Comparison of the effect of organic and chemical fertilizer on crop yield in Mongolian agriculture

In Mongolia, the rapid increase of extensive cropping areas without fertilization has created a serious need for land conservation technology. This paper describes the field study we conducted in a semi-arid region of Mongolia from 2010 to 2013 in which we used animal composts as a self-support fertilizer for two field experiments. In the first field experiment (Experiment-1), from 2010 to 2012, potato, rye, pea and turnip crops were cultivated in the compost plot with the application of animal compost (3-month matured dung of sheep and goats) of 40 Mg /ha /y, and in the NPK plot with the application of chemical fertilizer (90kg /ha /y of N, P2O5, and K2O) under traditional extensive land management without weed control. In the second field experiment (Experiment-2) in 2013, the effects of composts with different application amounts and maturing time were studied under weed control. The composts with a 2-year maturing time (2y-compost) and a 2-month maturing time (2m-compost) were applied in amounts of 20, 40, and 60 Mg /ha for potato and wheat. From the results of Experiment-1, during three years, we saw that the soil available-N values and crop yields tended to be higher for the compost plot and there was no effect from chemical fertilizer on crop yields. The low efficiency of chemical fertilizer might be due to insufficient precipitation and severe weed stress under extensive land management. However, the use of animal compost had an apparent positive effect in Experiment-2 with controlling the weed effect. We observed significantly higher yields for application of the 2y-compost compared to the control. The long maturing time compost was more effective to increase crop yields due to its higher N content. These results showed that the use of both chemical and organic fertilizer was not effective to increase crop production under the extensive cropping system traditionally used in Mongolia. Also it was shown that the compost application increases crop yield under intensive land management.