Global CA-CoP CONSERVATION AGRICULTURE COMMUNITY OF PRACTICE

for sustainable agriculture, land use and ecosystem management


Dear Subscribers,

Please see herebelow the  May 2021 Conservation Agriculture Scoopit Research Updatefrom Cornell University.

Thank you professor Peter Hobbs for sharing.

Amir Kassam

Moderator

Global CA-CoP

e-mail: [log in to unmask]

URL: http://www.fao.org/conservation-agriculture


---------- Forwarded message ---------
From: Peter Hobbs <[log in to unmask]>
Date: Fri, 30 Apr 2021 at 20:13
Subject: May Scoopit Cornell CA newsletter
To: Amir Kassam <[log in to unmask]>


Dear Amir: Here is our May 2021 Conservation Agriculture Scoopit Research Update. You can also view online at https://www.scoop.it/topic/conservation-agriculture-by-conservation-ag?curate=true&null 
Can you send this out to people who get your listserv material? The hard copy is below.

An easier link to see all the research papers on CA is as follows:

Also, visit our main website at http://soilhealth.org for news and other CA information. Please use this link since we had to move our web site to a new server and this links takes you to the CA web site.

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Increasing climate variability is affecting  smallholder farmers in southern Africa. This study looks at Conservation Agriculture (CA) as a way to improve the resilience of farming systems against the adversities of climate, specifically moisture stress.CA and CT practices are assessed over a 14 year trial period on soil moisture and infiltration rates in Zambia. Soil chemical properties were also evaluated for these two tillage systems. Results showed significant differences in average soil moisture in the first 60 cm among the cropping systems in different years with the basins plus mulching system having highest moisture content in most of the years. Water infiltration rates were highest and averaged 48.5 mm h−1 in the CA-based systems and the lowest in CT which averaged 12.6 mm h−1. Soil chemical properties did not differ across tillage systems. The increased infiltration and available moisture in CA systems can buffer the effects of climate variability and provide greater resilience.
In this paper, a process-based model, Denitrification-Decomposition (DNDC), was validated on midterm (9 years) and employed depending on the local climate, soil and management conditions, to assess the impacts of alternative management practices on SOC stock under two tillage systems, in a semi-arid region of Morocco. Modeled results pointed out that, under no-tillage practice (NT), the SOC content increased by 30% compared to conventional tillage (CT). During the simulated period (9 years), the SOC sequestration potential (CSP) has been greatly improved with increased crop residue rate and application of farmyard manure (FY-manure). They conclude that an increase in crop residue rate returned at surface after harvest and application of organic fertilizer, especially under NT practice, can substantially improve SOC stock in a semi-arid region.
This paper looks at ways to improve the productivity of the rice-wheat system in the eastern Gangetic Plains of South Asia. They evaluated the performance of three RW system intensification options with different management interventions over two years, comparing a conventional RW rotation (CS1), with two stages of conservation agriculture (CA) interventions, (i) the simple inclusion of mungbean (CS2), and (ii) the inclusion of mungbean together with full CA implementation (CS3) at two sites in the EGP that differed with respect to soil type, water table dynamics, and agro-climatic conditions. The addition of mungbean into the conventional RW rotation produced significantly higher system productivity (rice equivalent yield, REY) compared with the existing double-crop rotation across sites. The baseline system was enhanced further when CA-based management practices were adopted, however, the magnitude of system benefit from CA was site and situation-specific. 
This study looked at the physical attributes and organic carbon contents of a clayey Oxisol in an area under four different land uses for 10 years: afforestation (AF), no-tillage system with grass-grass succession (corn/corn), no-tillage systems with grass-legume succession (corn/Crotalaria juncea L.) and conventional soil tillage system (corn/fallow in Brazil. The areas were sampled at 3 different depths and evaluated for soil aggregation and porosity using multivariate factor analysis. The no-tillage system promoted soil aggregation and porosity similar to that of the planted forest and superior to those of the conventional tillage system. The type of crop succession in the no-tillage system caused differences in soil structure, and grass-grass succession (corn/corn) promoted better soil structure compared to other systems. The greater soil porosity generated by the conventional tillage system was limited to the most superficial layer but the presence of large amounts of smaller aggregates can clog the generated pores.
This paper reports on the effect of cover crops on modifying soil surface response to penetration and the relation to soil water content. The research used two crops, barley and vetch, as cover crops and compared them with a bare fallow in a 10 year long term trial in Spain. The soil resistance to penetration was closely related to the surface soil water content (R2 = 0.65) and cover crops affected it through soil moisture modification. The greater biomass of barley compared to vetch increased the soil water content prior to main crop seeding and reduced the resistance to penetration. The good performance of barley resulted in a reduction of more than 60% of the soil resistance to penetration between the 3rd and 8th year of the experiment. Even under bare fallow, soil strength was decreased after ten years with reduced tillage. The maintenance of cover crop residues over surface soil together with reduced tillage enhanced the soil surface conditions and steadily reduced the risk of crust formation.
This study evaluates the climate resilience in terms of profitability and risk management that determine farm-level adaptation. This 27 year long-term study looked at three agricultural treatments. for a corn-soybean-wheat rotation in Michigan. The three alternative treatments were no-till, reduced input and certified organic that were compared with conventional practices for the same rotation. Results demonstrate that the net revenues from the organic treatment are exceed the net revenues of conventional treatment. The no-till treatment dominates conventional and reduced input practices in annual net revenues with a relatively lower risk to those revenues in light of climate extremes. They concluded the organic and no-till treatments were deemed climate-resilient whereas the conventional and reduced input treatments did not show resilience will be vulnerable to the changing climate. But growers have been slow to adopt the two climate resilient practices and this needs further study.
This study was conducted at three different locations in South Dakota, USA, to compare the natural (undisturbed) ecosystem (NE) with the tilled (CT) and no-tilled (NT) practices, and to evaluate the tillage effects on soil organic carbon (SOC) and total nitrogen (TN) contents, bulk density (ρb), enzymatic activities and aggregate stability under a corn (Zea mays L.)-soybean (Glycine max L.) cropping system. Results support that NT practices improved soil aggregation as compared to the CT and stored higher SOC and TN concentrations in the aggregates, however, NE treatment outperformed both the tillage systems. Their comparative evaluation with a NE treatment concludes that tilled practices negatively affect soil properties but recommend adoption of NT farming to enhance the soil properties in agroecosystems.





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