| Songnen P lain is the largest area of soda saline alkali land in the wor ld, and the saline area of 3,7333 million ha, most soil p H more than 8.5 and severe saline alkali soil p H high reached 9. 0-10.5. The main crop in this region is maize. Field and pot exper iment of planting maize on saline alkali soil with gypsum and f ly ash was carr ied out in f ield and greenhouse in 2014, In view of the different inf luence among mechanism, the differ ent ratio test of gypsum, fly ash, and PAM was des igned in 2015, to analys is the inf luence of amendments on growth and phys iological character istics of maize seedling and the eff ect on soil amelior ation, and to compar ison the mechanis m differ ences of 3 kinds of amendments in impr oving the salt alkali tolerance of maize seedling, and to f ind the best combination The results showed that:(1) After adding the amendments, the chemical properties of s oil was improved s ignif icantly. Af ter a year, saline soil p H, s alinity and exchangeable sodium have increased,cation exchange capac ity unchanged, carbonate, bicar bonate, chlor ide, sodium, sulphate, calc ium, magnes ium, potass ium unchanged or increas ed s lightly. Amendments s ignif icantly r educed the soil cation exchange capacity, exchangeable sodium in soil, soil p H, decreased the content of harmf ul ions of carbonate, bicar bonate, chlor ide and sodium, and increased s ignif icantly the content of useful ion sulf ate, calc ium, magnes ium and potassium. F ly ash in reducing har mful ion eff ect is slightly infer ior to the gypsum, but it in increas ing the benef ic ial ion is slightly bet ter than gypsum, P AM role is much smaller than both. The content of sodium ion in soil is pos itively r elated w ith carbonate, bic arbonate and chlor ide, and negative related w ith sulf ate, calcium, magnes ium, potass ium ion content. CEC, p H and exchangeable sodium ion content were pos itively correlated with harmful ions content, and negative related benef ic ial ions content. Between the two types of ion and s alt content have the oppos ite r elationships to that of the former. Gypsum increas es soil salinity, ash and P AM don not. Chemical Pr oper ties of Soil were s ignif icantly correlated with the sodium ion content, CAT activity, MDA content, pr oline content and chlor ophyll content of maize plant(p <0.01),and s ignif ic antly correlated at 5% level with plant height, dry matter, leaf ar ea, root length, root volume and surface area.(2) Phys iological indexes of maize plants under S aline alkali str ess were clos ely r elated. Potass ium Content and SOD activity, sodium content and CAT activity, the calc ium content and POD activity were s ignif ic antly correlated; potass ium content and proline content, MDA, chlor ophyll content and sodium content wer e signif icantly correlated; POD activity and soluble sugar content, SOD activity and chlorophyll content, CAT activity and MDA content, pr oline and conchlorophyll content were s ignif icantly corr elated; MDA were s ignif icantly r elated to chlor ophyll and soluble sugar;soluble sugar and proline, proline and chlorophyll content were signif icantly correlated. Soluble sugar, chlorophyll content and potass ium, soluble sugars, proline content and sodium, soluble sugar content and calc ium wer e higher relat ed. S odium ion content, CAT activity and MDA content were s ignif ic antly related w ith plant growth par ameters; soluble sugar and chlor ophyll content wer e also s ignif icantly w ith most indic ators.(3) After adding the amendments, the phys iologic al and biochemical char acter istics of maize seedling and middle stage of gr owth were impr oved. Amendment r educes the content of sodium ions of maize plant, increases potass ium and calc ium ions content, and increases the POD, SOD, CAT activities, reduces the MDA, soluble sugar and proline content, the content of chlor ophyll espec ially chlorophyll a content was increased, the initial f luor escence F0 and maximal fluorescence Fm and Fv were also improved. The root morphology indicators of maize seedling were signif icantly improved, such as the number of root tips, root length, root surface ar ea and volume etc., plant height; leaf area and dry weight were also improved.(4) Saline Stress causes the maize to grow slow ly, the growth process is delayed. The use of amendment improved maize growth and development, s ignif icantly increased the yield of maize. Field test, applic ation of gypsum or f ly ash, maize leaf ar ea, chlorophyll content and photosynthetic rate were increas ed, dry weight and plant height were als o increased, the proportion of photosynthate allocat ed to ear was increased, Ear length, ear diameter, kernels number per row, 100 gr ain weight wer e increased, ear barren tip was r educed, ther eby impr oving the yield of maize per plant. The yield of gypsum and f ly ash treatment in Severe Saline alkali s oil w as increas ed by 57.9% and 30% respectively, while yield in light saline alkali soil was increas ed by 33.8% and 5.97% respectively.(5) The improvement mechanisms of diff erent amendments ar e diff erent. In terms of improving soil chemic al pr operties, Gypsum> F ly ash> P AM; in terms of impr oving plant osmotic adjustment substanc e, Fly as h > Gypsum> P AM; in terms of improving antioxidant enzyme activity, impact of thes e ar e var ies, for POD activity, effect of F ly ash is maximum; for S OD activity and CAT activity, effect of gypsum is maximum. In terms of the growth and yield, gypsum> F ly> P AM. Compr ehens ive f ield exper iment and pot exper iment results, in the cas e of single application, gypsum is better than f ly ash, and f ly ash is better than P AM. From pot exper iment eff ect, the diff erent r atio of the amendments has a diff erent degr ees of improvement effect, in general, the tr eat T6(12g Gypsum + 0.75 gP AM / Kg soil) is the best. |
PDF Full Text Request