Selection Of Saline Alkali Tolerant Forage Grass And Its High-Yield Cultivation Techniques

For better utilization of saline-alkali land and provide fodder support for the development of ecological and efficient Compound culture mode of grass and fish in the saline alkali land of the tidal flat,the selection of saline tolerant forage and high-yield cultivation technology experiments were carried out in Dongying District of Dongying City and Lijin County of Dongying City,Shandong Province from March to October 2021 and from May to September 2022.The forage varieties with good saline alkali resistance were screened through salt and alkali tolerance experiment during seed germination,pot planting experiments and field experiments.On this basis,field experiments were carried out on the influence of different cultivation techniques on forage yield to explore cultivation techniques to improve forage yield.The main research results are as follows:（1）We have selected Sorghum sudanense（Piper）Stapf,Sorghum bicolor×sudanense,Lolium perenne L,Sorghum bicolor’Dochna’,Echinochloa sp.,Sorghum bicolor（L.）Moench‘FS3501’and Sorghum bicolor（L.）Moench‘BMR3631’,carried out the germination experiment of saline alkali resistant seeds.We set 2‰,4‰,6‰,8‰and 10‰salt and alkali gradients of different concentrations in the 1:1 ratio of Na Cl and Na HCO₃,carried out the salt and alkali tolerance experiment of seed germination,and explored the salt and alkali tolerance threshold of seed germination through seed germination index.The results showed that forage with strong salt and alkali resistance during seed germination were Echinochloa sp.,Sorghum bicolor×sudanense and Sorghum bicolor（L.）Moench‘FS3501’.The threshold salinity of salt and alkali tolerance of Echinochloa sp.and Sorghum bicolor×sudanense was about6‰,and the p H was about 8.76.The threshold salinity of saline alkali tolerance of Sorghum bicolor（L.）Moench‘FS3501’is about 4‰,and the p H is about 8.66.（2）We further carried out pot experiment on saline alkali tolerant growth of herbage based on Echinochloa sp.,Sorghum bicolor×sudanense and Sorghum bicolor（L.）Moench‘FS3501’selected from the germination experiment of saline alkali tolerant seeds.We set the ratio of three mixed modes A,B and C,A:Na Cl:Na₂SO₄:Na HCO₃:Na₂CO₃=1:2:1:0;B:Na Cl:Na₂SO₄:Na HCO₃:Na₂CO₃=1:1:1:1;C:Na Cl:Na₂SO₄:Na HCO₃:Na₂CO₃=9:1:1:9.Three salinity gradients of 2‰,4‰and6‰were set under each mixed salt gradient.Through growth indicators and nutrient composition,the salt and alkali tolerance thresholds of the growth of three grasses under different salt and alkali gradients were explored.The results showed that Echinochloa sp.had the best salt and alkali tolerance,and could survive under the designed salinity gradient.The salt tolerance threshold of Sorghum bicolor×sudanense and Sorghum bicolor（L.）Moench‘FS3501’is about 2‰,and the alkali resistance is at p H=9.31.（3）In the field experiment of salt tolerant forage screening,we used a randomized block design to determine the plant height,stem diameter,leaf length,leaf width,aboveground dry weight and underground dry weight of forage under different salt gradients（<0.5‰（CK）,0.5‰～1.0‰,1.0‰～1.5‰,1.5‰～2.0‰,2.0‰～4.0‰）.The results showed that when the growth days were 40 days,the appropriate salinity could promote the growth of Echinochloa sp.and Sorghum bicolor（L.）Moench‘FS3501’.Through yield analysis,the forage yield of Echinochloa sp.increased by 48.73%compared with the control group under the salinity of 1.5‰～2.0‰,and the forage yield of Sorghum bicolor（L.）Moench‘FS3501’decreased by 64.94%compared with the control group under the salinity of1.5‰～2.0‰.Under the salinity of 1.0‰～1.5‰,the yield of Sorghum bicolor×sudanense decreased by 46.89%.The order of salt resistance was Echinochloa sp.,Sorghum bicolor（L.）Moench‘FS3501’and Sorghum bicolor×sudanense.（4）The results of nutrient composition analysis of herbage under different salinity showed that salinity stress had different effects on the indicators of nutrient composition of different herbages.Compared with the control group,the crude fat of Sorghum bicolor×sudanense at the salinity of 1.0‰～1.5‰decreased significantly（p<0.05）,with a relative decrease of 43.91%.Compared with the control group,the crude ash content of Echinochloa sp in 1.5‰～2.0‰salinity decreased significantly（P<0.05）,with a relative decrease of 17.88%The content of acid detergent fiber and crude ash in Sorghum bicolor（L.）Moench‘FS3501’at 2.0‰～4.0‰salinity decreased significantly compared with the control group（P<0.05）,with a relative decrease of 4.65%and 25.15%respectively.（5）The analysis of herbage growth and yield under different cultivation methods showed that the yield of Echinochloa sp.was significantly higher than that of the other two experimental groups（20 cm and 40 cm row spacing）when the row spacing was 30 cm（p<0.05）,and the yield of Sorghum bicolor×sudanense and Sorghum bicolor（L.）Moench‘FS3501’was significantly higher than that of the other two experimental groups（30 cm and 40 cm row spacing）when the row spacing was50 cm（p<0.05）.When Sorghum bicolor（L.）Moench‘FS3501’grew for 60 days,ridge planting could significantly increase its aboveground and underground dry weight（p<0.05）,and both ridge planting and soil improvement could significantly increase its yield（p<0.05）by 48.28%and 18.67%,respectively.The yield of Echinochloa sp.under the cultivation mode of soil improvement increased significantly（p<0.05）when it grew for 60 days,and that under the cultivation mode of ridge planting increased significantly（p<0.05）when it grew for 85 days,which increased by 37.75%and 22.03%respectively.There was no significant difference between the yield of Sorghum bicolor×sudanense and that of the control under the ridge cultivation mode（p>0.05）,but its growth potential was better.The yield of Sorghum bicolor×sudanense under the mixed planting cultivation mode decreased significantly（p<0.05）at 60 days and 110 days of growth.The yield of Sorghum bicolor×sudanense under the soil improved cultivation mode decreased significantly（p<0.05）at 85 days of growth of growth.（6）We measured the nutrient composition of four kinds of forage grass,Echinochloa sp.,Sorghum bicolor×sudanense and Sorghum bicolor（L.）Moench‘FS3501’,at different growth stages,namely 40,60 and 90 days.The results showed that the quality of forage grass at different growth stages was different.Based on the analysis of nutrient composition changes in different days,Echinochloa sp.and Sorghum bicolor（L.）Moench‘FS3501’had better cutting quality in about 60 days,and Sorghum bicolor×sudanense had better cutting quality in about 40-60 days.In this paper,three forage grasses with good salt and alkali tolerance were selected through the experiment of salt and alkali tolerance,namely Lolium perenne L,Sorghum bicolor（L.）Moench‘FS3501’and Sorghum bicolor×sudanense.Through the analysis of high-yield cultivation technology field experiment,it can be concluded that in the early growth period,Lolium perenne L in the row spacing of 30 cm,under the cultivation mode of soil improvement,the yield was increased by 37.75%,and the60 day cutting quality was the best;The planting row spacing of Sorghum bicolor×sudanense is 50 cm,and the cutting quality is better after 40-60 days.The yield of Sorghum bicolor（L.）Moench‘FS3501’herbage was increased by 48.28%under the ridge cultivation mode with row spacing of 50 cm,and the cutting quality was the best at 60 days.