| For irrigated plains of Inner Mongolia, because of the regular use of small power caused by shallow topsoil tillage operations, plow thick and hard subsoil Yung significant difficulties tie maize roots, deep soil moisture on nutrient absorption difficulties, low production situation The test set of deep spin35cm (TS), subsoiling35cm (SS), deep plowing35cm (SF) Three roots approach to shallow rotary tillage15cm (CK) as a control, through a comparative study of different soil physical properties, maize roots and canopy structure, filling characteristics and operation as well as the accumulation of dry matter and nitrogen, deep plowing to explore the mechanism of stimulation. Test results are as follows:(1) deep plowing can reduce soil bulk density, SF for15-45cm soil bulk density decreased significantly effect, TS for the0-15cm soil layer, SS on15-30cm soil bulk density decreased greater impact. After the maize roots can effectively improve the silking stage20-80cm of soil water content. After cultivating topsoil structure index (GSSI) increased closer to the ideal state value of100, three-phase structure of soil from (STPSD) closer to the ideal state to reduce the value of0, the physical structure of the soil tilth more approximate the ideal state, and increase gas compared and a liquid compared to the solid reduced compared. After the SF20-60cm soil structure index has a larger and a smaller three-phase from the soil, soil physical structure is most reasonable, better than the other treatments.(2) cultivating maize root dry weight, total root length and total root surface area were higher than CK, promote Root Penetration,20-60cm soil root length and root surface area was significantly higher than CK. In the0-0.5mm diameter class roots range,0.2mm or less fine root diameter class the largest proportion was significantly higher than other fine root diameter class proportion. SF conditions under root dry weight, total root length, total root surface area was significantly higher than other treatments, and the amount of20-50cm soil roots larger fine root length and fine root surface area was significantly higher than other treatments.(3) deep plowing can increase leaf area index, within30days after silking ear leaf and lower leaf SPAD values remain high, able to maintain maize ear leaf and lower leaves to maintain a more extended period after silking high maximum photochemical efficiency and net photosynthetic rate. Canopy LAI, SPAD, Fv/Fm, Pn are expressed as SF> SS> TS> CK. SF can effectively delay the maize ear leaf and lower leaf senescence, while the SS and TS only affect the lower leaves of maize obvious.(4) Active maize roots can extend the filling period (1.7d-3.7d) and effective filling period (2.0d-4.1d), increase the maximum filling rate and mean filling rate, increase the filling mid and late grain filling on dry matter accumulation contribution rate.In summary, deep plowing can reduce soil bulk density, increased soil moisture maize silking soil20-80cm soil, improve water storage capacity; increase soil structure index, decreased soil from the three-phase structure, the physical structure of the soil is more reasonable; promote maize root penetration, increasing the proportion of fine roots, root distribution to improve the situation is conducive to root in the soil to absorb water and nutrients. After cultivating groups leaf area index and SPAD value after silking, the maximum photochemical efficiency and photosynthetic rate are improved, and can effectively delay the ear lobe and lower leaves of aging, increase grain dry matter accumulation rate of time and ultimately increase production. |
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