褐土容重、紧实度、水分动态变化及对玉米生长的影响
发布时间：2018-09-09 17:32
【摘要】：辽西褐土作为辽宁主要地带性土壤之一,其土地和光热资源十分丰富,广泛种植玉米等粮食作物。但其降水变率较大,旱灾频繁;且由于长期旋耕、有机质含量下即缺少有机物料投入引起耕层变薄、犁地层变浅、土壤板结、容重增大等物理性质的恶化,严重制约玉米生长的问题已经受到人们广泛的关注。然而土壤物理性质之间的相互影响,对玉米不同生育期生长发育的影响及合理的耕层结构仍缺乏系统、定量的研究。本文利用根箱模拟研究了褐土容重、紧实度和水分的动态变化,三者相互关系及对玉米生长的影响,并通过深翻、秸秆还田、施用有机肥及覆膜对三种土壤物理性质进行改善,以促进玉米生长发育。该研究结果可为建立褐土合理耕层评价指标体系和选择合理耕层构造技术提供理论依据。研究结论如下:(1)不同耕翻深度其容重随生育期推近及深度增加逐渐增大。0～25 cm 土层容重主要受耕作深度影响,深翻能显著降低旋耕土壤15～25 cm 土层容重。25～45 cm 土层容重由于拔节期根系生长及灌浆期土壤含水量23%呈降低趋势。(2)在玉米生育期内,不同耕翻深度土壤紧实度主要受土壤含水量影响。耕作对土壤紧实度的影响在0～25 cm 土层大于含水量影响,在25～45 cm 土层小于含水量的影响。深翻能显著降低15～25 cm 土层紧实度,在玉米拔节和抽雄期最为明显,较旋耕紧实度最大值出现深度可降低7.5～12.5 cm。(3)施入有机物料及覆膜均能降低各时期各土层容重和紧实度,其中覆膜处理下的容重及紧实度变化最小最稳定,容重变化幅度平均为0.11g·cm-3,较不覆膜处理变幅至少减小0.04 g·cm-3;紧实度变幅平均为0.064 MPa,较不覆膜处理至少降低0.05 MPa。(4)无作物生长影响时,通过对褐土设定不同含水量、容重对紧实度的影响研究发现:容重和含水量对紧实度均有影响,其关系式为P=0.03070-0.5229ρ6.9739(P为紧实度、θ为含水量、ρ为容重)当含水量低于5%时,紧实度受容重影响大于含水量;当容重高于1.3 g.cm-3时,紧实度受含水量影响大于容重;且当容重高于1.3 g.cm-3或者含水量低于5%时,土壤紧实度≥2MPa,限制作物根系生长。(5)有作物生长影响时,通过对不同耕作及改良措施下土壤紧实度与含水量和容重的关系拟合出指数方程如下:翻耕 15 cm 耕层 0～15 cm P=0.04274θ(-1.049)ρ20.79 R2=0.9201下层15～45 cm P=0.019860(-1.328)ρ21.77 R2=0.6547翻耕25 cm 耕层 0～25 cm P=0.09702θ(-1.523)ρ18.73 R2=0.8652下层25～45 cm P=1.605θ(-2.593)ρ19.54 R2=0.8134其拟合优度均在0.65以上,上述方程均能定量地拟合出褐土地区不同耕作深度及措施下紧实度与土壤含水量和容重的关系。与无作物生长影响的方程对比,水分动态变化过程是导致二者差异的主要因素。(6)深翻其根总长和根总表面积在0～15 cm 土层与旋耕处理无差异,在15～25 cm土层显著高于旋耕处理;玉米株高茎粗及叶绿素含量则均表现为深翻处理更高,说明深翻有利于玉米根系在15～25 cm 土层生长及玉米地上部的生长。三种改良措施均能促进根系及地上部生长,主要表现为覆膜有机肥配施秸秆秸秆。(7)紧实度主要影响15～25 cm根系生长。在抽雄期紧实度增大至2 MPa,玉米根总长增加显著缓慢及根总表面积增长加快,根径变粗。当紧实度达到2 MPa时,土壤容重达到1.4 g·cm-3,此时玉米根系生长受到严重限制;且紧实度增加对玉米生长速率影响显著,主要表现为玉米株高茎粗长势减缓,叶绿素含量增加缓慢。(8)深翻其玉米产量显著高于旋耕,说明耕层深厚能促进玉米增产。各改良措施(秸秆、有机肥及覆膜)均对产量有显著贡献,除单施秸秆外其余措施对产量均达到极显著贡献,但交互作用不显著。(9)通过通径分析证实土壤物理性质对产量的影响主要表现为紧实度含水量容重/总孔隙度。在玉米生育期除播种期应注意翻耕后水分易流失的问题;其他时期均表现为紧实度对产量有显著影响,因此应重视土壤紧实度的变化,尤其是干旱季节应加重防范作物既受水分胁迫又受紧实胁迫。综上可知,辽西褐土区由于气候少雨,耕作方式单一等问题均导致耕层浅、容重及紧实度增大,通过对耕作及改良措施对容重、紧实度、水分的动态变化及其相互关系研究,找出三者关系的数学模型,探究通过措施对紧实度改良对玉米地上地下部生长发育影响,为建立褐土合理耕层评价指标体系和选择合理耕层构造技术提供理论依据。
[Abstract]:As one of the main zonal soils in Liaoning Province, the cinnamon soil in Western Liaoning Province is rich in land, light and heat resources, and widely planted corn and other food crops. The deterioration of soil properties seriously restricts the growth of maize has attracted extensive attention. However, the interaction between soil physical properties and the effects of soil physical properties on the growth and development of Maize at different growth stages and the rational tillage structure are still lack of systematic and quantitative research. Dynamic changes, the relationship among the three factors and their effects on maize growth were studied. The physical properties of the three soils were improved by plowing, straw returning, organic fertilizer and plastic film mulching to promote maize growth and development. The conclusions are as follows: (1) The bulk density of different tillage depths increases gradually with the growth period and depth. The bulk density of 0-25 cm soil layer is mainly affected by the tillage depth. Deep tillage can significantly reduce the bulk density of 15-25 cm soil layer. The bulk density of 25-45 cm soil layer decreases due to the root growth at jointing stage and 23% soil water content at filling stage. Soil compactness at different tillage depths was mainly affected by soil water content during maize growth period. The effect of Tillage on soil compactness was greater in 0-25 cm soil layer than that of water content, and smaller in 25-45 cm soil layer than that of water content. Deep tillage significantly reduced soil compactness at 15-25 cm soil layer, especially at jointing and heading stages of maize. The maximum depth of tillage compactness could be reduced by 7.5-12.5 cm. (3) The application of organic materials and film mulching could reduce the