“La acidez y el encalado de los suelos”. Revista Ciencia y Técnica en la Agricultura Cañera (La Habana, Cuba) N° 2. Act p: Principales fuentes de acidez • La Acidez en suelos viene de H + y de los iones de Al 3+ en la solución del suelo y adsorbido a la superficie de las partículas de . Acidez y encalado de los suelos. Instituto de la Potasa y el Fósforo, Quito, Ecuador. 42pp. INPOFOS. Manual Internacional de Fertilidad de Suelos.
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The aim of this study was to assess the effect on soil quality of a governmental program whose objective is restoring the fertility of degraded acidic volcanic ash soils. The program consisted of i liming, ii correction of the P status, and iii sowing forage plants.
We measured soil fertility of fields after 1 to 4 years since start of the program, and compared these fields against fields under old permanent natural grasslands, used to estimate the baseline soil test values for the properties considered in this study. The impacts of the program on acidity pH and exchangeable aluminum were different among localities. At Cunco, exchangeable aluminum was not affected, while pH increased initially but decreased to its initial value within four years.
Instead, at Lonquimay exchangeable aluminum decreased significantly, and pH remained slightly higher than the control values through the first four years. At Lonquimay P-Olsen was initially increased, showing a positive short-term effect of the program, but gradually decreased after the first year, until it returned to the initial level.
This study provided important results for the improvement of the program. Andisols, phosphorus, aluminium toxicity, soil acidity. El impacto del programa sobre la acidez pH y aluminio intercambiable y disponibilidad de P fue diferente entre localidades.
In the Southern temperate part of Chile, andisols are the dominant soil type. Moreover, acidity is high in those soils, which is also detrimental to phosphorus availability Pinochet et al. These characteristics strongly impede soil productivity, especially in the pastures, which are vital for small cattle breeders. Moreover, those characteristics are also detrimental to the growth of legumes Ritchie, Therefore, native pastures of this region have a very low productivity and express a very specific flora, which consists essentially of grass, but contains also some legumes, adapted to the high acidity of the soil, and some other aluminium-tolerant species, adapted to an acidic environment Mora et al.
Since they have been used for agriculture, these soils hardly received a low amount of mineral fertilizers, calcium and organic amendments.
This has worsened the problems. Finally, overgrazing caused also problems of erosion. These conditions are very hard on the Mapuches farmers of this area, whose main activity is cattle breeding ovine and bovine and whose farms are very small.
The program focuses on improving the availability of phosphorus through phosphate supplements and liming, in order to decrease acidity and the content of free aluminium in the soil.
The program also aims at establishing a pasture with variable compositions to ensure a permanent coverage of the soil, thus limiting erosion and increasing productivity and quality of forages. The program also includes other actions such as the creation of terrasses to prevent erosion, the set up of cover-crops. However, these have been seldom applied in the area object of this study, and therefore they will not be discussed in this paper.
This program has been operational for more than a decade. The aim of this study was to evaluate its effects on soil properties and on pasture productivity in the region of the Araucania, home of small producers Mapuche. In order to answer these questions, we selec ted a series of fields that participated in the program in four municipalities of the Precordillera and in one municipality of the Andes Cordillera.
Acidez de los suelos y efectos del encalado
Our method was based on the comparison of native pastures with farmers’ grasslands after they have received, 1 to 4 years before our survey, the program actions. We measured soil characteristics and grassland productivity, but in this paper, only the soil data are presented. Arrows in Figure 1 shows relationships between program actions and changes expected in the soil. This, in turn, causes an increase in the mineralization of organic matter arrow 1a Campillo, and, by favouring the insolubilization of aluminium, affects the quantities of exchangeable aluminium arrow 1c.
Phosphoric fertilizers affect directly phosphorus availability Helyar, Finally, the productivity and the quality of the pasture should benefit from the decrease in pH arrow 6the decrease of exchangeable aluminium arrow 5 and the increased availability of phosphorus arrow 4. The actions of the program establishment of the pasture, liming, phosphoric fertilization are boxed with continuous lines; the soil properties acted upon are boxed with thick dashed lines; the sought-after quality of the sward in thin dashed lines.
Site description and experimental settings. Climate is humid with an average annual precipitation amount of 2, mm and temperate cold: We analysed the soil in those fields, for two consecutive years, characterized by very different weather conditions: We chose a synchronic approach.
In each area, we selected fields that had not been subjected to the program these old permanent grasslands were considered to represent the soils in their natural, poor fertility status, and therefore these soils were used to estimate the baseline or “initial” soil test values for the properties considered in this study.
Those fields are considered as control in the following tables. They were compared to fields that received the program one, two, three or four years earlier and were located near enough of the control plots so that the characteristics in terms of soil condition and cultivation history were similar.
The number of fields studied is shown in table 1. Subdivision of the 32 fields sampled in each municipality, with reference to the application of the program at the time of measurement. Soils of these five localities are classified as andisols Vitric-Silandic Andosol as mentioned by Salazar et al. Average Soil Organic Carbon content was g kg Cultivation practices of the different fileds studied are presented in table 2.
Cultivation practices in the five localities studied.
The fields received calcium carbonate and superphosphate the year before the grasslands were established and during the year following this establishement. No fertilization was applied afterwards, whatever the delay between the program application and our survey in and The pastures were sown with a mix of red clover Trifolium pratense L. Each value in tables 3 – 5 is the average of 4 to 8 measured values. Exchangeable Al content measured in different localities of the precordillera and the cordillera, Araucania Region south of Suekos.
P-Olsen measured in different localities of the precordillera and the cordillera, Araucania Region south of Chile. The cm layer was sampled in October and in Octoberusing a gauge.
The cm layer was sampled. We mixed the soil of eight sub-samples in each field. Each sample was analyzed at the soil laboratory of the Catholic University of Temuco.
All samples were prepared and analysed according to the Commission for Normalisation and Accreditation of the Chilean Society of Soil Science rules Sadzawka et al. For the analysis of exchangeable aluminium, 10 g of dry soil dd added to a solution of KCl 1M, then shaken for 30 minutes at room temperature.
After filtering, measurements were taken using an atomic absorbtion spectrophotometer. For the analysis of exchangeable aluminium, 5 g of dry soil were added to a solution of ammonium suelks 1M, and shaken for 30 minutes, before filtering. Then the concentration of aluminium was measured with an atomic absorbtion spectrophotometer.
To determine the P content, we chose the Olsen method. A sample of 2. The solution was shaked for 30 minutes and filtered. The phosphorus was determined by colorimetry with the blue of molybdene method, using ascorbic acid as a reducing agent. Application of the program sueos different effects on the pH of the soil in the different locations studied Table 3.
Acidez de los suelos y efectos del encalado | Horticulture International
At Lonquimay, the pH was stable over the whole period, and slightly higher lis the control value four years after the programm was applied. These changes show poor effectiveness of the program to recover soil acidity in the area investigated. Second, liming had a temporary effect: This outcome is consistent with a number of studies on liming in Southern Chile. The program had also contrasted effects on the exchangeable Aluminium Alex content Table 4.
The findings are not similar to those of Verde et al. They could be explained by the above-mentioned changes in the pH. Alex values were not significantly different between the first and the fourth year, but exhibiting a slight decrease during the period at Cunco. Those fluctuations in Alex values could be linked to the fluctuations in pH observed at Cunco.
At Villarrica Alex remained stable statistically except the value in the first year, as well as the pH values. As seen above, the actions taken in the program were unable to correct consistently the pH in all localities but Lonquimay. We do not think that this is linked to the fact that only at Lonquimai enczlado was cultivated.
It is more likely due to the unsufficient amount of lime added to the soil: A second possible explanation of these results can be given by the generalized use of urea for nitrogen fertilization in this area, it is the cheapest nitrogen fertilizer source. Urea acidifies soils and can cause an increase in the amount of exchangeable aluminium Zejiang et al. Finally, the impact of the program on phosphorus availability P-Olsen was also different between municipalities Table 5.
At Lonquimay, P-Olsen initially significantly increased, showing a positive short-term effect of the program. However, P-Olsen gradually decreased after the first year, until it returned to its initial level.
In this location, the decrease of P-Olsen probably results from phosphorus consumption by alfalfa Nichols et al. This explanation is more likely than the fixation by the soil, as the content of extractable aluminium is less than mg kg In this oos phosphoric suslos was first applied kg ha -1 of P 2 O 5just before the alfalfa was sown. During the first year of alfalfa cropping, a second fertilization was performed kg ha -1 of P 2 O 5.
These two fertilizations were not sufficient to guarantee the maintenance of available phosphorus levels in the years after the application of the program. Moreover, Alfalfa is able to absorb significant quantities of phosphorus, thanks to its well-developed root system Nichols et al. This plant also produces more biomass, thus increasing the exportation compared to native pastures.
Finally, afalfa was only harvested afidez hay, without any return of P to the soil, which probably impeded the P balance sheet. In this locality, exchangeable Al content was the highest among all the samples, which caused high toxicity and a poor growth in the grassland; this, in turn, strongly limited phosphorus uptake, which probably explains the observed imbalance.
That flora consisted mainly of grasses Agrostis capillaris, Holcus lanatus and some naturalized legumes plants e. Medicago hispida or Lotus uliginosus. Sudlos perennial ryegrass and red clover, species which are not well adapted to acid soils, caused also poor productivity of the pastures and, consequently, very low phosphorus uptake.
In those locations, phosphorus uptake by grasses was hampered by the presence of free aluminium.
Moreover, grasslands in those municipalities are grazed, as opposed to Lonquimay, where only hay is harvested. It is likely that the presence of livestock implies phosphorus return to the soil via the animal manure.