Differential responses of system of rice intensification (SRI) and conventional flooded-rice management methods to applications of nitrogen fertilizer

Author(s): Amod Kumar Thakur, Sreelata Rath, Krishna Gopal Mandal
Abstract
 
Background
 
Rising food demand, slowing productivity growth, poor N-use efficiency in rice, and environmental degradation necessitate the development of more productive, environmentally-sound crop and soil management practices. The system of rice intensification (SRI) has been proposed as a methodology to address these trends. However, it is not known how its modified crop-soil-water management practices affect efficiency of inorganic nitrogen applications.
 
Methods
 
Field experiments investigated the impacts of SRI management practices with different N-application rates on grain yield, root growth and activity, uptake of N and its use-efficiency, leaf chlorophyll content, leaf N-concentration, and photosynthetic rate in comparison with standard management practices for transplanted flooded rice (TFR).
 
Results
 
Overall, grain yield with SRI was 49 % higher than with TFR, with yield enhanced at every N application dose. N-uptake, use-efficiency, and partial factor productivity from applied N were significantly higher in SRI than TFR. Higher leaf nitrogen and chlorophyll contents during the ripening-stage in SRI plants reflected delayed leaf-senescence, extension of photosynthetic processes, and improved root-shoot activities contributing to increased grain yield.
 
Conclusions
 
Rice grown under SRI management used N fertilizer more efficiently due to profuse root development and improved physiological performance resulting in enhanced grain yield compared to traditional flooded rice.
 
 

Plant growth-promoting traits of biocontrol potential bacteria isolated from rice rhizosphere

PGP and biocontrol traits bacteria download paper

Subramaniam Gopalakrishnan, H D Upadhyaya, Srinivas Vadlamudi, Pagidi Humayun, Meesala Sree Vidya, Gottumukkala Alekhya, Amit Singh, Rajendran Vijayabharathi, Ratna Kumari Bhimineni, Murali Seema, Abhishek Rathore, and Om Rupela

Abstract

Seven isolates of bacter ia (SR I-156, SRI-158, SRI-178, SRI-211 , SRI-229, SRI-305 and SRI-360) were earlier reported by us as having poten tial for biocontrol of charcoal rot of sorghum and plant growth promotion (PGP) of the plant. In the present study, the seven isolates were ch aracterized for their physiological traits (tolerance to salinity , pH, temperature and resistance to antibioti cs and fungi cides) and further evaluate d i n the field for their PGP of rice. All the seven isolates were able to grow at pH values between 5 and 13, in NaCl concentrations of up to 8% (exc ept SRI-156 and SRI-360 ), temperatures between 20 and 40°C and were resistant to ampicillin (>100 ppm; except SRI-158 and SRI-178 ) but sensit ive (<10 ppm) to ch loramphenicol, kanamycin, nalidix ic aci d, streptomycin (except SRI-156 and SRI-211 ) and tetracycline. They were tolerant to fungicides benlate and captan, except SRI-158 and SRI-178, bavist in and sens itive to thiram (except SRI-156 and SRI-211 ) a t field application level. In the field, four of the seven isolates (SRI-158, SRI-211 , SRI-229 and SRI-360) significantly enhanc ed the tiller numbers, stover and grain yields, to tal dry matter, root length, volume and dry weight over the un-inocul ated control. In the rhizosphere soil at harvest, all the isolates signif icantly enhanced microb ial biomass carbon (except SRI-156 ), microbial biomass nitrogen and dehy drogenase activi ty (up to 33%, 36% and 39%, respectively) and total N, availabl e P and% organic carbon (up to 10%, 38% and 10%, respectivel y) compared to the control. This investigation further confirms that th e SRI isolates have PGP properties.

Increasing Cropping System Diversity Balances Productivity, Profitability and Environmental Health

Adam S. Davis1*, Jason D. Hill2, Craig A. Chase3, Ann M. Johanns4, Matt Liebman5

1 United States Department of Agriculture/Agricultural Research Service, Global Change and Photosynthesis Research Unit, Urbana, Illinois, United States of America, 2 Department of Bioproducts and Biosystems Engineering, University of Minnesota, St. Paul, Minnesota, United States of America, 3Leopold Center for Sustainable Agriculture, Iowa State University, Ames, Iowa, United States of America, 4 Department of Economics, Iowa State University Extension and Outreach, Osage, Iowa, United States of America, 5Department of Agronomy, Iowa State University, Ames, Iowa, United States of America

 

