Duez. Tunisia (May 07, 2023) – In Tunisia, oasis agriculture is based on the cultivation of date palms (Phoenix dactylifera L.) with which other crops are associated: market gardening, arboriculture or fodder to form an oasis agro-ecosystem. The production of date palm is very low and the average yield is estimated at about 50 kg per tree. This could be improved if the management practices of the palm groves mainly in the area of fertilization are done according to the appropriate standards. Farmyard manure is traditionally used and is strongly preferred to inorganic fertilizers, even on modern farms. Very few plantations receive special organic fertilizers.
Previous research in date palm growing regions around the world indicates that date palms require relatively large amounts of macronutrients to achieve good growth and production. The results agree that applications of N, P and K increase the number of leaves and bunches per palm, fruit yield and total sugar content, all contributing to high fruit quality and better production economics. Unfortunately, there is a lack of research focused on nutrient management for date palm in North Africa.
The present report is part of this research and describes the evaluation of the effect of biofertilisation with SANBIO products (EPSOMIT and PLANTA) on date palm productivity and soil characteristics. The effect of SANBIO biostimulants on the morphological and biochemical characteristics of the date palm and the microbiological characteristics of the soil was evaluated.
The products are Organic and registered in the List of Fertilizers and Soil Amendments authorized for use in Organic Agriculture in Tunisia. These products were supplied by AGRIUP Distribution, the exclusive representative of the German company SANBIO in Tunisia and Libya. AGRIUP Distribution is developing a new approach to agriculture based on strengthening the plants’ self-defence reactions to biotic and abiotic stresses. Through the products it distributes, AGRIUP Distribution defends an approach that aims to restore nature’s reason.
1. Aim of the experimental trial
The trial was conducted with the aim of addressing edapho-climatic problems. Indeed, the palms studied are grown on sandy gypsum soil and irrigated with water of 1.9 g/L salinity. This type of draining soil with low organic matter gives rise to conditions that strongly influence the absorption of nutrients and consequently the quantity and quality of production.
2.1 Presentation of biostimulans
2.1.1 Biostimulans Sanbio EPSOMIT
EPSOMIT is a premium immunity activator and growth stimulant for stress control and increase of productivity on all crops. EPSOMIT with its powerful formulation acts in the plant cells and by that it triggers the defensive and vegetative processes in the plant. EPSOMIT increases the tolerance and resistance towards environmental and pathological stress by activating the whole plant physiological system. EPSOMIT activates the metabolism that results in enhanced development of root system, shoots, leaves, fruits, improved mobilization and assimilation of nutrients, vegetative growth, early flowering and maturation, improved fruit quality and long storage life.
The advantages of EPSOMIT are:
- Improving crop yield, quality and storage parameters
- Increasing environmental stress tolerance
- Higher resistance against infections and pests
- Better utilization of nutrients and water
- Better growth under extreme conditions.
| Crops | Application time | Single rate |
Soil-grown agricultural crops Cereals, Pulses, Vegetables and Melons, Fruits, Nuts, Oilseeds, Sugars and Starches, Fibres, Beverages, Narcotics, Spices, Condiments, Rubber Forages, Green and Green leaf manure, Lawns | First application should be done in the early growth period (tillering, 3-5 leaves visible, stem elongation). Subsequent applications can be done optional during the shoot phase until end of flowering phase. | 1 kg/ha |
| Trees | First application should be done in the early growth period at white/colored bud stage. Subsequent applications can be done optional during the shoot phase until end of flowering phase. | 1 kg/ha/1m crown-height |
2.1.2 Biostimulans Sanbio PLANTA
PLANTA is a premium immunity activator and growth stimulant used in fertigation, stress control and increase of productivity on all crops. PLANTA with its powerful formulation acts in the plant cells and by that it triggers the defensive and vegetative processes in the plant. PLANTA increases the tolerance and resistance towards environmental and pathological stress by activating the whole plant physiological system. PLANTA activates the metabolism that results in enhanced development of root system, shoots, leaves, fruits, improved mobilization and assimilation of nutrients, vegetative growth, early flowering and maturation, improved fruit quality and long storage life.
