Long-term No-tillage Management Research Articles

Crop residue application at low rates could improve soil phosphorus cycling under long-term no-tillage management

A field experiment was conducted in northeastern China to study the effects of no-tillage (NT) and residue application rates (NT and residue application at 0% (NTR0%), 33% (NTR33%), 67% (NTR67%), and 100% (NTR100%)) on soil phosphatase activities and P species determined by 31P NMR, and their relationships at 0–10 and 10–20 cm depths. The NTR33% treatment showed significantly higher available P, microbial biomass P, pyrophosphate, scyllo-inositol hexakisphosphate (scyllo-IHP), and corrected diester contents than the NTR0% treatment. The myo-IHP concentration under the NTR33% treatment at the 0–10 cm depth was significantly greater than in all treatments except the NTR100% treatment at the 0–10 cm depth and the NTR67% and NTR100% treatments at the 10–20 cm depth. The corrected monoester content under the NTR33% treatment at the 0–10 cm depth was not significantly different from the NTR67% at the 0–10 cm depth and the NTR100% treatment at the 10–20 cm depth, but was significantly greater than in all other treatments. Both NTR33% and NTR100% treatments significantly increased acid phosphomonoesterase activity. Structural equation modeling suggested a relationship of organic P compounds with phosphodiesterase and acid phosphomonoesterase at 0–10 cm, and with alkaline phosphomonoesterase at 10–20 cm.

Iron oxides dynamics in a subtropical Brazilian Paleudult under long-term no-tillage management

Replacing conventional tillage (CT) with no-tillage (NT) management alters the pedoenvironment and the rate of topsoil processes, with possible effects on dissolution processes associated with iron oxides and therefore soil mineralogy. This study aimed to determine the effect of NT on the content and distribution of types of iron oxides in a Rhodic Paleudult in southern Brazil. Soil samples were collected at eight depths within the 0.00-0.80 m layer under CT and NT in a long-term experiment (21 years). Mineralogical identification was conducted by X-ray diffraction (XRD), and the Fe content related to specific types of iron oxides determined by selective dissolution and diffuse-reflectance spectroscopy. Kaolinite, quartz, goethite, hematite, and maghemite were identified in the clay fraction. In the NT-managed soil, there was a decrease in the content of crystalline iron oxides and an increase in the content of poorly crystalline iron oxides with increasing proximity to the soil surface. These results suggest that iron oxides are rearranged in this soil by reductive dissolution of the crystalline types and neoformation of metastable ferrihydrite in topsoil layers, which should be assessed further in laboratory studies.

Effects of different tillage system on arbuscular mycorrhizal fungal propagules and physical properties in a Mediterranean agroecosystem in central Chile

Arbuscular mycorrhizal (AM) fungi improve soil quality by increasing soil structure stability through the glomalin (glomalin related soil protein, GRSP) production, but diverse tillage systems can differentially affect AM activity and the consequential GRSP content in soil. The aim of this study was to evaluate the effect of no-tillage (NT) and conventional tillage (CT) on AM fungal propagules (spore density, total and active fungal hyphae), GRSP content, and its relationship with some physical–chemical soil properties in a Mollisol from Central Chile. For this study, two plots managed for 6 and 10 years under NT (NT6 and NT10), were compared with another plot maintained under CT management. In all cases a continuous spring wheat ( Triticum turgidum L.)–maize ( Zea mays L.) rotation was established. The number of mycorrhizal propagules, total soil carbon (T-C) and GRSP content in NT6 was higher compared to CT and NT10. This trend was also observed for water stable aggregates (WSA) and water drop penetration time. Significant relationships were found between total mycelium and GRSP ( r = 0.58, p < 0.05), GRSP and WSA ( r = 0.66, p < 0.01) and between GRSP and T-C ( r = 0.60, p < 0.05), suggesting an active role of AM fungi and GRSP on soil aggregation, particularly under NT6 management. In addition, the long-term NT management (NT10) produced a decrease in the parameters here assayed which suggest the application of one moderate plowing when parameters such as T-C and/or GRSP show a decrease in long-term programs of reduced or NT management applied in medium/heavy soils.

