Growth response of Meranti Liberoid coffee seedling to liquid organic fertilizer and dolomite application

Liberica coffee is a type of coffee that can grow in soils with low pH and low nutrients. One of the efforts to increase the strength of the coffee seedling is by improving the planting media, through organic fertilizers and ameliorants application. This study aimed to analyze the effect of liquid organic fertilizer (LOF) and dolomite on the growth of Meranti Liberoid 2 (LIM 2) coffee seedlings. This research was conducted at the Pakuwon Experimental Station, Sukabumi, from April 2021 to January 2022. The research design used was a factorial 2 factor with 3 replications. The first factor was the LOF concentration (0, 5, and 10%), and the second was the dolomite dose (0; 2.5; 5.0; 7.5; and 10 g seedling−1). The results showed that the highest seedling height, leaf, and root dry weight of LIM 2 coffee seedlings was achieved by dolomite treatment of 7.5 g seedling−1 without LOF. The use of LOF can be an alternative to the need for dolomite to increase the growth of LIM 2 coffee seedlings.


Introduction
The utilization of LOF is an alternative source of nutrients for plants.The application of LOF with a lower dose than solid organic fertilizer is a solution in the application of organic fertilizer in the field.This was stated by [1] that the application of liquid fertilizer is generally easier because the dose or amount required is much lower than that of solid organic fertilizer.Besides being able to increase plant growth, LOF is also able to save on the use of inorganic fertilizers.The LOF can help increase crop production and quality and reduce the need for inorganic fertilizers [2].Another ameliorant needed to improve the properties of the growing media, especially when using acid soils is lime or dolomite.The application of ameliorant or dolomite can increase soil pH, decrease its (Al), and solubility [3], and can increase soil cation exchange capacity (CEC) [4].Dolomite contains magnesium (Mg) and Calcium (Ca) which are useful for plants as nutrient enhancers.The advantage of dolomite is that the purchase price is relatively cheaper.Giving dolomite can be utilized to increase the growth of plants developed in acid soil.
Liberica coffee is mostly grown on peatlands which are acidic and poor in nutrients.Liberica coffee also has the potential to be developed in acid-mineral soils.Amelioration studies for Liberica coffee cultivation in acid soils using LOF and dolomite are still relatively limited.The provision of LOF and dolomite has the potential to improve the growth of LIM 2 coffee seedlings, which is one of the superior varieties of coffee with a high taste score.This study aimed to analyze the effect of LOF and dolomite on the growth of LIM 2 coffee seedlings.

The Research site and material
The research was carried out at the Pakuwon Experimental Station, Indonesian Industrial and Beverages Crop Research Institute, Sukabumi, at an altitude of 450 m above sea level with a climate type B (Schmidt and Ferguson), from April 2021 to January 2022.The planting media used was Inceptisol soil taken from Pakuwon Experimental Station.The soil was dried, then filtered using a <5 mm pass filter, and put 2.5 kg into polybags with a size of 40 cm x 20 cm.LIM 2 coffee seedlings were grown in the nursery for 82 days before being transferred to the growing media.The shade measures 8 x 8 m, using iron as a pole, and the roof net is made of nylon with 60% light intensity.

Experimental design
The experimental design used was a randomized complete block (RCB) in factorial 2-factors with 3 replications.The first factor was three levels of LOF concentration (0%, 5%, and 10%) and the second factor was five levels of dolomite dose (without dolomite as a control, dolomite 2.5 g seedling -1 , dolomite 5 g seedling -1 , dolomite 7.5 g seedling -1 , and dolomite 10 g seedling -1 ).Each experimental unit consisted of 10 seedlings.The application of dolomite according to treatment was done by mixing it with 2.5 kg of soil media and stirring it, then putting it in polybags.LOF application was done by dissolving it with water and watering it at the base of the seed stem.Fertilization was given once a month with a concentration according to the treatment being tried, namely without LOF (control), LOF 5%, and LOF 10% by dissolving in water and then spraying on the basal stem.The dissolving process for the 5% concentration treatment was carried out by dissolving 5 ml of LOF in 95 ml of water.For the 10% treatment, 10 ml of LOF was added to 90 ml of water.

