scholarly journals Distribution and vertical stratification of carbon and nitrogen in soil under different managements in the pampean region of Argentina

2011 ◽  
Vol 35 (6) ◽  
pp. 1985-1994 ◽  
Author(s):  
Carina Rosa Álvarez ◽  
Alejandro Oscar Costantini ◽  
Alfredo Bono ◽  
Miguel Ángel Taboada ◽  
Flavio Hernán Gutiérrez Boem ◽  
...  

One of the expected benefits of no-tillage systems is a higher rate of soil C sequestration. However, higher C retention in soil is not always apparent when no-tillage is applied, due e.g., to substantial differences in soil type and initial C content. The main purpose of this study was to evaluate the potential of no-tillage management to increase the stock of total organic C in soils of the Pampas region in Argentina. Forty crop fields under no-tillage and conventional tillage systems and seven undisturbed soils were sampled. Total organic C, total N, their fractions and stratification ratios and the C storage capacity of the soils under different managements were assessed in samples to a depth of 30 cm, in three layers (0-5, 5-15 and 15-30 cm). The differences between the C pools of the undisturbed and cultivated soils were significant (p < 0.05) and most pronounced in the top (0-5 cm) soil layer, with more active C near the soil surface (undisturbed > no-tillage > conventional tillage). Based on the stratification ratio of the labile C pool (0-5/5-15 cm), the untilled were separated from conventionally tilled areas. Much of the variation in potentially mineralizable C was explained by this active C fraction (R² = 0.61) and by total organic C (R² = 0.67). No-till soils did not accumulate more organic C than conventionally tilled soils in the 0-30 cm layer, but there was substantial stratification of total and active C pools at no till sites. If the C stratification ratio is really an indicator of soil quality, then the C storage potential of no-tillage would be greater than in conventional tillage, at least in the surface layers. Particulate organic C and potentially mineralizable C may be useful to evaluate variations in topsoil organic matter.

Weed Science ◽  
1989 ◽  
Vol 37 (2) ◽  
pp. 233-238 ◽  
Author(s):  
J. Anthony Mills ◽  
William W. Witt

Field experiments were conducted to evaluate the interactions of tillage systems with imazaquin and imazethapyr on weed control and soybean injury and yield. Control of jimsonweed, common cocklebur, ivyleaf morningglory, velvetleaf, and giant foxtail from imazaquin and imazethapyr in conventional tillage was generally equal to or greater than control in no-tillage. However, under limited rainfall, weed control in no-tillage was generally equal to or greater than control in conventional tillage. Reductions in soybean heights due to herbicide treatment were evident in both tillage systems in 1985 and 1986 but not in. Soybean yields were reduced in 1985 from imazaquin at 140, 210, and 250 g/ha and imazethapyr at 105 and 140 g/ha. Yields were not reduced in 1986 and. Imazaquin and imazethapyr appear to provide adequate control of jimsonweed, common cocklebur, ivyleaf morningglory, velvetleaf, and giant foxtail in conventional and no-till systems.


2019 ◽  
Vol 99 (2) ◽  
pp. 222-225
Author(s):  
Ben W. Thomas ◽  
Derek Hunt ◽  
Shabtai Bittman ◽  
Kirsten D. Hannam ◽  
Aimé J. Messiga ◽  
...  

The lower Fraser Valley is one of the most intensively cropped regions in Canada. Yet, how soil health indicators respond to long-term intensive agricultural management is poorly documented in this region. Thus, we evaluated a suite of soil health indicators in response to 21 growing seasons of continuous silage corn (Zea mays L.) under conventional tillage or no-tillage (0–20 cm soil layer). Wet aggregate stability, available water capacity, active carbon (permanganate oxidizable, POXC), and extractable potassium and extractable magnesium were significantly greater with no-till than conventional tillage, whereas 8 of 13 indicators were similar. Soil health indicators responded more favourably to no-till than conventional tillage.