Stratification ratio of soil organic matter pools as an indicator of carbon sequestration in a tillage chronosequence on a Brazilian Oxisol

Long-term no-tillage (NT) leads to profile stratification of soil organic matter (SOM) pools, and the soil organic carbon (SOC) stratification ratio (SR) is an indicator of soil quality. The objective of this report is to assess the feasibility of using SOC-SR as an index for estimating SOC sequestration in NT soils. The effect of a plow tillage (PT) and NT chronosequence on the SR of SOM pools was assessed in an Oxisol in Southern Brazil (50°23′W and 24°36′S). The chronosequence consisted of six sites: (i) native field (NF); (ii) PT of the native field (PNF-1) involving conversion of natural vegetation to cropland; (iii) NT for 10 years (NT-10); (iv) NT for 20 years (NT-20); (v) NT for 22 years (NT-22); (vi) conventional tillage for 22 years (CT-22). Soil samples were collected from four depths (0–5 cm; 5–10 cm; 10–20 cm; 20–40 cm layer) and soil parameters comprised by SOM pools [i.e., C, N, S, particulate organic C (POC), particulate N (PN), stable C (SC) and stable N (SN), microbial biomass C (MBC) and microbial biomass N (MBN), basal respiration (BR), dissolved organic C (DOC), total polysaccharides (TP) and labile polysaccharides (LP)] were measured. In undisturbed NF soil, the SR of all parameters increased with increase in soil depth. In contrast, the SR decreased in PT, and the SOM was uniformly distributed in the soil profile. All NT treatments restored the SR, and were characterized with higher values of all measured parameters compared to NF. The SR for SOC ranged from 1.12 to 1.51 for CT-22 compared with 1.64–2.61 SR for NT surface and sub-soil layers, respectively. The SR for POC and PN were higher than those for stable C and N. However, SR for the biological pools (e.g., MBC, MBN and BR) were the highest and strongly correlated with the rate of SOC sequestration. An increase in SR of SOC was also positively correlated with the rate and amount of SOC sequestered. Regression analyses indicated a strong correlation between SR of SOC and all parameters monitored in this study. The data showed that the SR of SOC is an efficient indicator of C sequestration in long-term NT management.

Impacts of long-term and recently imposed tillage practices on the vertical distribution of soil organic carbon

Although many studies suggest that no-tillage (NT) increases soil organic carbon (SOC) within the soil profile relative to mouldboard ploughing, other studies indicate that no net change occurs. The latter studies suggest that NT only stratifies the SOC, where a near-surface increase in SOC is offset by a concomitant decrease in the subsurface. We examined the SOC distribution and stocks in a cool, humid Brookston clay (Typic Argiaquoll) soil under four soil management systems with a corn–soybean rotation. The objectives of this study were to compare the profile distribution and total amount of SOC under long-term (21 years) NT and mouldboard plough (MP) tillage with the changes that occur over 8 years when 13-years continuous NT is converted to MP, and when 13-years continuous MP is converted to NT. In the top 5 cm of soil, the long-term NT management accumulated greater SOC compared with the long-term MP treatment. However, this near-surface increase was offset by lower SOC concentrations in the 10–20 cm depth, resulting in similar total amounts of SOC stored in 0–20 cm for both long-term NT and MP. The SOC stratification that existed after 13 years of NT management was eliminated with one mouldboard ploughing operation, however the total SOC content in the plough layer of the new-MP treatment remained relatively constant over the subsequent 8 years. Soil organic carbon stratification was evident in the new no-tillage treatment 3 years after the cessation of tillage. The continuous build-up of SOC in the surface of new-NT soils was associated with no change in the total amount of SOC in the plough layer relative to long-term NT. This implies that the diminution of SOC in the 10–20 cm depth was at the same rate as the accumulation of SOC in the 0–5 cm depth. Although there was no net effect of tillage on total carbon stocks in this fine-textured soil, SOC stratification required several years to build-up after adoption of NT, but only a single year to destroy under MP.

Surface-soil responses to paraplowing of long-term no-tillage cropland in the Southern Piedmont USA

