This study is a contribution to improving rice productivity on acidic plateau soils of the tropical rainforest zone. It is based on taking into account the cationic balances of the soil in order to optimize the phosph...This study is a contribution to improving rice productivity on acidic plateau soils of the tropical rainforest zone. It is based on taking into account the cationic balances of the soil in order to optimize the phosphorus (P) nutrition of rice on these acidic soils, where this nutrient constitutes a limiting factor for agricultural production. Three (3) pot trials were conducted in Adiopodoumé in the forested south of Côte d’Ivoire. The interactive effects of calcium carbonate (0, 25, 50 and 75 kg Ca ha<sup>−1</sup>) and magnesium sulfate (0, 25, 50 and 75 kg Mg ha<sup>−1</sup>) were evaluated on the response of NERICA 5 rice at doses 0, 25, 50 and 75 kg P ha<sup>−1</sup> of natural phosphate from Togo, applied only once at the start of the experiment. Additional fertilizers of nitrogen (N) (100 kg N ha<sup>−1</sup>) and potassium (K) (50 kg KCl ha<sup>−1</sup>) were added to each of the tests in a split-plot device. The test results revealed a paddy production potential of approximately 3 to 5 t⋅ha<sup>−1</sup> for NERICA 5 on an acidic soil, under the effect of the interaction of P, Ca and Mg. The quadratic response of rice yield to the doses of these fertilizers would be more dependent on their balance, itself influenced by Ca nutrition. For the sustainability and maintenance of rice production in agro-ecology studied, it was recommended doses of 38 kg Ca ha<sup>−1</sup>, 34 kg Mg ha<sup>−1</sup> in a Ca/Mg ratio (1/1) with intakes of 41 kg P ha<sup>−1</sup>, overall in a ratio 1/1/1 (P/Ca/Mg) more favorable to the availability of free iron considered a guiding element of mineral nutrition. Thus, these promising results should be confirmed in a real environment for better management of the fertilization of rice cultivated on acidic plateau soils in Côte d’Ivoire.展开更多
A leaching experiment was carried out with repacked soil columns in laboratory to stndy the leachingprocess of a red soil derived from sandstone as affected by warions fertilization practices. The treatments wereCK (a...A leaching experiment was carried out with repacked soil columns in laboratory to stndy the leachingprocess of a red soil derived from sandstone as affected by warions fertilization practices. The treatments wereCK (as a control), CaCO_3, CaSO_4, MgCO_3, Ca(H_2PO_4)_2, Urea, KCl, Mnltiple (a mixture of the above-mentioned fertilizers), and KNO_3. The fertilizers were added to the bare surface of the soil columns, andthen the columns were leached with 120 mL deionized water daily through peristaltic pumps over a periodof 92 days. At the end of leaching process, soils were sampled from different depths of the soil profiles, i.e.,0-5 cm, 5-10 cm, 10-20 cm, 20-40 cm, and 40-60 cm. The results showed when applying Ca, Mg, andK to the bare surface of the soil columns, exchangeable Ca￣(2+), Mg￣(2+), and K￣+ in the upper layer of thesoil profile increased correspondingly, with an extent depending mainly on the application rates of Ca, Mg,and K and showing a downward trend. CaCO_3, CaSO_4, MgCO_3, and Ca(H_2PO_4)_2 treatments had scarcelyany effect on movement of exchangeable K￣+, while CaCO_3, and CaSO_4 treatments significantly promotedthe downward movement of exchangeable Mg￣(2+) although these two treatments had no obvious effect onleaching losses of Mg. The fact that under Urea treatment, exchangeable Ca￣(2+) and Mg￣(2+) were higheras compared to CK treatment showed urea could prevent leaching of exchangeable Ca￣(2+) and Mg￣(2+). Theobvious downward movement of exchangeable Ca￣(2+) and Mg￣(2+) was noticed in KCl treatment. In Multipletreatment, the downward movement of exchangeable Ca￣(2+) and Mg￣(2+) was evident, while that of K￣+ was lessevident. Application of KNO_3 strongly promoted the downward movement of exchangeable Ca￣(2+) and Mg￣(2+)in the soil profile.展开更多
In order to simulate the evolution of affordable housing land use a dynamic model that combines cellular automata CA and a multi-agent system MAS is established.This paper aims to utilize the approach of decision fact...In order to simulate the evolution of affordable housing land use a dynamic model that combines cellular automata CA and a multi-agent system MAS is established.This paper aims to utilize the approach of decision factors on site selection of affordable housing through a literature review to construct a hierarchy model of those factors identifying the weight of each factor by an analytic hierarchy process AHP .Based on those weight factors the CA-MAS model is designed. Nanjing city is taken as an example to verify the feasibility of the model.The results show that the CA-MAS model is pragmatic and effective in simulating evolution of affordable housing land use which also promotes the fundamental understanding and perception of the development of affordable housing and urbanization.展开更多