2010 ◽  
Vol 34 (6) ◽  
pp. 1787-1793 ◽  
Author(s):  
Carina Rosa Álvarez ◽  
Federico Guillermo Micucci ◽  
Carolina Bustingorri ◽  
Miguel Angel Taboada

The Proctor test is time-consuming and requires sampling of several kilograms of soil. Proctor test parameters were predicted in Mollisols, Entisols and Vertisols of the Pampean region of Argentina under different management systems. They were estimated from a minimum number of readily available soil properties (soil texture, total organic C) and management (training data set; n = 73). The results were used to generate a soil compaction susceptibility model, which was subsequently validated using a second group of independent data (test data set; n = 24). Soil maximum bulk density was estimated as follows: Maximum bulk density (Mg m-3) = 1.4756 - 0.00599 total organic C (g kg-1) + 0.0000275 sand (g kg-1) + 0.0539 management. Management was equal to 0 for uncropped and untilled soils and 1 for conventionally tilled soils. The established models predicted the Proctor test parameters reasonably well, based on readily available soil properties. Tillage systems induced changes in the maximum bulk density regardless of total organic matter content or soil texture. The lower maximum apparent bulk density values under no-tillage require a revision of the relative compaction thresholds for different no-tillage crops.


HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 465A-465
Author(s):  
Jim E. Wyatt ◽  
Don D. Howard ◽  
Don D. Tyler ◽  
Craig H. Canaday

Reduced and no-tillage vegetable production is gaining in acceptance in the Southeastern United States. Conventional till, strip-till, and no-tillage systems with different methods of nitrogen application in staked tomatoes were studied in Tennessee. Conventional tillage plots were prepared by disking and harrowing, strip till plots were cultivated ≈16 cm deep with a rear-tine tiller (≈50 cm wide), and no-till plots were established in chemically killed wheat with no cultivation. Four nitrogen treatments were applied at 67.2 kg·ha-1 N using liquid KNO3. The treatments included applying the N either 1) in a 54-cm strip or 2) in a 108-cm strip over the row, 3) by banding ≈10 cm on each side of and ≈10 cm below the row, or 4) by injecting into the drip irrigation system in increments of 11.2, 22.4 and 33.6 kg·ha-1 N at 2, 4, and 6 weeks after transplanting, respectively. Tillage had little effect on tomato yield but the strip till and no-till plots allowed cultivation or spraying soon after a rainstorm. The improved trafficability was a distinct advantage over the conventionally tilled plots in the study. Total yield was significantly higher in strip tilled plots, but within fruit size categories (small, medium, large and extra large) no differences were found due to tillage system. The fertilizer treatments in which N was placed in 54- or 108-cm strips over the row produced the highest yield of early large and early extra large fruit, which are usually the most valuable portion of the crop. Banded and injected nitrogen treatments tended to produce large amounts of fruit late in the season, a period when tomato prices are generally lower.


2011 ◽  
Vol 183-185 ◽  
pp. 1185-1189
Author(s):  
Qi Wen Tang ◽  
Chang Sheng Jiang ◽  
Qing Ju Hao ◽  
Yan Wu

The effect of different tillage systems on the size distribution of aggregates and organic carbon distribution and storage in different size aggregates in a Hydragric Anthrosol were studied in a long-term experiment in Chongqing, China. The experiment included five tillage treatments, which are conventional tillage with rice only system (DP), conventional tillage with rotation of rice and rape system (SH), no-till and ridge culture with rotation of rice and rape system (LM), no-till and plain culture with rotation of rice and rape system (XM) and tillage and ridge culture with rotation of rice and rape system (LF), respectively. The results showed that the aggregates 0.25-0.05 mm in diameter accounted for the largest proportion in each soil layer under all treatments. The organic carbon mainly exist in aggregates in the 0.25-2 mm and 0.05-0.25 mm diameter in the plough layer, which mainly exist in the 0.25-2 mm in diameter in the bottom layer. Distribution of organic carbon in aggregates in the 0.05-0.25 mm diameter class was highest, followed by the aggregates in the 0.25-2mm diameter class. The organic carbon in aggregates under different tillage systems was in a decreasing order of LM (21.05 g·kg-1)> DP (14.13 g·kg-1)> XM (13.29 g·kg-1)> LF (12.54 g·kg-1) > SH (11.41 g·kg-1). The total organic carbon content showed a significant correlation with the amount of aggregates with diameter >0.005 mm. The results showed that the accumulation of soil organic carbon was mainly affected by aggregates in the >0.005mm diameter class.


