Crop Yields and Soil Nutrients in Response to Long-Term Fertilization in a Desert Oasis

Knowledge of the effect of long-term fertilizer application on arable lands reclaimed from the desert in arid regions is limited. In this study, we used data obtained from a 7-yr field experiment to determine the effect of different fertilizer application strategies on crop yields and soil nutrient status in a desert oasis of northwest China. Our results showed that integrated fertilizer application (HA) treatments produced average maize (Zea mays L.) and soybean [Glycine max (L.) Merr.] yields 10.3 and 13.3% greater than those under chemical fertilizer application (CFA) treatments and 56.0 and 7.3% greater than those under organic manure application (OMA) treatment. With one exception for a K treatment, the average grain yield during the 7 yr of the study tended to increase with increased nutrient rates, and reached the maximum value at a 281 kg ha(-1) N, 171 kg ha(-1) P2O5, and 544 kg ha(-1) K2O input level. At the end of the study, soil organic matter (SOM) and total N were the highest in the soil treated with OMA, followed by those treated with IFA and then CFA. High CFA rates increased soil phosphorus levels. The crop yield values linearly increased with the increase in SOM, total N, available N, and available K. Our findings suggested that in the desert oasis ecosystem, an IFA system increased both crop yields and soil nutrients.