The type of conservation-tillage management employed could impact surface-soil properties, which could subsequently affect relationships between soil and water quality, as well as with soil C sequestration and greenhouse gas emissions. We determined soil bulk density, organic C and N fractions, plant-available N, and extractable P on Typic Kanhapludults throughout a 7-year period, in which four long-term (>10 years), no-tillage (NT) water catchments (1.3–2.7 ha each) were divided into two treatments: (1) continuation of NT and (2) paraplowing (PP) in autumn (a form of non-inversion deep ripping) with NT planting. Both summer [cotton ( Gossypium hirsutum L.), maize ( Zea mays L.), sorghum ( Sorghum bicolor L. Moench), soybean ( Glycine max L. Merr.)] and winter [wheat ( Triticum aestivum L.), barley ( Hordeum vulgare L.), rye ( Secale cereale L.), crimson clover ( Trifolium incarnatum L.)] crops were NT planted throughout the study under each management system. Soil bulk density was reduced with PP compared with NT by as much as 0.15 Mg m −3, but the extent of reduction was inversely related to the time lag between PP operation and sampling event. Soil organic C became significantly enriched with time during this study under NT (0.49 Mg C ha −1 year −1), but not under PP, in which poultry litter was applied equivalent to 5.7 Mg ha −1 year −1 to all water catchments. Soil maintained a highly stratified depth distribution of organic C and N fractions and extractable P under both NT and PP. Inability to perform the PP operation in the last year of this study resulted in rapid convergence of soil bulk density between tillage systems, suggesting that PP had <1-year effectiveness on soil loosening. The high energy cost of PP (ca. 30 kW shank −1) and the lack of sustained improvement in surface-soil properties put into question the value of PP for improving upon long-term NT management in sandy loam and sandy clay loam Ultisols of the Southern Piedmont USA, unless large effects on crop yield, water quality, or other ecosystem processes warrant its use.

Stepwise time response of corn yield and economic return to no tillage

The adoption of no tillage (NT) in crop production has been encouraged primarily due to its more significant benefits to the environment compared with other conservation tillage systems. There are nevertheless concerns about NT corn ( Zea mays L.) performance from both short- and long-term perspectives. This study was conducted near Burlington, Nashua, Newell, Sutherland, and Crawfordsville in Iowa from 1978 through 2001 to evaluate corn production in 4- to 5-year phases under long-term NT management. Field experiments were conducted using a complete randomized block, or split-plot design. Seven tillage systems including NT, moldboard plow (MP), ridge tillage (RT), chisel plow (CP), reduced tillage (RDT), field cultivation (FC), and tillage-plant (TP) were evaluated in terms of corn yield and economic return. Differences between NT and other tillage systems in either corn yield or economic return did not change with the 4- to 5-year phases within the entire study period. The competitiveness of NT over MP, RT, CP, or other tillage systems in the early years (first 4–5 years) since tillage adoption, was as strong as that after 8–10 years. This finding is encouraging to those corn producers who are reluctant to use NT, because of their concern about the poor performance of NT corn during the early years. Yield differences between NT and other tillage systems in each 4- to 5-year phase, or averaged over the entire study period, were mostly within 5% in a corn–soybean ( Glycine max (L.) Merr.) rotation. No tillage generally had equal or greater economic return than other tillage systems in each 4- to 5-year phase and over the entire study period. The yield and economic return benefits of a corn–soybean rotation relative to continuous corn remained generally the same over time under long-term NT management. Therefore, the adoption of a NT system can be accomplished without lowering the economic return from both short- and long-term perspectives.

Stepwise time response of corn yield and economic return to no tillage

The adoption of no tillage (NT) in crop production has been encouraged primarily due to its more significant benefits to the environment compared with other conservation tillage systems. There are nevertheless concerns about NT corn ( Zea mays L.) performance from both short- and long-term perspectives. This study was conducted near Burlington, Nashua, Newell, Sutherland, and Crawfordsville in Iowa from 1978 through 2001 to evaluate corn production in 4- to 5-year phases under long-term NT management. Field experiments were conducted using a complete randomized block, or split-plot design. Seven tillage systems including NT, moldboard plow (MP), ridge tillage (RT), chisel plow (CP), reduced tillage (RDT), field cultivation (FC), and tillage-plant (TP) were evaluated in terms of corn yield and economic return. Differences between NT and other tillage systems in either corn yield or economic return did not change with the 4- to 5-year phases within the entire study period. The competitiveness of NT over MP, RT, CP, or other tillage systems in the early years (first 4–5 years) since tillage adoption, was as strong as that after 8–10 years. This finding is encouraging to those corn producers who are reluctant to use NT, because of their concern about the poor performance of NT corn during the early years. Yield differences between NT and other tillage systems in each 4- to 5-year phase, or averaged over the entire study period, were mostly within 5% in a corn–soybean ( Glycine max (L.) Merr.) rotation. No tillage generally had equal or greater economic return than other tillage systems in each 4- to 5-year phase and over the entire study period. The yield and economic return benefits of a corn–soybean rotation relative to continuous corn remained generally the same over time under long-term NT management. Therefore, the adoption of a NT system can be accomplished without lowering the economic return from both short- and long-term perspectives.