The trend of soil chemical properties, and rapeseed productivity under different long-term fertilizations and stubble management in a Ferralsols of Northeastern Brazil

Abstract

The influence of stubble management and fertilization systems on soil chemical properties and rapeseed (Brassica napus L.) yield was investigated in a long-term field study. We compared soil pH, soil organic carbon, total nitrogen, available phosphorous, and rapeseed yield under two different stubble managements (stubble retention and stubble removed) and three fertilization systems (organic fertilization, mineral fertilization, and non-fertilization) in a long-term field experiment (5 years). We found that organic fertilization combined with stubble retained significantly increased soil organic carbon, total nitrogen, and available phosphorous. The highest values of rapeseed yield were found for the organic fertilization and stubble retention after the fifth year of their implementation. Mineral fertilization can maintain sustained rapeseed yield until the third year of its use, while the organic fertilization was able to maintain high rapeseed yield (>1500 kg ha−1) over a longer period (independently of the stubble management). Our findings suggest that inputs of organic matter can change positively the soil chemical properties and increase rapeseed yield. Our results also highlight the importance of considering the long-term effect of organic fertilization combined with stubble management on the yield of annual crops, in this case, rapeseed.