scholarly journals Evaluation of Cool-season Vegetable Rotations in Organic Production

2016 ◽  
Vol 26 (5) ◽  
pp. 637-646 ◽  
Author(s):  
George E. Boyhan ◽  
Julia W. Gaskin ◽  
Elizabeth L. Little ◽  
Esendugue G. Fonsah ◽  
Suzanne P. Stone
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Vigna Unguiculata ◽  
Cover Crops ◽  
Organic Production ◽  
Green Bean ◽  
Cool Season ◽  
Cash Crops ◽  
Sunn Hemp ◽  
Disease Pressure

Certified organic production is challenging in the southeastern United States due to high weed, insect, and disease pressure. Maintaining and building soil organic carbon in midscale organic production systems can also be difficult due to the warm, moist conditions that promote decomposition. Focusing on cool-season cash crops paired with warm-season cover crops may help alleviate these production problems. This 3-year study (2011–13) evaluated two vegetable rotations of cool-season crops with cover crops for their productivity, disease management, and soil building potential in Watkinsville, GA. In the first rotation, cool-season cash crops included onion (Allium cepa), strawberry (Fragaria ×ananassa), and potato (Solanum tuberosum). These crops were rotated with green bean (Phaseolus vulgaris), oats/austrian winter pea (Avena sativa/Pisum sativum ssp. arvense), southernpea (Vigna unguiculata), and sunn hemp (Crotalaria juncea). In the second rotation, cool-season cash crops included onion, broccoli (Brassica oleracea Italica group), lettuce (Lactuca sativa), and carrot (Daucus carota ssp. sativus). These were rotated with millet (Urochloa ramosa), sunn hemp, egyptian wheat/iron clay pea (Sorghum sp./Vigna unguiculata), and sorghum × sudangrass (Sorghum bicolor × S. bicolor var. sudanese)/iron clay pea. Onion yields in both rotations were at least 80% of average yields in Georgia. Lettuce yields were at least double the average yields in Georgia and were comparable to national averages in the 2nd and 3rd years of the study. Strawberry yields in these rotations were lower than Georgia averages in all 3 years with a trend of lower yields over the course of the study. By contrast, potato, although lower than average yields in Georgia increased each year of the study. Broccoli yields in the first year were substantially lower than average Georgia yields, but were comparable to average yields in the 2nd year. Carrot remained less than half of average Georgia yields. Green bean were half of average Georgia yields in the 2nd year and were comparable to average yields in the 3rd year. As expected from what is observed in cool-season organic vegetable production in Georgia, disease pressure was low. Cover crops maintained soil organic carbon (C) with a small increase in active C; however, there was a net loss of potentially mineralizable nitrogen (PMN). Active C averaged across both rotations at the beginning of the study at 464 mg·kg−1 and averaged 572 mg·kg−1 at the end of the study. On the basis of this study, using cover crops can maintain soil carbon without the addition of carbon sources such as compost. Finally, longer term work needs to be done to assess soil management strategies.

scholarly journals Sunn Hemp: A Legume Cover Crop with Potential for the Midwest?

2018 ◽  
Vol 7 (4) ◽  
pp. 63
Author(s):  
Esther Shekinah Durairaj ◽  
James K. Stute
Keyword(s):  
Soil Erosion ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Cover Crops ◽  
Warm Season ◽  
Nutrient Loss ◽  
Residue Management ◽  
Crop Failure ◽  
Weed Biomass ◽  
Sunn Hemp

Crops like corn and soybean occupy vast area in the Midwest, USA. When land is left fallow after the harvest of these crops, a number of degradation factors operate and bring about soil erosion, nutrient loss, decreased soil organic carbon, reduced biological activity and increase in weed biomass. Integrating cover crops (CCs) into this system would build benefits that the very system lacks. There are various CCs available, but leguminous CCs allows for reduced application of fertilizer nitrogen and builds the soil fixed atmospheric nitrogen. Winter CCs are restricted in the Midwest because of the short planting window which greatly minimizes the biomass accumulation. Warm season CCs would serve well here. Sunn hemp is one such tropical CC that grows well in temperate conditions too, without producing seeds. It comes with many benefits - including decreased soil erosion, improved soil organic carbon, increase in soil fixed nitrogen, higher biomass that adds organic matter and N to the soil, reduced weed density and weed biomass. The timing and method of termination influences the residue management. Going by the benefits it adds, sunn hemp is a viable warm season CC that can be grown in the Midwest and has great potential in fallows, prevented plant acres, areas of crop failure (planted and failed) and also in areas after the harvest of the short season small grains or processing crops. However, intensive research on sunn hemp is needed in the Midwest which is discussed. 

Alternatives to Glyphosate in conservation agriculture: effects on carbon sequestration in a field experiment in northern Italy

2020 ◽  
Author(s):  
alessia perego ◽  
marco acutis ◽  
calogero schillaci
Keyword(s):  
Carbon Sequestration ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Field Experiment ◽  
Biomass Production ◽  
Cover Crops ◽  
Management Practices ◽  
Block Design ◽  
Northern Italy ◽  
Cash Crop

