Relationship Pattern of Nutrient Content in Leaves, Rachis, Stalk, Spikelet, and Mesocarp to Oil Content of Fresh Fruit Bunches of 3 Varieties (Socfindo, Topaz, Damimas) of Oil Palm Plants in Mineral Soils of Central Kalimantan

The potential oil content in oil palm plants is influenced by genetic and environmental factors. Several factors affect the quality of palm oil, including variety and nutrition, such as macro nutrients, especially N, P, K, and Mg. These nutrients play a role in fruit formation, increase in average weight bunches (BJR), plant health and play a role in increasing oil content. This study aims to the relationship of leaf, stalk, spikelet, and mesocarp nutrients to oil content. This exploratory study uses a quantitative descriptive method on 3 varieties of DxP Oil Palm: Socfindo, Topaz and Damimas: with year of planting 2014, each covering an area of ± 10 Ha and the observation period 2018-2019. The results showed that there was a relationship between leaf K nutrient on the Damimas variety, leaf Ca nutrient on the Socfindo variety and leaf B, leaf Zn, K rachis and Mg rachis nutrient on the Topaz variety to the O/B value. The regression model for this relationship sequentially is Y = 13.68 + 10.97 K_ leaf (R2 = 0.336); Y = 14,917 + 13,915 Ca_leaf (R2 = 0.314); and Y = 39.645 - 0.519 B_ leaf + 0.728 Zn_ leaf - 9.519 K_rachis - 41.434 Mg_rachis (R2 =0.595). In addition, only the Socfindo variety found an effect of stalk and spikelet nutrient content on the O/B value. These nutrients are K stalk nutrients with the regression model Y = 0.42 + 6.29 K_stalk (R2 = 0.372), and P, K, Mg and Ca spikelet nutrients with the regression model Y = 6.851 - 233.372 P_Spikelet + 14.585 K_Spikelet + 141.326 Mg_Spikelet - 66.348 Ca_Spikelet (R2 = 0.635).


Introduction
Central Kalimantan Province has an area of oil palm plantations in 2020 covering 1,880,820 ha with a production of 8,072,879 tons and a productivity of 4,862 kg/ha.In 2022 it is estimated that the area of oil palm plantations will increase by 1.32% with an increase in production of 10.64% and an increase in productivity of 12.98% [1].Factors that affect the productivity of oil palm plants include plant variety, plant age, soil type, fertilization, climate, and one of them is also influenced by nutrient content.Plant nutrients are very influential on the development of tissues to plant organs, namely the vegetative and generative components so that they affect production [2].Deficiency of one of the nutrients can cause inhibition of vegetative growth and can also reduce the production of oil palm [3].Oil palm require more macro nutrients than micro nutrients.Nutrients N, P, K, and Mg are the main nutrients needed in large quantities.These elements are needed for the formation of fruit, increase the average length (BJR), maintain plant health and are expected to also play a role in increasing oil content [4].Apart from plant nutrients, other factors such as mesocarp weight are also thought to have an effect on the increase in oil content [5].Other fresh fruit bunches (FFB) components such as stalk and spikelet have not been studied much related to the relationship between these components and oil content.The FFB stalk is the stalk of the oil palm fruit bunch, while the FFB spikelet is the place where the loose fruit of the oil palm attaches.Large FFBs usually have large stalks and a large number of spikelets.It is necessary to examine the nutrient content of stalk and spikelet for its effect on the formation of oil content.In addition, the quality of the oil produced in oil palm plants varies depending on the variety.This study aims to study the relationship of leaf, stalk, spikelet, and mesocarp nutrients to oil content.

Experimental Sites
This study was conducted at PT Sawit Sumbermas Sarana Tbk, Estate Batu Kotam (BKE), Afdeling Alfa, Block F06, Kotawaringin Barat Regency, Pangkalan Bun, Central Kalimantan Province with coordinates 2º20'29.91"S,111º30'8.61"E.The experimental location is included in the category of mineral soil types (Typic Hapludults) with a tropical climate type, the peak of the rainy season occurs in April at 329 mm/month and the dry season occurs in June-July at 116 mm/month (2014 -2018).The average rainfall in BKE is 231 mm, the average monthly rainy day is 12 days/month, while the average dry spell is 9 days/month.During this period there was a water deficit in 2015 for 4 months from July to October of 367 mm.