Observed variables and data analysis
The soil used was first analyzed for pH, organic C, total N, CEC, available P, potential P, potential K, exchangeable cations, and texture.While the LOF used were analyzed on pH, total N, organic C, total nutrient content (P, K, Ca, Mg, Na), and hormone content IAA, GA3, trans-zeatin, and kinetin.The observed were: (1) the pH of the growing media was measured at 4 month after planting (MAP) on a composite 500 g soil sample from a plant sample of 10 polybags per plot, (2) seedling height, number of leaves, and stem diameter at 7 MAP on 10 sample seedling per plot, and (3) leaf, stem and root dry weight were measured at 7 MAP on 3 samples per plot.The data collected were analyzed by ANOVA.And if the F test was a significant effect, it continued with a comparison test of the average treatment using the Tukey test at a 95% confidence level.

Soil characteristics and LOF chemical content
In general, the soil has an acidic pH with low organic matter content.However, the exchangeable K, Ca, Na, and Mg was high, and the potential P was very high but its availability was very low.Based on the content of the fraction of sand, dust, and clay, this soil texture is the clay loam (Table 1).
Due to the nutrient content in the solution conditions, chemical and growth hormone content in LOF was generally relatively low (Table 2).This is presumably due to differences in LOF sources and soil types.The results of this study also seem to be found by Arangote et al. [5] who reported that the application of organic fertilizer with dolomite resulted in lower soil pH than the dolomite treatment single.The acidification process is thought to be caused by the increase in pH by the administration of dolomite which stimulates microbial activity and causes the nitrification process from ammonium to nitrate to be more intensive, resulting in the release of H + and a decrease in soil pH.N fertilization can cause a decrease in soil pH [6].Likewise, the application of LOF, directly and indirectly, can increase N in the soil.

The ANOVA result
The results of the analysis of variance on the 7 observed variables were presented in Table 3.The Soil pH, plant height, and dry weight of leaf, stem, and root are affected significantly by the interaction between LOF and dolomite application.

The interaction effect of LOF and dolomite on soil pH
Increasing the dose of dolomite to 10 g seedling -1 can significantly increase soil pH, especially at 5% LOF.While at LOF 0% and 10%, the increase in pH was only up to a dose of 7.5 g seedling -1 dolomite, then decreased at a dose of 10 g seedling -1 .(Table 4).Giving 10% of LOF decreased pH significantly compared to no LOF when combined with dolomite doses of 7.5 and 10 g seedling -1 .There was a process of acidification of the soil with the addition of LOF to the dolomite-treated soil.The highest pH was achieved at a dose of 7.5% dolomite but without LOF.The application of dolomite and liquid organic fertilizer on acid soil aims to increase soil pH and increase the availability of soil nutrients so that it was optimal for plant growth.The soil used in this study had a low initial pH before planting (4.87).There was an interaction effect between the administration of LOF and dolomite on soil pH (Table 4).The increase in dolomite doses up to 10 g seedling -1 together with the application of 5% LOF concentration can increase growing media linearly from pH 5.14 to 6.53.However, at 0% and 10% LOF concentrations, increasing the dolomite dose did not result in a linear increase in soil pH, so the soil pH decreased again at high dolomite doses (10 g seedling -1 ).LOF treatment up to a concentration of 10% on media without dolomite had no significant effect on soil pH.However, the addition of LOF to the soil that was given dolomite doses above 7.5 g seedling -1 resulted in a lower pH compared to the treatment without LOF at the same dose of dolomite.The opposite result was reported by Rahmayanti et al. [7] that giving LOF can increase soil pH.

