scholarly journals The role of cover crops for cropland soil carbon, nitrogen leaching, and agricultural yields – A global simulation study with LPJmL (V. 5.0-tillage-cc)

2021 ◽  
Author(s):  
Vera Porwollik ◽  
Susanne Rolinski ◽  
Jens Heinke ◽  
Werner von Bloh ◽  
Sibyll Schaphoff ◽  
...  

Abstract. Land management practices can reduce the environmental impact of agricultural land use and production, improve productivity, and transform cropland into carbon sinks. We applied the global vegetation model LPJmL5.0-tillage-cc with a modified representation of cover crop practices. We assessed simulated responses to cover crop practices on agroecosystem components in comparison to bare soil fallow between two consecutive primary crops’ growing seasons on global cropland for a simulation period of 50 years. With cover crops and tillage, we obtained annual global median soil carbon sequestration rates of 0.52 and 0.48 t C ha−1 yr−1 for the first and last decades of the entire simulation period, respectively. We found that cover crops with tillage reduced annual nitrogen leaching rates from cropland soils by a median of 39 % and 54 % but also the productivity of the following main crop by average of 1.6 % and 2 % for the two analyzed decades. Largest reduction of productivity were found for rice, modestly lowered for maize and wheat, whereas soybean yield revealed an almost homogenous positive response to cover crop practices during fallow periods. Further, the results suggest that no-tillage is a suitable complementary practice to cover crops, enhancing their environmental benefits and reducing potential trade-offs with the main crop productivity due to their impacts on soil nitrogen and water dynamics. For cover crops applied in conjunction with no-tillage across the mapped Conservation Agriculture cropland area for the period 1974–2010, we estimated a cumulative soil carbon net-accumulation of 1.4 PgC, an annual median reduction of soil nitrogen leaching by 57 %, as well as mostly enhanced yields of the following main crop. The spatial heterogeneity of simulated impacts of cover crops on the variables assessed here was related to the time period since the introduction of the management practice as well as to environmental and agronomic conditions of the cropland. This study supports findings of other studies, highlighting the substantial potential contribution of cover crop practices to the sustainable development of arable production.

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 387
Author(s):  
Miguel A. Repullo-Ruibérriz de Torres ◽  
Manuel Moreno-García ◽  
Rafaela Ordóñez-Fernández ◽  
Antonio Rodríguez-Lizana ◽  
Belén Cárceles Rodríguez ◽  
...  

Almond (Prunus dulcis Mill. [D.A. Webb]) is the third most widely spread crop in Spain and has traditionally been cultivated in marginal areas and shallow soils under rainfed conditions. However, it recently has been progressively introduced in flat irrigated areas. The implementation of cover crops in the inter-rows of woody crops has been proven as a suitable strategy to reduce the runoff and soil erosion but they also can boost soil quality and health. A field experiment was conducted during two-monitoring seasons to examine the soil nitrogen and carbon sequestration potential of three seeded cover crops [barley (Hordeum vulgare L.), hairy vetch (Vicia villosa Roth), and a mixture of 65% barley and 35% vetch] and a control of spontaneous flora in irrigated almond orchards (SW Spain). Here, we show that barley provided the highest biomass amount, followed by mixture covers, vetch, and the control treatment. Also, vetch covered the soil faster in the growing stage, but its residues were decomposed easier than barley and mixture treatments during the decomposition period after mowing, providing less soil protection when the risk of water erosion with autumn rainfall is high. On the other hand, vetch improved soil nitrate content by over 35% with respect to barley and mixture treatments at 0–20 cm soil depth throughout the studied period. In addition, a greater carbon input to the soil was determined in the barley plot. That is, the mixture and barley cover crops had higher potential for carbon sequestration, augmenting the soil organic carbon by more than 1.0 Mg ha−1 during the study period. Thus, taking into consideration the findings of the present experiment, the establishment of a seeded cover crop would be more advisable than spontaneous flora to mitigate soil erosion, enhancing soil fertility and carbon sequestration in irrigated almond plantations in Mediterranean semi-arid regions.


