Rhizosphere modulation for higher productivity in long pepper (Piper longum Linn)

Abstract

Increasing demand of plant based raw materials to user industries has emphasised the need to promote commercial cultivation of medicinal species. Integration of medicuIture with agriculture offers tremendous possibilities for improving crop productivity and profitability besides generation of employment. Development of a sustainability pathway to soil fertility management is a necessity for popularization of intercropping of long pepper in coconut gardens. Two experiments under the project, "Rhizosphere modulation for higher productivity in long pepper (Piper longum Linn.)" were carried out at the College of Agriculture, Vellayani during 2002-03 to standardise nursery management practices for quality planting material production and to manage the rhizosphere for maximising the yield of spikes and biochemical constituents in long pepper under partial shade. The pot culture experiment consisted of combinations of eight levels of bio inoculants, viz., Azospirillum (AZ), Fluorescent pseudomonads (FP), AMF (AM), Azospirillum + Fluorescent pseudomonads (AZ + FP), Azospirillum + AMF (AZ + AM), Fluorescent pseudomonads + AMF (FP + AM). Azospirillum + Fluorescent psuedomonads + AMF (AZ + FP + AM) and no bio inoculants (BO) and four composition of rooting media viz, FYM: Sand: Soil(I:I:I), Vermicompost : Sand: Soil (1:1:1), Coir pith compost: Sand: Soil (1 : 1 : 1), and Poultry manure: Sand: Soil (1: 1 : 1). Dual inoculation of FP+AM followed by combined inoculation of AZ+FP+AM gave maximum leaf number. Integrated application of FY+FP+AM and VC+AZ+FP+AM recorded maximum dry matter production. Maximum root number, root length, root spread and root weight were recorded by AZ+FP+AM, AM, AZ+FP+AM and FP+AM respectively. Inclusion of VC and FYM in the rooting media, enhanced root length and root spread respectively.

Integration of dual inoculation with vermicompost resulted in maximum colonisation of Azospirillum. Single inoculation of FP recorded higher colonisation. Dual inoculation of FP with AM and combined inoculation of FP with AMF and AZ also recorded higher value. The treatment combinations, FY/VC+FP+AM and FY/VC+AZ+FP+AM recorded maximum AMF inoculation In the field experiment, the response of long pepper to five sources of organic manures viz, FYM, vermicompost, coir pith compost, neemcake, and no organic manure, three levels of inorganic fertilizers viz, 0:0:0, 30:30:60, 60:60: 120 kg NPK halyrland three levels of bio inoculants viz, AZ+FP+AM, FP+AM, and no bio inoculant were studied. Application of FYM/VC, moderate dose of NPK (@30:30:60 kg halyr ") and combined inoculation of AZ+FP+AM were beneficial for the development of an efficient root system. In general, FY IVC, application of moderate dose of NPK and B I enhanced spike number. Source of organic manure significantly influenced spike yield and application of VC followed by FYM resulted in higher total fresh and dry spike yield. Moderate dose of NPK, was found sufficient in maximising the total spike production. With respect to bio inoculants, B I followed by B2 recorded higher yield. Incorporation of FYM without the addition of inorganic fertilizers but integrating with combined inoculation of AZ+FP+AM recorded the maximum alkali od content. It is concluded that integrated nutrient management system involving incorporation of verrnicompost @6.25 t halyr', addition of NPK @30:30:60 kg halyrland combined application of bio inoculants viz, Azospirillum, Fluorescent pseudomonads and AMF was found favourable for enhancing both total fresh and dry spike yield and total alkaloid production in long pepper under partial shade.