Enhancing Productivity and Zn-Use Efficiency of Basmati Rice through Summer Green Manuring and Zn Fertilisation

摘要

Field experiments were conducted for two consecutive years during summer and rainy seasons (April-November) of 2009 and 2010 to study the efficacy of summer green manuring crops [Sesbania aculeata, Crotalaria juncea and Vigna unguiculata] and zinc (Zn) fertiliser sources [EDTA-chelated Zn (12% Zn), ZnSO4.7H2O (21% Zn), ZnSO4.H2O (33% Zn), ZnO (82% Zn) and ZnSO4.7H2O + ZnO (50% + 50%)] on productivity, Zn-content and Zn-use efficiencies of Basmati rice (Oryza sativa L.)at the research farm of the Indian Agricultural Research Institute, New Delhi. Incorporation of Sesbania aculeata led to a significant increase in the yield attributes, grain and straw yields, Zn content and Zn-use efficiencies (of applied Zn) of succeeding Basmati rice. With the incorporation of Sesbania aculeata, grain and straw yields of Basmati rice was 3.57% and 2.12%, 7.63% and 4.33%, and 13.97% and 7.11% higher over Crotalaria juncea, Vigna unguiculata and summer fallow, respectively. Among the Zn fertiliser sources, application of EDTA-chelated Zn was found to be best with respect to yield attributes, grain and straw yields, Zn content and Zn-use efficiencies (of applied Zn). It recorded the highest Basmati rice grain (5.461 ha"1) and straw yields (9.891 ha"1), and the increase was registered to the tune of 23.5% and 12.9%, 5.6% and 2.9%, 8.98% and 5.1%, 17.4% and 9.8%, 12.67% and 7.2% over control (no Zn application), ZnSO4.7H2O, ZnSO4.H2O, ZnO and ZnSO4.7H2O+ZnO (50% + 50%), respectively. Partial factor productivity (PFP) of applied Zn varied from 781-1,091 kg grain kg~(-1) Zn, agronomic efficiency (AE) varied from 48-207 kg grain kg~(-1) Zn (applied) and physiological efficiency (PE) of Zn varied from 1,339-2,091 kg grain kg~(-1) Zn absorbed. Zn harvest index (ZnHI) varied from 6.50-9.83%. Zinc mobilization efficiency index (ZnMEl) of applied Zn varied from 0.138-0.198. Sesbania aculeata incorporation and EDTA-chelated Zn treatments were found a better combination with respect to Basmati rice productivity. Thus, adequate Zn fertilization along with green manure crop incorporation can lead to higher productivity of Basmati rice.