Weed Science ◽  
2021 ◽  
pp. 1-26
Author(s):  
Roberto Botelho Ferraz Branco ◽  
Fernando de Carvalho ◽  
João Paulo de Oliveira ◽  
Pedro Luis da Costa Alves

Abstract Cover crop residue left on the soil surface as organic mulch in no-tillage crop production provides several environmental benefits, including weed suppression. Thus, many farmers who use cover crops attempt to reduce the use of agricultural inputs, especially herbicides. Therefore, our objectives were to study the potential of different cover crop species to suppress weeds and produce an in situ organic mulch, and evaluate the effect of the organic mulch with and without spraying glyphosate on weed suppression for vegetable (tomato (Solanum lycopersicum L. and broccoli (Brassica oleracea L. var. botrytis) growth and yield. Five cover crop treatments (sunn hemp (Crotalaria juncea L.), jack bean [Canavalia ensiformis (L.) DC.], pearl millet [Pennisetum glaucum (L.) R. Br.], grain sorghum [Sorghum bicolor (L.) Moench ssp. bicolor] and a no-cover crop (control)) were used in the main plots; and spraying or no spraying glyphosate on the flattened cover crop in the sub plots of split-plot experimental design. Organic mulch from pearl millet, sorghum and sunn hemp resulted in lower weed biomass during the early season of both tomato and broccoli than jack bean and no-cover crop (control). Spraying glyphosate after roller crimping reduced weed biomass by 103 g m−2 and 20 g m−2 by 45 and 60 days after transplanting (DAT) of tomato, respectively and resulted in a better tomato yield compared to non spraying. Glyphosate reduced weed biomass by 110 g m−2 in the early season of broccoli (30 DAT), but did not affect yield. Terminating high biomass cover crops with a roller crimper is a promising technique for weed management in vegetable crops, which has the potential to reduce or even eliminate the need for herbicide.


2018 ◽  
Vol 31 (2) ◽  
pp. 264-270 ◽  
Author(s):  
JOÃO LUÍS DA SILVA FILHO ◽  
ANA LUÍZA DIAS COELHO BORIN ◽  
ALEXANDRE CUNHA DE BARCELLOS FERREIRA

ABSTRACT No-tillage cotton systems require soil coverage with cover crop residue for a longer time due to the late cycle of cotton. However, decomposition rates may vary between cover crops, and the adjustment of models to describe it is critical to no-tillage cotton management. Two non-linear regression models, exponential (EM) and Michaelis-Menten (MM), were adjusted to dry matter decomposition of cover crops in a cotton no-tillage system, in Brazil. Three field trials were performed in 2012 for the cover crops Urochloa ruziziensis (brachiaria), Pennisetum glaucum (pearl millet), and Cajanus cajan (pigeon pea). Samples of cover crop were collected at 20, 50, 70, 110, 140, and 170 days after sowing upland cotton to measure dry matter decomposition. MM showed better adjustment than EM for all cover crops. The estimations of half-life parameters were different between the cover crops, suggesting that each cover crop has its own rate of decomposition. For pearl millet, brachiaria, and pigeon pea, the half-life estimation by exponential model was over the MM in 9, 12, and 12 days.


Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 840 ◽  
Author(s):  
Ahmed Laamrani ◽  
Paul R. Voroney ◽  
Aaron A. Berg ◽  
Adam W. Gillespie ◽  
Michael March ◽  
...  

The impacts of tillage practices and crop rotations are fundamental factors influencing changes in the soil carbon, and thus the sustainability of agricultural systems. The objective of this study was to compare soil carbon status and temporal changes in topsoil from different 4 year rotations and tillage treatments (i.e., no-till and conventional tillage). Rotation systems were primarily corn and soy-based and included cereal and alfalfa phases along with red clover cover crops. In 2018, soil samples were collected from a silty-loam topsoil (0–15 cm) from the 36 year long-term experiment site in southern Ontario, Canada. Total carbon (TC) contents of each sample were determined in the laboratory using combustion methods and comparisons were made between treatments using current and archived samples (i.e., 20 year and 9 year change, respectively) for selected crop rotations. Overall, TC concentrations were significantly higher for no-till compared with conventional tillage practices, regardless of the crop rotations employed. With regard to crop rotation, the highest TC concentrations were recorded in corn–corn–oats–barley (CCOB) rotations with red clover cover crop in both cereal phases. TC contents were, in descending order, found in corn–corn–alfalfa–alfalfa (CCAA), corn–corn–soybean–winter wheat (CCSW) with 1 year of seeded red clover, and corn–corn–corn–corn (CCCC). The lowest TC concentrations were observed in the corn–corn–soybean–soybean (CCSS) and corn–corn–oats–barley (CCOB) rotations without use of cover crops, and corn–corn–soybean–winter wheat (CCSW). We found that (i) crop rotation varieties that include two consecutive years of soybean had consistently lower TC concentrations compared with the remaining rotations; (ii) TC for all the investigated plots (no-till and/or tilled) increased over the 9 year and 20 year period; (iii) the no-tilled CCOB rotation with 2 years of cover crop showed the highest increase of TC content over the 20 year change period time; and (iv) interestingly, the no-till continuous corn (CCCC) rotation had higher TC than the soybean–soybean–corn–corn (SSCC) and corn–corn–soybean–winter wheat (CCSW). We concluded that conservation tillage (i.e., no-till) and incorporation of a cover crop into crop rotations had a positive effect in the accumulation of TC topsoil concentrations and could be suitable management practices to promote soil fertility and sustainability in our agricultural soils.


