Global CA-CoP CONSERVATION AGRICULTURE COMMUNITY OF PRACTICE

for sustainable agriculture, land use and ecosystem management


Dear Subscribers,

Please see herebelow, the March 2021 Cornell CA Newsletter.

Thank you Professor 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: Mon, 1 Mar 2021 at 00:28
Subject: March 2021 Cornell CA Scoopit newsletter
To: Amir Kassam <[log in to unmask]>


Dear Amir: Here is our March 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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Conservation agriculture (CA) has been promoted to mitigate climate change, reduce soil erosion, and provide a variety of ecosystem services. Yet, its impacts on crop yields remains controversial.This paper looks at the probability of yield gain when switching from CT to CA worldwide. Relative yield changes were estimated with machine learning algorithms trained by 4403 paired yield observations on 8 crop species extracted from 413 publications. CA has better productive performance than a no-till system (NT), and it stands a more than 50% chance to outperform CT in dryer regions of the world, especially with proper agricultural management practices. Residue retention has the largest positive impact on CA productivity comparing to other management practices. The paper concludes CA appears as a sustainable agricultural practice if targeted at specific climatic regions and crop species.
This study looks at the effect on no-tillage on soil microbial diversity. The study used 43 peer reviewed articles with 141 observations from around the World. No-tillage had different effects on bacterial and fungal community diversity — increasing soil bacterial diversity, with no significant change to fungal diversity — and soil type and stubble had a significant impact on soil bacterial diversity.  No-tillage significantly increased the relative abundance of Acidobacteria, decreased Actinobacteria, and had little effect on Proteobacteria, Chloroflex, Firmicute, and Bacteroides. A structural equation model showed that retaining stubble under no-tillage had the most significant effect on soil microbial diversity by changing soil organic carbon and total nitrogen contents. 
The paper looked at the issue of seed degradation in an undisturbed and a no-till soil, trying not only to uncover where seeds are more degraded, but also to investigate the microbial activities that could be involved in this process in Northern Italy. Seed decay was tested in two different sites, a no-till field and the adjacent buffer zone. Soil microbial activity was also measured. Degradation of the buried seeds was higher in the no-till field soil than in the buffer strip for all the studied species as was the microbial cellulolytic activity. The paper concluded that no-till management can improve weed seed suppression in the soil. Moreover, cellulolytic microorganisms play an important role in seedbank longevity, so cellulolytic activity surveys could be used as an early monitoring bioindicator for weed seed suppression in soil.
This meta-analysis paper looks at the impact of tillage practices on insect pests and slugs with the hypothesis that using reduced/zero-tillage increases predator populations that help biological control. The paper evaluates the effects of reduced-tillage practices (e.g., no-till, harrowing, shallow disking) on the abundance of invertebrate pests and natural enemies relative to high-disturbance tillage practices (e.g., moldboard plowing), using studies published between 1983 and 2017. Results show that insect and slug pests were not more abundant in reduced-tillage systems than in high-disturbance tillage systems. Pest herbivores that spend part of their life-cycle in the soil followed this pattern, but foliar pests were more abundant in systems with more intense tillage practices. The abundance of arthropod predators that spend part of their life-cycle in the soil were significantly lower in high-disturbance tillage systems compared with no-disturbance tillage systems, regardless of the intensity of the disturbance.
This study aimed to evaluate the long-term (23-yrs) effect of soil tillage systems and winter cover crops on (i) soil acidity, (ii) nutrient availability, and (iii) P and K budget in a subtropical Oxisol from Southern Brazil.They used 6 cover crops and CT vs NT. Continuous NT system for 23-years resulted in higher soil fertility in the topsoil (0–10cm) compared to CT, but with some limitations of nutrient availability and soil acidity below 10cm depth compared to CT. Surface application of lime in NT reduced soil acidity up to 20cm compared to CT. The budget of P was negative for all treatments, highlighting the P-sink behavior of this strongly weathered subtropical Oxisol. Among the cover crops tested, black oat stood out by its greater production of biomass, resulting in higher P and K availability in the soil surface.
This paper tested whether cover crops are a suitable management tool to reduce fertilizer input, tillage intensity and herbicide use in Swiss arable cropping systems. They compared the effects of four different cover crop treatments (fallow, radish, subterranean clover and hairy vetch) on maize at two fertilization levels combined with three levels of tillage intensity. They used spectral NVDI imagery to assess vegetation. Cover crops on average increased yields by 12 % (+7 % to +20 %) and cover crop effects depended on tillage intensity, fertilization level and cover crop treatment for most of the assessed maize parameters. Hairy vetch was the best cover crop. Spectral imagery analysis showed that legume cover crops compensated for delayed N availability in reduced and no tillage systems and cover crops contributed to enhanced N uptake and crop growth later in the season. They  provide evidence that cover crop based cropping systems can be used to reduce synthetic inputs and tillage without compromising yield.






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