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Zhang B.-G.E.,Guangdong Academy of Agricultural Sciences | Zhang B.-G.E.,Key Laboratory of Plant nutrition and Fertilizer | Zhang B.-G.E.,China Agricultural University | Li Q.,Guangdong Academy of Agricultural Sciences | And 4 more authors.
Research on Crops | Year: 2013

Chinese kale (Brassica alboglabra Bailey) production faces growing challenge from long-term over fertilizing. Potassium is the biggest demand and one of the most frequently overused nutrients for Chinese kale, inducing extensive environment and safe concern. Quick and accurate response to nutrient requirement is an effective solution. Therefore, pot experiments were conducted to study the influence of potassium fertilizer in different rates on the growth and nutrition utilization capacity of Chinese kale and the SPAD-502 chlorophyll meter was evaluated throughout season for its potential to determine the need for K fertilizer by Chinese kale. Potassium fertilizers were added to soil at five levels : 0, 100, 200, 300 and 400 mg/kg soil as KCl. The K rates were found to affect the growth of the leaves and stems, morphology of roots and utilization of K nutrition. Three hundred mg/kg K significantly increased stem/leaf ratio and K content in above-ground. The highest dry weight and K utilization of whole plant were obtained under 200 mg/kg K conditions and were associated with increased root length and surface area compared to other treatments. In quik-leaf-growth stage, relatively strong correlationship between SPAD and dry weight, K fertilizer amount and K content in stem was observed. These data provide preliminary results to establish the final proposal for environmentally and economically use of K fertilizer and it is the first step to further develop precision agriculture for vegetables in tropic and sub-tropical regions of China. Source

Qiu S.J.,Key Laboratory of Plant nutrition and Fertilizer | He P.,Key Laboratory of Plant nutrition and Fertilizer | Zhao S.C.,Key Laboratory of Plant nutrition and Fertilizer | Li W.J.,Key Laboratory of Plant nutrition and Fertilizer | And 5 more authors.
Agronomy Journal | Year: 2015

Optimizing N fertilization is important to improve both maize (Zea mays L.) yield and nitrogen use efficiencies (NUEs). A 3-yr maize field experiment (2008-2010) was conducted to evaluate the response of grain yield, aboveground biomass, plant N concentration, N uptake, and NUEs to fertilizer N rates from 0 to 280 kg N ha-1 at three di erent rain-fed Haplic Phaeozem soils (FAO classification) in Northeast China. When N application rate increased from 70 to 280 kg N ha-1 across all site-years, N recovery efficiency, N agronomic efficiency, N internal efficiency and N partial factor productivity decreased from 76.5 to 9.0%, 25.3 to 0.1 kg kg-1, 70.7 to 40.8 kg kg-1, and 145.6 to 22.8 kg kg-1, respectively. Differences observed among the years and experimental sites were primarily caused by variability in rainfall and soil characteristics. The maximal grain yield of 11.0 Mg ha-1 was achieved at an N rate of 210 kg N ha-1 with normal rainfall. Nitrogen application beyond the optimal N rate did not consistently increase grain yield, and caused a decrease in NUEs. The range of optimal N rate for maize grain yield fell between 140 and 210 kg N ha-1 at the three sites from 2008 to 2010 in Northeast China based on the best fitted models (quadratic, linear plus plateau, and quadratic plus plateau). The results provide guidelines for selecting N application rates to optimize both maize yield and NUEs in Northeast China. © 2015 by the American Society of Agronomy, 5585 Guilford Road, Madison, WI 53711. All rights reserved. Source

Liu Y.,Guangxi Academy of Agricultural science | Liu Y.,Key Laboratory of Plant nutrition and Fertilizer | Xiong L.,Guangxi Academy of Agricultural science | Xiong L.,Key Laboratory of Plant nutrition and Fertilizer | And 11 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2014

