Effect Of Long-term Potassium Fertilizer Application On Apple Yield, Quality And Storability Of Fuji Apple

Generally, apple trees need a large amount of potassium(K) nutrient, while in Shaanxi province, apple growers normally apply less amount of K fertilizer, and moreover, high population density per unit area is adapted in recent years. Apple orchards in Shaanxi are in K deficiency. It is very important to be considered to reach adequate K fertilization for apple. Therefore, Three kinds of K fertilizers application experiments(i.e., different KCl rates, different potassium fertilizers and different KCl application time) were conducted on the young Fuji apple trees to to study effect of potassium fertilizer application on tree growth, nutrient absorption, apple yield, quality, postharvest storage quality and chloride content of soil and new shoot leaves. The aim was to achieve scientific recommended use of K fertilizer on apple production. The main results show as follows:1. Effect of different KCl rates on apple yield, quality and storabilityA three-years(from 2011 to 2014) field experiment was conducted on 8-year Fuji apple trees, There were five levels of KCl fertilizer rates(i.e.,0, 0.15,0.30,0.45,0.60 kg K2O/plant) with 3 replications according to the complete randomized block design. Results showed that 1)the highest average apple yield in three years was 0.45 kg K2O/plant treatment which was 72.99 t/ha, and it is 31.81% higher than that of CK. 2) Compare to CK, all other treatments lead to higher mean fruit weight and fruit ratio which diameter was above 80 mm, the 0.30 kg K2O/plant treatment was most effective in enlarging apple fruit.3) all KCl application treatments enhaced the souble solids, titratable acidity, souble sugar and vitamin c but decreased the fresh firmness.4) During storage period under room temperature, the soluble solid contents of low K2 O rates treatments(0.15-0.30 kg K2O/plant) increased gradually firstly and decline after 50 days.while the soluble solid declined constantly in high K2 O rates treatments(0.45-0.60 kg K2O/plant).At 90 days after harvest, the 0.60 kg K2O/plant treatment improved the fruit rotten ratio. 5) The chloride content of 40-60 cm soil depth and new shoot leaves in June increased with the KCl application rate increase.2. Effects of different potassium fertilizers on apple yield, quality and storabilityA three-year field experiment was conducted from 2011 to 2014 to investigate the effect of different potassium(K) fertilizers on Fuji apple tree. There were three treatments(i.e., withoutk(ck),kclandk2so4).theresultshowedthat1)bothkclandk2so4improvedappleyield,in2012and2013,theappleyieldofkcltreatmentwashigherthank2so4(butnosignificantdifference).in2014,theappleyieldofk2so4 exceedtokcl.2)averagemeanfruitweightandthefruitratiowhichwasabove80mmwereaskcl>k2so4>ck.3)bothkclandk2so4increasedthetitratableacidity,solublesugarandvccontentoffreshfruitattheharvesttime,however,fruitfirmnesswasdeclinedinkclandk2so4 treatments.4)thesolublesolidcontentsinthekclandk2so4treatmentswereincreased,whileitdeclinedconstantlyinthecontroltreatmentduringstorage.at90 daysaftertheharvest,thefruitfirmnessratesweredecreased19.23%,6.96%and22.19%intheck,kclandk2so4 treatmentsrespectively,meanwhiletheratiosofrottenappleswere11.11%inck,9.25%inkcland5.55%ink2so4treatment.5)theapplicationofkclincreasedthechloridecontentinthesoilof20-60 cmdepthandtenderleavesofnewspringshoot.3effectofdifferentkclapplicationtimeonappleyield,qualityandstorabilityA three-years(from2011to2014)fieldexperimentwasconductedon8-yearfujiappletreestoinverstigatedifferentkclapplicationtimeonappleyield,qualityandstorability.therewerefivetreatments:ck(withoutk),100%b(100%kclappliedasbasefertilizerinautum),50%b50%f(50%kclappliedinautumandtheleft50%kclappliedinfloweringtime),50%f50%e(50%kclappliedinfloweringtimeandtheleft50%kclappliedfruitexpansionperiod),100%e(100%kclappliedinfruitexpansionperiod).theresultshowsthat1)comparewithck,thetreatmentsof50%b50%f、50%f50%eand100%eimprovedthefruitnumberpertree,meanfruitweightandlargesizefruitratio,andtherewasnosignificantdifferentbetweenckand100%btreatmentinfruitnumberpertree,however,the100%btreatmentssignificantlyincreasedthenewshootlength.2)theaverageyieldinkclfertilizertreatmentswerehigherthanckas3.73%(100%b),21.35%(50%b50%f),32.16%(50%f50%e),25.15%(100%e)respectively.3)dfferentkclapplicationtimetreatmentsdecreasedthefruitfirmnessandincreasedthevitaminccontentatharvesttime,100%etreatmentcanbefoundoutthemoreoboviousdecendinfruitfirmness.4)solublesoildincreasedafterharverstindifferentkclapplicationtimetreatmentexceptfor100%etreatment.attheendofthestorageperiod,thefruitrottenratiodeclinedindifferentkclapplicationtimetreatment.5)50%b50%fand50%f50%eimprovedthenewshootleaveschloridecontentinmid-may,50%f50%eand100%etreatmentincreasedthenewshootleavescontentinmid-july.therewasnotsomucheffectof100%btreatmentonthenewshootleavescontentfrommaytojuly.