犁底层

其保水增产效果在干旱年份更加明显。深松可有效打破犁底层降低其密度，可增加作物根深、根长及根重，提高作物产量和水分利用效率。

Subsoiling effectively disrupted the plough pan and decreased the soil bulk density resulting in increase of the length , depth and mass of crop root , the yield of summer maize and water use efficiency following subsoiling increased .

犁底层对环境变化的响应较慢，其含量在初期略有上升，随后缓慢降低，在开垦12a后基本上达到平衡。

The contents of Hg and organic matter at plough pan layer increased a little in the initial stages of reclamation , then decreased slowly and became stable during the 12th year after reclamation .

受粘粒含量影响，黄土性土壤中Cr（）运移的速度不同，其顺序为粘化层<犁底层+老耕层<耕层<钙积层。

The migration velocities of Cr ( VI ) in soil was relevant to contents of clay , and they were in an order : argillic horizon calcic horizon .

结果表明：1土娄土不同土层对Cr（）的吸附量大小顺序为粘化层>犁底层+老耕层>耕层>钙积层；

The results showed that : ① The absorption amount of different soil layers to Cr (ⅵ) were in an order of argillic layer > plow pan > top soil > calcic layer .

通过野外布点试验，应用双环入渗仪测得了犁底层土壤各点的稳渗率fc和入渗经验指数α。

The steady water infiltration rate fc and infiltration experiential index α of the bottom of ploughed stratum are measured at about forty-eight points in the field by means of double ring method .

比较单个组分含量在土壤剖面中的变化，在犁底层以下，Bap的含量基本上低于检测限，而Nap的含量在整个土壤剖面中均高于Bap。

Most of Bap concentration was found lower than the limit of detection below the plough layer , while Nap concentration is higher than Bap concentration through the soil profile .

犁底层土壤入渗参数的空间变异性

Spatial variability of the bottom of ploughed stratum

采用深松耕作法后，可以打破犁底层，加深耕作层。

Sub-soiling method , you can break the plow pan , and deepen the arable layer .

连年干旱、土地板结及坚硬的犁底层等不利因素，严重地制约着农业的发展。

Some years drought , soil crust and hard plow - sole restrict the development of agriculture .

平面型犁底层剖面构造有利于改善土壤结构。

The plow pan profile constitution of the " flat type " helps to improve soil structure .

不同犁底层含锰量对小麦、油菜锰营养状况的影响

Effects of available Mn contents in different plow pans on Mn status of wheat and oilseed rape

而砂质田使耕作层变浅，犁底层加深且压实。

While in a sandy field the cultivated soil is shallowed with the hard pan compacted and deepened .

结果表明：地表层土壤的透水性能较犁底层土壤透水性能好；

The results have shown that the surface stratum 's infiltration capacity was better than the bottom of ploughed stratum 's.

因此，运用深耕深松技术来打破犁底层，是提高烟草种植质量行之有效的方法。

Therefore , the use of deep plowing technology to break the hard bottom is the effective method to improve the quality of tobacco growing .

黑土耕层各复合体中有机碳含量均明显减少，犁底层亦表现出降低的趋势。

The organic carbon content in each organic-mineral complex of tillage layer is decreasing obviously with tillage period increasing , and that also has a decreasing trend in below plough layer .

因此，存在不透水底层或入渗速率低的犁底层坡地，具有潜在的严重土壤侵蚀与磷钾流失趋势，尤其在初始土壤含水量较高的情况下。

Therefore , the existing impervious base and low-infiltrate rate ploughed-base slope lands are the potential hazards of soil erosion and phosphorus and potassium loss ,( especially ) under initial soil water high content .

打破犁底层后，各层土壤中根量分布都有明显的下移趋势，而且能提高玉米生长后期的根系活力和抗逆性，使玉米百粒重增加26%～31%。

The distribution of corn roots in various soil layers tended to go down after the measure , which increased root activity and led to a better drought resistance in the late period of corn growth and the increase of about 2.6 % to 3.1 % grams per 100 grains .