Experimental Design
This exploratory study uses a quantitative descriptive method in the Best Management Practice (BMP) block on 3 varieties of DxP Oil Palm (Socfindo, Topaz and Damimas) with TT 2014 each covering an area of ± 10 ha.The observation period was carried out from 2018 -2019 with the main points of observation being randomly selected for each variety and a total sample of 198 FFB.Parameters observed include: 2.2.1.Nutrient content of leaves and rachis Sampling of leaves and rachis aims to identify nutrient needs in oil palm plants, because the nutrient status of plant tissue is an illustration of the nutrient status in the soil.Sampling of leaves and rachis (LSU) was carried out at 07.00 -12.00 WIB.Sampling is not carried out when it rains and is at least 1 month after the fertilization application.This is done so that the results of the leaf analysis are not biased due to contamination of rainwater and due to fertilization.Leaf and rachis samples were taken from the 17th midrib.The leaf and rachis samples were put into labeled plastic and sent to the Sulung Research Station Analytical Laboratory, PT Citra Borneo Indah for analysis.

Analysis of bunches and stalk, spikelet, and mesocarp nutrient content
Observations were made simultaneously with production observations.The selection of FFB samples was based on the fruit set class (class A (>75%), B (50 -75%), and C (<50%)), so that in each variety there were 3 representatives of the FFB class.Fruit set describes the ratio of finished fruit to all fruit in one bunch, where a good fruit set standard is above 75% (Wiranda et al, 2022).The FFB, spikelet, and stalk samples were taken into 3 parts, namely the top, middle, and bottom, so that in one FFB there are 3 representative samples.Each FFB sample to be sent to the laboratory includes: 30 loose leaf samples per part of the sample (top, middle and bottom), 10 spikelet samples and one stalk sample.The variables observed were fruit set and oil potential, as well as nutrient content of FFB stalk and FFB spikelets

Relationship of leaf, rachis, and mesocarp nutrients to oil content
Based on the results of laboratory analysis of leaf and rachis nutrient content in the Damimas, Socfindo and Topaz varieties aged 4-5 years there was generally no difference (Table 1).The K leaf and rachis nutrient content in these 3 varieties were both still in deficiency status (<0.90%), however, the rachis nutrient was still above the standard of 1.01% [6].Nutrient K is needed by oil palm in large quantities compared to other nutrients [7].In general, absorption of K by oil palm plants will be accumulated first in the rachis component and then translocated to the leaves.The Socfindo variety has a higher K rachis nutrient content compared to other varieties.K rachis nutrient content is more sensitive to fertilizer application compared to leaf K nutrient and has a strong correlation with production where production will begin to decrease if the content is below 1.0% and will remain stable with values of 1.3% and 1.6% [8 ].In the Socfindo variety, the increase in O/B had a positive correlation with the nutrient content of leaf P, leaf Ca and rachis.The application of P, K, and Mg can increase the nutrient content of bunches [9].Oil palm has thick flesh or mesocarp and contains lots of oil [10].The thickness of the mesocarp affects the oil content [11].The thickness of the mesocarp varies depending on the variety of oil palm.Mesocarp weight (WM/F) has a positive correlation with the value of oil to bunch (O/B), the higher the WM/F value, the higher the O/B potential value (Table 2).This is because the O/WM value has a positive correlation with the O/B value.The oil content in the mesocarp (O/WM) for ripe fruit ranges from less than 40% to more than 60% [12].In this study, the average O/WM score was 52.20%.The results of the statistical analysis showed that the leaf K content was significantly correlated with the increase in the oil to bunch (O/B) value of the Damimas and Topaz varieties.The application of K fertilizer can increase the O/B value [13], the application of P fertilizer can also increase the WM/F value [11].The results of the analysis of the nutrient content of FFB showed that the Damimas variety required more P, K, Mg, and Ca nutrients than the other varieties, while the Topaz variety required higher N and B nutrients than Damimas and Socfindo.This shows that the need for nutrients in each variety is different (Table 2).The results of statistical analysis of FFB nutrients showed that N and K FFB had a significant effect on O/B in the Socfindo variety, while the other varieties showed no effect.This shows that the Socfindo variety requires greater N and K nutrients than the other varieties.Based on the regression model above, it shows that in the Damimas variety the K value of the leaves has an effect on increasing the O/B value with an effect of 33.6%.This is in line with research conducted by [12] that K element with oil palm productivity has a very strong and positive relationship.The higher the K nutrient content in plants, the plant productivity will also increase.Whereas in the Socfindo variety, leaf Ca content has a positive relationship to O/B, the higher the leaf Ca value, the O/B value will also increase with an effect of 31.4%.A different matter was found in the Topaz variety, where the leaf B, K rachis, and Mg rachis values had an effect on decreasing the O/B value, while the leaf Zn value had an effect on increasing the O/B value with an effect of 59.5%.

