Effect Of Organic Fertilizer Instead Of Chemical Fertilizer On Maize Growth And Soil Physical And Chemical Properties In Yellow River Irrigation Area

Dafeng 636 was selected as the experiment target in order to find the best ratio of organic fertilizer which replaces chemical fertilizer for maize’s growth and development in Ningxia Yellow River Irrigation area.By using randomized block test,with five different fertilizer levels(respectively,replacing the ratio of 0,25%,50%,75%,100%),this experiment systematically studied the maize’s growth,physiological characteristics,nutrient uptake and utilization,soil physical and chemical properties and the features of the change of the yield and quality under the treatment of different organic fertilizer’s substitution.The main researching results are as follows:(1)The height,stem diameter,leaf area and dry matter accumulation of maize increased firstly and then decreased along with the increase of the proportion of organic fertilizer substitutes.In silking stage,the plant height,stem diameter and leaf area of T2 treatment were 16.5%,26.9%and 8.3%higher than before,respectively.The dry matter content in T2 treatment was 65.6%higher than that in CK treatment,and the high proportion of organic fertilizer was not conducive to the continuous increase of dry matter,or even decreased the dry matter content.(2)Using proper amount of organic fertilizer’s substitute can effectively improve the photosynthesis of maize.When the substitution ratio of organic fertilizer is 50%,Fv/F0、Fv/Fm and PI of organic chemical fertilizer are higher;However,the content of pure organic fertilizer treatment is the lowest,indicating that the rational use of organic fertilizer substitutes can enhance the chemical efficiency of photosystem II to a certain extent.However,when the proportion of organic fertilizer is too high,the photosynthesis of leaves will be affected.(3)When 50%chemical fertilizer(T2 treatment)and 75%chemical fertilizer(T3 treatment)were used to replace organic fertilizer,the content of proline in maize leaves decreased significantly compared with that in pure chemical fertilizer treatment.The activities of SOD,cat and pod in maize were higher than those in pure chemical fertilizer treatment in the later stage of growth.When the proportion of organic fertilizer substitutes exceeded 50%(T2 treatment),the effect would be opposite.In the silking stage,when organic fertilizer was used to replace 50%chemical fertilizer treatment(T2 treatment),the root activity and leaf chlorophyll content of maize were increased by 6.6%and 8.8%respectively compared with pure chemical fertilizer treatment(CK treatment).However,when applying organic fertilizer alone,the root activity and leaf chlorophyll content of maize decreased significantly,which showed that the replacement of organic fertilizer could delay the senescence of leaves and promote the activity of roots.(4)Proper use of organic fertilizer substitutes can promote the accumulation of nutrients in maize plants.Among them,when the proportion of organic fertilizer substitutes is 50%,the accumulation of nitrogen,phosphorus and potassium in chemical fertilizer treatment is 125.8%,55.0%,45.8%and 50.9%higher than that in pure chemical fertilizer treatment,respectively.Meanwhile,the substitution of organic fertilizer also improved the transfer of nitrogen,phosphorus and potassium from vegetative organs to ears,thus promoting the accumulation of nutrients in ears of maize.However,with the increase of the substitution ratio of organic fertilizer,the accumulation of nitrogen,phosphorus and potassium in maize decreased significantly.(5)Reasonable replacement of organic fertilizer can improve grain quality without reducing maize yield.Ear traits such as ear diameter and ear length of maize did not change significantly with the increase of organic fertilizer’s replacement.Proper amount of organic fertilizer’s substitution can promote the increase of maize grain yield.The contents of crude protein and soluble sugar in maize grains increased firstly and then decreased with the increase of the replacement ratio of organic fertilizer.The crude protein and soluble sugar in T2 treatment increased by 18.1%and 7.4%compared with CK treatment,respectively.(6)Appropriate use of organic fertilizer’s substitution can improve the soil’s available nutrients,0-20cm soil ammonium nitrogen content,but it can reduce soil pH value,which has no significant effect on the mature soil bulk density,total nitrogen,total phosphorus,nitrate nitrogen and heavy metal content.Rational use of organic fertilizer’s replacement will not affect the physical and chemical properties of soil.Based on the above factors,under the conditions of this experiment,when the substitution ratio of organic fertilizer is 50%,it can not only promote the growth of plants and the accumulation of nutrients,but also maintain soil fertility and improve the quality of maize on the basis of ensuring the yield.