Response of nitrate leaching to no‐tillage is dependent on soil, climate, and management factors: A global meta‐analysis

Abstract

No tillage (NT) has been proposed as a practice to reduce the adverse effects of tillage on contaminant (e.g., sediment and nutrient) losses to waterways. Nonetheless, previous reports on impacts of NT on nitrate (NO −3 ) leaching are inconsistent. A global meta-analysis was conducted to test the hypothesis that the response of NO − 3 leaching under NT, relative to tillage, is associated with tillage type (inversion vs non-inversion tillage), soil properties (e.g., soil organic carbon [SOC]), climate factors (i.e., water input), and management practices (e.g., NT duration and nitrogen fertilizer inputs). Overall, compared with all forms of tillage combined, NT had 4% and 14% greater area-scaled and yield-scaled NO − 3 leaching losses, respectively. The NO − 3 leaching under NT tended to be 7% greater than that of inversion tillage but comparable to non-inversion tillage. Greater NO − 3 leaching under NT, compared with inversion tillage, was most evident under short-duration NT (<5 years), where water inputs were low (<2 mm day −1 ), in medium texture and low SOC (<1%) soils, and at both higher (>200 kg ha −1 ) and lower (0-100 kg ha −1 ) rates of nitrogen addition.Of these, SOC was the most important factor affecting the risk of NO 3 − leaching under NT compared with inversion tillage. Globally, on average, the greater amount of NO 3 − leached under NT, compared with inversion tillage, was mainly attributed to corresponding increases in drainage. The percentage of global cropping land with lower risk of NO 3 − leaching under NT, relative to inversion tillage, increased with NT duration from 3 years (31%) to 15 years (54%). This study highlighted that the benefits of NT adoption for mitigating NO − 3 leaching are most likely in long-term NT cropping systems on high-SOC soils.

Effects of Different Tillage and Fertilization Methods on the Yield and Nitrogen Leaching of Fragrant Rice

“…This study was conducted during the second and third years of no-tillage cultivation, during which nitrogen leaching levels in no-tillage were observed to be higher compared to conventional tillage practices. These findings align with the data collected by Li and colleagues [22].…”

“…Ref. [22] demonstrated that, the response of NO 3 − -N leaching is closely tied to soil attributes like Soil Organic Carbon (SOC), climatic factors (particularly water input), and management practices like the duration of no-tillage (NT) and nitrogen fertilizer input. Significantly, SOC emerges as the key factor influencing the risk of NO 3 − -N leaching under NT conditions.…”

Crop Rotation and Nitrogen Fertilizer on Nitrate Leaching: Insights from a Low Rainfall Study

“…During periods with lower rainfall (10,11,20, and 21, Figure 2), the unfertilized plots exhibited significantly higher NO 3 − leaching than those fertilized (Tables 5 and 6). NO 3 − leaching in no-tillage areas without fertilization has already been reported by Rosolem et al [38], who evaluated the phenomenon in these situations over a year without rainfall restrictions and found NO 3 − concentrations of up to 111 mg L −1 .…”

“…In addition, corn provides a large amount of plant residues for soil cover, and soybean fixes atmospheric N. Regardless of these positive aspects, the continuous implementation of soybean-corn rotation subverts one of the fundamental principles of the no-tillage system, which is the diversification of plant species through crop rotation [16,17]. Despite controversies and only a few conclusive studies on the subject, long-term no-tillage with diversified crop rotation (cover crops and commercial species) is considered a soil management system with lower NO 3 − loss through leaching than conventional management [18][19][20][21]. However, studies on NO 3 − leaching in long-term no-tillage systems that compare diversified and simplified cropping rotations under subtropical agricultural conditions are scarce.…”

Effects of Warming and No-Tillage on Soil Carbon, Nitrogen, Phosphorus and Potassium Contents and pH of an Alpine Farmland in Tibet

“…Last, nitrate nitrogen leaching can be an important mechanism in regulating soil pH [58]. Thus, a no-tillage-induced increase in nitrate nitrogen leaching [59] can be an important cause of potential soil acidification under no-tillage conditions. However, the positive effect of no-tillage on nitrate nitrogen leaching declined with increasing initial soil organic carbon [59].…”