| Phosphorus is one of the three nutrition elements which are indispensable to plants, Phosphorus is easy to be fixedand has obviously lower absorption efficiency in comparison to nitrogen and potassium, In this study, several commonly used rootstocks and their grafted grapevines were selected to study the absorption kinetics of phosphorus, phosphorus efficiency of rootstock graftings,and the impacts of fertilizing time,root restriction and biochar on P absorption and utilization in grapevine. The main results were as follows:1. The capacity of phosphorus absorption for different rootstocks was1103P> Beta>101-14M>5BB. Under the conditions of normal P-supply and P-deficiency (20%of normal P-supply), the root length, root surface area, root volume of CS/1103P were significantly higher than the other three combinations. Under the phosphorus stress, compared with the other three combinations(CS/101-14M, CS/Beta and CS/5BB), the root tips of CS/1103P were increased by2.25%,,27.94%and43.80%, respectively; the root surface area of CS/1103P up22.77%,30.72%and34.28%, respectively; the root volume of CS/1103P up23.10%,36.92%and33.35%, respectively; the root length of CS/1103P up44.64%,36.90%and44.64%, respectively. Under the stress of low phosphorus, the phosphorus uptake of CS/1103P was higher than the other three respectively47.35%,44.64%,36.90%. Under normal P-supply, the phosphorus uptake of CS/1103P was32.08%,40.31%,27.19%higher than the other three combinations, respectively32.08%,40.31%,27.19%; besides, CS/1103P showed significantly higher biomass as well.2. Compared to the control without P application, P treatments had a positive effect on improvement of the dry matter accumulation, P uptake and utilization rate of phosphate fertilizer as well as fruit quality. Fertilizing twice showed the best effect on the grapes. Compared with fertilizing once and three times, fertilizing twice increased dry matter accumulation by7.45%and5.41%, increased P uptake by15.38%and8.72%, and increased Utilization efficiency by5.14%and3.09%. In addition, fertilizing twice produced the highest cluster weight, hundred-berry weight, soluble solids content, total sugar content, but lowest total acid content. Fertilization twice during rapid growth of new shoots and fruit swelling is a reasonable way to meet P absorption and improves the utilization ratio of phosphate fertilization in Moldova grapevines.3. The effect of biochar on soil showed that addition of biochar decreased soil bulk density and increased total porosity increased, the water-holding capacity of the soil as well as soil fertilizer performance. Besides, biochar application significantly increased catalase activity, urease activity and alkaliner phosphatase activity. On the other hand, biochar also increased the net photosynthesis ratio, the soil available p content, p uptake and dry matter accumulation of grape.4. Root restriction treatments could increase soluble solids and total sugar content and reduced total acid content. Combination of root restriction and retaining water and fertilizer showed the best effects. Compared with the treatment without restricting root, root restriction alone and combination of root restriction and biochar, root restriction plus retaining water and fertilizer increasedsome parameters, i.e., dry matter accumulation up23.17%,27.60%and11.57%, respectively, phosphorus uptake by up30.60%,28.83%and11.44%, respectively, the SPAD of leaf up8.28%,15.82%and3.98%, respectively, leaf net photo synthetic up51.77%,53.24%and19.47%, respectively, utilization efficiency up2.87%,2.73%and1.25%, respectively. Compared with unrestricted treatment, root restriction alone limited the growth of overground vines and reduced dry matter accumulation of grape berries... |
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