Amaranthus cruentus is one of the sixty Amaranthus species of world. It is widely grown as a green leafy vegetable and for its grain in many tropical countries of Africa, Central and South American, Canada, Mexico and...Amaranthus cruentus is one of the sixty Amaranthus species of world. It is widely grown as a green leafy vegetable and for its grain in many tropical countries of Africa, Central and South American, Canada, Mexico and parts of Asia. Depleted soil fertility under intensive cultivation is a major limitation to production of the vegetable. The study investigated the effects of two types of poultry manure on biomass yield and nutrient uptake of Amaranth cruentus in a greenhouse at the University of Manitoba, Winnipeg, Manitoba, Canada in 2011. The experiment was a 2 × 3 × 3 factorial arranged into a Randomized Completely Block Design and replicated three times. The factors were two soil types, two sources of poultry manure and urea, and N rates at 0, 60 and 120 kg⋅N⋅ha−1. Nitrogen uptake by the plants that treated with poultry manure from Canada (PMC) and Urea was 172.5 vs. 171.4 mg⋅pot−1 and 169.5 vs. 163.7 mg⋅pot−1 respectively which were significantly greater than the poultry manure from Nigeria (PMN), 100.6 mg⋅pot−1 and 110.0 mg⋅pot−1 for Red River and Glenhope soil series, respectively. Nitrogen uptake was similar at the N rates of 60 and 120 kg⋅N⋅ha−1 (140.7 vs. 155.6 mg⋅pot−1) in the Red River soil, while N uptake at 120 kg⋅N⋅ha−1 was greater than at 60 kg⋅N⋅ha−1 in Glenhope soil. Shoot dry matter of the vegetable grown in soils treated with PMC and urea was significantly greater than from PMN in Red River soil (10.1, 9.6 and 6.7 g⋅pot−1) and in Glenhope soil (8.8, 8.1 and 6.4 g⋅pot−1). Phosphorus, K, Ca and Mg uptake at 60 and 120 kg⋅</展开更多
Two field studies were carried out using Solanum macrocarpon and Solanum scabrum to investigate the effects of planting methods and seed density required for optimum biomass yield and nutrient content in southwest Nig...Two field studies were carried out using Solanum macrocarpon and Solanum scabrum to investigate the effects of planting methods and seed density required for optimum biomass yield and nutrient content in southwest Nigeria. Two planting methods (drilling and broadcasting), and two seed densities (4 and 8 table spoon full) were investigated as a 2×2×3 factorial experiment in randomized complete block design and replicated three times. Four seed spoons gave 25.78 kg seeds ha-1 for S. macrocarpon and 20.67 kg·seeds·ha-1 for S. scabrum. Significant highest S. macrocarpon shoots (2.75 kg·m-2) and Ca, K, Fe and Zn contents and S. scabrum (2.95 kg·m-2) and Zn content, were obtained with drilling and four spoons of seeds compared with broadcasting and 8 spoons of seeds. This treatment gave average values for N, P, K, Mg, Ca, Na, Fe, Zn, Mn, Cu, Ca/P and Na/K ratio were 2.79%, 0.03%, 3.37%, 1.64%, 0.02%, 300 mg·kg-1, 100 mg·kg-1, 300 mg·kg-1, 8 mg·kg-1, 1.22 and 0.008 for S. macrocarpon and 2.05%, 0.27%, 5.81%, 3.27%, 2.91%, 0.09%, 280 mg·kg-1, 52.99 mg·kg-1, 359.35 mg·kg-1 and 22.42 mg·kg-1, 11.63 and 0.016 for S. scabrum. It was concluded that planting in drilling made weeding, fertilizer application, irrigation and harvesting more effective rather than by broadcasting, and four spoons of seeds per 9 m-2 produced deep green and broader leaves and balanced nutrient contents than eight spoons of seeds.展开更多
As an essential property of frozen soils,change of unfrozen water content(UWC)with temperature,namely soil-freezing characteristic curve(SFCC),plays significant roles in numerous physical,hydraulic and mechanical proc...As an essential property of frozen soils,change of unfrozen water content(UWC)with temperature,namely soil-freezing characteristic curve(SFCC),plays significant roles in numerous physical,hydraulic and mechanical processes in cold regions,including the heat and water transfer within soils and at the land–atmosphere interface,frost heave and thaw settlement,as well as the simulation of coupled thermo-hydro-mechanical interactions.Although various models have been proposed to estimate SFCC,their applicability remains limited due to their