Field traffic-induced soil compaction under moderate machine-field conditions affects soil properties and maize yield on sandy loam soil

Soil compaction due to field trafficking involves a complex interplay of machine-soil properties. In contrast to previous studies simulating worst field scenarios, this two-year field experiment investigated the effects of traffic-induced compaction involving moderate machine operational specifications (axle load, 3.16 Mg; mean ground contact pressure, 77.5 kPa) and lower field moisture contents (< field capacity) at the time of trafficking on soil physical properties, spatial root distribution, and corresponding maize growth and grain yield in sandy loam soil. Two compaction levels, i.e. two (C2) and six (C6) vehicle passes, were compared with a control (C0). Two maize (Zea mays L.) cultivars, i.e. ZD-958 and XY-335, were used. Results showed topsoil (< 30 cm) compaction with increases in bulk density (BD) and penetration resistance (PR) up to 16.42% and 127.76%, respectively, in the 10-20 cm soil layer in 2017. Field trafficking resulted in a shallower and stronger hardpan. An increased number of traffic passes (C6) aggravated the effects, and the carryover effect was found. Higher BD and PR impaired root proliferation in deeper layers of topsoil (10-30 cm) and promoted shallow horizontal root distribution. However, XY-335, compared with ZD-958, showed deeper root distribution under compaction. Compaction-induced reductions in root biomass and length densities were respectively up to 41% and 36% in 10-20 cm and 58% and 42% in the 20-30 cm soil layer. Consequent yield penalties (7.6%-15.5%) underscore the detriments of compaction, even only in topsoil. In crux, despite their low magnitude, the negative impacts of field trafficking under moderate machine-field conditions after just two years of annual trafficking foreground the challenge of soil compaction

Effect of rotational tillage regimes on water-use efficiency and yield of wheat under corn–wheat cropping system (Case Study: North China Plain)

Tillage practices have been widely acknowledged to play a critical role in optimizing water use efficiency (WUE) for winter wheat production in the Northern China Plain (NCP) where drought is a critical limiting factor. Therefore, the WUE of wheat as influenced by annual rotational tillage under the corn–wheat cropping system during 2016–2018 has determined. The tillage regimes in the corn season were either N: no–tillage or SR: sub–soiling with rotary tillage). One of three regimes, sTR: strip rotary tillage; R: rotary tillage; and SR: sub–soiling with rotary tillage) were the tillage practices in the wheat seasons. Thus, making a total of 6 treatments. N–SR markedly decreased the penetration resistance, while the soil water storage was enhanced in the 60-100 cm layer during the wheat season, over both years. On the other hand, the use of SR during the wheat-growing season increased evapotranspiration. Compared with other tillage practices, the photosynthesis rate enhanced under the N–SR. As a result, the highest yield and WUE of wheat were recorded in the N–SR regime. Our findings suggest that no–tillage in the corn season and sub–soiling with rotary tillage in the succeeding wheat season can improve wheat yield by promoting deep soil water, enhancing the leaves photosynthesis rate and increasing WUE