[Adaptability of Broussonetia papyrifera to sewage sludge and its characteristics of nutrient and heavy metal uptake and accumulation]. / æž„æ ‘çš„æ±¡æ³¥é€‚åº”æ€§åŠå »åˆ†å’Œé‡é‡‘å±žå¸æ”¶ç´¯ç§¯ç‰¹å¾.

Broussonetia papyrifera, an important fast-growing economic tree species in China, has the advantages of strong adaptability, high-biomass, and high bioconcentration of heavy metals. Sewage sludge contains a great deal of nutrients and heavy metals. Planting B. papyrifera with sewage sludge can achieve the goals of sewage sludge remediation as well as resources production of B. papyrifera. A pot experiment was conducted to investigate growth, uptake and accumulation of nutrient and heavy metal in different organs (root, stem, leaf) of B. papyrifera, with treatments of control (lateritic red soil), 50% sewage sludge (mixed substrates of 50% sewage sludge and 50% lateritic red soil based on weight) and 100% sewage sludge. The comprehensive evaluation of capacity of uptake and accumulation was also carried out by principal component analysis and membership function. The results showed that B. papyrifera could grow normally in both 50% and 100% sewage sludge substrates, with higher plant height and biomass than that in the control, especially in 100% sewage sludge substrate. The quality index in 100% sewage sludge substrate (1.02) was 4.3 times and 2.4 times as that of the control and 50% sewage sludge substrate, respectively. The content of N in different organs and P in stem increased significantly in both 50% and 100% sewage sludge substrates. The content of K in stem and leaf was significantly decreased in 100% sewage sludge substrate, which were significant lower than that of control. The uptake of heavy metals such as Cu, Zn, Pb, Cd, Ni for B. papyrifera were mainly through roots. There was positive correlation between the content of heavy metals in root and sewage sludge ratio. The content of Pb and Cd in leaves were lower than the limit value of Hygienic Standard For Feeds (GB 13078-2017). The capacity for absorption and accumulation of Cd was better than that of other heavy metals. Compared with the control, rootretention rates of Zn, Pb and Cd significantly increased in both 50% and 100% sewage sludge substrates (57.8%-85.8%), while Cu and Ni significantly increased in 100% sewage sludge substrate (67.5% and 74.8%). Nutrient and heavy metal accumulations in total plant in both 50% and 100% sewage sludge substrates were significantly higher than that in the control, with 100% sewage sludge substrate being significantly higher than that in 50% sewage sludge substrate. Compared with 50% sewage sludge substrate, the increment rates of nutrient and heavy metal accumulations in different organs as well as total plants in 100% sewage sludge substrates were greatly increased. The rank of comprehensive evaluation scores of adaptability, element uptake and accumulation was in an order: 100% sewage sludge substrate (0.848) > 50% sewage sludge substrate (0.344) > control (0.080). With good adaptability to sewage sludge, B. papyrifera could grow normally in sewage sludge andeffectively absorb and fix nutrients and heavy metals. It is feasible to plant B. papyrifera into the sewage sludge for remediation of sewage sludge and resource production.

Effects of sewage sludge and other wastes application on the growth and element uptake of Jatropha curcas in abandoned rare-earth mine soil.

The wastes such as sewage sludge (SS) can be used to amend soil of abandoned rare-earth mine land (ARL). The energy plant Jatropha curcas could be used as a pioneer tree species in the ARL. In a pot experiment to address the responses of growth and element uptake of J. curcas, three treatments were established: adding SS to the soil of ARL (T1), adding SS and bagasse to the soil of ARL (T2), adding SS, bagasse and passivator to the soil of ARL (T3), with the untreated soil of the ARL as the control (CK). The results showed that compared with CK, T1 only significantly increased the plant height of J. curcas, T2 and T3 significantly increased the plant height, ground diameter and dry biomass of J. curcas, of which the total dry biomass increased by more than 184.7%. All the three treatments significantly increased the contents of N, P, K and Cu in J. curcas. T1 and T2 significantly increased the proportion of exchangeable Zn, Cd and Ni in the substrates, while T3 showed the opposite effects. T3 significantly decreased the migration factor (M) and mobility factor (MF) of Zn, Cd, Ni in the substrates, and significantly reduced the contents of Zn, Pb, Cd, Ni in J. curcas, with an inhibition rate of over 36.1%. The comprehensive evaluation of the membership function showed that the order of growth promotion effects on J. curcas was T2>T3>T1>CK, while the order of capacity of inhibiting J. curcas to accumulate Cu, Zn, Pb, Cd, Ni was T3>CK>T2>T1. The combined application of SS and bagasse significantly promoted the growth and element accumulation of J. curcas, and the addition of passivator significantly reduced heavy metals uptake without affecting the growth of J. curcas.

