Forage sorghum quantity and quality as affected by biological phosphorous fertilization

Abstract

To investigate the effects of seed inoculation with phosphate affecting microorganisms on the quantitative and qualitative traits of two forage sorghum (Sorghum bicolor (L.)), genotypes were investigated during 2011 and 2012 field experiments. The experimental treatments consisted of chemical (triple super phosphate (TP)), and biological P fertilizers [mycorrhizal fungus (Rhizophagus intraradices) (AM) + Pseudomonas fluorescens strain 93 (PB)] as well as sorghum genotypes (Speedfed and Jumbo) factorially arranged on the basis of a randomized complete block design with three replications. The results revealed that seed inoculation by AM fungi and its combined inoculation with PB significantly influenced sorghum growth, P concentration and acid detergent fibre (ADF%). Rhizophagus intraradices appeared to be better adapted for association with sorghum than P. fluorescens strain 93 under the environmental conditions of the experiment. The significant differences in the quantity and quality of the two genotypes as affected by chemical and biological fertilization indicate the importance of selecting the right genotype, which results in higher growth and yields with a better forage quality. Although in most cases, the biological fertilization was the more recommendable, the use of chemical P fertilization up to some level was essential for the production of sorghum forage yield affecting crop quality. It is more beneficial to use the integrated beneficial microorganisms (AM + PB) instead of their single use to achieve better crop growth, yield and nutrient status for both plant and soil health.

Sorghum Genotypes Response to Inoculation With Phosphate Solubilizing Bacteria

“…In general, plant growth-promoting bacteria (PGPB) are more efficient under conditions of limited nutrient supply and depend on the interaction with other soil microorganisms and plant genotype (Ehteshami et al, 2018). These bacteria must colonize the roots and remain in the rhizosphere or in the interior of the plants in sufficient numbers to produce the beneficial effects (Ehteshami et al, 2018). In Brazil, sorghum has been cultivated as second crop after maize or soybean and they are frequently sharing the same soil.…”

“…Therefore, one option would be the partial substitution of the soluble fertilizers by the combined use with RP and the inoculation of the plants with PSB, which would increase the availability of this nutrient, reducing the costs of production. Ehteshami et al (2018) indicate the use of soluble chemical fertilizers in some plant growth stages with high nutrient demand, such as seedling and flowering. Thus, synthetic fertilization could be combined with the use of microbial inoculants (biological fertilization), since the microorganisms may not be able to supply all the P demanded by the plant.…”

“…Thereby, some alternatives have been studied to increase the solubility of this P source, making its use even more attractive, such as the use of phosphate solubilizing bacteria (PSB) as biofertilizers. An enhanced P acquisition after PSB inoculation has been reported in several crops, including wheat (Emami et al, 2019), pearl millet (Ribeiro et al, 2018), maize (Venkatesha et al, 2019;Sousa et al, 2020), and sorghum (Ehteshami et al, 2018).…”

“…Sorghum inoculated with two P-solubilizing fungi and fertilized with RP increased P uptake, shoot dry matter yield and plant height, under controlled conditions (Steiner et al, 2016). However, sorghum response to the inoculation with PSB can differ depending on plant genotype, microorganism strain, soil and climate conditions (Ehteshami et al, 2018;Schlemper et al, 2018). The objective of this work was to evaluate, under greenhouse and field conditions, the effect of two P solubilizing bacteria on plant development, P accumulation and grain yield of two sorghum genotypes with different P responsiveness (BR007 -efficient and responsive to P and SC283 -efficient and nonresponsive to P), cultivated on soil fertilized with RP in the presence and absence of triple superphosphate (TSP).…”

Nutritive value for ruminants of different fresh and ensiled sorghum (Sorghum bicolor (L.) Moench) varieties harvested at varying maturity stages

“…Besides high yield, an alternative to forage maize should have a high metabolisable energy content as forage maize is often used as complement to protein-rich grassland feeds in ruminant feeding. Earlier studies have shown significant effects of variety (Oliver et al 2004;Cattani et al 2015;Ehteshami et al 2018) and harvest date (Black et al 1980;Lyons et al 2019) on nutritive value of sorghum. Furthermore, certain types of sorghum varieties have similar nutritive value as forage maize while others have not (Aydin et al 1999;Oliver et al 2004;Sánchez-Duarte et al 2019).…”