derivation from specific soil types,soil treatments,and test devices.Accordingly,this study proposes a novel data-driven model to predict the SFCC using an extreme Gradient Boosting(XGBoost)model.A systematic database for SFCC of frozen soils compiled from extensive experimental investigations via various testing methods was utilized to train the XGBoost model.The predicted soil freezing characteristic curves(SFCC,UWC as a function of temperature)from the well-trained XGBoost model were compared with original experimental data and three conventional models.The results demonstrate the superior performance of the proposed XGBoost model over the traditional models in predicting SFCC.This study provides valuable insights for future investigations regarding the SFCC of frozen soils.展开更多
Inappropriate nitrogen fertilizer management for the intensive Chinese vegetable production has caused low N use efficiency(NUE),high reactive nitrogen(Nr)losses and serious environmental risks with limited yield incr...Inappropriate nitrogen fertilizer management for the intensive Chinese vegetable production has caused low N use efficiency(NUE),high reactive nitrogen(Nr)losses and serious environmental risks with limited yield increase.Innovative N management strategy is an urgent need to achieve sustainable vegetable production.This paper summarizes recent studies on Nr losses and identifies the limitations from Chinese vegetable production systems and proposes three steps for sustainable N management in Chinese vegetable production.The three N management steps include,but are not limited to,(1)knowledge-based optimization of N fertilizer rate strategy,which maintains soil N supply to meet the dynamic vegetable demand in time,space and quantity;(2)innovative products and technology,which regulates the soil N forms and promotes the vegetable root growth to reduce the Nr loss;(3)integrated knowledge and products strategy(IKPS).The knowledge-based optimization of N fertilizer rate strategy and innovative products and technology,can maintain or increase vegetable yield,significantly improve NUE,and mitigate the region-specific and crop-specific Nr losses.More importantly,IKPS,based on combination of in-season root-zone N management strategy,innovative products and technology,and best crop cultivation management,is needed to produce more vegetables with lower Nr losses.展开更多
文摘Amaranthus cruentus is one of the sixty Amaranthus species of world. It is widely grown as a green leafy vegetable and for its grain in many tropical countries of Africa, Central and South American, Canada, Mexico and parts of Asia. Depleted soil fertility under intensive cultivation is a major limitation to production of the vegetable. The study investigated the effects of two types of poultry manure on biomass yield and nutrient uptake of Amaranth cruentus in a greenhouse at the University of Manitoba, Winnipeg, Manitoba, Canada in 2011. The experiment was a 2 × 3 × 3 factorial arranged into a Randomized Completely Block Design and replicated three times. The factors were two soil types, two sources of poultry manure and urea, and N rates at 0, 60 and 120 kg⋅N⋅ha−1. Nitrogen uptake by the plants that treated with poultry manure from Canada (PMC) and Urea was 172.5 vs. 171.4 mg⋅pot−1 and 169.5 vs. 163.7 mg⋅pot−1 respectively which were significantly greater than the poultry manure from Nigeria (PMN), 100.6 mg⋅pot−1 and 110.0 mg⋅pot−1 for Red River and Glenhope soil series, respectively. Nitrogen uptake was similar at the N rates of 60 and 120 kg⋅N⋅ha−1 (140.7 vs. 155.6 mg⋅pot−1) in the Red River soil, while N uptake at 120 kg⋅N⋅ha−1 was greater than at 60 kg⋅N⋅ha−1 in Glenhope soil. Shoot dry matter of the vegetable grown in soils treated with PMC and urea was significantly greater than from PMN in Red River soil (10.1, 9.6 and 6.7 g⋅pot−1) and in Glenhope soil (8.8, 8.1 and 6.4 g⋅pot−1). Phosphorus, K, Ca and Mg uptake at 60 and 120 kg⋅</