Abstract Top

Balancing productivity, profitability, and environmental health is a key challenge for agricultural sustainability. Most crop production systems in the United States are characterized by low species and management diversity, high use of fossil energy and agrichemicals, and large negative impacts on the environment. We hypothesized that cropping system diversification would promote ecosystem services that would supplement, and eventually displace, synthetic external inputs used to maintain crop productivity. To test this, we conducted a field study from 2003–2011 in Iowa that included three contrasting systems varying in length of crop sequence and inputs. We compared a conventionally managed 2-yr rotation (maize-soybean) that received fertilizers and herbicides at rates comparable to those used on nearby farms with two more diverse cropping systems: a 3-yr rotation (maize-soybean-small grain + red clover) and a 4-yr rotation (maize-soybean-small grain + alfalfa-alfalfa) managed with lower synthetic N fertilizer and herbicide inputs and periodic applications of cattle manure. Grain yields, mass of harvested products, and profit in the more diverse systems were similar to, or greater than, those in the conventional system, despite reductions of agrichemical inputs. Weeds were suppressed effectively in all systems, but freshwater toxicity of the more diverse systems was two orders of magnitude lower than in the conventional system. Results of our study indicate that more diverse cropping systems can use small amounts of synthetic agrichemical inputs as powerful tools with which to tune, rather than drive, agroecosystem performance, while meeting or exceeding the performance of less diverse systems.

Citation: Davis AS, Hill JD, Chase CA, Johanns AM, Liebman M (2012) Increasing Cropping System Diversity Balances Productivity, Profitability and Environmental Health. PLoS ONE 7(10): e47149. doi:10.1371/journal.pone.0047149

Editor: John P. Hart, New York State Museum, United States of America

 

Received: July 12, 2012; Accepted: September 10, 2012; Published: October 10, 2012

This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.

Funding: Funding for the study was provided by the US Department of Agriculture National Research Initiative (Projects 2002-35320-12175 and 2006-35320-16548), the Leopold Center for Sustainable Agriculture (Projects 2004-E06, 2007-E09, and 2010-E02), the Iowa Soybean Association, and the Organic Center. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

* E-mail: adam.davis@ars.usda.gov

Possible consequences of the overlap between the CaMV 35S promoter regions in plant transformation vectors used and the viral gene VI in transgenic plants

Possible consequences of the overlap between the CaMV 35S promoter regions in plant transformation vectors used and the viral gene VI in transgenic plants Download

Multiple variants of the Cauliflower mosaic virus 35s promoter (p35s) are used to drive the expression of transgenes in genetically modified plants, for both research purposes and commercial applications. The genetic organization of the densely packed genome of this virus results in sequence overlap between p35s and viral gene VI, encoding the multifunctional p6 protein. The present paper investigates whether introduction of p35s variants by genetic transformation is likely to result in the expression of functional domains of the p6 protein and in potential impacts in transgenic plants. A bioinformatic analysis was performed to assess the safety for human and animal health of putative translation products of gene VI overlapping p35s. No relevant similarity was identified between the putative peptides and known allergens and toxins, using different databases. From a literature study it became clear that long variants of the p35s do contain an open reading frame, when expressed, might result in unintended phenotypic changes. A flowchart is proposed to evaluate possible unintended effects in plant transformants, based on the DNA sequence actually introduced and on the plant phenotype, taking into account the known effects of ectopically expressed p6 domains in model plants.

Comparative aspects of Cry toxin usage in insect control

Székács, A. and Darvas, B. (2012): Chapter 10. Comparative aspects of
Cry toxin usage in insect control. pp 195-230. In. Ishaaya, I., Palli,
S. R. & Horowitz, A. R. (Eds) Advanced Technologies for Managing Insect
Pests. Springer Science+Business Media Dordrecht.

András Székács and Béla Darvas:
Chapter 10. Comparative aspects of Cry toxin usage in insect control

“Based on the above, Bt-based bioinsecticides and crops
cannot be considered by far as equivalent technologies. Their
application differs as Bt bioinsecticides allow singular applications,
while Bt crops exert a continuous production of the Cry toxin. This
results in higher environmental doses of the plant-expressed toxin(s)
than in the case of the Bt bioinsecticide. For example a single
treatment of Dipel bioinsecticide at the registered dosage (1 kg/ha)
contains 4.8–60.2 mg/ha (average 20.6 mg/ha) of bioavailable Cry1Ab
toxin, while the amount of bioaccessible amount of Cry1Ab toxin is
0.085–8.16 g/ha. In contrast, the production of plant-expressed Cry1Ab
toxin was found to be 147–456 g Cry1Ab toxin/ha, representing 18–56
treatments with Dipel (on the basis of its maximally detected
bioaccessible Cry1Ab toxin content, 8.16 g/ha). The level of
plant-expressed Cry1Ab toxin can be further elevated by soil
fertilization (2.3–6.8-fold) and the use of long maturation maize
varieties (2.5–5.8-fold), representing, in worst case scenarios, in
625–1,930 treatments with Dipel. Moreover, it has to be mentioned that
stacked genetic events may further elevate toxin production (twofold).
These ratios are even higher if lower bioaccessible Cry1Ab protoxin
content biopesticides or bioavailable Cry1Ab toxin contents are
considered.
Beside toxin ratios, another characteristic difference is
that while Bt bioinsecticides are composed of several crystalline
toxins, single genetic event Bt crops express only a single toxin
molecule. This has severe consequences in resistance development, which
may be alleviated, yet not eliminated by the use of “pyramid” Bt event
varieties, expressing several Cry toxins acting on the same insect
order, as the evolutionary driving force remain the same. The active
ingredient of Bt bioinsecticides are bacterial protoxins stabilized in
crystalline form and requiring enzymatic activation, while Bt plants
(e.g., MON 810) express a truncated form of the protoxin, so-called
preactivated toxin. This has severe consequences in product
registration, as the active ingredient toxin in the Bt crop is not the
registered active substance of the corresponding Bt bioinsecticide, and
the required toxicology studies have been carried out not with the
plant-expressed preactivated toxin, but with the bacterial protoxin or
the enzyme-activated active toxin. Moreover, commercial ELISA systems
utilizing antibodies against the bacterial protoxin and analytical
standards of that protoxin consistently underdetect actual toxin content
in Bt plants due to their lower cross-reactivities to the
plant-expressed preactivated toxin. As a result, all reported results
obtained by protoxin-based ELISAs, including manufacturer documentation,
are subject to correction. And finally, although Bt crops have been
widely advocated to be included in integrated pest management (IPM)
practices or even in ecological agriculture, Bt crops cannot fulfill the
main ecological principle of IPM that any protection measures should be
timed only to the period(s) when pest damage exceeds the critical level,
and therefore, regardless how environmentally mild their active
ingredient is, do not comply with IPM.”