[Heavy metal tolerance of Miscanthus plants and their phytoremediation potential in abandoned mine land]. / èŠ’å±žæ¤ç‰©é‡é‡‘å±žè€æ€§åŠå ¶åœ¨çŸ¿å±±åºŸå¼ƒåœ°æ¤è¢«æ¢å¤ä¸­çš„åº”ç”¨æ½œåŠ›.

Miscanthus has been recognized as promising candidate for phytoremediation in abandoned mine land, because of its high tolerance to heavy metals and bioenergy potential. Miscanthus has been reported tolerant to several heavy metal elements. However, it has not been recognized as hyperaccumulator for these elements. The detailed mechanisms by which Miscanthus tolerates these heavy metal elements are still unclear. According to recent studies, several mechanisms, such as high metabolic capacity in root, an abundance of microbes in the root-rhizosphere, and high capacity of antioxidation and photosynthesis might contribute to enhance the heavy metal tolerance of Miscanthus. Miscanthus has a certain potential in the phytoremediation of abandoned mine land, because of its high suitability for the phytostabilization of heavy metals. Moreover, Miscanthus cropping is a promising practice to enhance the diversity of botanical species and soil organism, and to improve soil physical and chemical properties. Here we reviewed recent literatures on the biological characteristics and the heavy metal tolerance of Miscanthus, and its phytoremediation potential in abandoned mine land. A basic guideline for using Miscanthus in abandoned mine land phytoremediation and an outlook for further study on the mechanisms of heavy metals tolerance in Miscanthus were further proposed. We hoped to provide theoretical references for phytoremediation in abandoned mine land by using Miscanthus.

[Effects of sewage sludge compost on the growth and element uptake of Neolamarckia cadamba seedlings]. / æ±¡æ³¥å †è‚¥å¯¹é»„æ¢æœ¨å¹¼è‹—ç”Ÿé•¿å’Œå ƒç´ å¸æ”¶çš„å½±å“.

Sewage sludge compost (SSC) is rich in organic matter and nutrient elements indispensable to plant growth. Utilizing SSC as seedling growing substrate is generally recognized as a new ecological method for utilization of sewage sludge. We investigated impacts of SSC treatments including 0% (CK), 25% (T1), 50% (T2), 75% (T3), and 100% (T4) on the growth and nutrient uptake of Neolamarckia cadamba seedlings in a 7-month pot experiment. The changes in element contents in substrate after pot experiment were also addressed. Results showed the SSC treatments had significant impacts on the growth of N. cadamba seedlings. The seedlings in T4 treatment grew abnormally and all died in two weeks after transplanting. Seedling height, ground diameter and biomass in T1, T2 and T3 treatments were significantly higher than CK, with those in T2 being the best among all treatments. Seedlings in T2 and T3 treatments took up significantly more N, P, K, Cu, Zn, Pb and Cd, while those in T1 treatment absorbed significantly more N and Pb than CK. The heavy metal uptake amount of each treatment exhibited the order of Zn＞Cu＞Pb＞Cd. At the end of the pot experiment, the contents of organic matter, N, P and K in growing substrate were still relatively high, and a certain portion of heavy metals still remained in the substrate, but with lower contents than the standards set for agricultural usage-oriented sewage sludge, indicating that the post-experiment substrate may be reused.

[Effects of simulated nitrogen deposition on soil acid phosphomonoesterase activity and soil available phosphorus content in subtropical forests in Dinghushan Mountain].

An in situ field experiment was conducted to study the effects of simulated nitrogen (N) deposition on soil acid phosphomonoesterase activity (APA) and soil available phosphorous (AP) content in Pinus massoniana forest (PF), coniferous and broad-leaved mixed forest (MF), and monsoon evergreen broad-leaved forest (MEBF) in Dinghushan Mountain. In PF and MF, three treatments were installed, i.e., CK (0 kg N x hm(-2) x a(-1)), low N (50 kg N x hm(-2) x a(-1)), and medium N (100 kg N x hm(-2) x a(-1)); in MEBF, four treatments were installed, i.e., CK, low N, medium N, and high N (150 kg N x hm(-2) x a(-1)). The soil APA and soil AP content decreased with soil depth. The soil APA was the highest in MEBF, while the AP content had no significant difference in the three forests. The effects of N addition on soil APA differed with forest types. In MEBF, the APA was the highest (19.52 micromol x g(-1) x h(-1)) in low N treatment; while in PF and MF, the APA was the highest (12.74 and 11.02 micromol x g(-1) x h(-1), respectively) in medium N treatment. In the three forests, soil AP content was the highest in low N treatment, but had no significant differences among the N treatments. There was a significant positive correlation between soil APA and soil AP content.

[Soil organic carbon density of Eucalyptus plantations in Guangdong province of China and related affecting factors].

