Effects Of Planting Density And Configuration Mode On Growth,Development Of Sorghum And Micro Environmental Factors

The experiment was carried out at the experimental base of Agricultural College of Shenyang Agricultural University.The study were set up with Liaoza19 as experimental material.Three different planting densities were 75000 plants/ha?D1?,105000 plants/ha?D2?and 135000 plants/ha?D3?.Three different configuration modes were 60 cm equal row spacing planting with planting density of 105000 plants/ha?T1?,2-0 culture?row spacing 60cm,species 2 rows empty 1 row?with planting density of 105000 plants/ha?T2?and 2-0culture?row spacing 60 cm,species 2 rows empty 1 row?with planting density of 70000plants/ha?T3?.The effects of different planting densities and different configuration modes on sorghum growth and development and microenvironment ecological factors were studied in order to provide basis for establishing rational high-yield population structure and high-yield cultivation of sorghum.The results showed that:1.The sorghum dry matter accumulation per plant decreased as plant density increasing.From jointing stage,the dry matter accumulation of leaves,stems,sheaths and panicles increased slightly in D3 treatment at different growth stages.With the increase of planting density,leaf area index showed an upward trend.At flowering stage,the leaf area index of D3treatment was the largest,while that of D3 treatment declined rapidly in the later stage.With the increase of planting density,the plant height of sorghum gradually increased,while the stem diameter gradually decreased.2.With the decrease of canopy position,photosynthetic rate and transmittance decreased.At flowering stage,photosynthetic rate of D1 treatment was 28.4%higher than that of D3treatment in lower canopy,and that of D2 treatment was 17.8%higher than that of D3treatment.During the filling stage,D1 treatment was 27.0%higher than D3 treatment,and D2treatment was 17.8%higher than D3 treatment.The intercellular CO₂ concentration increased gradually,and there were significant differences among different treatments in the middle and lower canopy.With the increase of density,the water consumption increases,and the soil water content in tillage layer decreases.The evaporation of surface soil in D1 treatment was relatively more than other two treatments,and the water consumption of plants in D3treatment was more than other two treatments.The water absorption capacity of D2 root system was moderate to that of surface soil,and the soil moisture value was the highest.The water absorption capacity of D2 root system treated with medium density is moderate with the evaporation capacity of topsoil,and the soil moisture value is the highest.3.The yield of sorghum increased first and then decreased with the increase of planting density.In 2018,the economic yield of D2 treatment was significantly higher than that of D1treatment,and the economic yield of D2 and D3 treatment was 24.8%and 15.1%higher than that of D1 treatment,respectively.In 2017,the economic yield of D2 treatment was significantly higher than that of D1 and D3 treatment,which were 33.2%and 4.2%higher respectively.The biological yield of D1 treatment was significantly lower than that of D2 and D3 treatment in 2017 and 2018.The number of grains per plant treated with D1 and D2 in two years was significantly higher than that treated with D3.The economic coefficient of D2treatment were significantly higher than those of D3 treatment in 2018.Low and high planting density is not conducive to the development potential of sorghum plants.Reasonable planting density makes the population and individual coordinated development.Under the experimental conditions,105000 plants/ha was the best planting density.4.At different growth stages,the dry matter accumulation per plant in T3 treatment increased rapidly,and the dry matter accumulation in T2 was higher than that in T1.Leaf area index of equal row spacing planting T1 was lower than that of T2 and T3 under 2-0 culture at different growth stages,the increase of T2 treatment was obvious.At later stage,the decrease of T2 and T3 treatments was smaller.The overall trend of sorghum plant height was higher in T2 treatment than that in T1 treatment and higher in T3 treatment,while stem diameter showed the opposite trend.5.Compared with T1,T2 and T3 enhanced light intensity in upper,middle and lower canopy,enhanced photosynthetic rate and enhanced CO₂ communication with the outside world.At flowering stage,the light transmittance of upper canopy T3 treatment was significantly higher than that of T1 and T2 treatment,and the increase ranges were 14.2%and11.2%respectively.The transmittance of T2 and T3 in middle canopy was significantly higher than that of T1,33.5%and 38.5%respectively.Configuration mode has obvious influence on soil moisture.Compared with the equal row spacing planting treatment,the soil moisture of the 2-0 culture treatment was lower in the whole growth period.6.Two years experiment showed that the biological yield of T3 treatment was significantly lower than T1 and T2 treatment in 26.1%,23.3%,27.2%and 22.2%respectively.The economic yield of T2 treatment was higher than that of the other two treatments,and was significantly higher than that of T3 treatment.The economic coefficient,1000-grain weight and grain number per plant of T3 treatment were higher than those of the other two treatments.Reasonable row spacing allocation can improve the micro-environmental factors such as light,air and water among plants,and give full play to the development potential of sorghum plants.Under the experimental conditions,2-0 culture?row spacing 60 cm,species 2 rows empty 1row?with planting density of 105000 plants/ha is the best configuration mode.