Study On Effects Of Soil Conditioners On The Growth Of Malus Hupehensis Rehd. Seedlings And Utilization, Loss Of¹⁵N-urea

The study was carried out in orchard of Shandong Agricultural University fruit researchstation from2011to2012. One-year-old potted Malus hupehensis Rehd. seedlings and¹⁵Ntrace technique were used to explore the effects of three kinds of soil conditioners（zeolite,PAM, PASP） on plant growth and the utilization, loss of¹⁵N-urea. The main results were asfollows:1. The effects of different zeolite amount on the growth of potted Malus hupehensisRehd. seedlings and utilization, loss of¹⁵N-urea was studied.The results showed that thegrowth of plant, utilization of¹⁵N-urea under the low zeolite levels （Z1, Z2） were the highestat the early growth stage, and then they were higher with the high zeolite level. At the latestage, the plant height, total wet weight and¹⁵N utilization ratio were the highest for Z4, theywere29.78cm,29.64g and17.91%respectively, which were obviously higher than CK（23.28cm,22.52g and8.81%）. Ndff values of shoots were higher than roots for all treatmentsduring the whole stages. At the early stage, Ndff values of both shoots and roots were thehighest for the low zeolite level treatments（Z1, Z2）, while at the late stage, the values of Z4were the highest, they were19.04%and8.34%respectively, which were obviously higher thanCK（16.27%and5.83%）. The loss of nitrogen decreased by using zeolite, and the more zeoliteused, the more effective was the result. As a whole, with the application of zeolite, the growthof plant and the utilization of¹⁵N were significantly increased and the loss of nitrogendecreased, with2.4g zeoliteï¹'kg-1soil treatment showing the best.2. The effects of different PAM amount on the growth of potted Malus hupehensis Rehd.seedlings and utilization, loss of¹⁵N-urea was studied.The results showed the growth of plant,¹⁵N utilization ratio under M3was the highest at the early growth stage. With the growthproceeded, at the late stage, plant height, total wet weight and¹⁵N utilization ratio were thehighest for M4, they were29.57cm,31.29g,17.42mg and18.93%respectively, which wereobviously higher than CK（18.93cm,24.07g,10.08mg and10.95%）. Ndff values of shootswere higher than roots for all treatments during the whole stages. At the early stage, Ndffvalues of both shoots and roots were the highest for M3, while at the late stage, the values ofM4were the highest, which were obviously higher than CK. The loss of nitrogen decreasedby using PAM, and the more PAM used, the more effective was the result. As a whole, with the application of PAM, the growth of plant and the utilization of¹⁵N were significantlyincreased and the loss of nitrogen decreased, with240mg PAMï¹'kg-1soil treatment showingthe best.3. The effects of different PASP amount on the growth of potted Malus hupehensis Rehd.seedlings and utilization, loss of¹⁵N-urea was studied.The results showed the growth of plantand the utilization of¹⁵N under low PASP levels were the highest at the early growth stage,and as the growth stages proceeded, both of them became higher with the increase of PASP.The¹⁵N distribution of aerial part was higher than that of underground part in all treatmentsduring the whole growth stages, but as the growth stages proceeded, both the distribution of¹⁵N and the ratio of¹⁵N in aerial part were higher with the increase of PASP. The loss ofnitrogen decreased significantly by using PASP, and the more PASP used, the more effectivewas the result. As a whole, with the application of PASP, the growth of plant and theutilization of¹⁵N were significantly increased and the loss of nitrogen decreased, with the400mg PAMï¹'kg-1soil treatment showing the best.4. The effects of different soil conditioners on the growth of potted Malus hupehensisRehd. seedlings and utilization, loss of¹⁵N-urea was studied.The results showed theapplication of soil conditioners effectively alleviate the inhibitory effect of high nitrogen onplant growth, on nitrogen uptake and utilization, and the loss of nitrogen decreasedsignificantly.The effects of different soil conditioners on different indexes were different.Thebiomass of plant, root/shoot ratio, total root length, root surface area and root tips of MN werethe largest, while the root activity of ZN was the higest; total N of plant of ZN was the higest,while the¹⁵N uptake amount and utilization ratio of SN were the lagest, and the effect of ZNto reduce nitrogen was the best.