What is an inoculant and what is it used for?
It is a product that contains a high concentration of beneficial microorganisms (generally bacteria) for vegetables; some of these bacteria are catalogued like PGPR (Plant Growth Promoting Rhizobacteria). Inoculants are formulated on a support that allows the survival of the microorganism(s) and the application on the seeds or the crop in which it is going to be used.
Inoculants are specific, that is to say, that depending on the microorganism species and strain which they contain, they can be used in a certain vegetal species.
The basis of the legume inoculants is the symbiosis that legume plants achieve with atmospheric nitrogen fixating bacteria (generally rizhobia). By means of this symbiosis the plant manages to supply itself of atmospheric nitrogen, in exchange for providing photosintates (mainly carbohydrates) to the rhizobia lodged in its roots, in structures denominated nodules.
The inoculants for gramineae plants contain bacteria that exert beneficial actions on the vegetable with which they are associated;. A very important function of some bacteria is the production of biostimulating phytohormones for gramineaes, like auxins, citoquinines and giberelins. In addition, some of these bacteria also have the capacity to fixate atmospheric nitrogen. One of the most widely studied gramineae promoting bacteria is Azospirillum.
Which is the contribution of the Biological Nitrogen Fixation to the nitrogen necessities of a soybean crop?
It is estimated that a soybean crop needs approximately 80 kg of nitrogen per ton of produced grain, which represents very high amounts. The Biological Nitrogen Fixation obtained through the inoculation with specific rhizobia, is the main source for this total demand. Depending on the soil type and the particular environment conditions, the BNF contributes with 35% to 95% of the total needs.
This means that the BNF is highly important in the nitrogen provision to the soybean crop, since it allows the supply of this nutrient in elevated amounts. Due to the great nitrogen needs of the soybean crop, the possibility of managing it based on chemical fertilization is totally economically nonviable. In this sense, our production conditions have not shown positive response to the additon of nitrogened chemical fertilizers in crops which have an adequate nodulation.
What special characteristics does the inoculation of different lotus species present?
In the inoculation of forage legumes of the Lotus family, some points must be considered. This is due to the fact that, for Lotus, there are basically two groups of species of rhizobia with contrasting characteristics. One group includes rhizobia species used in the inoculants for L. corniculatus and L. tenuis and the other, those used in the inoculants for L. subbiflorus and L. pedunculatus. The strains of rhizobia used in the specific inoculants for L. corniculatus and L. tenuis is inefficient in L. subbiflorus and L. pedunculatus. This means that although they form nodules, the nitrogen fixation is practically null. The same happens inversely, where rhizobia species used in inoculants for L. subbiflorus and L. pedunculatus are inefficient in L. corniculatus and L. tenuis. In this sense, a nodulation that results inefficient in nitrogen fixation will directly damage the establishment and production of the pasture.
Based on the previous explanation if a lotus species is sown in a field that has had some of the species which are inoculated with the opposite group, problems can be generated due to the non desired infection with rhizobia present in the ground. Therefore, one must know if the field which is going to be sown has recent history of some Lotus species in order to evaluate the possible impact on the sowing that is going to be done.
What factors should be taken into account in the inoculation of White Volver – Trifolium repens?
In the inoculation of White Clover, certain precautions must be taken because some factors can condition the achievement of a correct nodulation and nitrogen fixation. The risk factors are:
a) in our fields the polimorfo Clover or Field Clover (T. polymorphum) exist naturally. It is associated with rizobios that are parasitic of the white clover. Therefore, the introduction of white clover in fields where this species has been sowed recently or in natural fields which have not been seeded, can have problems because the plants of white clover will be nodulated partially by the rizobios that are normally associated to the polimorfo clover and are present naturally in the soil.
b) The reduced size of the white clover seed implies that the rhizobia quantities of the inoculant that may be adhered to each seed, is less than the one achieved in other species with bigger seeds.
Based on these factors, one is due to pay special attention when inoculating white clover, considering the following recommendations:
- if one is going to seed in cover (with nonremoved ground and without incorporating the seed), the use of double dose of inoculant per 25 kg of seed is recommended, to favor a greater concentration of rizobios of the inoculant on each seed.
- sow when there is good ground humidity, that allows a fast germination and emergency of the plants
- make an inoculation of excellent quality, through a correct preparation of the inoculant-bioprotector solution, following all the recommendations specified in the label of products.
- cover all the seeds with the inoculant solution in a uniform way.
- inoculate and sow immediately.
In what situation is the use of covering powder suggested in the inoculation of forrage seeds?
The covering dust allows to form an outer cover on the forrage seed (as the last treatment), obtaining certain protection of the rizobios and an increase of seed weight.
The covering dust protects to rizobios of:- the excessive drying that can occur by lack of humidity in the ground or when the seed is sowed in cover, without being incorporated to the ground.
- the acidity of chemical fertilizers and the acidity of the ground.
Based on this, the covering dust use is recommended when:- sowings of extensive improvements in cover or direct sowing (without previous removal of the ground) of prairies when the seed of legumes is sowed to the voleo without incorporating it into the soil.
