Abstract:

The aim of this study was to investigate the abilities of organic-inorganic amendments to improve and fertilize saline-alkaline soils. An experiment was conducted using a one-way Latin square design with the following treatments： CK （no soil amendment materials）， PM ［phosphogypsum （22.5 t·ha^-1）+well-decomposed goat manure （15 t·ha^-1）］， CM ［calcium superphosphate （300 kg·ha^-1）+well-decomposed goat manure （15 t·ha^-1）］， PCM₁ ［phosphogypsum （22.5 t·ha^-1）+calcium superphosphate （300 kg·ha^-1）+well-decomposed goat manure （15 t·ha^-1）］， PCM₂ ［phosphogypsum （30.0 t·ha^-1）+calcium superphosphate （600 kg·ha^-1）+well-decomposed goat manure （30.0 t·ha^-1）］， and PCM₃ ［phosphogypsum （30.0 t·ha^-1）+calcium superphosphate （900 kg·ha^-1）+well-decomposed goat manure （30.0 t·ha^-1）］. These six treatments were designed to study the effects of varying ratios of organic-inorganic amendment materials on the soil quality and the yield of Echinochloa frumentacea grown in saline-alkaline soil. The results indicate that organic and inorganic materials at varying ratios decreased soil pH， total dissolved salt （TDS）， and bulk density， and increased soil nutrient contents and the proportion and stability of aggregates larger than 0.25 mm. Among the treatments， PCM₂ and PCM₃ had better effective. The soil pH， total salt， and bulk density were decreased by 2.40%， 27.33%， and 16.17%， respectively， in the PCM₂ treatment， and by 1.83%， 17.42%， and 12.94%， respectively， in the PCM₃ treatment， compared with CK. The soil organic matter （SOM）， alkaline nitrogen （AN）， available phosphorus （AP）， and available potassium （AK） contents in the 0-40 cm soil layer were significantly increased in the PCM₂ and PCM₃ treatments compared with CK. The mean weight， diameter， geometric mean diameter， and aggregates content of particles larger than 0.25 mm were increased by 131.43%， 164.07%， and 97.22%， respectively， in PCM₂， and by 78.58%， 81.68%， and 57.41%， respectively， in PCM₃， compared with CK. Additionally， the seedling emergence rate and yield were improved by 62.84% and 50.07%， respectively， in PCM₂，_{and by 68.24% and 47.76%， respectively， in PCM3，compared with CK. Soil aggregate stability was positively correlated with porosity， SOM， AN， AP， and AK， and negatively correlated with bulk density， pH， and total salts. In addition， the PCM2 and PCM3 treatments enhanced soil quality by improving salinity indicators （pH， TDS） and fertility levels （AN， AP， AK， and SOM）. The PCM2 treatment was more effective than the PCM3 treatment in both respects， resulting in the highest hay yield. After evaluating the effects of various ratios of organic and inorganic materials on the enhancement and fertilization of saline-alkaline land， the treatment PCM2， comprising a combination of phosphogypsum （30.0 t·ha^-1）， calcium superphosphate （600 kg·ha^-1）， and decomposed goat manure （30.0 t·ha^-1） was found to be the most suitable soil amendment for this region.}

Key words: saline soils, organic-inorganic modified materials, aggregates, soil quality, crop yield