to fixing nitrogen? - Correct Answer 32 to 112 1 / 2
Do legumes fix more nitrogen with sunny or cloudy days? - Correct Answer Sunny What essential element is most essential to converting elemental nitrogen to ammonia nitrogen? - Correct Answer Molybdenum Nebraska soil normally contains enough molybdenum for plants, what can limit this and how can it be fixed? - Correct Answer Acid soils and liming How does high nitrogen affect legumes? - Correct Answer Will fix less nitrogen Definition of a physical change - Correct Answer Change from solid to solution Definition of a chemical change - Correct Answer change from one ionic form to another Definition of a biological change - Correct Answer Change by soil micor organisms Definition of Nitrification - Correct Answer micro biological changes of ammonium nitrogen to nitrite and then nitrate Nitrite salts chemical form - Correct Answer NO2 Nitrate Salts Chemical Form - Correct Answer NO3 Ammonium Salts chemical form - Correct Answer NH4 What causes the first step in Nitrification? - Correct Answer Nitrosomonas and Nitrosococus bacteria What causes the second step of Nitrification? - Correct Answer Nitrobacter bacteria What environmental conditions are the best for nitrification? - Correct Answer 80 to 90 degree soils, neutral pH, high soil moisture but with adequate oxygen
- / 2