Author:
Nkebiwe Peteh Mehdi,Stevens Lekfeldt Jonas D.,Symanczik Sarah,Thonar Cécile,Mäder Paul,Bar-Tal Asher,Halpern Moshe,Biró Borbala,Bradáčová Klára,Caniullan Pedro C.,Choudhary Krishna K.,Cozzolino Vincenza,Di Stasio Emilio,Dobczinski Stefan,Geistlinger Joerg,Lüthi Angelika,Gómez-Muñoz Beatriz,Kandeler Ellen,Kolberg Flora,Kotroczó Zsolt,Kulhanek Martin,Mercl Filip,Tamir Guy,Moradtalab Narges,Piccolo Alessandro,Maggio Albino,Nassal Dinah,Szalai Magdolna Zita,Juhos Katalin,Fora Ciprian G.,Florea Andreea,Poşta Gheorghe,Lauer Karl Fritz,Toth Brigitta,Tlustoš Pavel,Mpanga Isaac K.,Weber Nino,Weinmann Markus,Yermiyahu Uri,Magid Jakob,Müller Torsten,Neumann Günter,Ludewig Uwe,de Neergaard Andreas
Abstract
Biostimulants (Bio-effectors, BEs) comprise plant growth-promoting microorganisms and active natural substances that promote plant nutrient-acquisition, stress resilience, growth, crop quality and yield. Unfortunately, the effectiveness of BEs, particularly under field conditions, appears highly variable and poorly quantified. Using random model meta-analyses tools, we summarize the effects of 107 BE treatments on the performance of major crops, mainly conducted within the EU-funded project BIOFECTOR with a focus on phosphorus (P) nutrition, over five years. Our analyses comprised 94 controlled pot and 47 field experiments under different geoclimatic conditions, with variable stress levels across European countries and Israel. The results show an average growth/yield increase by 9.3% (n=945), with substantial differences between crops (tomato > maize > wheat) and growth conditions (controlled nursery + field (Seed germination and nursery under controlled conditions and young plants transplanted to the field) > controlled > field). Average crop growth responses were independent of BE type, P fertilizer type, soil pH and plant-available soil P (water-P, Olsen-P or Calcium acetate lactate-P). BE effectiveness profited from manure and other organic fertilizers, increasing soil pH and presence of abiotic stresses (cold, drought/heat or salinity). Systematic meta-studies based on published literature commonly face the inherent problem of publication bias where the most suspected form is the selective publication of statistically significant results. In this meta-analysis, however, the results obtained from all experiments within the project are included. Therefore, it is free of publication bias. In contrast to reviews of published literature, our unique study design is based on a common standardized protocol which applies to all experiments conducted within the project to reduce sources of variability. Based on data of crop growth, yield and P acquisition, we conclude that application of BEs can save fertilizer resources in the future, but the efficiency of BE application depends on cropping systems and environments.