Soil quality indicators as influenced by 5-year diversified and monoculture cropping systems

Abstract

Increasing crop diversity has been highly recommended because of its environmental and economic benefits. However, the impacts of crop diversity on soil properties are not well documented. Thus, the present study was conducted to assess the impacts of crop diversity on selected soil quality indicators. The cropping systems investigated here included wheat (Triticum aestivum L.) grown continuously for 5 years as mono-cropping (MC), and a 5-year cropping sequence [(wheat–cover crop (CC)–corn (Zea mays L.)–pea (Pisum sativum L.) and barley (Hordeum vulgare L.)–sunflower (Helianthus annuus L.)]. Each crop was present every year. This study was conducted in the northern Great Plains of North America, and soil quality data were collected for 2016 and 2017. Selected soil quality indicators that include: soil pH, organic carbon (SOC), cold water-extractable C (CWC) and N (CWN), hot water-extractable C (HWC) and N (HWN), microbial biomass carbon (MBC), bulk density (BD), water retention (SWR), wet soil aggregate stability (WAS), and urease and β-glucoside enzyme activity were measured after the completion of 5-year rotation cycle and the following year. Crop diversity did not affect soil pH, CWC, CWN, HWC, HWN and SWR. Cropping systems that contained CC increased SOC at shallow depths compared to the systems that did not have CC. Crop diversity increased WAS, MBC, and urease and β-glucoside enzyme activity compared with the MC. Comparison of electrical conductivity (EC) measured in this study to the baseline values at the research site prior to the establishment of treatments revealed that crop rotation decreased EC over time. Results indicate that crop diversity can improve soil quality, thus promoting sustainable agriculture.

No differences in soil structure under winter wheat grown in different crop rotational positions

“…The overall higher BD at Hohenschulen compared to Harste was likely caused by the higher sand content at Hohenschulen. At Harste, AS was slightly higher for WM than for W1, which is in contrast to Feng et al (2020), who reported growing wheat in a crop rotation compared to monoculture cropping increased the AS in a loamy soil in 0-5 cm soil depth, while this effect was not detectable in 5-15 cm soil depth. However, since in our study values for W2, also from the crop rotation, were even higher than for W1, the effect of rotational diversity seems to be modified by other factors.…”

“…Concerning WW crop rotations, Feng et al (2020) found in a 17-year-long study that crop diversity of wheat rotations improves AS, while lowering dry BD. Pranagal and Wo źniak (2021) did not detect differences between wheat monoculture (WM) and wheat grown as rotational crop regarding soil physical properties after 30 years.…”

“…As soil microbial activity is a crucial predecessor of soil structural improvements, this seems contradictive to other results. Thus, the effect of wheat crop rotations on soil structural properties is not clear and is likely dependent on soil texture, which varied among studies from sand to clay soil (Agomoh et al 2020;Feng et al 2020;Pranagal and Wo źniak 2021). Furthermore, the above studies focused on long-term winter WM compared to the first wheat after a break crop.…”

Cover crops affect pool specific soil organic carbon in cropland – A meta‐analysis

“…Further, the moderator “number of main crop species in the rotation”, which can be seen as a proxy for main crop diversity, followed a positive trend (Figure 9d,f, respectively). Diverse crop rotations, in comparison to monocropping, provide abundant plant biomass inputs and rhizodeposits, which are known to stimulate microbial growth and, hence can promote MBC accrual (Feng et al, 2020; Motta et al, 2007). Additionally, crop rotations are recognized for their capacity to enhance soil structure, providing an environment favourable to microbial development (Kennedy, 1999) and hence MBC accrual.…”

Effects of Crop Rotation on Maize Soil Fertility in Alluvial Soil

“…There is mixed conclusion on the impact of crop rotation experimental duration on soil properties [13]. Numerous studies have reported that the influence of crop rotation on soil quality improvement depends on the type of crops cultivated in a particular rotation system [14,15].…”