锌肥种类和施用方式对土壤锌形态及有效性的影响

Effect of Zn source and application method on Zn form and availability in soil

【目的】探索谷类作物适宜的锌肥种类及施用方式,为高效土施锌肥提供参考。【方法】设置连续两季小麦田间定位试验,以不施锌肥为对照,选取ZnEDTA(4kg/hm^2)和ZnSO_4(20kg/hm^2)2种锌源,采用均施和条施2种施锌方式,比较不同锌肥以不同方式施入土壤后,在连续两季小麦种植过程中土壤Zn形态的转化规律及有效性的差异。【结果】与均施锌肥相比,条施ZnEDTA和ZnSO_42种锌肥后,在第1季土壤有效锌、交换态锌、松结有机态锌的增加率分别为20.87%和374.03%,3 497.36%和1 077.39%,41.14%和256.38%,第2季增加效果有所降低;与4kg/hm^2 ZnEDTA处理相比,20kg/hm^2 ZnSO_4处理采用均施和条施2种方式均可以增加土壤有效锌及松结有机态锌、碳酸盐结合态锌含量,且两季的增加效果均较好,但与第1季相比,第2季的效果极大降低;ZnEDTA处理均施和条施均可在第1季保持较高的交换态锌含量(平均为0.26mg/kg),而在第2季该形态锌大部分被固定(平均含量为0.02mg/kg)。【结论】条施较低量的ZnEDTA可有效增加当季作物土壤中的有效锌含量,但对后季作物生长过程中土壤有效锌含量的提升效果较小。

[Objective] This study obtained suitable Zn sources and application methods to provide basis for efficient application of Zn fertilizer. [Method] A field trial was carried out over two consecutive cropping seasons,with no Zn application as control and four treatments of two Zn sources （ZnEDTA with 4 kg/hm^2 and ZnSO4 with 20 kg/hm^2） and two application methods （broadcast and band）. The soil zinc fractions and Zn availability during the two consecutive wheat cropping seasons were compared. [Result] Compared to broadcast application, band application of ZnEDTA and ZnSO4 increased soil DTPA-Zn, exchangeable Zn （Ex-Zn）,and weakly bond to organic matter Zn （Wbo-Zn） by 20. 87% and 374. 03%, 3 497.36% and 1 077. 39%,and 41. 14% and 256. 38M in the first season,and these fractions reduced slightly in the subsequent season. Compared to 4 kg/hm2 EDTA-Zn application,20 kg/hm2 ZnSO4 application increased the contents of soil DTPA-Zn,Wbo-Zn,and carbonate bond Zn （Carb-Zn） in both seasons, although the effect in the subsequent season was lower. EDTA-Zn application could maintain high content of Ex-Zn in the first season （with an average of 0.26 mg/kg） ,and most of the Ex-Zn was fixed in the subsequent season（with an average of 0.02 mg/kg）. [Conclusion] In conclusion, band application of low level of EDTA-Zn could effectively increase soil DTPA-Zn content in the first cropping season, while the efficiency was lower in the subsequent cropping season.