Variations in Soil Properties, RhizomeYield and Quality as Influenced byDifferent Nutrient Management Schedulesin Rainfed Ginger

Abstract

While there are numerous reports on nutrient management in ginger (Zingiber officinaleRoscoe), a compre-hensive study dealing with the simultaneous influence of different nutrient management schedules on ginger yield, rhizome quality, nutrient uptake (oleoresin, essential oil, essential oil constituents) and soil properties (physico chemical and biochemical) is found wanting. Hence, field experiments were conducted between 2007 and 2016 involving (1) organic nutrient management (ONM) consisting of exclusive use of biological fertilizers, viz.Bacillus megaterium, Azospirillumlipoferum, farmyard manure, vermi compost, neem cake and ash, (2) chemical nutrient management (CNM) consisting ofonly inorganic sources of nutrients, viz. nitrogen, phosphorus and potassium applied @ 75–50–50 kg ha-1in the form ofurea, rock phosphate and muriate of potash, respectively, and (3) integrated nutrient management (INM) encompassing both organic sources and biological fertilizers, viz. FYM and N applied at 50% of CNM and P, K applied at 100% of CNM,i.e. 37.5–50–50 kg ha-1. The results on soil properties revealed that soil pH was lowest in CNM (5.03), while soil organiccarbon (SOC) level was markedly higher by 39.0% in ONM and by 32.8% in INM compared with CNM. Bray P level wasgreater in ONM by 119.0% compared with CNM and by 72.0% compared with INM. Exchangeable Ca and Mg weregreater in ONM and INM, and among available micronutrients, available Cu and Fe levels were greatest in ONM andavailable Mn level was greatest in CNM. Among the soil biochemical parameters, microbial biomass C increased markedlyby 81.0% in ONM and 48.0% in INM. This was responsible for enhanced b glucosidase, acid phosphatase and dehy-drogenase activities in ONM and INM, though urease activity was greatest in CNM. In case of rhizome yield, CNMregistered significantly lower yield (mean 11.14 Mg ha-1) in comparison with ONM and INM (mean 18.64 and18.50 Mg ha-1, respectively) across all the years. With regard to rhizome quality, the essential oil content in ONM andCNM was almost identical (1.0–1.7%), while it was slightly higher at 1.32–4.0% in INM. Results on rhizome oil components showed that pinene,d-camphene andb-phellandrene contents were higher in CNM,b citral (neral) andcitronellol in ONM anda-citral (geranial) in INM. The study, in general, indicated the distinct possibility of reducing oravoiding application of chemical fertilizers while simultaneously sustaining ginger rhizome yield and quality throughONM or INM