Objective The Shiquanhe ophiolite is an important tectonic belt in western Tibet. It has been debated whether the Shiquanhe ophiolite represents an allochthonous nappe derived from the Bangong-Nujiang suture zone to t...Objective The Shiquanhe ophiolite is an important tectonic belt in western Tibet. It has been debated whether the Shiquanhe ophiolite represents an allochthonous nappe derived from the Bangong-Nujiang suture zone to the north or the展开更多
文摘This study is a contribution to improving rice productivity on acidic plateau soils of the tropical rainforest zone. It is based on taking into account the cationic balances of the soil in order to optimize the phosphorus (P) nutrition of rice on these acidic soils, where this nutrient constitutes a limiting factor for agricultural production. Three (3) pot trials were conducted in Adiopodoumé in the forested south of Côte d’Ivoire. The interactive effects of calcium carbonate (0, 25, 50 and 75 kg Ca ha<sup>−1</sup>) and magnesium sulfate (0, 25, 50 and 75 kg Mg ha<sup>−1</sup>) were evaluated on the response of NERICA 5 rice at doses 0, 25, 50 and 75 kg P ha<sup>−1</sup> of natural phosphate from Togo, applied only once at the start of the experiment. Additional fertilizers of nitrogen (N) (100 kg N ha<sup>−1</sup>) and potassium (K) (50 kg KCl ha<sup>−1</sup>) were added to each of the tests in a split-plot device. The test results revealed a paddy production potential of approximately 3 to 5 t⋅ha<sup>−1</sup> for NERICA 5 on an acidic soil, under the effect of the interaction of P, Ca and Mg. The quadratic response of rice yield to the doses of these fertilizers would be more dependent on their balance, itself influenced by Ca nutrition. For the sustainability and maintenance of rice production in agro-ecology studied, it was recommended doses of 38 kg Ca ha<sup>−1</sup>, 34 kg Mg ha<sup>−1</sup> in a Ca/Mg ratio (1/1) with intakes of 41 kg P ha<sup>−1</sup>, overall in a ratio 1/1/1 (P/Ca/Mg) more favorable to the availability of free iron considered a guiding element of mineral nutrition. Thus, these promising results should be confirmed in a real environment for better management of the fertilization of rice cultivated on acidic plateau soils in Côte d’Ivoire.
文摘A leaching experiment was carried out with repacked soil columns in laboratory to stndy the leachingprocess of a red soil derived from sandstone as affected by warions fertilization practices. The treatments wereCK (as a control), CaCO_3, CaSO_4, MgCO_3, Ca(H_2PO_4)_2, Urea, KCl, Mnltiple (a mixture of the above-mentioned fertilizers), and KNO_3. The fertilizers were added to the bare surface of the soil columns, andthen the columns were leached with 120 mL deionized water daily through peristaltic pumps over a periodof 92 days. At the end of leaching process, soils were sampled from different depths of the soil profiles, i.e.,0-5 cm, 5-10 cm, 10-20 cm, 20-40 cm, and 40-60 cm. The results showed when applying Ca, Mg, andK to the bare surface of the soil columns, exchangeable Ca￣(2+), Mg￣(2+), and K￣+ in the upper layer of thesoil profile increased correspondingly, with an extent depending mainly on the application rates of Ca, Mg,and K and showing a downward trend. CaCO_3, CaSO_4, MgCO_3, and Ca(H_2PO_4)_2 treatments had scarcelyany effect on movement of exchangeable K￣+, while CaCO_3, and CaSO_4 treatments significantly promotedthe downward movement of exchangeable Mg￣(2+) although these two treatments had no obvious effect onleaching losses of Mg. The fact that under Urea treatment, exchangeable Ca￣(2+) and Mg￣(2+) were higheras compared to CK treatment showed urea could prevent leaching of exchangeable Ca￣(2+) and Mg￣(2+). Theobvious downward movement of exchangeable Ca￣(2+) and Mg￣(2+) was noticed in KCl treatment. In Multipletreatment, the downward movement of exchangeable Ca￣(2+) and Mg￣(2+) was evident, while that of K￣+ was lessevident. Application of KNO_3 strongly promoted the downward movement of exchangeable Ca￣(2+) and Mg￣(2+)in the soil profile.
基金The National Social Science Foundation of China(No.14AJY013)the Scientific Innovation Research of College Graduates in Jiangsu Province(No.CXLX13_126)
文摘In order to simulate the evolution of affordable housing land use a dynamic model that combines cellular automata CA and a multi-agent system MAS is established.This paper aims to utilize the approach of decision factors on site selection of affordable housing through a literature review to construct a hierarchy model of those factors identifying the weight of each factor by an analytic hierarchy process AHP .Based on those weight factors the CA-MAS model is designed. Nanjing city is taken as an example to verify the feasibility of the model.The results show that the CA-MAS model is pragmatic and effective in simulating evolution of affordable housing land use which also promotes the fundamental understanding and perception of the development of affordable housing and urbanization.
基金financially supported by the National Natural Science Foundation (grants No. 41102065 and 41872110)the Sichuan Science and Technology Program (grant No. 2018JY0465)
文摘Objective The Shiquanhe ophiolite is an important tectonic belt in western Tibet. It has been debated whether the Shiquanhe ophiolite represents an allochthonous nappe derived from the Bangong-Nujiang suture zone to the north or the