Weed Science ◽  
1989 ◽  
Vol 37 (2) ◽  
pp. 217-222 ◽  
Author(s):  
J. Anthony Mills ◽  
William W. Witt ◽  
Michael Barrett

Experiments were conducted in 1985 to 1987 to evaluate the effects of conventional and no-tillage systems on the weed control provided by clomazone applied preemergence in soybeans. The persistence of clomazone in soil of the two tillage systems was also determined. Increasing the clomazone rate from 0.8 to 1.4 kg/ha did not increase weed control. Clomazone controlled 80% or more of jimsonweed, velvetleaf, and giant foxtail. Common cocklebur control ranged from about 50 to 70% in no-till and from 80 to 90% in conventional tillage. Generally, soybean pods/plant and yields were lower from clomazone treatments than from handweeded treatments due to inadequate common cocklebur control. Over 40% of the clomazone applied did not reach the soil surface; it was either intercepted by wheat straw, volatilized, or both. Clomazone persisted longer in conventional tillage than in no-tillage in. However, in 1986, clomazone was equally persistent in the two tillage systems. The half-life of clomazone was 34 and 6 days in 1985 in conventional and no-tillage, respectively, and in 1986, 18 and 16 days in conventional and no-tillage, respectively. Significant clomazone concentrations were not found below 10 cm in the soil profile. Corn planted without tillage (no-till) approximately 1 yr after clomazone application was not injured and yields were not reduced due to prior clomazone use.


2011 ◽  
Vol 183-185 ◽  
pp. 2163-2167
Author(s):  
Yan Wu ◽  
Qing Ju Hao ◽  
Chang Sheng Jiang

The effect of different tillage systems on the soil organic carbon (SOC), active organic carbon (AOC) and remaining organic carbon (ROC) were studied in a long-term experiment in Chongqing, China. The experiment included five tillage treatments, which are conventional tillage with rice only system (DP), conventional tillage with rotation of rice and rape system (SH), no-till and ridge culture with rotation of rice and rape system (LM), no-till and plain culture with rotation of rice and rape system (XM) and tillage and ridge culture with rotation of rice and rape system (LF), respectively. The results showed that the content of SOC declined as the soil depth increased, and presented obvious surface enrichment phenomenon under the no-tillage systems. The order of SOC, AOC, ROC and ROC/SOC in the 0–60 cm soil layer under different tillage systems was LM (22.74 g kg-1) > DP (14.57 g kg-1) > XM (13.73 g kg-1) > LF (13.10 g kg-1) > SH (11.92 g kg-1), DP (3.67 g kg-1) > LF (3.49 g kg-1) > LM (3.28 g kg-1) > XM (3.17 g kg-1) > SH (2.69 g kg-1), LM (18.09 g kg-1) > DP (10.34 g kg-1) > XM (10.12 g kg-1) > LF (9.20 g kg-1) > SH (8.80 g kg-1) and LM (85%) > SH (78%) > XM 77%) > LF (75%) > DP (74%). Compared with other systems, LM significantly increased SOC, ROC and ROC/SOC, which indicated long-term LM system performed good effect for carbon sequestration.


Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1233
Author(s):  
Yuqiong Luo ◽  
Anas Iqbal ◽  
Liang He ◽  
Quan Zhao ◽  
Shangqin Wei ◽  
...  

Conservation farming practices, such as no-tillage and crop residue retention, have been proposed as sustainable management practices. However, it remains unclear how different tillage practices and rice straw retention affect the soil bacterial community (SBC) and the soil C/N ratio in the long term. The objective of this study was to evaluate changes in SBC composition and abundance and soil properties (e.g., carbon (C), nitrogen (N)) and determine their relationship to the soil C/N ratio under long-term no-tillage and straw retention techniques. This study investigates the effect of a long-term field experiment begun in 2008 and continued until 2019 to measure the response of the SBC and soil properties and their relation to different tillage practices, including no-tillage (NT), no-tillage and straw mulching (NT-SM), conventional tillage (CT), conventional tillage and straw mulching (CT-SM), and conventional tillage and straw retention (CT-SR). Soil samples were collected at depths of 0–5 cm (A), 5–10 cm (B), and 10–20 cm (C) after rice harvesting in the early and late growing seasons in 2018–2019. The Illumina MiSeq sequencing and quantitative polymerase chain reaction (PCR) technology was used to analyze changes in SBC diversity in soil and determined the changes in the soil C/N ratio and their relationship with the SBC diversity. The results showed that the Proteobacteria, Acidobacteria, and Chloroflexi were the dominant phyla in the soil and accounted for 61.26%, 59.39%, and 55.62% of the total bacteria in the A, B, and C soil layers, respectively. The NT treatment increased SBC diversity, the number of operational taxonomic units (OTUs), and the proportion of Proteobacteria across the soil depths. Similarly, straw retention also significantly improved SBC diversity, soil organic C (SOC), total N (TN), soil C/N ratio, and the abundance of Proteobacteria and Acidobacteria in the soil layers A and B. The NT-SM treatment increased the SOC, TN, and soil C/N ratio by 30%, 21%, and 6% in 2018 and by 33, 25% and 7% in 2019, respectively, across the seasons and layers compared to the CT treatment. The NT-SM treatment had the highest soil bacterial diversity index, and the CT-SR treatment had the highest soil bacterial abundance and number of OTUs. The redundancy analysis showed that Acidobacteria were highly positively correlated with the soil C/N ratio. The results demonstrate that conservation tillage practices, i.e., no-tillage and straw retention, increase the SBC diversity and soil C/N ratio, thereby enhancing soil organic C and total N and changing soil microbial ecology. As a result, sustainable crop production and profitable agro-ecosystems are ensured.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 476d-476
Author(s):  
Gary R. Cline ◽  
Anthony F. Silvernail

