In the present work, experiments were carried out to determine the suitability and usefulness of both fresh and dried Azolla as biofertilizer for Scotch Bonnet. Azolla biofertilizer may be a promising approach to achieve better N use efficiency (NUE) in paddy rice fields due to its great potential for biological N fixation. A field study was conducted to observe the effect of Azolla on rice yield, N uptake and its residual effect on subsequent wheat crop. Azolladeveloped into a thick.

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To receive biofertulizer and publication updates for International Journal of Agronomy, enter your email address in the box below. This is an open access article distributed bioofertilizer the Creative Commons Attribution Licensewhich permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Azolla is a floating pteridophyte, which contains as endosymbiont the nitrogen-fixing cyanobacterium Anabaena azollae Bioffrtilizer family. Widely cultivated in the Asian regions, Azolla is either incorporated into the soil before rice transplanting or grown as a dual crop along with rice.

Of the biofwrtilizer tested, Propanil permitted the survival of growing Azolla. Azolla is a heterosporous pteridophyte, with seven species. It contains, as endosymbiont, Anabaena azollae Strasburger, a nitrogen fixing cyanobacterium Nostocaceae family. Available bibliographical data on its environmental development are principally related to experiments carried out in Asian countries [ 1 — 3 ].

However, the wide ranges of temperature, humidity, and solar radiation in which the fern flourishes suggest the possibility of using Azolla outside these regions [ 4 ]. At 3 million tonnes per year, the EU ranks 17th 0.

The main areas of cultivation are in the western part of the Po valley in Northern Italy and in the river delta areas, Ebro and Guadalquivir, in Spain. Rice yields decline with time, as noted by Ladha et al. Long-term effects of urea and green manure on rice yield and nitrogen balance were also verified in temperate conditions [ 6 ] where the biofertilizet use efficiency NUE was particularly low. It is particularly important to increase the efficiency of biifertilizer use and concomitantly to reduce water pollution, by changing strategies of mineral use and by integrating organic fertilizers in the rice production system.

These strategies seem particularly important if we consider the current increase and interest in organic products in all EU States. It is also important to remember that agriculture can play a significant role in the reduction of greenhouse gases, particularly for CO 2 if the rice farmers can increase the soil stable biifertilizer matter and treat agricultural soils as powerful carbon sinks. Moreover, to use the fern as a biofertilizer in conventional farming, not just in organic farming, some resistance to the most popular herbicides is bioofertilizer.

In other words, the fern should reach a good growth rate during spring, with a high percentage of nitrogen, and should azilla quite resistant to the most common herbicides used in the rice areas. Until now, most of the up-to-date research on Azolla in rice has been carried out in tropical or subtropical environments [ 7 — 9 ] and there are only a few reports from temperate ones [ azollq11 ].

Therefore, this study was carried out biofertipizer a temperate environment, aimed at a comparing different Azolla strains, chosen on the basis of their resistance to low temperatures, b analysing the spring growth rate of the most resistant one, c determining the concentration of N in the Azolla before the sowing of rice to evaluate it as rice biofertilizer, and d assessing the morphological modification of Azolla in response to treatments with three kinds of commonly used herbicides.

Azolla filiculoides strains considered resistant to low temperatures were acquired from viofertilizer Biofertilizer Germplasm Collections BGC of N 2 fixing organisms of the I. International Rice Research Institute in the Philippines. The winter experiment, carried out to biofertiliizer cold biofertklizer through growth analysis of the 5 strains, started on Dec.

Tanks were arranged in three replicates per strain and set in a completely randomized block design. Before weighing, the fern was dried with blotting paper. During the entire period, the water lost through evapo-transpiration was replenished every day with deionized water and the nutrient content in the solution was continuously controlled and maintained at a constant level. In all cases, growth proceeded without reaching a surface-limiting condition, where an increase of thickness, due to the leaf growth, could have changed growth dynamics.


The sample, enclosed in a tin cap, is released from an auto sampler in an oxidation column at C in a helium current; oxygen is then injected to allow instantaneous combustion of the sample. The Nitrogen and Carbon concentrations in the samples were calculated from the relative area of peaks in the chromatographic traces, using a calibration curve obtained by subjecting a known material, atropine and grapevine leaves, to standard analyses.

Phosphorus concentration was also analyzed for each tank in order to estimate the P uptake relative to Azolla growth as a guide for the programming of bioofertilizer to the medium. Observations of morphological variation were biofertliizer out to associate the relevant data to the increase of biomass.

Variation in colour from green to red to tawny, together with the leaf dimensions and the surface covered by the plants, was used as a stress index. This strain alone was used for the second and third experiments. The growth in spring conditions was tested in the following year, in order to assess the potential of Azolla as a biofertilizer at high latitudes in terms of quantity. Water lost by evapo-transpiration was replaced with deionized water every day.

Fresh weight was evaluated biotertilizer seven days and weight determinations were made after drying Azola biomass with blotting paper. Finally, in a third separate experiment started on Mar.

International Journal of Agronomy

The most popular herbicides, Oxadiazon, Propanil, and Cinosulfuron, were distributed on the fern at the rates usually used in the field. A randomized block design with three replications was used, including three vessels and three tanks for control. For the water floating samples, boifertilizer drying on blotting paper, the biomass was weighed. For the humid soil sample, biomass variations were estimated from measurements of total leaf surface szolla. Both, weigh and estimation where made after 7 and 15 days.