- the inoculated seed is in contact with the fertilizer in the hopper of the sowing machine during sowing.
- sowing is carried out in soils with high acidity.
In case of having a lot of inoculated forrage seed that could not be sowed, how many hours after the inoculation can it be sown without risks of having a deficient nodulation?
The greater productive response to the inoculation is obtained when the seed is inoculated and seeded within the 12 following hours to the inoculation. In spite of this, when sowing is impossible due to rain or not planned operational problems, a maximum period of 48 hours between the inoculation and sowing can be considered, after which high risks of having faults in the nodulation and nitrogen fixation exist.
What is recommended for the inoculation of soybean when curasemillas is going to be used?
The treatment of seeds with chemical curasemillas, that is with fungicides or insecticides, can be detrimental for the rizobios of the inoculante and therefore a risk factor to obtain a correct nodulation and biological fixation of nitrogen.
For this reason, despite the answer we present here, we always advise to consult directly with the technical department of Lage y Cia. S.A.
For a better interpretation, we divided the answer according to the curasemillas to be used, insecticide or fungicide.
Insecticide Curasemillas: all curasemillas insecticide are very detrimental for the rizobios, since they cause an important death rate after a short time of exhibition to it.
It is recommended:
- to separate the curado time and the inoculation, treating the seed with chemical curasemillas at least 10 days before the inoculation.
- to use Nitrasec inoculant , peat based, together with bioprotector.
- to inoculate and to sow within the 24 following hours.
- to sow in small farms/lots with good conditions of humidity, so that a fast germination of the seeds is favored.
Fungicide Curasemillas: the presence of fungicide curasemillas is very risky for the rizobios; however, some formulations of less damaging active principles exist, that is to say, compatible with the inoculant.
It is recommended:
- in case of being possible, to cure the seed some days before the inoculation.
- in case of making the cure and the inoculation in the same moment, the seed must first be dealt with C+T, to be covered then with the inoculant+bioprotector suspension. That is to say, the curasemillas and the inoculant must not be mixed in the same container. When the curadora and inoculadora Treater is used, curasemillas must be placed in the inferior dispenser bucket (next to the hopper of seeds) and the suspension of inoculant+bioprotector in the superior dispenser bucket.
- when compatible fungicide curasemillas is used, the preinoculation times are shorter to those than can be handled when the chemical is not used.
Are there any differences among the different ways of inoculating soybean?
Yes, there are very important differences among the different ways of inoculating. The inoculation methodology of soybean is a basic theme, because it incides directly in the inoculation quality, which affects later the nodulation and Biological Fixation of Nitrogen. Lage y Cía. S.A. has studied different methods of inoculation in terms of quality in the achieved inoculation. The following is a summary of the results obtained of the comparative study of different methods of inoculation, considering the same seed lot and the same inoculant lot:
Bradyrizobia count per seed 48 hours after inoculation, according to the inoculation method.
Based on the previous results, it is concluded that the different ways of inoculation have an influence in its quality. The inoculating machine Treater, specially design for such end, allows to achieve the maximum concentration of Bradyrizobia on the seed, permitting a homogeneous covering of all the seeds of the lot, thus achieving an inoculation of the highest quality.
Apart from using biological Trichosoil in the production of plantils or in a specific culture, is it posible to use a chemical fungicide with complimentary action to Trichosoil?
In many oportunities, depending on the culture in question and the diseases that affect it, it is not possible to plan a scheme of sanitary work based exclusively in the biological control. It may be necessary to combine chemical and biological control. This is possible due to the fact that not all chemical fungicides affect Trichoderma (control agent of Trichosoil fungicide), existing various degrees of compatibility between Trichosoil and chemical fungicides.In order to make the best suggestion for each situation, we advise you always consult directly to the technical department of Lage y Cia.S.A.
When is it necessary to use coadyuvantes in the aplication of phitosanitaries?
A coadyuvante is a product that when used with a specific phitosanitary, benefits its action, considering many aspects. The term “coadyuvante” is very wide and includes products with diverse functions, existing coadyuvantes with more than one function.
The most wanted actions when using a coadyuvant are:- Correction of the pH of the pulverization water. The different phitosanitaries present an optimum action on a determined pH of pulverization water. Most phitosanitaries must be prepared in water with acid pH. Thus, the use of a coadyuvant with pH correction action allows the phitosanitary to be in an adecuate means for its best performance.
- Correction of hard water. Water called “hard” contains an excessive quantity of free cationes, principally calcium and magnesium. A high concentration of these cationes interferes with the phitosanitary, reducing its activity.
- Moisturing: It is always desirable to achieve a homogeneous wetness and covering of all the pulverized area, in a short time. This permits a faster absorbtion, diminishing the risks of loss of the applied phitosanitary. The coadyuvants with moisturing function decrease the superficial tension of the caldo pulverized, favouring a more homogeneous wetting and moisturing. According to the formulation, very important differences exist in the power of reduction of the superficial tension of the different moisturers.