Application of Compost and Manure in the Biopore Infiltration Hole to Improve Saturated Hydraulic Conductivity (SHC) of Soil in the Coffee Root Zone

Kopi merupakan salah satu sumber devisa utama di Indonesia. Faktor penyebab fluktuasi produksi kopi adalah perubahan iklim, kepadatan tanah yang tinggi, bahan organik yang kurang sehingga menyebabkan akar kopi tidak mampu menyerap air dan unsur hara secara optimal. Pergerakan air tanah diukur dengan konduktivitas hidrolik


Introduction
Coffee is one of the main commodities that support Indonesian economy.The Directorat General of Estate Crops (2020) stated that there were fluctuations in coffee production, especially in 2017-2019 of 717,962 tons, 756,051 tons, and 752,511 tons, respectively.One of reasons for this fluctuation in coffee production is coffee areas which has also fluctuated from 2013-2019.Furthermore, causes of the low coffee production is climate change which is currently happening to cause problems with the water availability to supply the needs of plants in the vegetative and generative growth stages.Efforts to increase coffee production are based on several factors such as fluctuating rainfall, soil fertility, productive land area, water stress, and temperature that can have an impact on coffee productivity (Harahap et al., 2019;Iskandar et al., 2019).One of measurements of the soil water movement in saturated state are also called the soil saturated hydraulic conductivity.The low value of the soil saturated hydraulic conductivity represents an increasingly inhibited soil water movement.This causes plant roots to be unable to absorb nutrients and water optimally to meet their metabolic needs.Soil organic matter affects nutrient availability and soil physical conditions.If the physical condition of soil is good, it will have an impact on nutrient supply and the movement of soil water will also be good (Aranda et al., 2015;Castellini & Ventrella, 2012;Iwasaki et al., 2017).
One of the applications of compost and manure is the biopore infiltration hole (BIH) technology.This is the effective technology in reducing runoff, as well as soil and water conservation (Mulyawati, 2021).This BIH can also be filled with organic wastes, compost or manure which functions to support communities of soil organisms, and in the end, can improve soil quality.Earthworms and soil fauna in these BIH will form burrows or tunnels into surrounding soil which can accelerate movement of soil solution into the soil (Gaiser et al., 2013;Khusna et al., 2020).
Efforts to overcome problems that have been described above are by applying compost and manure in the biopore infiltration hole (BIH).The biopore infiltration hole technology will increase the movement of soil-solution into surrounding soils (Khusna et al., 2020;Watiniasih, 2016).This research focuses on effects of compost and manure application in the BIH on soil saturated hydraulic conductivity and its impact on the coffee yield.

Materials and Methods
The research was conducted at Agro Techno Park Jatikerto, which is located at Dusun Cupak, Jatikerto Village, Kromengan District, Malang Regency.The topography of this area which is about 390 m above sea level.Geographically, Jatikerto Village is located at 7°21'-7°31' south latitude and 110°10'-111°40' east longitude, with average of an annual air temperature of 25 o C-30 o C. The research was carried out from September 2020 to February 2022.Agro Techo Park Jatikerto (ATP Jatikerto) is one of the coffeeproducing locations in the Malang Regency area.The coffee cultivars are Robusta and Excelsa (Liberica) coffee.In the actual conditions in the research area, are dominated by the clayey soils.The soil order found at the research site is Alfisols.This causes the value of soil bulk density are high (Table 1.), and the saturated hydraulic conductivity (SHC) are relatively slow (Table 1.) The field experiment was designed in the Randomized Block Design (RBD) with four treatments and four replications, and tree sample of coffee tree in each treatment plot.The treatments used were P1 as control (without BIH), P2 (BIH only), P3 (BIH+compost), P4 (BIH+goat manure).Each treatment was repeated four times to produce 16 experimental plots.Measurement of SHC (Soil Hydraulics Concuctivity) with the auger hole method were carried out at two depths of each treatment resulting in 32 units of the auger hole.Measurement of soil properties were carried out every two months in tree depth of soil in root zone of coffee tree, namely 0-20 cm, 20-40 cm, and 40-60 cm.
Data obtained were then analyzed using analysis of variance (Ftest) at 5% level and then it is continued with a further analysis using the Least Significant Difference (LSD 5%) test.Correlation analysis was conducted to determine correlation among the soil characteristics.

