Phosphatase activity in sandy soil influenced by mycorrhizal and non-mycorrhizal cover crops

Abstract

SUMMARYCover crops may difffer in the way they affect rhizosphere microbiota nutrient dynamics. The purpose of this study was to evaluate the effect of mycorrhizal and non-mycorrhizal cover crops on soil phosphatase activity and its persistence in subsequent crops. A three-year experiment was carried out with a Typic Quartzipsamment. Treatments were winter species, either mycorrhizal black oat (Avena strigosa Schreb) or the non-mycorrhizal species oilseed radish (Raphanus sativus L. var. oleiferus Metzg) and corn spurry (Spergula arvensis L.). The control treatment consisted of resident vegetation (fallow in the winter season). In the summer, a mixture of pearl millet (Pennisetum americanum L.) with sunnhemp (Crotalaria juncea L.) or with soybean (Glycine max L.) was sown in all plots. Soil cores (0-10 cm) and root samples were collected in six growing seasons (winter and summer of each year). Microbial biomass P was determined by the fumigationextraction method and phosphatase activity using p-nitrophenyl-phosphate as enzyme substrate. During the flowering stage of the winter cover crops, acid phosphatase activity was 30-35 % higher in soils with the non-mycorrhizal species oilseed radish, than in the control plots, regardless of the amount of P immobilized in microbial biomass. The values of enzyme activity were intermediate in the plots with corn spurry and black oat. Alkaline phosphatase activity was 10-fold lower and less sensitive to the treatments, despite the significant relationship between the two phosphatase activities. The effect of plant species on the soil enzyme

Cover crops as modifying agents of microbiological soil attribute

“…The highest acid phosphatase activity (Table 3) was observed for U. brizantha and U. ruzizienses cover crops, although there was no higher phytomass production ( Figure 5) when compared to the other cover crops. It can be said that the roots of these plants influenced the acid phosphatase activity due to their morphology (Mendes et al, 2012 ) is similar to the results described by Kunze et al (2011), in which the authors obtained higher values of this enzyme in soil cultivated with forage turnip when compared to the fallow area soil through evaluating the effect of mycorrhizal and nonmicrocytic cover plants on the acid phosphatase activity at different periods of cultivation. Β-glycosidase is also an enzyme of great importance within biogeochemical cycles, participating from a finalizing group of cellobiose hydrolysis to glucose, promoting the release of nutrients from organic matter, and its activity is related to the amount of mineralizable C (Lisboa et al, 2012;Tabatabai, 1994).…”

Antagonistic bacteria in the soil after cover crops cultivation

“…As reported by Kunze et al (2011), the development of those bacteria could be supported by secondary metabolites introduced into the soil of cover crops.…”

Hidden miners – the roles of cover crops and soil microorganisms in phosphorus cycling through agroecosystems

“…Raphanus sativus var. oleiferus (oilseed radish) exudes large amounts of acid phosphatase and other rhizodeposits into the rhizosphere (Kunze et al 2011); the exceptional P-mining strategies of Lupinus sp. have been described above.…”