Relationship of stalk and spikelet nutrients to oil content
The Damimas variety had a stalk dry weight higher than the other varieties, but the spikelet dry weight was lower than the other varieties.The Topaz variety has an average number of spikelets more than the Damimas and Socfindo varieties.In general, for all varieties, the nutrient content of the stalk and spikelet was dominated by K and B and was higher than the other parameters.The results of the stalk nutrient analysis for the Damimas variety had higher P and K nutrient values, whereas the Topaz variety contained Mg and B nutrients higher than the other varieties (Table 5).The results of nutrient analysis on the spikelets showed that there were differences between the 3 varieties.The Damimas variety had higher N, P, K, Mg, Ca, and B spikelet values than the other varieties.The number of spikelets also tended to be positively correlated with the N and B spikelet content in all varieties, while the number of spikelets in the Damimas variety tended to be negatively correlated with the P and Mg spikelet content.Based on the results of statistical analysis, it was shown that for the Damimas and Topaz varieties, the nutrient content of stalk and spikelet had no correlation with O/B.Meanwhile, the K stalk and spikelet nutrient Socfindo varieties significantly had a positive correlation with the O/B value.Nutrient K plays an important role in increasing the oil content, where FFB with high O/B values also has high K values for leaves, stalks and spikelets.Nutrient K is required in large quantities by oil palm plants both in the leaves and in the FFB components.Based on the regression model above, for the Socfindo variety, the K stalk value has an effect on increasing the O/B value with an effect of 37.2%.In addition, the P spikelet and Ca spikelet values had an effect on decreasing the O/B value, while the K spikelet and Mg spikelet values had an effect on increasing the O/B value with an effect of 63.5%.This shows that in the Socfindo variety, the higher the K stalk, K and Mg spikelet content, the O/B value also increases, while the spikelet P and Ca nutrients are not needed in large quantities to increase O/B.The nutrient content of stalk and other spikelets has no effect on the O/B value even if the nutrient content has a high or low value.

Concluding
In the damimas variety, the K leaf value has an effect on increasing the O/B value with an effect of 33.6%, the regression model is Y = 13.68 + 10.97(K).In the Socfindo variety the Ca leaf content has a positive relationship to O/B with an effect of 31.4%, the regression model is Y = 14.917 + 13.915(Ca).
In addition to these varieties, the K stalk and spikelet nutrients significantly had a positive correlation with the O/B value.The K stalk value has an effect on increasing the O/B value with an effect of 37.2%, the regression model is Y = 0.42 + 6.29(K).The P spikelet and Ca spikelet values had an effect on decreasing the O/B value, while the spikelet K and Mg spikelet values had an effect on increasing the O/B value with an effect of 63.5%.The regression model for these varieties is Y = 6.851 -233.372(P)+ 14.585(K) + 141.326(Mg) -66.348(Ca).In the Topaz variety, the B leaf, K rachis, and Mg rachis values had an effect on decreasing the O/B value, while the Zn leaf value had an effect on increasing the O/B value with an effect of 59.5%, the regression model was Y = 39.645-0.519( B) + 0.728(Zn) -9.519 (K_rachis) -41.434 (Mg_rachis).

Table 1 .
Results of analysis of nutrient content of leaves and rachis

Table 2 .
Fruit set results and analysis of mesocarp nutrient content

Table 3 .
Statistical results of the correlation of leaf and rachis nutrients to O/B

Table 4 .
Regression model of leaf and rachis nutrients on O/B

Table 5 .
Results of stalk and spikelet nutrient analysis of FFB

Table 6 .
Statistical results of the correlation of stalk nutrients to O/B

Table 7 .
Statistical results of spikelet nutrient correlation to O/B

Table 8 .
Regression model of stalk and spikelet nutrients to O/B on the socfindo variety