Soil Characteristics
The characteristics of the soil before application showed that at the study site, the texture of the soil was clay, which resulted in high soil density.This can be seen from the value of the bulk density which ranges from 1.24 g cm -3 to 1.31 g cm -3 with very high criteria.This also affects other parameters (Table 1.) such as the value of the saturated hydraulic conductivity (SHC) from slow to very slow and also low organic matter content.

Results and Discussion
Application of compost and manure in BIH can improve soil quality in terms of soil physics chemistry, and soil biology.This causes an increase in coffee beans yields.

Soil Physical Properties
Making these biopore infiltration holes can provide input for rainwater infiltration into the soil and become groundwater that can be utilized by plants.Therefore, rainwater conservation can be done by making biopore infiltration holes.The use of leaf litter (or compost) as a filler for BIH provides the benefit of reducing the volume of household waste disposal to water disposal sites.Results of variance analysis (Table 2) show that application of compost and manure in BIH suggested significant effects on the soil bulk density.At the observation of 120 DAA, the treatment of BIH+compost (P3) and BIH+manure (P4) had a significant effects on soil bulk density at a depth of 0-20 cm and 20-40 cm.This indicates that a decrease of soil bulk density occurred over a certain period.Observations at 180 DAA and 240 DAA showed that the BIH+compost treatment (P3 and P4) had a significant effect on bulk density at all soil depths compared with control treatment (P1).Results of Cahyono et al. (2017) study suggested that application of compost and manure over a certain time have resulted in decrease of soil bulk density.The value of soil bulk density is strongly influenced by the increase of soil porosity.In this case, compost and manure increases the portion of meso and macro pores due to significantly enhanced soil aggregation and stabilization of the soil aggregates due to activities of various types of soil organisms There are several advantages of using organic fertilizers (materials) compared to inorganic fertilizers.This organic fertilizer (material) not only supplies several plant nutrients but can also improve soil characteristics.The results of the study prove that the application of organic fertilizers can improve soil characteristics, such as available water capacity (Herawati et al., 2021;Li et al., 2021), soil aggregation, and soil structure (Cao et al., 2021;De Notaris et al., 2021;Iwasaki et al., 2017), soil bulk density, permeability & soil hydraulic properties (Li et al., 2021;Valentine et al., 2012), soil penetration resistance; soil chemical properties such as cation exchange capacity, soil buffer capacity, nutrient retention; and soil biological properties such as soil microbial activity and development.
Porosity represents the amount of water that can seep in, but not how fast or how well it absorbs.The results of the analysis of variance showed that the application of composted biopore infiltration holes was proven to increase the percentage of soil porosity (Table 3.).The decrease in the value of bulk density (Table 2.) is in line with the increase in soil porosity.The results showed that the improvement of soil quality in terms of soil physics between parameters was very continuous so that it would affect the chemical characteristics of the soil and crop yields.The best results were found in the BIH+compost treatment of 67.74%, this can happen because, in biopore infiltration holes containing organic matter, soil fauna will work to make small holes from the bottom layer to the soil surface layer.If the application of biopore infiltration holes is carried out on a large scale and permanently, it will be one solution to the problem of land degradation.
The combination of biopore infiltration hole technology with organic fertilizer has been proven to improve soil quality.Khusna et al. (2020) suggested that the use of biopore infiltration holes (BIH) by inserting organic matter into the biopore holes can add nutrients to the soil to increase soil fertility.They have conducted a study to evaluate the use of biopore in increasing soil fertility in Gambiran, Besole Village, Besuki District, Tulungagung Regency.The level of soil fertility was measured by field observations and analysis of soil samples.The results showed that the use of biopore can increase soil fertility in karst area.The saturated hydraulic conductivity of soil represents flow rate of a liquid (soil solution) in soil.In the application of compost and manure in BIH, it is proven to be able to improve value of saturated hydraulic conductivity of soil from very slow to moderate criteria (Table 4.).
Results of variance analysis (Table 4.) showed that application of compost and manure in BIH suggested significant effects on soil characteristics.In the control treatment (P1), the SHC value showed very slow criteria at 60 DAA in all treatments, then SHC increased significantly up to 120 DAA, 180 DAA, and 240 DAA become the moderate criteria.However, treatment of BIH+compost (P3) did not significantly different with the BIH+manure (P4).Activities of soil organisms has an important role in improving soil pores so that it affects SHC value of soil.At 240 DAA observations, SHC value increased at all of soil depths (Table 4.).Application of compost and manure in BIH increased activities of soil organisms and increases availability of nutrients in the soil.This triggers increasing of SHC values of a dense soils in coffee fields.In line with the research of Fitria & Soemarno (2022) explained that application of organic fertilizers tends to reduce soil density and it results in higher value of soil permeability.The magnitude of the soil permeability rate is also influenced by soil aggregates stability and content of soil organic matter.Soil hydraulic conductivity is a function of groundwater pressure, soil moisture content, and soil moisture retention.Soil hydraulic properties are needed to understand water balance, irrigation, and transport processes.Therefore, the saturated hydraulic properties of the soil surface affect precipitation and snowmelt into runoff and groundwater storage.Soil hydraulic conductivity is indispensable for designing water control structures, groundwater storage facilities, and run off forecasting.Siltecho et al. (2015) suggest that adequate water management is necessary to improve the efficiency and sustainability of agricultural systems when water is scarce or water is abundant, especially in relation to land use change.In order to quantify, predict, and ultimately control water and solute transport into the soil (mass flow), it is necessary to determine the hydraulic properties of the soil precisely.Many alternative fields and laboratory techniques are available.Mulyawati (2021) conducted research on the use of biopore infiltration holes (BIH) as a form of flood mitigation by absorbing some rainwater into the ground through the BIH.Based on the soil permeability values measured in the BIH, it can be interpreted that soil texture greatly determines the value of soil permeability.The difference in the value of soil permeability is also influenced by soil structure and soil porosity.

