群体密度对玉米茎秆性状、土壤水分的影响及其与产量、倒伏率的关系

Effects of Population Density on the Stem Traits and Soil Moisture in Maize and Their Correlation with Yield and Lodging Rate

为探明黄土高原雨养区不同春玉米品种茎秆性状、田间土壤水分对种植密度的响应及其与产量和倒伏率的关系,于2015,2016年选用不同茎秆抗倒性的2个品种(郑单958和晋单86)作为材料,设置了5.25万,6.00万,6.75万,7.50万,8.25万株/hm^2共5个种植密度的田间试验,分析了玉米茎秆农艺性状、抗倒力学特性、土壤水分的变化及其与产量和倒伏率的相关性。结果表明,随群体密度增加,郑单958株高和穗位高先升高后降低,但穗位高系数变化不大,晋单86株高、穗位高和穗位高系数逐渐增加;基部第3节间农艺性状和力学性状均先增加后降低,郑单958以种植密度7.50万株/hm^2达最大值,且节间直径处理间差异显著,而晋单86种植密度6.00万株/hm^2达最大值,且种植密度6.00万株/hm^2以上处理间差异显著;随群体密度增加,拔节-吐丝期0~200 cm土壤蓄水量均先上升后降低,且郑单958和晋单86分别以种植密度7.50万,6.00万株/hm^2达最大值,而灌浆-成熟期先降低后上升。相关性分析结果表明,拔节期、大喇叭期和吐丝期土壤蓄水量与节间直径、节间干质量和单位茎长干物质量呈显著正相关;单位茎长干物质量与茎秆硬皮穿刺强度和弯曲性能呈显著正相关;茎秆硬皮穿刺强度、弯曲性能、节间干质量和单位茎长干物质量与产量呈显著正相关,而与倒伏率呈显著负相关。产量和水分利用效率郑单958和晋单86分别以7.50万,6.00万株/hm^2最高,产量分别提高7.67%~25.74%,20.36%~29.63%,水分利用效率分别提高6.45%~17.71%,14.14%~20.38%,而种植密度达7.50万株/hm^2时出现倒伏,且郑单958较低。根据品种特性进行合理密植,协调茎秆生长、土壤水分应用,更有利于降低倒伏率,提高产量。

To explore the response of different spring maize species and soil moisture to the planting density,and the relationships among these factors,yield and lodging rate in the Loess Plateau rainfall area,Zhengdan 958 and Jindan 86 were selected as research materials in the program,which were of special lodging resistance. Five kinds of planting density（ 52 500,60 000,67 500,75 000,82 500 plants/ha） were set in the field experiment,corn agronomic traits,the property of anti-lodging mechanism,and the variation of soil humidity individually were analyzed,then further revealed their correlation with yield and lodging rate ways. The results indicated that with the increased of population density,for the Zhengdan 958,the plant height and ear height increased first and then decreased,but the coefficient of ear height changed smooth,for the Jindan 86,the plant height,ear height and the coefficient of ear height increased gradually. The agronomic traits and mechanics properties of base third internode increased at the beginning and then decreased,the species of Zhengdan 958 reached the highest value at the 75 000 plants/ha,and there were significant difference on the internode of diameter among five planting densities. The species of Jindan 86 reached the highest value at the 60 000 plants/ha,and there were significant difference under the67 500,75 000,82 500 plants/ha. With the increased of population density,the soil moisture from the soil suface to200 cm depth increased first then decreased during the jointing stage and silking stage,and Zhengdan 958 and Jindan 86 reached the highest values at the 75 000,60 000 plants/ha accordingly,the soil moisture decreased then increased from the pustulation period to mature period. The correlation analysis results showed in the jointing period,trumpet period and silk period,there were positive correlation between the soil moisture and internode diameter,dry weight of internode and the biomass of per unit of stem length,the biomass of per unit of stem length and the strength of stem puncture and flexural property,there were positive correlation among the strength of stem puncture,flexural property,biomass of internode,biomass of per unit of stem length and yield,by contrast,these index were negative correlation with lodging rate. The yield and water use efficiency of Zhengdan 958 and Jindan 86 reached to the highest value at the 75 000,60 000 plants/ha,respectively,and the yield increased from 7. 67% to 25. 74%,from 20. 36% to 29. 63%,respectively. The water use efficiency enhanced from 6. 45% to 17. 71% and from 14. 14% to 20. 38%for Zhengdan 958 and Jindan 86,respectively,the highest lodging rate appeared under 75 000 plants/ha and Zhengdan 958 was lower. We can choose rational planting density according to the maize species,then integrate the stem growth and soil water use efficiency,which will be useful to decrease the lodging rate and raise yield.