soil bulk density and compactness at all stages. The change of bulk density and compactness under film mulching treatment was the smallest and the most stable, and the average change of bulk density was 0.11 g.cm-3, which was at least 0.04 g.cm-3 less than that of non-film mulching treatment. The average amplitude is 0.064 MPa, which decreases at least 0.05 MPa. (4) When there is no effect of crop growth on the compactness of cinnamon soil, the influence of bulk density on compactness is studied by setting different water content in cinnamon soil. It is found that both bulk density and moisture content have influence on compactness, and the relationship is P = 0.03070-0.5229 P 6.9739 (P is compactness, theta is water content, P is bulk density). Compactness is more affected by bulk density than water content when bulk density is less than 5%; when bulk density is higher than 1.3 g.cm-3, compactness is more affected by water content than bulk density; and when bulk density is higher than 1.3 g.cm-3 or water content is lower than 5%, soil compactness is more than 2 MPa, which limits the growth of crop roots. (5) When crop growth is affected by different tillage and improvement measures, soil compactness is greater than 2 MPa. The relationship between soil compactness and soil water content and bulk density fitted the exponential equation as follows: 0-15 cm tillage layer 0-15 cm P = 0.04274 thetheta (-1.04274)(-1.049) P 20.79 R2 = 0.9201 lower layer 15-45 cm P = 0.019860 (-1.328) P = 0.019860 (-1.328) P 21.77 R2 = 0.77 R2 = 0.77 R2 = 0.6547 tillag25 cm tillag25 cm 0-25 cm P = 0.09702 thethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethe0 The goodness of fit of 8134 was above 0.65, and the above equations could quantitatively fit the relationship between soil compactness and soil water content and bulk density under different tillage depths and measures in brown soil area. There was no difference between 0-15 cm soil layer and rotary tillage treatment, but in 15-25 cm soil layer it was significantly higher than rotary tillage treatment. The height, stem diameter and chlorophyll content of maize were higher under deep tillage treatment, which indicated that deep tillage was beneficial to the growth of maize roots in 15-25 cm soil layer and the growth of maize shoots. (7) Compactness mainly affected the root growth of 15-25 cm. At the heading stage, the total root length increased slowly, the total root surface area increased rapidly, and the root diameter became thicker. When the compactness reached 2 MPa, the soil bulk density reached 1.4 G. (8) Deep plowing significantly increased the yield of maize, indicating that deep plowing could promote the yield of maize. All the improvement measures (straw, organic fertilizer and film mulching) contributed significantly to the yield of maize. The other measures except straw application contributed significantly to the yield, but the interaction was not significant. (9) Path analysis showed that the main effect of soil physical properties on yield was compactness, water content, bulk density and total porosity. Compactness has a significant effect on yield, so we should pay more attention to the change of soil compactness, especially in dry season to prevent crops from both water stress and compaction stress. The dynamic changes of soil bulk density, compactness and water content and their relationship were studied. The mathematical models of the three relationships were found. The effects of compactness improvement on the growth and development of maize aboveground and underground parts were explored. The theoretical basis was provided for the establishment of the evaluation index system of rational tillage layer in cinnamon soil and the selection of reasonable tillage layer structure technology.