文摘Two field studies were carried out using Solanum macrocarpon and Solanum scabrum to investigate the effects of planting methods and seed density required for optimum biomass yield and nutrient content in southwest Nigeria. Two planting methods (drilling and broadcasting), and two seed densities (4 and 8 table spoon full) were investigated as a 2×2×3 factorial experiment in randomized complete block design and replicated three times. Four seed spoons gave 25.78 kg seeds ha-1 for S. macrocarpon and 20.67 kg·seeds·ha-1 for S. scabrum. Significant highest S. macrocarpon shoots (2.75 kg·m-2) and Ca, K, Fe and Zn contents and S. scabrum (2.95 kg·m-2) and Zn content, were obtained with drilling and four spoons of seeds compared with broadcasting and 8 spoons of seeds. This treatment gave average values for N, P, K, Mg, Ca, Na, Fe, Zn, Mn, Cu, Ca/P and Na/K ratio were 2.79%, 0.03%, 3.37%, 1.64%, 0.02%, 300 mg·kg-1, 100 mg·kg-1, 300 mg·kg-1, 8 mg·kg-1, 1.22 and 0.008 for S. macrocarpon and 2.05%, 0.27%, 5.81%, 3.27%, 2.91%, 0.09%, 280 mg·kg-1, 52.99 mg·kg-1, 359.35 mg·kg-1 and 22.42 mg·kg-1, 11.63 and 0.016 for S. scabrum. It was concluded that planting in drilling made weeding, fertilizer application, irrigation and harvesting more effective rather than by broadcasting, and four spoons of seeds per 9 m-2 produced deep green and broader leaves and balanced nutrient contents than eight spoons of seeds.
基金supported by the National Natural Science Foundation of China(Grant No.42177291)Innovation Capability Support Program of Shaanxi Province(2023-JC-JQ-25 and 2021KJXX-11).
文摘As an essential property of frozen soils,change of unfrozen water content(UWC)with temperature,namely soil-freezing characteristic curve(SFCC),plays significant roles in numerous physical,hydraulic and mechanical processes in cold regions,including the heat and water transfer within soils and at the land–atmosphere interface,frost heave and thaw settlement,as well as the simulation of coupled thermo-hydro-mechanical interactions.Although various models have been proposed to estimate SFCC,their applicability remains limited due to their derivation from specific soil types,soil treatments,and test devices.Accordingly,this study proposes a novel data-driven model to predict the SFCC using an extreme Gradient Boosting(XGBoost)model.A systematic database for SFCC of frozen soils compiled from extensive experimental investigations via various testing methods was utilized to train the XGBoost model.The predicted soil freezing characteristic curves(SFCC,UWC as a function of temperature)from the well-trained XGBoost model were compared with original experimental data and three conventional models.The results demonstrate the superior performance of the proposed XGBoost model over the traditional models in predicting SFCC.This study provides valuable insights for future investigations regarding the SFCC of frozen soils.
基金supported by the Regional Innovation and Development Joint Fund project of National Foundation of China(U20A2047).
文摘Inappropriate nitrogen fertilizer management for the intensive Chinese vegetable production has caused low N use efficiency(NUE),high reactive nitrogen(Nr)losses and serious environmental risks with limited yield increase.Innovative N management strategy is an urgent need to achieve sustainable vegetable production.This paper summarizes recent studies on Nr losses and identifies the limitations from Chinese vegetable production systems and proposes three steps for sustainable N management in Chinese vegetable production.The three N management steps include,but are not limited to,(1)knowledge-based optimization of N fertilizer rate strategy,which maintains soil N supply to meet the dynamic vegetable demand in time,space and quantity;(2)innovative products and technology,which regulates the soil N forms and promotes the vegetable root growth to reduce the Nr loss;(3)integrated knowledge and products strategy(IKPS).The knowledge-based optimization of N fertilizer rate strategy and innovative products and technology,can maintain or increase vegetable yield,significantly improve NUE,and mitigate the region-specific and crop-specific Nr losses.More importantly,IKPS,based on combination of in-season root-zone N management strategy,innovative products and technology,and best crop cultivation management,is needed to produce more vegetables with lower Nr losses.
