Effect Of The Soil Nutrient Space Regulation On Characteristics Of Nitrogen Absorption, Distribution And Growth Of Peach Tree

Tow-year-old peach trees （Chunxue/wild peach） were used in the present study to explorethe effects of ridging cultivation and different root zone fertilization on physicochemicalcharacters of soil, characteristics of nitrogen absorption, distribution and growth for peachplant with¹⁵N tracing pot culture. The main results were as follows:1、Comparison with different ridging width, the relative water content of the1.5m ridgingwidth and the1.8m ridging width treatments could maintain in58.89%-76.29%under thecondition of no obvious rainfall. The treatment of ridge culture restrained the soil bulk densityand increased soil porosity obviously; the treatment of ridging cultivation increased the soiltemperature in5-25cm soil layer during May and July. Ridging treatment can improve soiltemperature of20cm soil layer, the effect of raising temperature was obvious in sunnyweather than the rainy weather. Ridging treatment improved the soil environment of peachtree root zone and promoted the root growth. The roots distribution extent of the1.2m ridgingwidth, the1.5m ridging width, and the1.8m ridging width treatments in horizontal directionwas1.19-fold,1.25-fold and1.28-fold than not ridging processing, respectively. Ridgingtreatments increase the active soil layer of peach tree rhizosphere significantly. The treatmentof ridge culture increased root distribution depth.The change range of root depth was from8.7to10.7cm. Ridging cultivation promoted the growth and dry matter accumulation of peachtree.The trunk diameter growth rate of the1.2m ridging width, the1.5m ridging width, andthe1.8m ridging width treatments was1.2-fold,1.69-fold and1.35-fold than not ridgingprocessing,respectively. The total dry matter accumulation of the1.5m ridging width washighest.2、The root zone were evenly divided into four areas in the horizontal direction to thebackbone for center. Choose one to four areas for nitrogen treatment. There were2timestreatments during the growing season, and keep fertilizer and position unchanged. Theresult show that: the Ndff%values of fertilization zone root was obviously higher thannon-fertilization zone root; The Ndff%values of fine root of fertilization zone were highestunder1/4root zone fertilization, reaching to4.28%, it was1.39-fold,1.62-fold and1.68-foldthan2/4root zone fertilization,3/4root zone fertilization and4/4root zone fertilization. TheNdff%values of large root of fertilization zone were highest under1/4root zone fertilization, reaching to3.98%, it was1.22-fold,1.24-fold and1.39-fold than2/4root zone fertilization,3/4root zone fertilization and4/4root zone fertilization respectively. The¹⁵N distributionrates were different in the treatment of different root zone fertilization. The¹⁵N distributionrate of fertilization area root was more than that in non fertilization area. The¹⁵N distributionrate of fine root were highest under1/4root zone fertilization, reaching to1.84%, it were1.01-fold,1.53-fold and1.77-fold than2/4root zone fertilization,3/4root zone fertilizationand4/4root zone fertilization respectively. The¹⁵N distribution rate of large root were highestunder1/4root zone fertilization, reaching to2.75%, it were1.23-fold,1.86-fold and1.83-foldthan2/4root zone fertilization,3/4root zone fertilization and4/4root zone fertilizationrespectively. The nitrogen utilization rate of4/4root zone fertilization was highest, reachingto4.16%, and it was3.62-fold,1.65-fold and1.24-fold than1/4root zone fertilization,2/4root zone fertilization and3/4root zone fertilization respectively. The dry weight offertilization area fine root was higher than that of non fertilization area and control in thetreatments except of1/4root zone fertilization. Overall the growth rates in the treatment of4/4root zone fertilization was the highest, reaching to0.57cm/month.3、Compared to the fixed partial root zone fertilization and the alternate partial root zonefertilization, the results showed that: the Ndff%of thick root and fine root respectively was3.04-fold,2.52-fold than non fertilization area in the treatment of fixed partial root zonefertilization. The Ndff%of fine root was no significant differences among the first and afterfertilization edge in the treatment of alternate partial root zone fertilization, but also, theNdff%of thick root was significant differences, the treatment of after significant differenceswas1.29-fold than the first. The¹⁵N distribution rate of large root and fine root in thefertilization area was more than that in the non fertilization area in treatment of fixed partialroot zone fertilization. The¹⁵N distribution rate of fine root was no significant differencesamong first and after fertilization edge, The¹⁵N distribution rate of large root in the afterfertilization area was more than that in the first fertilization area in treatment of alternatepartial root zone fertilization. The nitrogen utilization rate of fixed partial root zonefertilization was2.5%and was1.25-fold than that of alternate partial root zone fertilization.The growth rates in the treatment of fixed partial root zone fertilization, alternate partial rootzone fertilization and control were0.50cm/month,0.49cm/month and0.46cm/month,respectively.4、We used the nitrogen fertilizer fertilized to the root in the pot and the root out of the potunder the pot.And used the method of simulation to analysis the variance of the nitrogen uptake between surface roots and deep roots.The result showed that the Ndff%values weredifferent at the fertilized in the pot and fertilized out of the pot. The Ndff%values offertilizing out of the pot can reach to1.17%in the autumn shoots, while it can reach to3.99%in the large root which was fertilized in the pot.The¹⁵N urea partition ratio of shoot systemsfertilized out of the pot was70.52%,and the root systems was29.48%.The¹⁵N urea partitionratio of shoot systems fertilized in the pot was59.49%,and the root systems was40.58%.Nutilization rate of fertilizeing in the pot was3.75-fold than out of the pot, significantlydifference. The shoot growth which fertilized in the pot was greater than it fertilized out of thepot.The total dry biomass which fertilized in the pot was93g was greater than it fertilized outof the pot which was79.83g.They had significantly difference.5、Rooting-zone restriction used different length PE pipe.The result showed that rooting-zonerestriction controlled the vegetative growth to the young peach,and the level of control waspositive correlation with the length of the PE pipe.The relationship of total length of therooting-zone restriction was:70cm PE pipe treatment<50cm PE pipe treatment<30cm PE pipetreatment<CK.The growth rate of70cm PE pipe treatment,50cm PE pipe treatment,30cm PEpipe treatment and CK from May to August was0.08cm/month,0.16cm/month,0.31cm/monthand0.70cm/month, respectively.The plant height of30cm PE pipe,50cm pipe and70cm pipewas respectively lower0.28-fold,0.41-fold and0.61-fold as CK. Rooting-zone restrictionrestrained the accumulation of the dry matter, and improveed the root-top ratio consequently.The root-top ratio of treatments,30cm PE pipe treatment,50cm PE pipe treatment and70cmPE pipe treatment, was1.02-fold,1.06-fold, and1.16-fold as CK, respectivly.The number ofroots of treatments were less than CK significantly in15-25cm soil layer and35-45cm soillayer.