RESUMO
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.
RESUMO
Sorghum holepense is an extremely wide spread species, being met in many European, Asian, American and African countries and covering approximately 1/3 of the land cultivated with fields crops, grapevine, fruit trees and vegetables. In Romania, Sorghum halepense is present in almost all the country, invading in hoed-plants ad vegetable crops as well as grapevine and fruit-tree plantations. The losses caused by Sorghum halepense are enormous; in case of maize and sugar beet crops, these losses reach and extremely high rate of 30-70%. For these reasons, at the University of Agricultural Sciences and Veterinary Medicine, Timisoara, city in western part of Romania, a study was made having as objects the latest herbicides synthesized in the world: Equip--which contains 22.5 g/l foramsulfuron + 22.5 g/l isoxadifen-ethyl (safener); Mais-Ter--which contains 300 g/kg foramsulfuron + 10 g/kg iodosulfuron-methyl sodium + 300 g/kg isoxadifen-ethyl (safener); Terano--which contains 600 g/kg flufenacet + 25 g/kg metasulfuron; Mistral (standard)--which contains 40 g/l nicosulfuron. Each of these herbicides (in commercial form) was applied in four doses. The best results in the control of Sorghum halepense obtained by applying the Mistral herbicide. In second place from the point of you of its efficacy came the herbicide Mais-Ter and third place the herbicide Equip. The lowest degree of efficacy was recorded by the herbicide Terano. The grain yield in case of maize crops treated with before mentioned herbicides was in strict correlation with the efficacy of the herbicides and especially with the dose applied per hectare.