Global CA-CoP CONSERVATION AGRICULTURE COMMUNITY OF

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Dear Subscribers,

Please see below the September 2022 Cornell Conservation Agriculture Scoopit Research Update from Professor Peter Hobbs.

Thank you Professor Hobbs for sharing.

Apologies for any cross-posting.

Amir Kassam

Moderator

Global CA-CoP

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

 

Regional CA websites:

URL: http://www.act-africa.org/

URL: https://ecaf.org/
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URL: http://caapas.org/


---------- Forwarded message ---------
From: Peter Hobbs <[log in to unmask]>
Date: Thu, 1 Sept 2022 at 14:44
Subject: September 2022 Cornell CA Research Update
To: Amir Kassam <[log in to unmask]>


Dear Amir: Here is our September 2022 Cornell 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.

Many thanks for helping to distribute this. Peter


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One issue this paper raises is that benefits from cover crops and no-tillage may take years to improve soil health, but costs for cover crop establishment and no-till equipment occur before benefits accrue. This study measured soil properties, cash crop yield, and annual production costs in a three-year maize /soybean study comparing a conservation system to a conventional production system in Mississippi. The CS was compared with five different levels of conservation systems, including a conservation system with no-tillage and cover crops (no-till + cover). They found a lack of consistent improvement of soil properties in the 3 years of the experiment. Essentially more time is needed. The economic benefits of substituting no-tillage and cover crops for expensive conventional inputs were much greater than the modest soil property improvements.  The greatest resource benefit from the conservation system was a reduction in estimated soil loss, as mean soil loss in no-till and cover crop decreased by 86% compared to the conventional system and makes the farming operations and agroecosystems more resilient.
This study looks at tillage intensity, crop residue management and green manure (GM Sesbania) on SOC within micro- and macro-aggregates after 6 years of growing rice-wheat in India. The plot treatments included ZT and CT with and without different % of residues and with and without GM. The ZT with 100% rice residue  (ZTWR100) significantly increased soil moisture retention compared to CT w/o residue (CTWR0) and also increased the dehydrogenase (DHA), cellulase, and β-glucosidase activities and the easily extractable glomalin (EEG)- and total glomalin (TG)-related soil protein compared with the CTWR0 treatment. Crop residue retention plus GM significantly improved the proportion of total water-stable aggregates (WSA), mean weight diameter (MWD), and aggregate ratio (AR), compared with the treatments involving residue removal and no GM. 
SOC is a major indicator of soil health but has a slow short-term response to management, so this study investigated the short-term effects of crop rotation and residue management under NT. There were 4 rotations involving maize, soybean, wheat, and fallow. There was residue retention and removal with crops sown using NT. Measures were SOC, microbial biomass carbon (MBC), mineralisable carbon (Cmin) and particulate organic matter carbon fractions (POM-C). Crop rotation systems significantly influenced Cmin and POM-C fractions whereas residue management practices significantly affected all the carbon fractions. Crop residue retention as opposed to its removal enhanced all the carbon pools. The POM-C and Cmin fractions were more sensitive to short-term CA management interventions than SOC and MBC, and can be used for monitoring SOM changes and microbial activities. 
This paper provides information on the combined impact of tillage, residue, and cropping system on the major and micro-nutrient availability in the rainfed farming systems in a vertisol in central India. There were two tillage treatments, reduced tillage (RT) and CT; and 6 cropping systems as sub-plots. After 4 cropping cycles soil samples were taken for macro- and micro-nutrient status. The major and micro-nutrient concentrations were higher in the surface layer (0-5cm) than subsurface layers, regardless of tillage and cropping systems. Tillage and cropping systems had a significant effect on major available nutrients (N, P, and K) at 0–5-cm depth. The DTPA extractable Fe, Mn, Cu, and Zn concentrations exhibited decreasing trends with increasing depth. The paper concludes that RT practices, coupled with crop residue retention, positively affected major and micro-nutrient distribution and availability in this soil. 
This is an interesting study on the utility of various two-wheel tractor seeders for wheat and maize in Ethiopia. Seeders tested came from Brazil, Bangladesh, China, India, and USA. Field operating capacity, fuel consumption, and crop yield were evaluated over two years in two locations. Fuel consumption was between 9.4 L ha-1 and 12.6 L ha-1 depending on seeding depth. A ten-fold reduction in operating time was possible relative to the non-mechanized conventional practice. Improved uniformity and timing of planting resulted in yield increments of 29% and 22% for wheat and maize, respectively. The Bangladeshi and Chinese equipment was best for wheat. For maize, the John Morrison and VMP seeders outperformed all other units. The paper recommends the possibility of manufacture of this equipment locally to reduce costs and increase adoption.
This farmer field trial in West Bengal, India looked at short-term impact of contrasting tillage (ZT and CT) and cropping systems (rice–wheat and rice–maize) on total organic carbon (TOC) and its fractions, after 4-years of conservation agriculture (CA) in old and recent alluvial soils. Soils samples were taken from 3 soil depths. Results showed that TOC and fractions under rice–maize (RM) cropping system were significantly greater (15–35%) than for rice–wheat (RW) as a result of higher residue biomass addition. Zero-tillage (ZT) improved the C fractions by 10–20% over conventional tillage (CT) in all aspects. TOC and its fractions were observed to be greater under the ZT system in the topmost soil depths (0–5 and 5–10 cm), but the same system failed to improve these at 10–20 cm. They conclude that  ZT under the RM system increases the turnover rates of C in both soil types but the amount of clay influences the stabilization/storage of C.
This is a second paper from the ASABE conference in Nebraska. It reports progress with CA in Cambodia. Adoption is slow at the moment because of low engagement of local services for machinery. This also compared different no-till seeders for maize. Sunn hemp was grown as a cover crop before planting maize. Three main treatments were implemented with (i) sunn hemp used as green manure crop and buried through tillage, (ii) sunn hemp crimped by Cambodia made crimper, and (iii) sunn hemp crimped by USDA crimper. Two different no-till seeders, the one-row Morrison seeder mounted on a 19-hp Oggun tractor and a four-row Brazilian seeder mounted on 75-hp John Deere tractor. The Brazilian seeder saved 50% seed and 80% of the time. Corn yield was also higher. Crimped plots had higher yields than disked plots. The conclude no-till seeders lead to higher corn yields.



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