| Corn is one of major food crops in China.As the main commodity grain base of China,the main soil types for corn cultivation in Jilin Province are Black soil and Chernozem.Due to the higher pH and carbonate content of Chernozem,the phenomenon of zinc deficiency is prone to occur.However,the demand for zinc is relatively high during the growth and development of corn,and the insufficient supply of zinc will lead to a decrease in the yield and quality of corn.Therefore,this paper uses the indoor simulation culture method to explore the influence of the main environmental factors on the occurrence and bioavailability of zinc in the Chernozem,combining with the characteristics of the soil types of the Chernozem and the climatic characteristics of the same period of rain and heat in the northeast,which is significant to guide the rational application of zinc fertilizer,to ensure the quality of the soil environment and to ensure the sustainable corn production in the Chernozem region.The results are as follows:(1)After application of exogenous zinc to Chernozem,the content of Effective zinc in Chernozem(C1,C2,C3,C4 and C5)with different carbonate contents was decreased with the culture time increasing.After one year incubation at constant temperature and constant humidity,the decrease in Effective zinc content was C1(29.20%)> C4(28.95%)> C2(27.85%)> C3(27.51%)> C5(23.87%).The initial content of carbonate in the Chernozem has a certain influence on the species and species transformation of zinc in soil.The higher initial content of carbonate in would further promote the transformation of zinc into stable form,and the bioavailability of zinc was also decreased.(2)In the range of pH value of this study(pH 7.0-8.5),Effective zinc content in Chernozem was gradually decreased with time increasing.One year later,the Effective zinc content in the Chernozem with higher pH was decreased more significantly.The bioavailability(K value)of Zn in Chernozem at different pH values was decreased after one year,and followed the order of pH7.5 ? pH7.0 < pH8.0 ? pH8.5.The zinc species of Chernozem changed with time and it was easier for zinc to exist in a more active fraction at pH 7.0 and7.5.Therefore,in the process of corn growth,adjusting the soil to a slightly alkaline environment is conducive to slow down the decrease of soil Effective zinc content,increase the bioavailability of zinc in soil,and prevent the occurrence of zinc deficiency during the growth and development of corn.(3)After one year of cultivation,the Effective zinc content in Chernozem was decreased significantly with different temperatures and water contents.At higher temperatures,the decrease in soil Effective zinc content was gentler,while the increase of humidity content accelerated the decrease in soil Effective zinc content.The EX-Zn,OM-Zn and RES-Zn content was gradually increased with temperature increasing.Under the condition of-10°C and 10°C,K(substitute of bioavailability)value was higher with 10% soil moisture content,and 20% soil moisture content was more conducive to increase the soil zinc bioavailability at 20°C and 30°C.Freeze-thaw effect reduced the effectiveness of exogenous zinc in Chernozem soil,and promoted the transformation of exchangeable state;iron-manganese oxidation combined state and organically combined zinc into residue state in soil,and promoted zinc stabilization in Chernozem.(4)The addition of organic and inorganic fertilizers and straw can increase Effective zinccontent to be steady.The organic material addition effect was more obvious within a short period.After one year of cultivation,the content change of Effective zinc in the soil: followed the order of inorganic fertilizer addition > straw addion > organic fertilizer addion > CK.The application of organic fertilizer can significantly increased the bioavailability of Chernozem zinc(K value)within a period of time,but after that,the addition of inorganic fertilizer and straw was more conducived to the improvement of zinc bioavailability in Chernozem. |
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