Multiple cropping and microsite enrichment in vetiver (Chrysopogon Zizanioides (L) Nash

Abstract

Vetiver (Chrysopogon zizanioides) is the only grass extensively cultivated specifically for its root essential oil, a complex mixture of sesquiterpene alcohols and hydrocarbons. The World Bank has promoted the Vetiver System (VS) since the 1980s for various applications. However, cost effective techniques for increasing root production in the humid tropics are lacking. Two separate experiments were conducted at the Instructional Farm attached to the College of Agriculture, Padannakkad during 201 1-13. PART A. Bio inoculants for Quality Planting Material Production The trial was conducted for three months to study the effect of single, dual and combined application of microbial inoculants on quality planting material production in vetiver. The ten treatments of the trial laid out in CRD were B .-Single inoculation with Azospirillum, B2-Single inoculation with PSB, Bj-Single inoculation with AMF, Ba-Single inoculation with Fluorescent Pseudomonads (FP), Bj-Dual inoculation with Azospirillum and PSB, Bx-Dual inoculation with Azospirillum and AMF, Be-Dual inoculation with Azospirillum and FP, B8- Combined inoculation with Azospirillum, PSB and AMF, Be-Combined inoculation with Azospirillum, PSB, AMF and FP and BlO-Control (No inoculation). Single, dual and combined inoculation of bioinoculants influenced sapling growth and vigour in different ways. In general, PSB favourably and significantly influenced sapling height, root number, root spread, shoot weight, root weight, total biomass accumulation, relative leaf water content, sturdiness quotient and sapling growth potential. Significant and positive influence of dual inoculation with Azospirillum and fluorescent pseudomonas was evident on length of root, root growth potential and Azospirillum population. Part B: Multiple cropping and micro site enrichment techniques for row zone and inter-row zone management The objective of this experiment was to develop eco-friendly techniques to achieve higher root and oil production in vetiver with special reference to climate change mitigation. The field experiment in factorial RBD with 12+2 treatment combinations was conducted for one year. The treatments consisted of combinations of four row zone management practices namely TI (in situ composting in trenches), T2 (in situ composting in trenches + stubble mulching), T3 (in situ composting in trenches+ stubble mulching + summer irrigation at 40 mm CPE), T4 (in situ composting in trenches+ stubble mulching + summer irrigation at 80 mm CPE); and three inter row zone management practices namely BI (multiple cropping), B2 (double cropping), B3 (Mono cropping), besides two control treatments namely SI sole cropping - Normal row planting and S2 : sole cropping - Paired row planting. The effect of row zone and inter row zone management practices and their interactions were inconsistent in significantly influencing various morphological characters and root parameters of vetiver during different stages of its growth. However, positive and significant influence of row zone and inter row zone management practices and their interactions benefitted vetiver in improving root , production and productivity besides, improvement in oil yield. Integration of in situ composting in trenches + stubble mulching; and multiple cropping was effective in enhancing total plant uptake of nitrogen, phosphorus and potassium. Seasonal consumptive use, mean daily consumptive use and crop coefficient were not at all influenced by row zone and inter row zone management practices and their interactions. The highest crop water use efficiency, field water use efficiency, higher gross income, net income, and BCR were recorded consequent to integration of in situ composting in trenches + stubble mulching + summer irrigation at 80 mm CPE; and multiple cropping.