The advantages of PLANTA are:
- Improving crop yield, quality and storage parameters
- Increasing environmental stress tolerance
- Higher resistance against infections and pests
- Microbiological enhancement of soil fertility
- Better utilization of nutrients and water
- Better growth under extreme conditions.
| Crops | Application time | Single rate |
Soil-grown agricultural crops Cereals, Pulses, Vegetables and Melons, Fruits, Nuts, Oilseeds, Sugars and Starches, Fibres, Beverages, Narcotics, Spices, Condiments, Rubber Forages, Green and Green leaf manure, Lawns | First application should be done in the early growth period (tillering, 3-5 leaves visible, stem elongation). Subsequent applications can be done optional during the shoot phase until end of flowering phase. | 1.5 kg/ha |
| Trees | First application should be done in the early growth period at white/colored bud stage. Subsequent applications can be done optional during the shoot phase until end of flowering phase. | 1.5 kg/ha/1m crown-height |
| Substrate | Prior sowing | 0.75 kg/m3 |
- Materials and methods
The palms studied in the present study are grown on sandy gypsum soil and irrigated with water of 1.9 g/L salinity. These conditions strongly influence the amount of nutrients absorbed.
The use of the biostimulants and the soil improver with useful microorganisms, during specific periods, represent solutions to increase tolerance to environmental stress as well as a better absorption of nutrients and water leading to an improvement in yield, quality and shelf life of the fruit.
AGRIUP Distribution recommended the application of two types of biostimulants: Sanbio EPSOMIT and PLANTA.
Table 1. Basic data
| Season | 2022 |
| Location | Jemna Oasis, Duez, SW of Tunis City, Tunisia
Picture 1: Location of the trial lot |
| Responsible organization | Sponsor: Khaled AYADI, AGRIUP Distribution – Tunisia Scientific monitoring: Dr. Hammadi HAMZA, Research Institute Of Regions Arides Ira Kebili, Tunisia |
| Crop | Date palm trees |
| Variety | Phoenix dactylifera L. |
| Trial field | 1 block system, 260 ha 10 palm trees per untreated lot 10 palm trees per treated lot |
| Soil quality | sandy gypsum soil |
| Pesticides | none |
| Irrigation | 2000 liter per palm tree every fortnight (each two weeks) water from well with 1.9 g/L salinity |
| Test product | Biostimulans Sanbio EPSOMIT Biostimulans Sanbio PLANTA manufactured by SANBOS GmbH, Germany |
| Date of planting | 1993 |
| Date of application | 11/08/2023: 50g EPSOMIT per palm tree, foliar spray, 1 application 03/06/2023: 25g PLANTA per palm tree, by irrigation, 1 application 28/07/2023: 25g PLANTA per palm tree, by irrigation, 1 application |
| Date of harvest | 09-12/2022 |
| Scoring | Yield, fruit quality parameter, soil parameter |
The application of biostimulants was carried out on 10 treated palm trees (Sanbio) compared with 10 untreated trees (Control).
The trial was installed by the company AGRIUP Distribution in a private plot of 1 ha located in the oasis of Jemna (Figure 1). The plot has an artesian well with solar pumping and the age of the palm trees is about 30 years.
The irrigation adopted is 2000 litres per plant every fortnight.
The results obtained are analysed statistically by SPSS 12.0.
Analyzed Parameters
Analysis of dates
For the quality criteria, the measurements concerned:
- The percentages of normal dates, desiccated dates and rotten dates
- The fresh weight of the fruit, the weight of the stone, the ratio Fruit/stone and the width and length of the dates.
Concerning the biochemical analysis of the dates, four contents were measured:
- Water content
- Mineral content
- Total sugar content
- Protein content.
Soil analysis
The parameters analysed are :
- pH
- Soil salinity and conductivity.
4. Results
4.1 Effect of treatments on date quality
Figure 2 shows the percentages of normal, dried out and rotten dates harvested from treated and untreated palms.