Soil Chemical Properties
The application of biopore infiltration holes in addition to affecting the physical characteristics of the soil also affects the chemical characteristics of the soil.The results of the analysis of variance showed that biopore infiltration holes were able to improve soil quality in terms of chemistry.The results of the analysis of the various effects of BIH treatment on soil pH showed a significant effect (Table 5).It can be seen that the BIH+manure treatment showed the highest soil pH results.Manure is the result of composting from the rest of animal manure, in this case, goat manure.Microorganism activity in goat manure is considered higher than in compost produced from organic waste.This is because the organic matter contained in the biopore infiltration hole affects the presence of H+ ions in the soil.As the amount of exchangeable H+ increases, the concentration of basic nutrients (cations) usually decreases as uptake by plants increases.The desired range of soil pH for optimal plant growth varies among plant species.While some plants grow best in a soil pH range of 6.0-7.0;others grow well in slightly acidic soil conditions.Soils become acidic when basic elements such as calcium, magnesium, sodium, and potassium held by soil colloids are replaced by hydrogen ions.Soils formed under conditions of high annual rainfall are more acidic than soils formed under drier climatic conditions.Intensive farming in the long term with nitrogen fertilizers can also result in soil acidification.
The results of the analysis of variance showed that the application of biopore compost affected the cation exchange capacity (Table 6.).The value of CEC is influenced by the organic matter content of the soil and the percentage of clay.The cation exchange capacity represents the number of cations that the soil can absorb and exchange (Solly et al., 2020).The results showed that the addition of organic matter was able to increase the value of soil cation exchange capacity, but with increasing depth the value of CEC decreased (Table 9.).This is because the percentage of organic matter will decrease with increasing soil depth.As a result, high oxygen concentrations in biopore can affect the microbial activity and nutrient uptake by roots which are limited by oxygen deficiency in dense soil layers.In line with the research results of (Prameswari et al., 2015) that the results of the analysis of the soil bases content showed that the exchange Ca content in the soil was very low (< 2 mg/100 g), the Ca exchange content tended to increase after one year of treatment.The CEC value of the soil at the skid trail location was lower than that in the natural forest (11.06 meq/100 g), and the CEC of the soil in the BIH treatment (19.87 meq/100 g) was higher than that of the soil in the natural forest.
Research by Domingues et al. (2020) mentions that the addition of organic matter will increase the load negative so that it will increase cation exchange capacity.Cation exchange capacity demonstrates the soil's ability to hold cations and process decomposition of organic matter is the source of negative ground charge.Clay content has the same effect.The finer the soil fraction, the more surface area particles, so it has a higher CEC.In addition, (Fitria & Soemarno, 2022) also discuss the results of their research that an increase in soil pH has the potential to increase the CEC value of the soil, this result will affect the availability of nutrients in the soil.
Root growth in natural biopore is then related to the mobilization and nutrient cycle by rhizosphere microorganisms.On the other hand, earthworms transport organic matter from the soil surface into the biopore and coat the burrow walls with their mucus substance, and show high microbial activity (Uksa et al., 2015).As a result of these two processes, natural biopore have the potential to present a nutrient source zone, due to enhanced nutrient biological cycles and due to increased nutrient availability to plants.The ability of BIH to accelerate the decomposition process of organic matter has something to do with the ability of BIH to improve air and water systems which are very much needed by decomposer bodies to remodel organic matter in BIH.This is due to the ability of BIH to maintain aeration in the infiltration hole so that the soil fauna gets sufficient oxygen to carry out the decomposition process of organic matter.
The BIH structure with its biopore holes becomes a pathway for the movement of water (soil solution) and air into the surrounding soil so that there is sufficient organic matter, water, oxygen, and nutrients suitable for the development of plant roots and soil organisms.Remarks: Numbers in the same column followed by the same letter is not significantly different at LSD 5%.DAA: Days After Application); BIH: Biopore Infiltration Hole.

Coffee Productions
The results of the analysis of coffee yields variance (Table 8.) showed that the biopore compost treatment had a significant effect on the control treatment (P1).It is proven that the best coffee production is seen in the biopore+manure treatment (P4), which is 3,29 t ha -1 .This is in line with the results of the analysis of variance on the physical and biological characteristics of the soil, where the BIH+goat manure treatment was able to improve the optimal soil quality.Treatment P3 (BIH+compost) with P4 (BIH+goat manure) showed insignificant results, this was because both the application of organic matter in the form of compost and manure was able to improve soil quality, although the increase was different.Optimal water and nutrient requirements are very important for coffee plant production so the application of biopore compost technology, is proven to be able to significantly increase coffee production.
Biopores can facilitate nutrient uptake from the subsoil by increasing the density of root lengths in most soils or absorption of nutrients from the pore walls.Crop production must be based on living soils © 2024, Program Studi Ilmu Lingkungan Sekolah Pascasarjana UNDIP and ecological processes.In addition, the high biopore density can facilitate the absorption of water and nutrients, especially in drought conditions, thereby contributing to increased stability of the cropping system, the overall goal of organic coffee plantation management.It is evident from the data analysis of variance (Table 8.) that the BIH application can optimize coffee production.The beneficial effects of biopore have been widely studied, on the one hand, they provide a preferential pathway for root growth, especially in dense subsoils, because the presence of natural biopore can reduce soil penetration resistance and improve soil aeration (Gaiser et al., 2013;Valentine et al., 2012).Simple indicators of crop and cultivation performance across a wide range of soil types and management are needed to design and test sustainable planting practices.

