Dissertation
Dissertation > Agricultural Sciences > Agriculture as the foundation of science > Soil > Soil improvement > Soil conditioner

Effect of Straw-Bentonite-Polyacrylamide on Soil and Crop

Author LiJiaJia
Tutor WangDingYong
School Southwestern University
Course Environmental Engineering
Keywords Straw PAM Bentonite Soil fertility Cole Yield
CLC S156.2
Type Master's thesis
Year 2011
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With the social development, population growth and accelerated urbanization, the world land seriously degraded, increasingly barren land, land declining quality of land productivity serious recession, the situation is very grim. In order to seek the solution of this problem, the research and development of practical, effective and low-cost soil conditioner to become one of the important research topics of the field of soil improvement at home and abroad. Straw is the main by-products, which are rich in organic matter, nitrogen, phosphorus, potassium and other trace elements, has a great potential of development and utilization of crop production. Bentonite has good adhesion, adsorption, cation exchange performance, catalytic activity, thixotropy and suspended Paul water and fertilizer, and a series of excellent physical and chemical properties, and contains the major and trace elements required by the plants and animals, is a better soil conditioner. Polyacrylamide (PAM) as a soil conditioner, which can effectively improve soil structure, so that the increase in the number of large soil aggregates, increasing the roughness of the surface of the soil, reduce soil bulk density, so that the increase in total soil porosity and capillary porosity, and thus make the soil particles stable soil infiltration rate improved significantly, increasing soil moisture and pore structure. In this study, straw, bentonite, PAM with facilities improved materials, through field trials to explore the three synergy effect on soil fertility and crop growth regulation, and explore its improved regulatory mechanism, and to draw the following conclusions: ( 1) improved materials can be a general increase in the alluvial soil (ordinary moist alluvial Entisols of the as Typic Udi-Alluvic Primosols), gray-brown-purple the mud the (ordinary moist purple Cambisols, Typic Purpli-Udic Cambosols) and dark purple red mud (lime purple wet prototype soil, Calcaric Purpli-Udic Cambosols) organic content. The processing of alluvial soil at three time points than CK increased from 2.54% to 19.41%, 2.66% to 21.59% in gray brown purple clay, dark purple red mud increased from 2.72% to 19.54%, with PAM improved materials, bentonite dosage increase, enhance its organic content, the better. Alluvial soil and gray brown purple clay, organic matter content over time showing a decreasing trend, the organic content of the dark purple red mud is showing an increasing trend over time. (2) applying a modified material can improve the humus content of alluvial soil, gray-brown - purple and dark purple red mud, the three humus content of the soil, respectively, than the corresponding CK increased from 4.25% to 25.58%, 1.80% and 21.82%, 2.52% to 32.06%. With the increase in the amount of improvement materials, PAM, bentonite, soil humus content also increased. From the time point of view, alluvial soil and gray brown purple mud each treatment humus content performance first declined and then stabilized, CK continued to decline. The three time points dark purple red mud CK including humus content first increased and then decreased. (3) improvement of material can effectively improve soil structure, promote the the arabica grade non-water soil stable aggregates reunion to the large grain size. 7-1mm grain size water stable aggregates content alluvial soil at three time points from 9.74% to 73.24% than the corresponding increase in CK lt; 0.5mm arabica grade non-water stable aggregates content less than CK 5.36 % ~ 33.37% ,5-1mm fraction aggregates (most soil Dohi value of structure) fractal dimension is reduced from 2.42% to 15.36%; gray brown purple mud three time points 7-2mm grain size nonaqueous stable aggregates content than the corresponding increase in CK 8.70% to 45.02% lt; 0.5mm arabica grade non-water stable aggregates content 1.16% -32.66% less than that of CK aggregates fractal dimension decreases 0.93 % -17.43%; dark purple red mud three time points 7-2mm large grain size non water-stable aggregates content than the corresponding increase in CK 5.61% -42.07% lt; a 0.5mm arabica non water stable aggregates content than CK reduced from 5.30% to 33.17%, the fractal dimension of the aggregates reduced from 2.45% to 24.08% in the corresponding CK. Treatments with PAM and bentonite dosage increases, large grain size non-water-stable aggregates content tended to increase, the the arabica level of content a decreasing trend, the fractal dimension of the aggregates decreases Description 5-1mm of soil grain size (most soil Dohi value of structure) aggregates content increase significantly. (4) improved materials can effectively reduce soil bulk density. Add improved materials, alluvial soil, ash brown - purple and dark purple red mud soil bulk density, respectively, than the corresponding CK reduced from 0.25% to 12.97%, from 0.60% to 12.37%, from 0.02% to 10.83%. Three soil bulk density were tested decreasing trend with increasing bentonite dosage. Alluvial soil, the higher the content of application of PAM, soil samples bulk density was significantly reduced trend; gray brown purple mud and dark purple red mud is concerned, PAM content too (16.67kg / acre), soil bulk density but larger . Soil bulk density, alluvial soil and gray brown purple mud all treatments except CK continued to increase over time, other processing time first decreases and then increases the trend: dark purple red mud all treatments including CK soil bulk density over time continuous decreasing trend. (5) Add the improved materials, soil water holding capacity increased significantly compared with the control (P lt; 0.05). Alluvial soil, ash brown - purple and dark purple red mud in the moisture content of the various time points than the corresponding CK increased by 1.26% to 29.42%, 1.51% / 31.44%, 1.11% and 21.39%. Three soils at each time point, the moisture content increases with the increased use of bentonite. Alluvial soil and gray brown purple mud PAM dosage should not be too large, otherwise it will lead to the water content is reduced. For dark purple red mud, the application of PAM The higher the amount, the more water content increases. The time variation of the soil moisture content is consistent with the rainfall, less rainfall, improved materials enhance the effect of soil moisture is particularly evident. (6) improved materials to promote crop growth. Improved materials applied canola plants in the three soils to the growth of the late plant height and leaf raw number than CK certain improved rapeseed yield and the rape biomass yield significantly improved. Corresponding CK ratio, alluvial soil, gray brown - purple and dark purple red mud rape biomass yield, respectively, an increase of 41.2 ~ 65.3kg / mu 41.2 ~ 63.8kg / acre and 2.3 ~ 26.4kg / mu, an increase of 13.27 percent to 21.03 %, from 5.95% to 19.36%, 0.71% to 8.17%; rapeseed production, respectively, compared with the corresponding CK increased 0.74-30.17kg / mu of 4.82 ~ 41.15kg / mu and 4.95 ~ 23.68kg / acre yield increase of 0.62% ~ 25.45%, 4.68% and 39.96%, 4.26% and 20.36%. The different processing biomass yield of rape and rapeseed production increased degree of both straw bentonite PAM gt; Straw Bentonite gt; straw. And with improved materials of bentonite and PAM dosage increase biomass yield of rapeseed and rapeseed production showed an increasing trend, bentonite dosage 110kg / mu obvious effect increased production PAM 16.67kg / mu significant influence on the yield.

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