Adaptation of feed crops to saline-alkali soil stress and effect of improving saline-alkali soil

Abstract

<p id="C3">Saline-alkali land widely distributes with large area in China. It is of great significance to select forage crops and realize planting and breeding cycle in saline-alkali land to promote the development of herbivorous animal husbandry and the improvement of saline-alkali land in China. In this study, the plots with high salinity difference were selected from the coastal saline-alkali land in Tianjin (NaCl type) and the inland saline-alkali land in northwest Xinjiang (Na₂SO₄-NaHCO₃ type), respectively, and six field crops such as corn, sorghum, wheat, millet, soybean, and rapeseed with feed value were planted to determine the biomass, crude protein content, sodium and potassium ion content, and other indicators. The results were as follows. When the salt content was less than 1.82 g kg^-1 and 2.00 g kg^-1 in saline-alkali land NaCl type and Na₂SO₄-NaHCO₃ type, respectively. The biomass and crude protein yield of the crops were close to those of conventional cultivated land, suggesting that saline-alkali land in low salt content could be used as forage production base. When the salt content reached 2.49 g kg^-1 in the Na₂SO₄-NaHCO₃ type saline-alkali soil, the biomass and crude protein yield of rapeseed were significantly higher than other crops. Thus, in the Na₂SO₄-NaHCO₃ type saline-alkali soil with salt content lower than 2.49 g kg^-1, rapeseed could be planted for fodder development and utilization. When the salt content in saline-alkali land of NaCl type and Na₂SO₄-NaHCO₃ type reached 3.63 g kg^-1 and 4.42 g kg^-1, respectively. The biomass and crude protein yield of each crop was lower than 51.72% of that in conventional cultivated land, which made the utilization value of the cultivated land low. Therefore, it was recommended to use these saline-alkali land of NaCl type and Na₂SO₄-NaHCO₃ with high content salt and alkali after improvement. In the different plots of the two experimental sites, the enrichment of Na⁺ in soil by rapeseed was significantly higher than the other crops at <italic>P </italic>&lt; 0.05, and it also significantly reduced the total soil salt and Na ⁺ content. In this experiment, in plots with salinity of 1.82, 2.00, and 2.49 g kg^-1, rapeseed had the most obvious Na⁺ enrichment effect. The enrichment of rapeseed on soil Na⁺ was 39.45, 102.24, and 57.19 kg hm^-2 respectively, accounting for 13.02%, 15.99%, and 8.94% of the Na⁺ in the 0-20 cm cultivated layer soil, respectively. The improvement effect of rapeseed on saline-alkali land was significant. The above results provide a reference for the utilization of the saline-alkali land in China for the production of herbivorous feed raw materials, the promotion of the development of herbivorous animal husbandry, and the improvement of saline-alkali land.