Fodder cultivations and fertilization efficiency
Source: Luis Romero and Oscar Bruno, Agriculture Engineers
Dairy
or meat production systems in Argentina are continuous through the year; therefore, high
offer season is autumn-winter. The primary factors of influence on the above mention
season are: the drop in temperature, time exposed to light and the irregular humidity
conditions.
Production curves of species that form part of the semi-permanent fodder (base alfalfa)
have a pronounce decline in their daily growth rates starting at the end of summer: 20Kg
DM/hectare/day for the autumn-winter period versus 70Kg DM/hectare/day for the
spring-summer period.
What are the possibilities of incrementing the production?
In general, it can be said that the technological tools that can be implemented may be some of the following:
- mixes and varieties that have better winter production
- pastures management during winter
- growth delay
- Annual farming
- Strategic fertilization
Fertilization
This last practice is very much in use world wide to improve annual crop production and perennials utilizing mainly, nitrogen fertilizers. In our country, this system has been adopted by cattle-breading.
Furthermore, the use of nitrogen must be considered as a tool to modify fodder distribution through out the year. By fractioning the doses we can achieve a more even distribution of dry material production, extend growth periods or achieve a faster growth allowing for early pasture.
Factors that affect the performance
The factors that affect nitrogen performance are:
- Soil’s fertility and type
- The species
- Plant’s physiological state
- Doses applied and its fractioning
- Frequency of use
- Weather conditions
The amount of nitrogen (N) available is the principal factor that affects the performance of the pastures.
The sources for this nutrient are: the soil, animal’s excreta, compost and fertilizers.
In real tests the response to the application of fertilizers with nitrogen had been very low (5 to 8Kg MS/Kg of applied N).
Others hIave found responses in the 15Kg MS/Kg of applied N for fertilizations of 0 to 400KgN/hectare and 14.5Kg MS/KgN for equal doses of fertilizer but lower purity, the response being 4.5Kg MS/KgN.
The decision of implementing or not this form of management depends primarily on the cost.
In
general, and for most situation the response to nitrogen fertilization is lower during
autumn than it is during spring.
Experinces in Santa Fe
Work done in the dairy farms of Santa Fe have obtained good results by using nitrogen in winter farmings (annual raygrass, oats or creole barley), about4 to 21 Kg of dry material per Kg of nitrogen added.
When annual graygras fertilized with a one time doses productions of 1000Kg Ms/hectare en el testigo and 1500Kg for a doses of 100Kg of nitrogen/hectare. In oats, the results have vary between 9.5Kg MS/Kg N (1750 and 2750Kg of MS/hectare for the sample and 100Kg N/hectare, respectively) and 21Kg of MS/Kg N (2000Kg the sample and 3100Kg for a doses of 50Kg N in two pastures).
Nitrogen and dry material
It is very important to point that the
use of nitrogen fertilizer causes a drop in the percentage of dry material (15% sample,
10% the fertilized lot). It also causes an improvement on the content of protein and a
drop on soluble carbohydrates, mainly in the first pasture. This has to be kept in mind to
achieve a balanced diet and in turn, we’ll have less poor weight gain problems and
milk production problems, which mainly occurred during autumn-winter.
In oats fertilized with different doses of N, it has been observed that the effects of
fertilization manifested it self in the PB content from the first pasture. Another effect
was detected in the content of CTNE, which dropped with the doses of N that was applied,
being more important during the first pasture.
Being
efficient
Is very important to pay attention to the efficiency of use of fertilizer, which
is going to depend on the factors mentioned above, which in turn will have an influence on
application cost and on the economical returns.
Studies show that, under the current prices for production, for winter fertilization to be economically viable we must achieve a response superior to 10Kg of DM per each Kg of N applied.
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