Relationship between Parameters
The results of the correlation test at the end of the observation (240 DAA) were still parameters at a depth of 0-20 cm, 20-40 cm, and 40-60 cm (Table 9.).BIH application shows an effect in improving soil quality both in terms of soil physics and soil chemistry.At the top layer depth (0-20 cm), the saturated hydraulic conductivity showed a significant positive correlation with soil organic matter (r=0.102** ).The SHC value also showed a significant correlation with porosity, pH, and CEC in the soil (r=0.917** ; r=0.837 ** ; and r=0.887 ** ) and SHC shows a negative correlation with the value of BD (r=-0.832** ), which means that the higher the density of the soil, the slower the SHC (Table 9.).Saturated hydraulic conductivity is one indicator to determine the movement of water in the soil.So that if the SHC value is higher, then the movement of water in the soil will also be faster.One of the factors that affect the value of the saturated hydraulic conductivity of the soil is the presence of soil organic matter.This is related to the activity of microorganisms so that the application of biopore infiltration holes can increase soil porosity.
The saturated hydraulic conductivity of the soil showed a significant positive correlation with soil porosity, soil pH, and SOC at 20-40 cm (r=0.932** ; r=0.855 ** ; r=0.928 ** ) (Table 9.).It can be concluded that the increase in soil organic matter will affect the quality of the soil.Rong et al. (2016) also explained that the addition of organic fertilizers such as compost had a positive effect on C-Organic soil due to the release of organic carbon in the soil.In addition to chemical properties, the application of composting also affects the physical properties of the soil.Giving compost affects the porosity of the soil.This happens because, in compost, there is a decomposition process by microorganisms which ultimately has an impact on increasing the stability of soil aggregates.
In the lower layer (40-60 cm), there is a correlation between treatment parameters (Table 9.).Saturated hydraulic conductivity showed a significant positive correlation with soil organic matter (r=0.747** ).The SHC value also showed a significant correlation to soil porosity and pH (r= 0.873 ** ; r=0.716 ** ).Saturated hydraulic conductivity is one indicator to determine the movement of water in the soil.
So that if the SHC value is higher, then the movement of water in the soil will also be faster.One of the factors that affect the value of the saturated hydraulic conductivity of the soil is the content of soil organic matter.
Results of regression and correlation analysis showed that organic matter was able to improve the physical and chemical properties of the soil (Figure 1).Application of compost and manure can affect soil physical characteristics, soil chemistry, soil biology, improve nutrient availability in the root zone of plants, and plant growth (Getahun et al., 2022).The high content of soil organic matter is able to hold the available nutrients and available soil moisture.There are several advantages to using organic fertilizers (organic matter) compared to inorganic fertilizers.This organic fertilizer not only supplies a number of plant nutrients but can also improve soil physical characteristics (Fukumasu et al., 2022;Thai et al., 2022).Application of BIH technology is also promote application of organic wastes which is then used as organic fertilizer.The purpose of the addition of organic matter is to improve effectiveness of biopore that has been embedded in the soil (Lynch et al., 2022;Uksa et al., 2015;Wendel et al., 2022).
The difference in the results of the increase at a depth of 0-20 cm, 20-40 cm, and 40-60 cm was due to variations in the characteristics of the different soils.The application of biopore infiltration holes tends to be able to improve soil quality in the upper layer more optimally than in the lower layer (20-40 cm; 40-60 cm) so that in the upper layer, the soil density will decrease more optimally compared to the lower layer.This causes the impact of the application of biopore to decrease as the soil depth increases.Another factor that causes it is possible because, in the upper layer, the soil will get more organic matter intake from the fallen coffee leaves coupled with soil fauna activity which is dominated in the top layer of soil.The results of Priori et al. (2021) explained that the root system of plants will affect soil characteristics and fauna activity in the soil.Varied soil characteristics coupled with external factors such as rainfall, the input of organic matter, and temperature will affect the availability of water in the soil and crop production.Soil fertility indicators are used to determine the response to land management and cropping patterns.The results of the study explained that the density of soil on the cultivated land and root penetration was considered high.This represents the inhibition of water movement and faunal activity in the soil (Boizard et al., 2017;De Notaris et al., 2021;Priori et al., 2021;Yang et al., 2021).SHC values at depths of 0-20 cm, 20-40 cm, and 40-60 cm (Figure 2.) indicate that SHC has a close relationship with the total chlorophyll of coffee plants.This means that the increase in SHC value is in line with the increase in total chlorophyll in coffee © 2024, Program Studi Ilmu Lingkungan Sekolah Pascasarjana UNDIP plants.This results in the process of photosynthesis in coffee plants.Yang et al. (2021) explained that Chlorophyll has a direct effect on the process of photosynthesis, namely producing organic compounds as assimilates derived from inorganic compounds with the help of sunlight.These organic compounds are needed by a plant in its metabolic process (plant height, number of leaves, leaf area, and yield) (Adugna Debela Bote & Jan, 2016;Chalchissa et al., 2022;Damatta et al., 2008;Praxedes et al., 2006).This argument is proven in the research results, that the increasing value of SHC is in line with the increase in the production of coffee plants.
The results of the analysis show that the value of SHC has an effect on the production of coffee plants (Figure 3.).The increase in SHC value is in line with the increase in coffee beans yield.This means that the application of BIH with the addition of compost or goat manure was able to increase the yield of coffee beans compared to the BIH treatment (control).SHC is characterized by increased soil porosity, so plant roots are more optimal in absorbing soil moisture and available nutrients in the soil (Marín-Castro et al., 2017;Silva et al., 2021).This affects the metabolic process of the coffee plant as evidenced by the increase in leaf chlorophyll content (Figure 2.) so that the photosynthesis process will run optimally and coffee beans yield will increase (Adugna D Bote & Struik, 2011;Chemura et al., 2017;Mayoli & Gitau, 2012;Netto et al., 2005;Reis et al., 2009;Sudirman & Hartono, 2020).
This research certainly has limitations.The main limitations of these results study will be valuable on the interaction in the use of composted biopore technology on soil saturated hydraulic conductivity values.This research only considers a number of supporting soil data and not too many soil samples are taken they adjust to the conditions of the available coffee grounds.In addition, the auger hole research method that used in this study is based on soil and vegetation conditions which are quite different from studies with similar topics and the limited number of recent sources that apply the same method so that the resulting data becomes variative.