The interaction effect of LOF and dolomite on seedling height and stem diameter of LIM 2
Application of LOF concentrations of 5% and 10% could increase the number of pouring leaves aged 7 MAP, even without dolomite treatment (Table 5).Therefore, to support the growth of pouring leaves, a combination of 10% LOF with 2.5 g seedling -1 of dolomite can be recommended because it can save the treatment of dolomite.The increase in pH due to liming using dolomite can have a positive impact on plants.Before being treated with LOF and/or dolomite, the condition of the growing media was generally poor in organic matter, but the exchangeable cation elements (K, Ca, Mg, Na) were categorized as high to very high.In addition, soil also has a very high potential P, but its availability to plants is very low (Table 1).This will increase the pH and supply of Mg in the soil and increase the availability of other macronutrients that are important for plants.The role of lime is to remove acid-forming cations such as H + and Al 3+ through their reaction with OH produced by the reaction of lime with water [8].pH affects the chemical solubility and availability of plant nutrients as well as the decomposition process of organic matter.Element macronutrients such as N, Ca, K, Mg, and S and P are more readily available at pH ranges of 6.5-8.0 [9].Coffee is generally optimal at a pH of 5-6 [8] so the improvement of soil quality as a result of LOF treatment with/or dolomite has an impact on the growth of LIM 2 coffee seedlings.

The interaction effect of LOF and dolomite on leaf, stem, and root dry weight of LIM 2
The seedling height, stem diameter, and leaf and root dry weight of coffee seedlings increased significantly by giving dolomite with the highest yield achieved by dolomite treatment.7.5 g seedling -1 without LOF (Table 5 and 6).
The use of LOF 5% seems to be an alternative to ameliorant besides dolomite because treatment with LOF 5% without dolomite can increase plant growth and does not show a significant difference with treatment using dolomite.The 5% of LOF with or without dolomite resulted in higher LIM 2 coffee seed growth compared to the 10%.The application of 10% of LOF seems too high so it has a negative impact on the growth of LIM 2 coffee seedlings.Previous research reported on the Robusta coffee [10], Arabica coffee [11] [12], tea [13], and ratoon rice plant [14].Yusdian et al. [15] suggested a concentration of 6 ml l -1 to support the growth of Arabica coffee seedlings.In Jabon plants, used a 10 ml LOF dose [16], while the experience Sutari [17] showed that the application of LOF with a dose of NPK in maize yields the same results as the full dose of NPK.In this study, the use of LOFs in addition to saving the need for dolomite in Acidic Inceptisol soils can also help for giving information the need for solid organic matter such as manure which is needed in large enough quantities.LOF is also relatively easy to manufacture and easy to distribute and apply.Li et al. [18] revealed that the addition of organic matter containing comprehensive nutrients and active ingredients, as well as in the form of a liquid fraction can improve the physicochemical properties of the soil.

Conclusion
The highest seedling height, and leaf and root dry weight of LIM 2 coffee seedling was achieved by dolomite treatment of 7.5 g seedling -1 without LOF.The 5% LOF combination also increased all observed growth parameters both without and with the dolomite combination.The use of LOF can be an alternative to the need for dolomite to increase the growth of LIM 2 coffee seedlings.

Table 1 .
Characteristics of the soil used in the study.

Table 2 .
Chemical content and growth-promoting hormones in liquid organic fertilizer (LOF).

Table 3 .
The probability value of Anova result for the soil pH and seedling growth of LIM 2.

Table 4 .
The interaction effect of LOF and dolomite on soil pH.
Notes: The numbers followed by the same letter are not significantly different according to the Tukey test at the 95% confidence level.Lowercase letters indicate the effect toward the column, while the capital letters toward row

Table 5 .
The interaction effect of LOF and dolomite on seedling height and stem diameter of LIM 2.Notes: The numbers followed by the same letter are not significantly different according to the Tukey test at the 95% confidence level.Lowercase letters indicate the effect toward column, while the capital letters toward row

Table 6 .
The interaction effect of LOF and dolomite on leaf, stem and root dry weight of LIM 2.Notes: The numbers followed by the same letter are not significantly different according to the Tukey test at the 95% confidence level.Lowercase letters indicate the effect toward column, while the capital letters toward rows