Figure 2: Effect of SANBIO products on date quality
Figure 3: Effect of SANBIO products on date quality
The percentage of normal dates was 94% in treated case against 75% in untreated case. This is mainly explained by the significant decrease of rotting which was reduced by 13% in treated samples. It is also noted that the percentage of dried dates was 4% in treated samples against 10% in the untreated plot.
4.2 Effect of treatments on the morphology of marketable dates
4.2.1 Besser stage
Figure 4 below represents the morphological description of dates at the Besser stage of treated and untreated palms.
Figure 4: Effect of treatments on date morphology (Besser stage)
Dates (Besser stage) from treated feet showed greater lengths than dates from untreated feet, with values of 43 mm and 37 mm respectively, and a significant increase in weight of 1.45g.
4.2.2 Tamer stage
Treated dates (Tamer stage) showed greater lengths than untreated dates (Figure 5). The weight of the fruits is improved when using biostimulans, an increase of 0.7g per fruit was noted or a percentage of 7.54%.
Figure 5: Effect of treatments on date morphology (Tamer stage)
4.3 Effect of treatments on the biochemical composition of marketable Tamer dates
4.3.1 Water content
The inputs of these biostimulans contribute to the increase of the water content of dates (Figure 6).
Figure 6: Date water content (%)
4.3.3 Sugar content
The sugar content for treated dates was 58g/100g of fresh material, while for untreated dates it decreased by 4g (Figure 7). We can conclude that the use of PLANTA and EPSOMIT allows a significant increase in sugar content.
Figure 7. Sugar content of dates untreated and treated with biostimulants
4.3.4 Protein content
Treatment with SANBIO biostimulans ensured an increase in protein content in dates (increase of 17.21mg/100g) (Figure 8). We can conclude that the use of Sanbio PLANTA and Sanbio EPSOMIT allows a significant increase in protein content.
Figure 8. Protein content of dates untreated and treated with biostimulants
4.3.5 Soil analysis
Soil pH and conductivity analysis
The results show that there was no significant effect of Planta on the soil pH despite the slight decrease. The pH of the treated soil was 7.70 and that of the untreated was 7.80 (Figure 9). Similarly, there was no significant effect of Planta treatment on electrical conductivity. The conductivity of the untreated soil is slightly higher than that of the treated soil and the values are 2.79 and 2.55ms, respectively (Figure 10).
Figure 9. pH of soils untreated and treated with Sanbio Planta
Figure 10. Electrical conductivity of soils untreated and treated with Sanbio Planta
5. Conclusion
The main results related to production and quality parameters are shown as below mentioned:
- Use of both biostimulants increased gain 13% in production quantity by reducing the number of rottenness
- Use of both biostimulants increased the quality of the product by 6% by reducing desiccated fruits
- Use of both biostimulants increased significant the marketable production of 19%
- At the Besser stage:
- An increase in the weight of the fruit of 1.45 g or 13.66% was observed
- An increase in fruit length of 4.52 mm or 12.22 mm was observed
- At the Tamer stage:
- An increase in fruit weight of 0.7 g or 7.5 % was observed
- An increase in fruit length of 1.4 mm or 3.8 % was observed
- The sugar content for the treated dates showed an increase of 4 g/100g of fresh matter or 7.5%.
- Protein content for treated dates showed an increase of 17.21 mg/100g of fresh matter or 1.5%.
These results show that this type of fertilisation is in favour of increasing the production of 19%, fruit weight by 13.66% (for the Besser stage) and 7.5% (for the Tamer stage). This concludes the role of Sanbio EPSOMIT and Sanbio PLANTA biostimulants in growth stimulation and the optimization of nutrient uptake.
Moreover, analytical data show that the application of the biostimulants Sanbio EPSOMIT and Sanbio PLANTA improve the organoleptic quality of dates through the increase of sugar and protein contents.
The main results related to soil parameters are as follows:
- A significant decrease in pH for treated soils in favour of a better assimilation of nutrients
- A slight decrease in EC for treated soils in favour of better nutrient availability
The soil sampled after the application of Sanbio Planta biostimulant is characterized by a good microbiological activity. The improved soil microflora is composed of different strains of fungi and bacteria supplied by the Sanbio Planta product.
Picture credits: adobe.com