增施有机肥改善黑土物理特性与促进玉米根系生长的效果

Effect of applying organic manure on improving soil physical properties and promoting root growth

为改善东北黑土区粘重耕层的土壤物理特性,通过玉米秸秆还田基础上增施有机肥试验,拟明确增施有机肥对黑土物理特性和根系生长的提升效果。利用2015~2018年吉林省公主岭市和黑龙江省克山县黑土区的定位试验,测定了玉米抽雄期3种秸秆还田处理及其增施有机肥(旋耕秸秆还田+有机肥RSM、深翻秸秆还田+有机肥DSM、深松秸秆还田+有机肥SSM)处理的土壤物理指标;并采用微根管法原位测定了根系生长指标,计算出增施有机肥后各土壤物理特性与根系生长指标的变化量。结果表明,相比秸秆还田处理,增施有机肥降低了土壤容重、土壤紧实度,提升了土壤含水量,同时根长密度、根尖数密度和根平均直径均显著增加,其中根长密度和根尖数密度各土层平均增加了0.18 cm/cm^2和34.9×10-3个/cm^2。不同秸秆还田方式增施有机肥后对黑土物理特性和根系生长的改善效果不同,其中0~15 cm土层RSM处理改善效果最明显,15~45 cm土层SSM和DSM处理改善效果最明显。有机肥和秸秆还田方式互作对黑土物理特性和促进根系生长指标具有显著的正向互作效应。上述结果表明,深松秸秆还田和深翻秸秆还田基础上增施有机肥模式更有利于改善黑土物理特性和促进根系生长,是改善东北黑土区粘重耕层的技术选择。

In order to improve the soil physical properties in the black soil area of Northeast China,the experiment of adding organic fertilizer on the basis of returning corn straw to the field was carried out to clarify the improvement effect of applying organic manure on the soil physical properties and root growth.Based on the in-situ experiments in Gongzhuling City of Jilin Province and Keshan County of Heilongjiang Province in 2015 ~ 2018,the soil physical indexes of three only straw returning treatments and their adding of organic manure treatments(rotary straw returning + manure RSM,deep straw returning + manure DSM,deep loose straw returning + manure SSM) were measured on maize’s tasseling stage in 2018,and the minirhizotron method was used to measure root growth index.The change value of each index was calculated. The results showed that,compared with the only straw returning,adding of organic fertilizer reduced soil bulk density and soil compactness,significantly increased soil moisture content,and significantly increased root length density,root tip number density and root average diameter,in which root length density and root tip number density increased by 0.18 cm/cm^2 and 34.9×10-3/cm^2 respectively.The organic manure effect of different straw returning methods on the soil physical properties and root growth is different,in which RSM treatment in 0 ~ 15 cm soil layer is the most significant,and SSM and DSM treatment in 15 ~ 45 cm soil layer is the most significant.The interaction of organic fertilizer and straw returning had a significant positive interaction effect on soil physical characteristics and root growth.The results showed that adding organic manure on the basis of subsoiling straw returning and deep plowing straw returning was more conducive to improving the physical characteristics of black soil and promoting the growth of root system,which was the technical choice to improve the clay heavy ploughing layer in the black soil area of Northeast China.