<p>Conservative Agriculture (CA) practices are recognized to enhance soil organic carbon stock and in turn to mitigate the effect of climate change. One of the CA principles is to integrate cover crops (CC) into the cropping systems. The termination of CC before the cash crop sowing and the weeds control are the most critical aspects to manage in the CA. The technique currently adopted by farmers for the termination of CC implies the use of Glyphosate. However, the European Commission is currently discussing the possibility of banning the use of this herbicide due to the negative effects on human health and the agro-environment. The disk harrow (DH) or the roller-crimper (RC) can be adopted in CA as an alternative to the use of Glyphosate for the devitalization of CC, their incorporation into the soil (in the case of the disk harrow), and the reduction of weed pressure on the subsequent cash crop.</p><p>From November 2017 to October 2019, soil organic carbon (SOC, g kg<sup>-1</sup>) and crop biomass production were observed in a 2-year field experiment located in Lodi (northern Italy), in which minimum tillage (MT) has been applied for the last 5 years. The soil was loamy and SOC was 16.2 g kg<sup>-1</sup> at the beginning of the experiment. The winter CC was barley (from November to May) and the cash crop was soybean (from June to October). The experiment consisted in three treatments replied for two consecutive years in a randomized block design: Glyphosate spray + DH + sowing + hoeing (MT-GLY); DH + sowing + hoeing (MT-ORG); RC + sod seeding (NT-ORG).</p><p>At the end of 2019, SOC resulted in a higher increase in MT-GLY (+15%) and in MT-ORG (+14%) than in NT-ORG (+6%; p<0.01). This was due to the fact that CC litter in NT-ORG was not in direct contact with soil particles and the process of immobilization was lower than in the other treatments.</p><p>Moreover, the increase in SOC resulted positively correlated to the CC biomass (2018+2019), which was significantly lower in NT-ORG. In particular, no differences of soybean and CC between the three treatments were observed at the end of 2018, but MT-GLY resulted in significantly higher CC and soybean biomass at the end of the second year (+32%, p<0.01). MT-GLY allows to stock more carbon via photosynthesis that in turn results in higher SOC content.</p><p>However, if we consider the tractor fuel consumption (for Glyphosate spray, DH, RC, hoeing), along with the biomass production, the carbon sequestration did not vary between the three treatments.</p><p>Further studies are needed for the definition of optimized field management practices to reduce the passage of machinery while increasing crop production and SOC.</p>

scholarly journals Long-term effect of tillage, nitrogen fertilization and cover crops on soil organic carbon and total nitrogen content

2011 ◽  
Vol 114 (2) ◽  
pp. 165-174 ◽  
Author(s):  
Marco Mazzoncini ◽  
Tek Bahadur Sapkota ◽  
Paolo Bàrberi ◽  
Daniele Antichi ◽  
Rosalba Risaliti
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Nitrogen Content ◽  
Total Nitrogen ◽  
Cover Crops ◽  
Nitrogen Fertilization ◽  
Term Effect ◽  
Total Nitrogen Content ◽  
Long Term Effect

scholarly journals Long-term organic farming on a citrus plantation results in soil organic carbon recovery

2019 ◽  
Vol 45 (1) ◽  
pp. 271 ◽  
Author(s):  
A. Novara ◽  
M. Pulido ◽  
J. Rodrigo-Comino ◽  
S. Di Prima ◽  
P. Smith ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Organic Farming ◽  
Cover Crops ◽  
Organic Management ◽  
Soil C ◽  
Soil Organic Carbon Sequestration ◽  
Sequestration Rate ◽  
Mediterranean Conditions

It has been shown that soil management under organic farming can enhance soil organic carbon, thereby mitigating atmospheric greenhouse gas increases, but until now quantitative evaluations based on long term experiments are scarce, especially under Mediterranean conditions. Changes in soil organic carbon (SOC) content were examined in response to organic management with cover crops in a Mediterranean citrus plantation using 21 years of survey data. Soil organic carbon increase was more apparent 5 years after a land management change suggesting that, for citrus plantations on Mediterranean conditions, studies should be longer than five years in duration. Soil organic carbon sequestration rate did not significantly change during the 21 years of observation, with values ranging from -1.10 Mg C ha-1 y-1 to 1.89 Mg C ha-1 y-1. After 21 years, 61 Mg CO2 ha-1 were sequestered in long-lived soil C pools. These findings demonstrate that organic management is an effective strategy to restore or increase SOC content in Mediterranean citrus systems.

Growth of Legume Cover Crops under Cassava and Its Effect on Soil Properties

2021 ◽  
Author(s):  
Suwarto . ◽  
Retno Asih
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Properties ◽  
Cover Crops ◽  
Cover Crop ◽  
Soil Moisture Content ◽  
Legume Cover Crops ◽  
Calopogonium Mucunoides ◽  
Legume Cover Crop

Background: Low soil organic carbon is a constraint to cassava tuber formation. Some legume cover crops could be an alternative to provide organic matter on the cassava field as a source of soil organic carbon. The study was aimed to evaluate the growth of some legume cover crops under cassava and their effects on soil properties. Methods: During September 2017-July 2018 legume cover crops (Calopogonium mucunoides, Centrosema pubescens, Pueraria javanica and the mixed) were planted under cassava variety of Mangu and UJ-5. The land coverage by the legume cover crops was measured monthly from 2 to 10 months after planting. Cassava growth was observed weekly from 8 to 32 weeks after planting. Soil properties were analyzed before planting and at harvesting of cassava. Result: Pueraria javanica was tolerant toward cassava shading. The land coverage was linearly increased along with the growth of cassava. At the end of cassava growth, the land area coverage by this legume cover crop was 98.08%. It produced more organic matter and could maintain soil moisture content than other legume cover crops. P. javanica could consider being a suitable legume cover crop under cassava to improve soil quality.

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