Conclusion
Compost and manure application in the biopore infiltration holes (BIH) can improve value of the saturated hydraulic conductivity of soil.The best results are seen in the treatment of BIH+goat manure.Results showed that application of BIH+manure improved soil characteristics such as soil porosity, soil organic carbon, soil pH, and soil CEC.Coffee beans yield after application of treatment also showed very significant increase.The highest coffee beans yield was 3,29 t ha -1 in the BIH+goat manure treatment.

Figure 3 .
Figure 3. Relationship between Coffee beans Yields and SHC (Saturated Hydraulics Conductivity of soil)

Table 1 .
Characteristics of Soil Sample Before BIH Applications

Table 2 .
Effect of Treatment on Soil Bulk Density

Table 4 .
Effect of Treatment on Soil Hidraulics Conductivity Numbers in the same column followed by the same letter is not significantly different at LSD 5%.DAA: Days After Application; BIH: Biopore Infiltration Hole

Table 5 .
Effect of Treatment on Soil pH Numbers in the same column followed by the same letter is not significantly different at LSD 5%.DAA: Days After Application; BIH: Biopore Infiltration Hole.

Table 6 .
Effect of Treatment on CEC Numbers in the same column followed by the same letter is not significantly different at LSD 5%.DAA: Days After Application); BIH: Biopore Infiltration Hole.

Table 7 .
Effect of Treatment on Content of Soil Organic Carbon (SOC)

Table 8 .
Effect of Treatment on the Coffee Yields Numbers in the same column followed by the same letter is not significantly different at LSD 5%.BIH: Biopore Infiltration Hole.