Coastal Soil Salinity Amelioration and Crop Yield Improvement by Biomaterial Addition in East China

A field experiment was conducted to investigate the effects of biochar (BC), fulvic acid (FA) and Bacillus subtilis (BS) on soil properties and crop growth in the coastal salt-affected soil. Four levels of BC (0, 7.5, 15, 30 t ha−1), two levels of FA (0, 1.5 t ha−1) and BS suspension (0, 108 CFU mL−1) were designed during the maize cultivation. The results showed that 30 t ha−1 BC treatment was the most beneficial for improving the soil qualities. The grain yields in treatments containing FA and BS were lower than that in the BC treatments, and they were lower than that in the CK treatment. The treatment of 15 t ha−1 BC + BS obtained the highest grain yield, which was 1.75 times more than CK. An antagonism effect of the combination of FA and BS induced a grain yield decrease, and a higher content application of BC alleviated the negative effects