| Saline and sodic soil block heavily sustainable development of agriculture innortheast China. On the base of the fact that awareness of information mechanism andamelioration studies of saline and sodic soil, and understanding of technical principleof tillage methods, barriers in two land use types,including paddy field and dry land,of saline and sodic soil were analysized respectively, and reveal the best ameliorationmethods of two land use types and went on to carry out.An experiment was conducted to test the effectiveness of equidistant slotting,combined with gypsum applications, on the amelioration of saline-sodic soils in theSongnen Plain, North Eastern China. The results showed that slots placed in saline-sodic soils20cm deep and spaced1m apart, reduced the degree of soil compactionand improved soil physical characteristics in the slotted areas when gypsum was alsoadded. Moreover, such treatments reduced the soil compaction to some extentbetween slotting positions. However, when slotting was done without gypsum, thesoil chemical properties were not significantly improved over the un-treated controls.Significant reductions in pH and exchangeable sodium percentage(ESP) were onlyobserved between gypsum and no-gypsum treatments. The electrical conductivity(EC),on the other hand, was not significantly different among treatments. The effects of theamelioration of soil sodicity between phosphogypsum and desulfurized gypsum hadno remarkable difference. Therefore we found that gypsum applied to slots in the soilcould improve the physical and chemical properties and thereby improve the growingconditions while at the same time progressively ameliorate the soil conditionsbetween slotting locations.Based on the stimulation experiment of deep tillage, analysizing the differentspatial distribution of salinity and sodicity with the utilization of EM38, variabletillage motheds, combined with phosphogypsum(PG), were adapted to ameliorate thesoil in different degrees of salinity and sodicity. The results show that bulk subsoilingcould reduce evaporate ability of soil moisture than chisel plough. River waterirrigation after subsoiling was good to improve the ability of preserving soil moisture,and PG better. Effect of tillage and PG to progress electrical conductivity(EC) was notobvious, only worked on pH value and exchange sodium percentage(ESP) in the topsoil layer. perhaps little PG was washed downwards bottom because of the poor solubility of PG, thus amelioration effect was unconspicuous. PG could integrate tinyclay into big soil particle, then soil structure could be better, and subsoiling could helpthe bottom soil composition. According to the crops, only the treatment without PGgained low yield, and others high significantly. In sum, PG was the main factor of soilamelioration and crops harvest, and tillage is secondary one.Water scarcity is a bottleneck of agricultural production in arid and semiaridareas, efficient use of water resources is one of the important means to solve theproblem. An experiment was conducted to test the effectiveness of different ways ofsubsoiling, in order to improve soil tilth, on soil physical characters in the west ofJilin province China.The results indicated that sub-soiling could improve the soilphysical properties greatly, decrease the soil compactness of the plough pansignificantly, increase the soil moisture of the topsoil layer obviously, but the soildensity and porosity was influenced slightly. Effects of the soil physicalcharacteristics were different when using different means of sub-soiling. Plough panwas destroyed more greatly by Chiesl plough than bulk subsoiling, and Soilcompactness reduced more considerably than bulk subsoiling; Saturated hydraulicconductivity ratio both in topsoil and plough pan were increased more significantly bychiesl plough than bulk subsoiling, but only in plough pan that was improved moreobviously by bulk subsoiling than the un-treated control. Accroding to the crop, on theother hand, sub-soiling could enhance the growth of the roots and augment the yieldof the crops evidently, effect of sub-soiling on promoting the growth of roots indescending order was:S60>SQ40>S40, and on the yield:SQ40>S60>S40。... |
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