(At least temporarily) can be downloaded here:

http://bdarvas.hu/download/pdf/Bt2012.pdf

Crop and water productivity as influenced by rice cultivation methods under organic and inorganic sources of nutrient supply

Crop and water productivity as influenced by rice cultivation methods under organic and inorganic sources of nutrient supply
Author by Y.V. Singh, Centre for Conservation and Utilization of Blue Green Algae (CCUBGA), Indian Agricultural Research Institute, New Delhi – 110 012, India, Email: yvsingh63@yahoo.co.in; yvsingh_algal@iari.res.in
Source: Paddy and Water Environment [http://www.springerlink.com/content/j483155l860236t1/]
Publication Date: 28 August 2012

ABSTRACT

A field experiment was conducted during the wet seasons of 2010 and 2011 at New Delhi, India to study the influence of organic, inorganic, and integrated sources of nutrient supply under three methods of rice cultivation on rice yield and water productivity. The experiments were laid out in FRBD with nine treatment combinations. Treatment combinations included three sources of nutrient supply viz., organic, integrated nutrient management, and inorganic nutrition and three rice production systems viz., conventional transplanting, system of rice intensification (SRI) and aerobic rice system. indicated that the conventional and SRI showed at par grain and straw yields but their yields were significantly higher than aerobic rice. Grain yield under organic, inorganic and integrated sources of nutrient supply was at par since the base nutrient dose was same. Plant growth parameters like plant height, tillers, and dry matter accumulation at harvest stage were almost same under conventional and SRI but superior than aerobic rice system. Root knot nematode infestation was significantly higher in aerobic rice as compared to SRI and conventional rice. However, organic, inorganic and integrated sources of nutrient supply did not affect nematode infestation. There was significant advantage in term of water productivity under SRI over conventional transplanted (CT) rice and less quantity of water was utilized in SRI for production of each unit of grain. A water saving of 34.5–36.0 % in SRI and 28.9–32.1 % in aerobic rice was recorded as compared to CT rice.

Sustainable Sugarcane Initiative (SSI): A Methodology of ‘More with Less’

Sustainable Sugarcane Initiative (SSI): A Methodology of ‘More with Less’
Author(s): N. Loganandhan, Biksham Gujja, V. Vinod Goud and U. S. Natarajan
Source: SpringerLink | 16, September 2012

Sugarcane is a significant crop in contributing to the country’s economy and farmers’ livelihood development. In India, sugar is a 550 billion rupees worth industry, supporting more than 50 million farmers. There is a growing demand for sugar in India. Hence, there will be more and more stress on the sugarcane eco-system in future. But, the present scenario of cane cultivation is not sustainable enough to meet this demand as the input and labor costs are increasing and the national mean cane productivity (2007–10) is at 66.9 t ha-1 only. So, it is necessary to improve the cane productivity in a susta

inable way with minimum usage of inputs through some alternate methods on the principles of ‘‘more with less’’. A research study with the objectives of developing a methodology for sustainable sugarcane productivity was carried out at International Crops Research Institute for the Semi-Arid Tropics during 2008–11. As a result, a methodology was evolved encompassing six principle components, including improved bud chip method, under a concept called ‘‘Sustainable Sugarcane Initiative (SSI)’’. The evaluation trials conducted on the principle components revealed the optimum size and age of the bud chips (4–10 months old) and suitable media combination (cocopith ? sawdust) for raising better seedlings. SSI field trials resulted in about 20 % higher yields. The state governments are showing interest in covering larger areas under SSI. SSI method can revamp the sugarcane.

http://www.springerlink.com/content/fg32x113058rh413/?MUD=MP