Biomass increase, rates of growth RGR and survival at winter temperatures of the five strains from Dec. A progressive decrease of leaf dimensions aolla registered in all strains, associated with accumulation of anthocyanins.

As time passed, the Japan and Italy strains assumed a tawny colour an indicator of drying preceding death. After days from the beginning of the experiment, on the Apr. By the second half of April, the leaf dimensions of the remaining strains were comparable to those at the outset of the experiment, with the leaves of the Milan strain bigger than those of the Sweden and Germany strains. Temperature and biomass increase were clearly correlated for the Milan and Germany strains whereas the correlation index for the Sweden strain is lower and not significant.

We observed high quantities of nitrogen in the leaf of the Japan and Italy strains, which appeared to be related to the decrease of biofertikizer biomass during our test.

Fern biomass increased linearly from March 22nd to April 19th 28 daysfollowed by a more rapid growth until April 28th Figure 2.

However, when surface area is limiting, the fern will often grow as two or even three layers, potentially allowing the use of a nursery area around meters in length xzolla two meters wide. Finally, it should be noted that this study was performed during biofertilizeg relatively cold spring season. It can thus be assumed that Azolla growth would often be faster than that observed in this study.

Herbicide treatments Table 3 generally caused stress, with an associated fall in N and C azollaa until death ensued. At 13 days, the fresh weight of the samples treated with Cinosulfuron had shown slight increase of biomass in respect to initial inoculum. However, after this intermediate phase, Cinosulfuron caused a progressive deterioration leading biogertilizer the death of the fern. We could weigh only floating samples in the Cinosulfuron treatment, while for Propanil and Oxadiazon, we decided to divide the leaflet surface area into four categories from 1 to 4 where.

This research presents a first attempt to evaluate the possibility of using Azolla-Anabaena in rice fields in the Po Valley, as a source of easily mineralized organic Nitrogen. The information available from biofertllizer literature was not very useful because the climatic conditions where experiments have been performed in Asia are generally extremely different from those in the Po Valley.


It was therefore considered necessary to use strains adapted to high latitudes and to local agricultural practices. Results from these preliminary tests allow us to form several conclusions regarding the potential use of this bioofertilizer.

We show that Azolla-Anabaena is capable not only of surviving low winter temperatures, but of subsequently growing fast enough in order to produce a suitable inoculum for rice paddies in the spring.

The calculation of growth rate allowed us to determine the amount of inoculum required to allow complete coverage of flooded paddies by the time of rice sowing. As the fern is capable of growing two or three layers deep, it can also produce the same biomass also when less surface area is available and the addition of a little heat to the nursery e.

Our results were obtained with a strain particularly well adapted to local climatic conditions. This was verified in the comparative test in which 5 strains of various origins were compared. Although the 4 strains supplied by the IRRI are all recognized as cold resistant, adapted to continental climates or to cold winters, our results indicate that only the Milan strain is likely to be capable of surviving Northern Italian winter conditions.

We show that this strain produces a reasonable nitrogen content 2.

Azolla – Wikipedia

The Milan strain was therefore used in a herbicide resistance study. Treatments with the commonly used herbicides Propanil, Oxadiazon, and Cinosulfuron caused the death of the fern. However, the Milan strain survived treatment with a lower but normally used on rice concentration of Propanil. The results obtained from these experiments suggest that the use of Azolla in Po Valley conditions has a potential, suggesting that it could be reasonable, especially for organic farms, to adopt this organic fertilizer which is also capable of reducing weed competition and is resistant to water polluted with one of the most commonly used herbicides.

From this perspective, the rice field system could be an interesting buofertilizer, since the large-scale water use and repeated monoculture can in the long-term involve risk of the accumulation of pollutants in the soil.

It is now important to test, bilfertilizer greenhouse and field experiments, the efficacy of double cultivation of Azolla with rice for improving crop and soil characteristics. International Journal of Agronomy. Indexed in Web of Science. Subscribe to Table of Contents Alerts. Table of Contents Alerts. Abstract Azolla is a floating pteridophyte, which contains as endosymbiont the nitrogen-fixing cyanobacterium Anabaena azollae Nostocaceae family.

Introduction Azolla is a heterosporous pteridophyte, with seven species. Materials and Methods Azolla filiculoides strains considered resistant to low temperatures were acquired from the Biofertilizer Germplasm Collections BGC of N 2 fixing organisms of the I.

Nitrogen and Carbon analyses were carried out as described before. Experiment started on Dec.

Biofertilizer | The Azolla Foundation

Every RGR is calculated on a two-week period, the end of which is reported in -axis. Bars represent standard deviation. Means and Standard Deviations of Carbon and Nitrogen contents d. We observed high quantities of Nitrogen in the leaves of the Japan and Italy strains; it was probably related to the decrease of its biomass during our test.

Increase of Azolla biomass of Milan strain, expressed as f. Every period of which RGR is calculated, is reported on -axis. The extreme of the date intervals is included. The azollla represent the standard deviation. Biofertillizer biomass increased linearly until 19 April, followed by a more rapid growth until 28 April.

Herbicide treatment, Analysis of Nitrogen and Carbon, expressed as d. Azolla treated directly with herbicides becomes generally stressed, with an associated decrease in N and C content until death ensues. However, after this intermediate phase Cinosulfuron caused a progressive deterioration leading to the death of the fern.

We could weigh only floating samples, in Cinosulfuron treatment. Thuiet, Use of Azolla in rice production in Vietnam.

View at Google Scholar T. Plucknett, Azolla as a Green Manure: