1. Introduction
Camelina (
Camelina sativa L.) is a member of the Brassicaceae family [
1]. It has been cultivated for centuries as an oilseed crop for human food [
2]. The high oil content in camelina seeds increases the plant’s potential as a new source of biofuel [
3,
4]. Camelina is an annual herbaceous plant, which can sometimes act as if it is biennial. In its maturity, it can measure between 60 and 120 cm in height [
1,
5]. Its fruit is a pear-shaped, indehiscent silique [
1] and can reach between 5 and 6 mm in diameter. Each silique contains between eight and 15 seeds, each of which is very small, measures around 2 mm in length, and has a golden or brown color [
1,
5].
Camelina seeds contain between 30% and 45% oil, and over 80% of the fatty acids in this oil are unsaturated [
6,
7]. Of these fatty acids, the main fatty acids are linolenic (27.9%–39.7%), linoleic (13.5%–18.7%), oleic (14.2%–17.5%) and gondoic (15.1%–16.4%). Erucic, palmitic, oleic, arachidic, eicosadienoic, and eicosatrienoic acids are also found [
6,
7]. Camelina oil has characteristics that distinguish it from other vegetable oils; above all, it has high α-linolenic acid content, which is an essential fatty acid and is added to foods [
8]. However, camelina oil also contains erucic acid, which can have negative effects on animal growth and development [
6]. The presence of erucic acid has led to improved rapeseed varieties, obtaining the canola variety (with low erucic acid and glucosinolate contents) in the 1970s [
9].
The geographic origin of camelina is not precisely known, though its predecessors existed in three distribution areas: the region surrounding the Mediterranean Sea, Northern Europe, and East Asia [
1]. It was an important oilseed until the mid-20th century and was produced in several European countries, particularly in the central and northern continent, though its production declined afterward [
2,
6]. Recently, interest in this species has grown and many diverse studies have been undertaken to evaluate its adaptability in different agro-climatic conditions [
2,
10,
11,
12,
13,
14,
15].
Zubr [
2] tested seven summer varieties in different locations of Northern Europe and Scandinavia, and found that the results were more influenced by climate and soil conditions than by the origin or strain used. The average oil content in camelina varieties was 42.1% and the average protein content was 43.3% [
2]. Angelini et al. [
10] evaluated camelina in a Mediterranean climate, in Pisa, Central Italy, and it reached a maximum oil content of 33%. This case showed that the oil content dramatically decreases when high temperature/low precipitation events exist, reaching 23.6%. Despite this, seeds with a high oil content (41.4%) have successfully been produced in Maricopa, Arizona, as a winter crop for the Northern Hemisphere [
11]. In this case, the yield per hectare was low, reaching approximately 1000 kg·ha
−1 [
11], which is much lower than that obtained by Vollmann et al. [
12], who found over 2200 kg·ha
−1.
Winter [
13], spring [
14,
15], and autumn-sown [
15] varieties have been evaluated in the northern United States as low-cost productive alternatives. Gesch and Cermak [
13] conducted their studies in Morris, Minnesota, sowing two winter varieties between September and October. They reached seed yields of up to 1300 kg·ha
−1, with oil contents between 28.2% and 42.0%. Meanwhile, Gesch [
14] obtained between 780 and 1800 kg·ha
−1, with oil contents between 37.7% and 41.6%, using the same study location, but sowing spring cultivars between April and June. Guy et al. [
15] tested 18 distinct genotypes, sown during different seasons (spring and autumn) and in different locations. They obtained 25% higher yields when camelina was sown in spring compared to autumn sowing. In addition, they determined that camelina is sensitive to drought. When precipitation was lower than 200 mm·year
−1, the yield was 127 kg·ha
−1, whereas when precipitation was 580 mm·year
−1, the yield was 3300 kg·ha
−1.
In Chile, three spring varieties were planted in the central southern regions with five different locations and sowing dates. The highest average yields were obtained in Los Angeles and Osorno, with 1600 kg·ha
−1 and 1552 kg·ha
−1, respectively, though Osorno gave the highest absolute yield of 2314 kg·ha
−1 when sown in May. Oil production was between 39.8% and 45.8% [
5], close to the maximum oil production value of 48%, obtained via elite ecotype selection [
12].
Camelina has low nutritional requirements. The oil content of its seeds decreases as it releases nitrogen into the soil, and it is not replenished after fertilization with phosphorus and sulfur [
16]. Camelina has a higher tolerance to drought, frost, and heat, and is less susceptible to pests and disease when compared to canola [
15,
17]. It is also more adaptable to marginal soils [
16] and has lower production costs [
4], contributing to environmental sustainability and climate change mitigation [
18].
Camelina is appreciated for its high adaptability to diverse conditions, though it varies depending on the variety used and the harvest season, as well as the local soil and climate conditions. In Chile, high experimental productivity has been achieved, with high oil contents, making it an interesting productive alternative that could contribute to second-generation biofuel production. The present study determined the Chilean territory potential for camelina cultivation, considering its climate and soil requirements, as well as the availability of existing territory in Chile, avoiding competition with current land uses.
4. Discussion
In Chile, Santibañez et al. [
37] determined bioclimatic adaptability for moringa (
Moringa oleifera Lam.); they used the minimum and maximum temperature, degree days and days with frost. Zoning was carried out through bioclimatic analogies, where the conditions among locations from South Africa and Kenya were different with bioclimatic conditions of the country, reducing potential areas.
Falasca et al. [
38] carried out a climate zoning for camelina in Argentine territory. They used annual precipitation, precipitation during the productive period (August–December) and average temperatures during periods of vegetative and reproductive growth as factors in evaluating camelina suitability. The use of variables relevant for camelina production seasons permit greater specificity regarding land suitability; however, it is also necessary to consider variety in use, especially if there are certain cultivars for different seasons [
7,
13,
15] in which case variable ranges must be considered according to the cultivar in use. The present work considers generic ranges for the selected variables, where information was used for existing cultivars. It is a first approximation for camelina production in Chile, which can be used as a tool to support decision-making and to evaluate the species’ introduction as a raw material for biodiesel production or other industrial products.
The present work considered the entire productive period for degree day calculation, which in Chile was 221 days for spring cultivars [
5]. Gesch [
14] determined productive cycles that oscillate between 75 and 100 days between sowing and harvest for spring cultivars sown in Morris, Minnesota, in the north central United States. Gesch and Cermak [
13] used winter cultivars, also in Morris, Minnesota, but had a productive cycle around 226 days between sowing and blooming.
It was determined that, with a water deficit greater than 500 mm annually, the area was considered to be restricted during water zoning (
Table 2). This is manageable, because there are irrigation alternatives that must be developed for industrial crops, especially regarding biofuel production. In the north of Chile, where water and agriculturally viable soil are scarce [
18], use of treated wastewater could be an effective option to habilitate territory for non-food crops [
39]. Only one [
11] of the 27 locations considered in this study has an arid climate. French et al. [
11] evaluated camelina production in Maricopa, Arizona, United States, where they found productivity of up to 1500 kg·ha
−1, with approximately 2900 degree days. This way, applying irrigation for camelina production in arid climates can be an alternative, for which future studies can evaluate the possibility of growing camelina in the northern territory of Chile using irrigation with treated wastewater.
Soil zoning in Chile is complicated, due to the scarcity of existing information. Soil type data was only obtainable from Chile and the United States, and even then, only for 11 types of soils. In addition, not all of these soils are registered in the country, so a large part of the national territory is categorized as without information during soil zoning (
Figure 2). Information on soil resources is still insufficient for accurate zoning. Soil type and quality are relevant parameters for agricultural production, since crops depend on these factors to develop favorably [
40].
The agro-ecological zoning results obtained are in accordance with those published by Berti et al. [
5] and Solis et al. [
16], who conducted studies between the Biobío and Los Lagos regions, and determined that south central Chile possesses adequate conditions for camelina production. These precise regions possess the most land surface area for camelina production. The Biobío, Araucanía, Los Ríos and Los Lagos regions hold 93.1% of suitable lands, where 49.0% of land is without thermic restriction, mild water restriction, and mild soil restriction or without information (
Table 6).