title: Organic Wheat Farming Improves Grain Zinc Concentration.
abstract: Zinc (Zn) nutrition is of key relevance in India, as a large fraction of the population suffers from Zn malnutrition and many soils contain little plant available Zn. In this study we compared organic and conventional wheat cropping systems with respect to DTPA (diethylene triamine pentaacetic acid)-extractable Zn as a proxy for plant available Zn, yield, and grain Zn concentration. We analyzed soil and wheat grain samples from 30 organic and 30 conventional farms in Madhya Pradesh (central India), and conducted farmer interviews to elucidate sociological and management variables. Total and DTPA-extractable soil Zn concentrations and grain yield (3400 kg ha-1) did not differ between the two farming systems, but with 32 and 28 mg kg-1 respectively, grain Zn concentrations were higher on organic than conventional farms (t = -2.2, p = 0.03). Furthermore, multiple linear regression analyses revealed that (a) total soil zinc and sulfur concentrations were the best predictors of DTPA-extractable soil Zn, (b) Olsen phosphate taken as a proxy for available soil phosphorus, exchangeable soil potassium, harvest date, training of farmers in nutrient management, and soil silt content were the best predictors of yield, and (c) yield, Olsen phosphate, grain nitrogen, farmyard manure availability, and the type of cropping system were the best predictors of grain Zn concentration. Results suggested that organic wheat contained more Zn despite same yield level due to higher nutrient efficiency. Higher nutrient efficiency was also seen in organic wheat for P, N and S. The study thus suggests that appropriate farm management can lead to competitive yield and improved Zn concentration in wheat grains on organic farms.
authors.affiliation: Institute of Agricultural Sciences, ETH Zurich, 8315, Lindau, Switzerland.
authors.forename: Julian
authors.initials: J
authors.lastname: Helfenstein
authors.affiliation: Institute of Agricultural Sciences, ETH Zurich, 8315, Lindau, Switzerland.
authors.forename: Isabel
authors.initials: I
authors.lastname: Müller
authors.affiliation: Institute of Terrestrial Ecosystems, ETH Zurich, 8092, Zurich, Switzerland.
authors.forename: Roman
authors.initials: R
authors.lastname: Grüter
authors.affiliation: Department of International Cooperation, Research Institute of Organic Agriculture (FiBL), 5070, Frick, Switzerland.
authors.forename: Gurbir
authors.initials: G
authors.lastname: Bhullar
authors.affiliation: Research Division, bioRe Association, Kasrawad, Madhya Pradesh, India.
authors.forename: Lokendra
authors.initials: L
authors.lastname: Mandloi
authors.affiliation: Institute of Terrestrial Ecosystems, ETH Zurich, 8092, Zurich, Switzerland.
authors.forename: Andreas
authors.initials: A
authors.lastname: Papritz
authors.affiliation: Institute for Environmental Decisions, ETH Zurich, 8092, Zurich, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Siegrist
authors.affiliation: Institute of Terrestrial Ecosystems, ETH Zurich, 8092, Zurich, Switzerland.
authors.forename: Rainer
authors.initials: R
authors.lastname: Schulin
authors.affiliation: Institute of Agricultural Sciences, ETH Zurich, 8315, Lindau, Switzerland.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Frossard
mesh_terms: D002523:Edible Grain / Q000737:chemistry* / Q000254:growth & development; D058871:Organic Agriculture / Q000379:methods*; D012987:Soil / Q000737:chemistry; D014908:Triticum / Q000737:chemistry* / Q000254:growth & development; D015032:Zinc / Q000032:analysis*
chemical_list: D012987:Soil; D015032:Zinc