A split-plot factorial experiment examined effects of tillage and winter cover crops on sweet corn in 1997. Main plots received tillage or no tillage. Cover crops consisted of hairy vetch, winter rye, or a mix, and N treatments consisted of plus or minus N fertilization. Following watermelon not receiving inorganic N, vetch, and mix cover cropsproduced total N yields of ≈90 kg/ha that were more than four times greater than those obtained with rye. However, vetch dry weight yields (2.7 mg/ha) were only about 60% of those obtained in previous years due to winter kill. Following rye winter cover crops, addition of ammonium nitrate to corn greatly increased (P < 0.05) corn yields and foliar N concentrations compared to treatments not receiving N. Following vetch, corn yields obtained in tilled treatments without N fertilization equaled those obtained with N fertilization. However, yields obtained from unfertilized no-till treatments were significantly (P < 0.05) lower than yields of N-fertilized treatments. Available soil N was significantly (P < 0.05) greater following vetch compared to rye after corn planting. No significant effects of tillage on sweet corn plant densities or yields were detected. It was concluded that no-tillage sweet corn was successful, and N fixed by vetch was able to sustain sweet corn production in tilled treatments but not in no-till treatments.In previous years normal, higher-yielding vetch cover crops were able to sustain sweet corn in both tilled and no-till treatments.


1993 ◽  
Vol 73 (1) ◽  
pp. 39-50 ◽  
Author(s):  
D. A. Angers ◽  
N. Bissonnette ◽  
A. Légère ◽  
N. Samson

Crop rotations and tillage practices can modify not only the total amount of organic matter (OM) in soils but also its composition. The objective of this study was to determine the changes in total organic C, microbial biomass C (MBC), carbohydrates and alkaline phosphatase activity induced by 4 yr of different rotation and tillage combinations on a Kamouraska clay in La Pocatière, Quebec. Two rotations (continuous barley (Hordeum vulgare L.) versus a 2-yr barley–red clover (Trifolium pratense L.) rotation) and three tillage treatments (moldboard plowing (MP), chisel plowing (CP) and no-tillage (NT)) were compared in a split-plot design. Total organic C was affected by the tillage treatments but not by the rotations. In the top soil layer (0–7.5 cm), NT and CP treatments had C contents 20% higher than the MP treatment. In the same soil layer, MBC averaged 300 mg C kg−1 in the MP treatment and up to 600 mg C kg−1 in the NT soil. Hot-water-extractable and acid-hydrolyzable carbohydrates were on average 40% greater under reduced tillage than under MP. Both carbohydrate fractions were also slightly larger in the rotation than in the soil under continuous barley. The ratios of MBC and carbohydrate C to total organic C suggested that there was a significant enrichment of the OM in labile forms as tillage intensity was reduced. Alkaline phosphatase activity was 50% higher under NT and 20% higher under CP treatments than under MP treatment and, on average, 15% larger in the rotation than in the continuous barley treatment. Overall, the management-induced differences were slightly greater in the top layer (0–7.5 cm) than in the lower layer of the Ap horizon (7.5–15 cm). All the properties measured were highly correlated with one another. They also showed significant temporal variations that were, in most cases, independent of the treatments. Four years of conservation tillage and, to a lesser extent, rotation with red clover resulted in greater OM in the top soil layer compared with the more intensive systems. This organic matter was enriched in labile forms. Key words: Soil management, soil quality, organic matter, carbohydrates, microbial biomass, phosphatase


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