Field evaluation of Zincated nanoclay polymer composite (ZNCPC): Impact on DTPA-extractable Zn, sequential Zn fractions and apparent Zn recovery under rice rhizosphere

摘要

Zinc (Zn) deficiency is a widespread phenomenon globally. Conventional Zn fertilizers (ZnSO4 center dot 7H(2)O) are reported to have very low use efficiency of applied Zn (1-5%). Hence, technological interventions in increasing Zn efficiency are of utmost importance. Keeping in this background, the present investigation was undertaken with the objectives of evaluating ZNCPC (Zincated nanoclay polymer composites), Nano ZnO and ZnSO4 center dot 7H(2)O on various fractions of soil Zn and agronomic parameters under rice rhizosphere in field experiment for two consecutive growing seasons. Nano Zn carriers (ZNCPC at three doses 100%, 75% and 50%) and nano ZnO were evaluated in comparison with ZnSO4 center dot 7H(2)O in a field experiment under rice (Rajendra Mahsuri) rhizosphere. DTPA Zn was significantly increased under 100% ZNCPC (1.99 mg kg(-1)). Sequential Zn fractionation revealed that under ZNCPC treatments there was significant increase of water soluble, exchangeable and organically bound Zn, whereas there was significant increase of residual and specifically adsorbed Zn under ZnSO4 center dot 7H(2)O. Grain Zn content was maximum under 100% ZNCPC treatment (40.57 mg kg(-1)) followed by nano ZnO (34.71 mg kg(-1)). Maximum AZR (Apparent Zn recovery) was found in case of 100% ZNCPC (26.35%) followed by 75% ZNCPC (21.22%) and nano ZnO (18.73%). ZNCPC was found to be promising Zn formulation for increasing Zn use efficiency. Nano ZnO at foliar spray was also proved to be effective in increasing the grain Zn concentration. However, ZNCPC and nano ZnO need to be evaluated in long-term experiment in various soil types and cropping system for evaluating benefit: cost ratio and wide scale farmers' adaptability.