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Yang S.,Shandong Forestry Academy | Yang S.,China Agricultural University | Xing S.,Shandong Forestry Academy | Liu C.,Shandong Agricultural University | And 3 more authors.
Horticultural Science | Year: 2010

The effects of root pruning on the vegetative growth and fruit quality of six-year-old Zhanhuadongzao (Ziziphus jujuba Mill.) trees were evaluated. Three root pruning treatments (severe, moderate and light degree) were conducted at the distance of 3, 5 and 7 times trunk diameter from trunk on both inter-row sides of the trees, respectively. The results showed that the severe root pruning decreased the length of primary branch by 27.9% and the number of primary branches by 12.1% in contrast to the control of no root pruning. Compared to the control, both severe and moderate root pruning had no apparent effects on nitrogen, phosphorus and potassium contents of leaves after 35 days, but had significant effects after 161 days. Severe root pruning had larger effectiveness of controlling vegetative growth than the moderate one. By root pruning, the contents of vitamin C and total sugar were increased but the content of cypermethrin was decreased in fruits and no effects were found on total acid content of fruit and yield at harvest. In the rhizosphere soil, root pruning decreased the microbial populations and enzymes activities but increased the concentrations of cypermethrin, available nitrogen, phosphorus and potassium. It is proposed that the removal of root at 3 times trunk diameter distance from trunk was feasible to regulate the vegetative growth and fruit quality of Zhanhuadongzao tree. Source

Jing D.-W.,Dezhou University | Jing D.-W.,Shandong Forestry Academy | Xing S.-J.,Shandong Forestry Academy | Du Z.-Y.,Shandong Forestry Academy | Liu F.-C.,Shandong Forestry Academy
Chinese Journal of Applied Ecology | Year: 2013

A pot experiment was conducted to study the effects of different water treatments (normal irrigation, light drought, moderate drought, and severe drought) on the growth, gas exchange, chlorophyll fluorescence characteristics, and active oxygen metabolism of poplar (Populus × euramericana cv. 'Neva') seedlings in the experimental nursery of Shandong Forestry Academy from April to October, 2011. As compared with those under normal irrigation, the growth of the seedling's basal diameter under light, moderate, and severe drought stress decreased by 12.8%, 44.5%, and 65.6%, and the height growth decreased by 12.2%, 43.1%, and 57.2%, respectively. With the increasing extent and duration of drought stress, the maximal photochemical efficiency of PSII, quantum yield, photochemical quenching coefficient, net photosynthetic rate, and stomatal conductance of the seedling leaves decreased gradually under light drought stress, while decreased rapidly under both moderate and severe drought stress. The non-photochemical quenching coefficient increased significantly under light drought stress, but decreased after an initial increase under moderate and severe drought. The leaf superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities under drought stress decreased after an initial increase, but definite differences existed in the responses of the three enzymes to drought stress and reactive oxygen. The leaf relative electric conductivity and malondialdehyde (MDA) content under drought stress increased significantly, plasma membrane was damaged, and massive ions leaked out. The most serious damage of plasma membrane was found under severe stress. Under light drought stress, the seedlings had higher photosynthetic efficiency and stronger oxidative enzyme defense system; under moderate and severe drought stress, the photosynthetic efficiency decreased significantly, and the oxidative enzyme defense system was damaged remarkably. Source

Yang S.J.,China Agricultural University | Du Z.Y.,Shandong Forestry Academy | Yu Y.,China Agricultural University | Zhang Z.L.,China Agricultural University | And 2 more authors.
Plant, Soil and Environment | Year: 2011

The root system of six-year-old winter jujube (Zizyphus jujuba Mill. cv. Zhanhua) trees were manually pruned at 3, 5 or 7 times trunk diameter distance along both inter-row sides, to study the effects of root pruning on physico-chemical characteristics and biological properties of winter jujube rhizosphere soil. The results showed that the root pruning of 3 and 5 times trunk diameter distance increased the available nitrogen, phosphorus, potassium concentrations and pH values in the rhizosphere soil and decreased organic matter concentrations, the contents of amino acids, organic acids and total sugars in the root exudates, the populations of bacteria, actinomyces and fungi, and inhibited the activities of catalase, invertase and urease enzymes in contrast to the control in early stage when root pruning was applied. The determined indexes presented a reverse trend as those in early stage after new roots appeared. Compared to the control, the trees by root pruning had higher pesticides residues of the rhizosphere soil in the whole experiment. No differences were noticed between 7 times trunk diameter distance and the control. It is proposed that root pruning had greater impacts on physico-chemical characteristics and biological properties of the rhizosphere soil depending on root pruning intensity. Source

