Exploring relationships between soil compaction, amelioration and functioning

Abstract

Background:The compaction of subsoils in agriculture is a threat to soil functioning. Measures aimed at the prevention, amelioration, and/or impact alleviation of compacted subsoils have been studied for more than a century, but less in smallholder agriculture. Methods: A meta-analysis was conducted to quantitatively examine the effects of the prevention, amelioration, and impact alleviation measures in mechanized and small-holder agriculture countries, using studies published during 2000~2019/2020. Results: Mean effect sizes of crop yields were large for controlled traffic (+34%) and irrigation (+51%), modest for subsoiling, deep ploughing, and residue return (+10%), and negative for no-tillage (−6%). Mean effect sizes of soil bulk density were small (<10%), suggesting bulk density is not a sensitive 'state' indicator. Mean effect sizes of penetration resistance were relatively large, with large variations. Controlled traffic had a larger effect in small-holder farming than mechanized agriculture. Conclusion: We found no fundamental differences between mechanized and smallholder agriculture in the mean effect sizes of the prevention, amelioration, and impact alleviation measures. Measures that prevent soil compaction are commonly preferred, but amelioration and alleviation are often equally needed and effective, depending on site-specific conditions. A toolbox of soil compaction prevention, amelioration, and alleviation measures is needed, for both mechanized and smallholder agriculture.

Potential of boreholes combined with deep-rooted cover crops to ameliorate subsoil compaction : Results from 2021-2022

“…Previous research on large boreholes on sandy loam soil resulted in the highest yield. Although roots grow preferably in bore-holes, no significant difference was found in root weight (Yang, 2022b).…”

“…Plant roots used these artificial macro pores because of a reduced resistance to root penetration and an improvement in air permeability. Other studies show no indication that roots make use of the smaller boreholes (Yang, 2022b).…”

Techniques for the recovery of compacted soils in Europe

“…This resulted in a higher yield depending on soil type and year. There was no indication that roots make use of the smaller bore-holes (Yang, 2022b). The effect of the loose soil in bore-holes can be optimized when plants grow above these bore-holes.…”

“…Experiments with pierced holes of Ø 1 cm (5 holes in a circle around a plant) and hand-drilled bore holes of different diameters (Ø 6-10 cm) and depths (30-60 cm) were performed by Yang in 2017 and 2018 on a compacted sandy soil in the Netherlands and a sandy loam soil in China (Yang, 2022b) see Table 2-1. The experiment in the Netherlands contained three bore-hole treatments, two manure treatments and two crops (silage maize and sorghum).…”

“…The experiment with small pierced holes was performed in 2017 in the Netherlands only. In China, the experiment was conducted in 2018 on two plots (Yang, 2022b). Plant density was 9 plants/m 2 for maize with a plot size of 1,34 x 1,34 m and there was a bore-hole of Ø 7 cm or Ø 10 cm for each plant in two depths (30 or 60 cm).…”