【学位授予单位】：沈阳农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S513
，
本文编号：2233085
[Abstract]:As one of the main zonal soils in Liaoning Province, the cinnamon soil in Western Liaoning Province is rich in land, light and heat resources, and widely planted corn and other food crops. The deterioration of soil properties seriously restricts the growth of maize has attracted extensive attention. However, the interaction between soil physical properties and the effects of soil physical properties on the growth and development of Maize at different growth stages and the rational tillage structure are still lack of systematic and quantitative research. Dynamic changes, the relationship among the three factors and their effects on maize growth were studied. The physical properties of the three soils were improved by plowing, straw returning, organic fertilizer and plastic film mulching to promote maize growth and development. The conclusions are as follows: (1) The bulk density of different tillage depths increases gradually with the growth period and depth. The bulk density of 0-25 cm soil layer is mainly affected by the tillage depth. Deep tillage can significantly reduce the bulk density of 15-25 cm soil layer. The bulk density of 25-45 cm soil layer decreases due to the root growth at jointing stage and 23% soil water content at filling stage. Soil compactness at different tillage depths was mainly affected by soil water content during maize growth period. The effect of Tillage on soil compactness was greater in 0-25 cm soil layer than that of water content, and smaller in 25-45 cm soil layer than that of water content. Deep tillage significantly reduced soil compactness at 15-25 cm soil layer, especially at jointing and heading stages of maize. The maximum depth of tillage compactness could be reduced by 7.5-12.5 cm. (3) The application of organic materials and film mulching could reduce the soil bulk density and compactness at all stages. The change of bulk density and compactness under film mulching treatment was the smallest and the most stable, and the average change of bulk density was 0.11 g.cm-3, which was at least 0.04 g.cm-3 less than that of non-film mulching treatment. The average amplitude is 0.064 MPa, which decreases at least 0.05 MPa. (4) When there is no effect of crop growth on the compactness of cinnamon soil, the influence of bulk density on compactness is studied by setting different water content in cinnamon soil. It is found that both bulk density and moisture content have influence on compactness, and the relationship is P = 0.03070-0.5229 P 6.9739 (P is compactness, theta is water content, P is bulk density). Compactness is more affected by bulk density than water content when bulk density is less than 5%; when bulk density is higher than 1.3 g.cm-3, compactness is more affected by water content than bulk density; and when bulk density is higher than 1.3 g.cm-3 or water content is lower than 5%, soil compactness is more than 2 MPa, which limits the growth of crop roots. (5) When crop growth is affected by different tillage and improvement measures, soil compactness is greater than 2 MPa. The relationship between soil compactness and soil water content and bulk density fitted the exponential equation as follows: 0-15 cm tillage layer 0-15 cm P = 0.04274 thetheta (-1.04274)(-1.049) P 20.79 R2 = 0.9201 lower layer 15-45 cm P = 0.019860 (-1.328) P = 0.019860 (-1.328) P 21.77 R2 = 0.77 R2 = 0.77 R2 = 0.6547 tillag25 cm tillag25 cm 0-25 cm P = 0.09702 thethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethethe0 The goodness of fit of 8134 was above 0.65, and the above equations could quantitatively fit the relationship between soil compactness and soil water content and bulk density under different tillage depths and measures in brown soil area. There was no difference between 0-15 cm soil layer and rotary tillage treatment, but in 15-25 cm soil layer it was significantly higher than rotary tillage treatment. The height, stem diameter and chlorophyll content of maize were higher under deep tillage treatment, which indicated that deep tillage was beneficial to the growth of maize roots in 15-25 cm soil layer and the growth of maize shoots. (7) Compactness mainly affected the root growth of 15-25 cm. At the heading stage, the total root length increased slowly, the total root surface area increased rapidly, and the root diameter became thicker. When the compactness reached 2 MPa, the soil bulk density reached 1.4 G. (8) Deep plowing significantly increased the yield of maize, indicating that deep plowing could promote the yield of maize. All the improvement measures (straw, organic fertilizer and film mulching) contributed significantly to the yield of maize. The other measures except straw application contributed significantly to the yield, but the interaction was not significant. (9) Path analysis showed that the main effect of soil physical properties on yield was compactness, water content, bulk density and total porosity. Compactness has a significant effect on yield, so we should pay more attention to the change of soil compactness, especially in dry season to prevent crops from both water stress and compaction stress. The dynamic changes of soil bulk density, compactness and water content and their relationship were studied. The mathematical models of the three relationships were found. The effects of compactness improvement on the growth and development of maize aboveground and underground parts were explored. The theoretical basis was provided for the establishment of the evaluation index system of rational tillage layer in cinnamon soil and the selection of reasonable tillage layer structure technology.
【学位授予单位】：沈阳农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S513
，
本文编号：2233085
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