AM fungi lead to fertilizer phosphorus economy and enhanced system productivity and profitability in okra (Abelmoschus esculentus L.)–pea (Pisum sativum L.) cropping system in Himalayan acid Alfisol

Abstract

ABSTRACTThe present investigation was carried out at CSK Himachal Pradesh Agricultural University, Palampur, Himachal Pradesh, India, during 2009–2011 to economize inorganic phosphorus (P) and enhance profitability of okra (Abelmoschus esculentus)–pea (Pisum sativum) cropping system through arbuscular mycorrhizal fungi (AMF). A field experiment was replicated thrice in a randomized block design comprising 14 treatments involving AMF (Glomus mosseae) at varying inorganic P (50%, 75%, and 100% of recommended soil test-based P dose) and irrigation regimes (40% and 80% available water capacity] in a Himalayan acid Alfisol. In okra, AMF inoculation at varying P and irrigation regimes registered higher P response ratio (PRR), net returns (10–18%), and benefit:cost (B:C) ratio (17–49%) compared to “generalized recommended P dose (GRD)” and their non-AMF counterparts. Similarly in pea, AMF inoculation at varying P and irrigation regimes again registered higher PRR, net returns (14–23%), and B:C ratio (10–58%) compared to GRD and non-AMF counterparts. Higher system productivity (7–16%) and profitability in terms of net returns (9–23%) and B:C ratio (10–54%) were also registered in AMF-imbedded treatments compared to non-AMF counterparts. Further, “AMF + 75% soil test-based P dose” at either of these irrigation regimes registered statistically similar okra–pea system productivity and profitability as that obtained under “100% soil test-based P dose” at either of two irrigation regimes, thus indicating an economy of soil test-based applied P dose by about 25%. Overall, the current study suggests that practice of AMF inoculation has great potential in enhancing system productivity and profitability besides cutting down about 25% inorganic P requirement in okra–pea production system in the Himalayan acid Alfisol.