Qin G.-H.,Shandong Forestry Academy | Jiang Y.-Z.,Shandong Forestry Academy | Qiao Y.-L.,Shandong Forestry Academy
Silvae Genetica | Year: 2013

As one of the fast-growing tree species, hybrid poplar (Populus ssp.) has been widely planted in Shandong Province, China. While poplar tree breeding program in the past few decades focused on the development of poplar clones with fast growth rate and disease resistance, little attention was paid to the tree traits of these clones in relation to industrial uses i.e. pulpwood as well as veneer. In this paper, growth performance of hybrid poplar clones from backcrossedprogenies obtained from cross fertilization within the Poplar Aigeiros Section was evaluated and stem traits as well as wood properties in relation to industrial use of some selected clones were assessed. Of the 40 hybrid poplar clones tested in the study, A50 and B69 were prominent in growth rate at three trial sites in Shandong Province, China.Wood properties in relation to industrial uses of the two clones were also better than or comparable to the control clone. It was concluded that A50 is more suitable for pulpwood production while B69 is suitable for a wide range of high value added application such as veneer and plywood. Further research is needed to evaluate the changes of some tree traits in relation to industrial raw materials through time. Source

Jing D.,Dezhou University | Jing D.,Shandong Forestry Academy | Xing S.,Shandong Forestry Academy | Liu F.,Shandong Forestry Academy | And 4 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2015

Super absorbent polymers can absorb water up to a few hundred or even a few thousand times their own mass. The special physical structure, unique chemical composition and characteristics of high water absorption capacity allow super absorbent polymers to be widely used in water-saving agriculture, horticulture and other industries to relieve drought and reserve water for farmland, seedling protection and crop yield improvement. A large number of studies have showed that super absorbent polymer has the properties of water saving and drought resistance. But the application amount of super absorbent polymer is an important parameter to evaluate. Applying with the improper amount can result in bad effects, either no effect, or soil permeability compromised if excess super absorbent polymer is used. This can cause plant roots to have difficulty in breathing or to get rotten. In the meantime, border irrigation is also an efficient measure which has the advantages of low cost, simple operation and easy popularization. Similarly, the irrigation quantity is a vital factor. Because excess irrigation not only causes the waste of water resource, but also poses a threat to the groundwater. While insufficient irrigation may have no effect. Therefore, it is speculated that super absorbent polymer co-applied with border irrigation should be an interesting thing, and investigating their appropriate proportion has important theoretic value and practical significance. However, there is little information on the effect of border irrigation measure co-applied with super absorbent polymer on the forest-tree plantation. With the purpose of promoting water-saving irrigation and poplar yield, a field experiment of 5 treatments, i.e. CK (conventional border irrigation), I60 (60% conventional border irrigation quantity), I30 (30% conventional border irrigation quantity), I60S (60% border irrigation quantity co-applied with super absorbent polymers) and I30S (30% border irrigation quantity co-applied with super absorbent polymers) was designed and performed. The present study was conducted to determine the effects of different treatments on bulk density, microbial biomass carbon (MBC), microbial biomass nitrogen (MBN) and microbial activity in the forest soil as well as the growth of poplar. Results showed that in comparison to CK treatment, I60S treatment significantly reduced soil bulk density and obviously increased soil total porosity and capillary porosity, indicative of 6.62%, 11.19%, 16.45% and 7.97% decreases in soil bulk density compared to the treatments of CK, I60, I30 and I30S, respectively. The I60S treatment also evidently increased MBC and MBN contents and significantly enhanced microbial respiration, showing 13.89%, 24.24%, 41.38% and 12.33% increases in microbial respiration rate over the treatments of CK, I60, I30 and I30S, respectively. At the same time, the metabolic quotient was reduced by the I60S treatment, demonstrating 5.96%, 8.84%, 11.72% and 4.78% decreases, respectively. Additionally, the volume growth rate of the I60S treatment also reached the maximum, which had significant differences with other treatments (P<0.05). However, in the I30S treatment, less effect on the forest soil characteristics and the volume growth were observed than that in the I60S treatment. The correlation analysis showed that the volume growth rate was extremely significantly correlated with capillary porosity and metabolic quotient, and had significant correlation with soil bulk density, MBC and MBN contents and microbial respiration. In conclusion, the proper water-saving irrigation measure (60% border irrigation quantity co-applied with super absorbent polymers) is beneficial to improving soil physical environment and enhancing microbial activity in forest soil, as well as the growth of poplar. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved. Source

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