| 11 Jun 2026
Soil-plant-water relationships and crop yield under conservation agricultural practices: A biophysical basis for tailored adoption
Abstract. Conservation agriculture is widely promoted to reduce soil degradation, restore and maintain soil health, enhance crop productivity, and mitigate greenhouse gas emissions. This generally entails three core practices: reduced soil disturbance, permanent organic soil cover, and crop rotation. However, the universal applicability of these practices across diverse biophysical and socioeconomic contexts is under debate due to inconsistent agronomic performance and practical challenges associated with implementing all three practices simultaneously. To better understand the associated biophysical dynamic, we evaluated changes in soil-plant-water relationships and crop yields under five practices: no-till without residue (NT), reduced tillage without residue (RT), no-till with residue (NT+RR), reduced tillage with residue (RT+RR) and conventional tillage with residue retention (CT+RR), each compared with conventional tillage without residue retention (CT), using a global meta-analysis of observations from 338 studies across 361 experimental sites. Overall, yield declined by 6.1% (p = 0.024) under NT. However, yield reductions diminished with increasing tillage intensity (from NT to CT) and residue retention (p = 0.041). Sensitivity analysis revealed that yield reductions under NT are likely driven by compaction-driven adverse changes in soil hydraulic and mechanical properties limiting water movement (infiltration, redistribution and drainage), retention, and availability to crops, and root growth. Specifically, NT, irrespective of residue management, reduced soil near-saturated hydraulic conductivity – a property governing soil water replenishment, redistribution and drainage – by 26.9% (p = 0.008), increased soil penetration resistance by 29.4% (p < 0.001), and changed the pore size distribution, resulting in smaller air-capacities and larger wilting points. When reduced tillage and residue retention treatments were combined (RT+RR), yield variability was more strongly associated with changes in soil organic carbon and saturated hydraulic conductivity than water retention, and penetration resistance. Yield responses varied with local climate and soil type. NT increased yields in semi-dry climates (aridity index: 0.3-0.65) by 16.3% (p = 0.004). In contrast, NT reduced yield in humid regions (-7.2%, p < 0.001) as well as in dry regions (-8.3%, p = 0.038) where irrigated agriculture is likely to dominate. These yield responses by climate context closely mirrored the observed differences in saturated hydraulic conductivity. Yield penalties were generally greatest in clayey soils (e.g., under RT -19.3%, p = 0.047) and consistently diminished toward sandy soils, both under NT and RT. These findings highlight the need for context-specific implementation of conservation agriculture to achieve balanced agronomic and environmental benefits.
This manuscript analysis soil-plant-water relationships and crop yield under conservation agricultural practices using global meta-analysis based on observations from 338 studies across 361 experimental sites worldwide. A series soil structural and mechanical parameters of convention tillage (CT) and conservation agricultural practices (NT, NT+RR, RT, RT+RR, CT+RR) under different regions (i.e., dry, semi-dry, and humid regions) were compared. The dataset is very impressive and the analyzed hydrological and mechanic parameters have a good link with crop yield. The manuscript is well-written and the results are important for the selection of the conservation agricultural in different regions. There are some comments needs to be considered before final publication on SOIL.
As is shown in Table 2, the penetration resistance largely depends on soil moisture conditions as well as measurement procedure (field measurement v.s., lab measurement under controlled moisture), but in the manuscript how to eliminate this difference on different studies? Are all the PenR from the same water content across the 361 experiment sites? Does the author filter or standardize the soil moisture status at which the PenR was measured? If it not, the authors should explicitly discuss how this affects the sensitivity analysis (Figure 6) where PenR shows lower importance for yield.
Besides, air-capacity (AC) is defined as the difference between moisture content at saturation and field capacity. However, across literature, water content at field capacity is defined differently at pF 2.0 (10 kPa) or pF 2.5 (33 kPa). The pore size boundary between 10 kPa and 33 kPa is significantly different, this boundary determines whether AC captures true aeration macropores or structural mesopores. It is recommended to clarify the proportion of studies using pF 2.0 versus pF 2.5 and whether this introduces a bias across soil textural classes (Figure 4).
In the discussion, Figures 7 and Figure 8 show new information about global correlation matrix and comprehensive pedoclimatic grid cross-referencing 12 soil properties with crop yields. However, the discussion part should be ideally reserved for mechanic interpretation, literature comparison, etc, rather than introducing new complex statistical analysis. Therefore, it’s recommended to create a new subsection in results part and put figure 7and 8 into this part, and this would make discussion more logical and coherent for readers.
Line 55: …plant CO2 uptake
Line 90: all reporting 90 overall yield reductions under no-till when it is adopted alone
Line 116: delete the repeated sentence “for identifying the conditions in which CA”
Table Formatting: For Tables 1 and 2, please reform them into the standard three-line table format as required by the SOIL journal guidelines. Remove all vertical lines and keep only three primary horizontal lines (top, bottom, and header line).
Figure 8: check the spelling error “Robust positive” in the legend.