Effect of fowl manure and chemical fertilizer on production of lettuce
禽畜粪肥和化肥对结球西生菜生产的影响

Research on lettuce nutrition and growth environment in paddy and red soils was conducted by field trials to investigate effects of fowl manure and chemical fertilizer. The results show that fowl manure significantly improves the physical and chemical characteristics and the activity of soil microorganism in both soil types. The soil bulk density in the different treatments is as follow: fowl manure treatment < 1/2 fowl manure treatment < chemical fertilizer + fowl manure < chemical fertilizer treatment. However, the order for total porosity and water stable aggregate content is quite the opposite. The use of chemical fertilizer decreases soil pH, whereas fowl manure has no obvious effect on soil pH. The use of fowl manure increases the contents of soil organic matter, available N, P and K, total microorganism, bacteria, fungi and actinomyce. Using a certain amount of fowl manure decreases heavy metal and nitrate content in lettuce, but equally poses high risk of increasing coliform number in lettuce. Hence fowl manure should be harmlessly treated before use. There is a positive correlation between applied N amount and nitrate content in lettuce. Nitrate in lettuce increases as N utilization rate increases. As P fertilizer, in itself, contains some amount of heavy metal, it has a positive effect on heavy metal content in lettuce if applied in large amounts. K fertilizer increases the lettuce yield and output. The use of B in B deficient red soils increases lettuce yield. Higher yield and good return of lettuce can be achieved by using chemical fertilizer and fowl manure in combination.