Soil temperature is an important variable governing plant growth and development. Studies were conducted under laboratory conditions to determine the effect of soil temperature on root and shoot growth of cotton durin...Soil temperature is an important variable governing plant growth and development. Studies were conducted under laboratory conditions to determine the effect of soil temperature on root and shoot growth of cotton during emergence. Cotton seedlings were grown for 192 h at 20, 32 and 38℃ in soil packed in 300 mm long and 50 mm diameter cylinders. The data indicated that the longest roots （173 ram） as well as shoots （152 mm） were recorded at 32℃ followed by 20 （130 mm root and 82 mm shoot） and 38℃ （86 mm root and 50 mm shoot）. Roots grown at 20 and 38 ℃ were 20% and 50% shorter, respectively, than those grown at 32℃ after 192 h. Roots and shoots exhibited the lowest length and dry biomass at 38 ℃. Shoot lengths grown at 20 （74 mm） and 38℃（51 mm） were 44% and 61% shorter than those grown at 32℃（131 mm） after 180 h growth period, respectively. Growth at all three temperatures followed a similar pattern. Initially there was a linear growth phase followed by the reduction or cessation of growth. Time to cessation of growth varied with temperature and decreased faster at higher temperatures. Sowing of cotton should be accomplished before seedbed reaches a soil temperature （≥ 38 ℃） detrimental for emergence. Further, the seedbeds should be capable of providing sufficient moisture and essential nutrients for emerging seedling before its seed reserves are exhausted to enhance seedling establishment in soil.展开更多
This model is dedicated to visualizing the nature of magnetite-water nanoliquid induced by a permeable plate having variable magnetic effect,non-linear radiation,heterogeneous and homogeneous chemically reactive spec...This model is dedicated to visualizing the nature of magnetite-water nanoliquid induced by a permeable plate having variable magnetic effect,non-linear radiation,heterogeneous and homogeneous chemically reactive species.The system of momentum,thermal and concentration expressions is formulated and transformed from the partial to ordinary differential systems by using the adequate transforms.This highly non-linear system is solved through RKF(Runge-Kutta-Fehlberg)numerical method.Important parameters such as suction/injection,magnetic,and radiation effects as well as other relevant parameters are investigated.The graphs show that the rise in radiation parameter numerically improves the thermal distribution,implying a faster heat transfer rate.Non-linear radiation has greater effect on temperature than the linear radiation.While the volume concentration effect reveals that the friction factor increase with the enhancement of nanoparticle concentration.It is also observed that,plate velocity decreases the skin-friction but increases the wall heat transfer for both suction and blowing cases.The results indicate that the current research has a strong agreement with the relevant data in a limiting approach.展开更多
基金Project supported by the Pakistan Agricultural Research Council,Islamabad,Pakistan.
文摘Soil temperature is an important variable governing plant growth and development. Studies were conducted under laboratory conditions to determine the effect of soil temperature on root and shoot growth of cotton during emergence. Cotton seedlings were grown for 192 h at 20, 32 and 38℃ in soil packed in 300 mm long and 50 mm diameter cylinders. The data indicated that the longest roots （173 ram） as well as shoots （152 mm） were recorded at 32℃ followed by 20 （130 mm root and 82 mm shoot） and 38℃ （86 mm root and 50 mm shoot）. Roots grown at 20 and 38 ℃ were 20% and 50% shorter, respectively, than those grown at 32℃ after 192 h. Roots and shoots exhibited the lowest length and dry biomass at 38 ℃. Shoot lengths grown at 20 （74 mm） and 38℃（51 mm） were 44% and 61% shorter than those grown at 32℃（131 mm） after 180 h growth period, respectively. Growth at all three temperatures followed a similar pattern. Initially there was a linear growth phase followed by the reduction or cessation of growth. Time to cessation of growth varied with temperature and decreased faster at higher temperatures. Sowing of cotton should be accomplished before seedbed reaches a soil temperature （≥ 38 ℃） detrimental for emergence. Further, the seedbeds should be capable of providing sufficient moisture and essential nutrients for emerging seedling before its seed reserves are exhausted to enhance seedling establishment in soil.
文摘This model is dedicated to visualizing the nature of magnetite-water nanoliquid induced by a permeable plate having variable magnetic effect,non-linear radiation,heterogeneous and homogeneous chemically reactive species.The system of momentum,thermal and concentration expressions is formulated and transformed from the partial to ordinary differential systems by using the adequate transforms.This highly non-linear system is solved through RKF(Runge-Kutta-Fehlberg)numerical method.Important parameters such as suction/injection,magnetic,and radiation effects as well as other relevant parameters are investigated.The graphs show that the rise in radiation parameter numerically improves the thermal distribution,implying a faster heat transfer rate.Non-linear radiation has greater effect on temperature than the linear radiation.While the volume concentration effect reveals that the friction factor increase with the enhancement of nanoparticle concentration.It is also observed that,plate velocity decreases the skin-friction but increases the wall heat transfer for both suction and blowing cases.The results indicate that the current research has a strong agreement with the relevant data in a limiting approach.
