摘要
研究品种与栽培方法的配合效应对改良３—１式棉花生育和产量影响的结果表明：现蕾前，不同品种相同栽培方法下的棉苗生育动态一致，且品种间差异不明显；相同品种不同栽培方法下的棉苗生育动态迥异。现蕾后，营养钵育苗移栽和地膜覆盖栽培有利于中熟品种棉株生育和产量形成，对于中早熟品种则利于其棉株前期生育，但中后期长势弱，伏桃和秋桃比例失调，产量降低；中熟品种直播则表现晚发，伏桃和秋桃比例失调，铃重、衣分、产量均降低，而中早熟品种直播则利于其品种特性发挥，伏桃和秋桃比例适宜。
The colour reaction of calcium with P-Cl-arsenazo has been studied.It is shown that the blue complex of Ca 2+ with P-Cl-arsenazo is formed in NaOH medium.Its maximum absorption wavelength is located at 635nm.The molar absorptivity ε 635 is 1.3×10 4.Beer's law is obeyed in the range of 0￣1.6 mg·L -1 for calcium.The composition of the complex was found to be Ca:R=1∶2.This method can be applied to the determination of trace calcium in soil extracting solution and water samples with favorable sensitivity and accuracy.The extraction of calcium is 92￣104 percent.
出处
《山东农业大学学报（自然科学版）》
CSCD
1996年第4期467-475,共9页
Journal of Shandong Agricultural University：Natural Science Edition