Changes of soil fertility under different stands was studied by investigating pH value; organic matter; whole amount of N, P, K; available N, P, K and CEC (cation exchange capacity) in 0—30cm depth of soil. Three main types of soils in guangxi was selected which includes mountain yellow soil, brown calcareous soil and lateritic red soil The results showed that stand type affected soil fertility status. For mountain yellow soil, soil organic matter content under Pine forest and adult birch were 2.55 and 3.16 times to natural forest, while the soil available nutrients of newly planted birch was significantly higher than natural forests. For brown calcareous soil, the organic matter, total nitrogen, total phosphorus, available of nitrogen, phosphorus, potassium and CEC under Zenia forest were the highest, and the pH value under loquat forest was significantly lower than the other three kinds of forest. For lateritic red soil, the available nitrogen under 2nd generation of fast-growing eucalyptus forests was significantly lower than natural pine broadleaf forest, but the organic matter, total nitrogen, total potassium, available potassium were slightly higher than the natural forest. The comprehensive evaluation showed soil fertility changed with stand type by the following sequence: natural forest> pine> Southwest birch for mountain yellow soil; Zenia forest= bamboo forest >loquat forest≈Leucaena forest for brown calcareous soil; and natural pine broadleaf forest抑the 2nd generation of fast-growing eucalyptus forests for lateritic red soil. © 2014, Science Press. All rights Reserved. Source

Deng H.,Key Laboratory of Plant nutrition and Fertilizer | Deng H.,Hainan University | Yu H.M.,China University of Mining and Technology | Chen M.,Chinese Academy of Sciences | And 2 more authors.
Advanced Materials Research | Year: 2014

On the basis of OCED Guideline 106, batch sorption studies were employed to reveal sorption of atrazine by amending biochar in tropical soils, namely, laterite, paddy soil and dry red soil. Biochar, a micro-porosity and great surface product, was generated by pyrolysis of manioc wastes at 750°C(BC750) and modified substances(MC750) were produced by loading Fe3+. The mechanism of sorption was examined by charactering BC750 and MC750. In this study, carbonization can improve aromaticity, specific surface and alkaline groups of biomass. The isotherms of atrazine in soil seemed closed to linear with partition, whereas the sorption of atrazine in biochar-added soil was a mainly pore-filling mechanism to exhibit nonlinearity. Temkin model was satisfactorily analyzed the sorption isotherm of atrazine by BC750/MC750 into soil with R2 between 0.92~0.998. HI of all the sorbents were greater than 1, which indicated that the desorption rate was higher than the sorption rate. BC750/MC750 had a greater affinity for atrazine in soil than that of unamended soil. And the sorption capacity of unmodified biochar is slightly less than modified biochar, but the desorbed amounts of atrazine are less. Results indicated that biochars derived from agricultural wastes can play a crucial role in the removal of hydrophobic organic chemicals. © (2014) Trans Tech Publications, Switzerland. Source

Feng D.,Key Laboratory of Plant nutrition and Fertilizer | Feng D.,Hainan University | Deng H.,Hainan University | Yu H.M.,China University of Mining and Technology | And 4 more authors.
Advanced Materials Research | Year: 2014

To study the biochar properties and its influence on Cu (II) adsorption, biochar was prepared from bagasse under the conditions of 350°C, 450°C and 550°C respectively, and biochar was added to three typical tropical soils (paddy soil, laterite and dry red soil). After mixed culture for 30 d, batch equilibrium experiment method was used to determine the effect of biochar on soil adsorption of Cu (II) before the characterization of biochar properties. Results showed that ash content, CEC and pH value of were increased with the increase of pyrolysis temperature. PH values ranged from 5.56 to 8.92. Moreover, the specific surface area and pore structure were affected by pyrolysis temperature. In addition, when biochar was added into soils, the adsorption capacity of Cu (II) in paddy soil, laterite and dry red soil increased by 85.98%, 89.07% and 94.73% respectively. Freundlich and Langmuir equation could be fit for adsorption isotherm of Cu (II). Results demonstrated that the Freundlich model (R2>0.976) was the better isotherm than Langmuir model (R2>0.917). © (2014) Trans Tech Publications, Switzerland. Source

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