Soil fertility and corn yield changes depending on the tillage system

Tillage system is one of the factors that influences crop yield. The aim of the research was to determine the influence of the basic tillage systems on the change in soil fertility, yield and quality of corn grain in the soil and climatic conditions of the central zone of the Krasnodar Territory. The surveys were conducted in 2018–2020 on the experimental fields of the FSBSO “National Center of Grain named after P. P. Lukyanenko”. Soil – chernozems leached. All the experiments were carried out according to the standard methodology. In a stationary experiment, observations were performed to study several tillage practices: conventional tillage (25 cm depth plowing), mulch tillage with soil decompaction (reduced tillage done with a chisel plow to a depth of 32 cm for row crops), mulch tillage (deep tillage is excluded, disking to a depth of 10 cm twice or thrice is used instead). Plowing to a 25 cm depth improves the bulk of the soil in the 0–30 cm layer. However, chiseling to a depth of 32 cm and disking to a depth of 10 cm twice or thrice caused soil compaction. Standard tillage practice led to a decrease in the number of agronomically valuable aggregates (61.1 %) and their water resistance (59.4 %) compared to soil decompaction and minimum-tillage systems. The highest rates of productive moisture reserves were on the plots with traditional tillage and decompaction (140.6 and 141.5 mm, respectively, which is 14.7 % higher compared to the minimum mulching). The studied soil cultivation systems did not affect “1000-grain weight” but significantly affected the yield of grain from one ear (124.3 g) and the number of formed ears per one plant (1.04 pcs.). The corn yield on the fields with traditional and decompaction tillage methods was 56.9 and 55.9 c/ha, respectively; on minimum-tillage system, it decreased by 4.8 %. Protein content in grain harvested from the plots with traditional tillage practice was 11.4 %, which is higher compared to the minimum-tillage system. No significant differences were detected for crude ash and dry matter.

Enzymatic and microbial activities as influenced by tillage and fertilization in a semi-arid Mediterranean agroecosystem

<p>Soil enzymes respond rapidly to changes in soil managements, and therefore are used as early and sensitive indicators of alteration in soil properties induced by tillage and additions of fertilizers. The aim of this work was to compare the effects of different tillage (no, minimum, and conventional tillage), fertilization and soil depth (0-30, 30-60 and 60- 90 cm) on the microbial biomass, enzyme activity and their relationship with soil nutrients in a semiarid Mediterranean agro-ecosystem. Growing and total microbial biomass decreased with depth together with the activities of β-glucosidase and N-acetyl-β-glucosaminidase presumably because of the reduced carbon and oxygen content in the deeper layers of soils. The fertilization stimulated fast-growing microorganisms with low affinity of enzyme systems to substrate, enhanced the growing microbial biomass and facilitated the turnover rate of soil organics. Under no tillage, all enzymes showed higher potential activity in top layers of fertilized plots as compared with non-fertilized ones. The minimum tillage practice increased the growing microbial biomass, and stimulated N- and P-acquiring enzymes due to  increased nutrients limitation. Parameters of microbial growth and enzyme kinetics are suitable indicators of microbial activity in semiarid Mediterranean agroecosystems.</p>

Tillage shapes the soil and rhizosphere microbiome of barley - but not its susceptibility towards Blumeria graminis f. sp. hordei

Long-term agricultural practices are assumed to shape the rhizosphere microbiome of crops with implications for plant health. In a long-term field experiment, we investigated the effect of different tillage and fertilization practices on soil and barley rhizosphere microbial communities by means of amplicon sequencing of 16S rRNA gene fragments from total community DNA. Differences in the microbial community composition depending on the tillage practice, but not the fertilization intensity were revealed. To examine whether these soil and rhizosphere microbiome differences influence the plant defense response, barley (cultivar Golden Promise) was grown in field or standard potting soil under greenhouse conditions and challenged with Blumeria graminis f. sp. hordei (Bgh). Amplicon sequence analysis showed that preceding tillage practice, but also aboveground Bgh challenge significantly influenced the microbial community composition. Expression of plant defense-related genes PR1b and PR17b was higher in challenged compared to unchallenged plants. The Bgh infection rates were strikingly lower for barley grown in field soil compared to potting soil. Although previous agricultural management shaped the rhizosphere microbiome, no differences in plant health were observed. We propose therefore that the management-independent higher microbial diversity of field soils compared to potting soils contributed to the low infection rates of barley.