1995 ◽  
Vol 46 (3) ◽  
pp. 553 ◽  
Author(s):  
RJ Stirzaker ◽  
I White

Excessive cultivation in many horticultural areas results in soil structural decline and poor utilization of water and nutrients. There are no reliable techniques for growing irrigated vegetables without cultivation. This work explores the hypothesis that a winter legume cover-crop can overcome the soil limitations of no-tillage and provide an alternative to excessive cultivation in the vegetable industry. We grew lettuce (Lactuca sativa) under no-tillage in field trials on a sandy loam soil following a bare winter fallow or a cover-crop of subterranean clover (Trifolium subterraneum), and compared this with cultivation by rotary hoe. The clover died naturally in early summer or was desiccated in the spring to form a mulch of at least 5 t ha-1 on the soil surface. The experiment was carried out over a 2.5 year period. The first crop was grown during hot weather and the soil in the no-tillage treatments was only moderately compacted. The yield of lettuce was similar in the no-tillage and cultivated treatments, and increased by about 30% when a mulch was added to each treatment. The soil was artificially compacted after the first crop. The second crop was grown 18 months later, during cooler spring weather, and following two further cover-crops. The yield of no-tillage lettuce was only 40% of that obtained with cultivation. Yield in the no-tillage treatment was doubled in two different ways: (1) by the addition of a surface mulch, and (2) through changes to soil structure stimulated by a cover-crop in the absence of a mulch. The experiments showed that a well-managed cover-crop can significantly ameliorate a compacted sandy soil by modifying soil temperature, soil strength, and by stimulating the formation of biopores.


HortScience ◽  
2004 ◽  
Vol 39 (6) ◽  
pp. 1262-1266 ◽  
Author(s):  
Lidia M. Carrera ◽  
Aref A. Abdul-Baki ◽  
John R. Teasdale

Cover crops combined with conservation tillage practices can minimize chemical inputs and improve soil quality, soil water-holding capacity, weed suppression and crop yields. No-tillage production of sweet corn (Zea mays var. `Silver Queen') was studied for 2 years at the USDA Beltsville Agricultural Research Center, Md., to determine cover crop management practices that maximize yield and suppress weeds. Cover crop treatments were hairy vetch (Vicia villosa Roth), rye (Secale cereale L.) and hairy vetch mixture, and bare soil (no cover crop). There were three cover crop killing methods: mowing, rolling or contact herbicide paraquat. All plots were treated with or without atrazine and metolachlor after planting. There was a 23% reduction in sweet corn plant population in the rye-hairy vetch mixture compared to bare soil. Averaged over both years, sweet corn yield in hairy vetch treatments was 43% greater than in bare soil, whereas yield in the rye-hairy vetch mixture was 30% greater than in bare soil. There were no significant main effects of kill method or significant interactions between kill method and cover crop on yield. Sweet corn yields were not different for hairy vetch or rye-hairy vetch treatments with or without atrazine and metolachlor. However, yield in bare soil without the herbicides atrazine and metolachor were reduced by 63% compared to bare soil with these herbicides. When no atrazine and metolachlor were applied, weed biomass was reduced in cover crops compared to the bare soil. Regression analysis showed greater yield loss per unit of weed biomass for bare soil than for the vetch or rye-hairy vetch mixture. This analysis suggests that cover crops increased sweet corn yield in the absence of atrazine and metolachlor not only by reducing weed biomass, but also by increasing the competitiveness of corn to weeds at any given biomass.


HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 461E-461
Author(s):  
H.J. Hruska ◽  
G.R. Cline ◽  
A.F. Silvernail ◽  
K. Kaul

Research began in 1999 to examine sustainable production of bell peppers (Capsicum annuum L.) using conservation tillage and legume winter cover crops. Tillage treatments included conventional tillage, strip-tillage, and no-tillage, and winter covers consisted of hairy vetch (Vicia villosa Roth), winter rye (Secale cereale L.), and a vetch/rye biculture. Pepper yields following the rye winter cover crop were significantly reduced if inorganic N fertilizer was not supplied. However, following vetch, yields of peppers receiving no additional N were similar to yields obtained in treatments receiving the recommended rate of inorganic N fertilizer. Thus, vetch supplied sufficient N to peppers in terms of yields. Pepper yields following the biculture cover crop were intermediate between those obtained following vetch and rye. When weeds were controlled manually, pepper yields following biculture cover crops were similar among the three tillage treatments, indicating that no-tillage and strip-tillage could be used successfully if weeds were controlled. With no-tillage, yields were reduced without weed control but the reduction was less if twice the amount of residual cover crop surface mulch was used. Without manual weed control, pepper yields obtained using strip-tillage were reduced regardless of metolachlor herbicide application. It was concluded that a vetch winter cover crop could satisfy N requirements of peppers and that effective chemical or mechanical weed control methods need to be developed in order to grow peppers successfully using no-tillage or strip-tillage.


HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 669d-669
Author(s):  
Gary R. Cline ◽  
Anthony F. Silvernail

A split-plot factorial experiment examined effects of tillage and winter cover crops on sweet corn. 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. No significant effects of tillage on sweet corn yields were detected. Following corn not receiving inorganic N, vetch produced cover crop total N yields of 130 kg·ha–1 that were over three-times greater than those obtained with rye. Following rye winter covercrops, addition of ammonium nitrate to corn significantly (P < 0.05) increased corn yields and foliar N concentrations compared to treatments not receiving N. However, following vetch, corn yields and foliar N concentrations obtained without N fertilization equaled those obtained with N fertilization following rye or vetch. Available soil N was significantly (P < 0.05) greater following vetch compared to rye for ≈9 weeks after corn planting and peaked ≈4 weeks after planting. It was concluded that no-tillage sweet corn was successful and N fixed by vetch was able to sustain sweet corn production.


HortScience ◽  
2011 ◽  
Vol 46 (3) ◽  
pp. 387-395 ◽  
Author(s):  
Matthew J. Leavitt ◽  
Craig C. Sheaffer ◽  
Donald L. Wyse ◽  
Deborah L. Allan

Winter annual cover crops, winter rye (Secale cereale L.) and hairy vetch (Vicia villosa Roth), can reduce weed density and build soil quality in organic production systems. There is interest in integrating cover crops and reduced tillage with organic vegetable production, but few studies have been conducted in regions with short growing seasons and cool soils such as the upper Midwest. We evaluated no-tillage production of tomato (Solanum lycopersicum L.), zucchini (Cucurbita pepo L.), and bell pepper (Capsicum annuum L.) planted into winter rye, hairy vetch, and a winter rye/hairy vetch (WR/HV) mixture that were mechanically suppressed with a roller–crimper at two locations in Minnesota. Average marketable yields of tomato, zucchini, and bell pepper in the rolled cover crops were reduced 89%, 77%, and 92% in 2008 and 65%, 41%, and 79% in 2009, respectively, compared with a no-cover control. Winter rye and the WR/HV mixture reduced average annual weed density at St. Paul by 96% for 8 to 10 weeks after rolling (WAR) and hairy vetch mulch reduced weeds 80% for 2 to 8 WAR, whereas at Lamberton, there was no consistent effect of cover treatments on weed populations. Winter rye and the WR/HV mixture had higher average residue biomass (5.3 and 5.7 Mg·ha−1, respectively) than hairy vetch (3.0 Mg·ha−1) throughout the season. Soil growing degree-days (SGDD) were lower in cover crop treatments compared with the no-cover control, which could have delayed early vegetable growth and contributed to reduced yields. All cover crop mulches were associated with low levels of soil nitrogen (N) (less than 10 mg·kg−1 N) in the upper 15 cm. Rolled winter annual cover crops show promise for controlling annual weeds in organic no-tillage systems, but additional research is needed on methods to increase vegetable crop yields in rolled cover crops.


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