Soil samples were collected from the Eucalyptus plantations in the north, east, and west Guangdong and Pearl River Delta region to study their organic carbon content and density, and the main factors affecting the organic carbon density. In the plantations, the soil organic carbon content and density in A and B horizons were significantly different, with the values of (23.94 +/- 2.97) g x kg(-1) and (9.68 +/- 1.05) g x kg(-1), and (27.64 +/- 7.72) t x hm(-2) and (108.36 +/- 9.37) t x hm(-2), respectively. In 0-50 cm soil layer, the organic carbon density was 66.72 +/- 6.53 t x hm(-2), being slightly higher than that in Masson pine and Chinese fir plantations in Guangdong. In both A and B horizons of Eucalyptus plantations, soil organic carbon density was significantly positively correlated with altitude, soil total porosity, capillary porosity, capillary moisture capacity, and total nitrogen content. Soil capillary porosity, capillary moisture capacity, and pH value were the main factors affecting the soil organic carbon density.

[Reducing nutrients loss by plastic film covering chemical fertilizers].

With the low utilization rate of fertilizers by crop and the growing amount of fertilizer usage,the agricultural non-point source pollution in China is becoming more and more serious. The field experiments planting corns were conducted, in which the applied chemical fertilizers were recovered with plastic film to realize the separation of fertilizers from rain water. In the experiments, the influences of different fertilizing treatments on the growing and production of sweet corn were observed. The fertilizer utilization rate and the nutrient contents in surface run-off water with and without the film covering were also determined. Results showed that, with only 70% of the normal amount of fertilizers,the sweet corn could already get high yield under the experimental soil conditions. Soil analysis after corn crops showed that the amounts of available N, P and K in the soil increased obviously with the film-covering, and the decreasing order was: 100% fertilizers with film-covering > 70% fertilizers with film-covering > 100% fertilizers, 70% fertilizers > no fertilizer. The average utilization coefficients of fertilizers by the crop were 42%-87%, 0%-3%, 5%-15% respectively for N, P and K. It was higher with film-covering than that without covering, especially for the high fertilization treatment. Analysis of water samples collected for eight run-off events showed that, without film-covering, N, P and K average concentrations in the runoff waters with fertilizations were 27.72, 2.70 and 7.07 mg x L(-1), respectively. And they were reduced respectively by 39.54%, 28.05%, 43.74% with the film-covering. This can give significant benefits to the decrease of agricultural non-point source pollution and water eutrophication.

Impact of fertilization on chestnut growth, N and P concentrations in runoff water on degraded slope land in South China.

Growing fruit trees on the slopes of rolling hills in South China was causing serious environmental problems because of heavy application of chemical fertilizers and soil erosion. Suitable sources of fertilizers and proper rates of applications were of key importance to both crop yields and environmental protection. In this article, the impact of four fertilizers, i.e., inorganic compound fertilizer, organic compound fertilizer, pig manure compost, and peanut cake (peanut oil pressing residue), on chestnut (Castanea mollissima Blume) growth on a slope in South China, and on the total N and total P concentrations in runoff waters have been investigated during two years of study, with an orthogonal experimental design. Results show that the organic compound fertilizer and peanut cake promote the heights of young chestnut trees compared to the control. In addition, peanut cake increases single-fruit weights and organic compound fertilizer raises single-seed weights. All the fertilizers increased the concentrations of total N and total P in runoff waters, except for organic compound fertilizer, in the first year experiment. The observed mean concentrations of total N varied from 1.6 mg/L to 3.2 mg/L and P from 0.12 mg/L to 0.22 mg/L, which were increased with the amount of fertilizer applications, with no pattern of direct proportion. On the basis of these experiment results, organic compound fertilizer at 2 kg/tree and peanut cake at 1 kg/tree are recommended to maximize chestnut growth and minimize water pollution.

[Leaching characteristics of nitrogen and phosphorus in inorganic compound fertilizer from latosolic red soil in south China].

A soil column experiment was conducted to investigate the leaching characteristics of nitrogen and phosphorus in inorganic compound fertilizer from latosolic red soil in South China. The results revealed that the leaching loss of soil total nitrogen (TN), NH4+ -N and NO3-N was increased with increasing application rate of inorganic compound fertilizer, and 36.8%-49.2% of fertilizer nitrogen was lost with leaching water. The regression equation of TN loss (y) and N application rate (x) was y = 0. 3667x + 66. 483 (R2 = 0.992). TN and NH4+ -N losses mainly occurred in the first 5 leaching events, while NO3- -N loss continued to be significant till the 9th leaching event. Fertilization rate had no obvious impact on soil dissolved phosphorus (DP), but the leaching loss of total phosphorus (TP) and particulate phosphorus (PP) was increased with increasing fertilization rate. The fertilizer phosphorus loss was within the range of 0.002%-0.01%, and the regression equation of TP loss (y) and P application rate (x) was y = 7e(-5)x + 0.0538 (R2 = 0.931). Quite different from that of N, the leaching loss of P was a slow and continuous process. Both the leaching loss of NO3- -N / NH4+ -N and of DP/PP was decreased with increasing fertilization rate.