Promoting smart agroforestry of sengon-based arrowroot and cardamom to support food security

The forest land has great potential to provide food and also contributes to achieving Indonesia’s forest and other land uses (FOLU) Net Sink 2030, as a concrete contribution of the forestry sector to addressing national and global needs, which can be done by promoting smart agroforestry. This research aims to provide smart agroforestry model of sengon (Falcataria moluccana) with arrowroot and cardamom, to analyze the sengon growth, the arrowroot and cardamom biomass productivities under the agroforestry models. The split-plot design was employed with six cropping pattern as the main plot, in three agroforestry models (sengon-arrowroot; sengon-cardamom; sengon-arrowroot-cardamom) and three monoculture plots, and three levels of the dosage of manure as subplots (0; 250; 500 g). The results showed that higher growth of sengon was found in the three agroforestry models (3.0-3.5 m3.ha−1) compared to monoculture (2.1 m3.ha−1). The highest dry weight of leaf, stem, root, tuber, fruit bunch and total biomass of arrowroot and cardamom was produced in the monoculture. These agroforestry models have the potential to support food security and Indonesia’s FOLU Net Sink 2030, which will be prospective mainstreaming in implementing Social Forestry programs.


Introduction
The ever-growing population demands increased amounts of food supply and good nutrition quality.The value of the national prevalence of undernourishment in 2021 was 8.49%, causing an increase of 0.15% compared to the previous year.The increase in food shortages in 2021 is also in line with the increase in the poverty rate which reaches 9.71% in 2021 [1].This is further exacerbated by the impact of climate change.The number of people experiencing poverty in Indonesia has shown an increasing trend since the pandemic, and more than half of 15.51 million are rural poor living in and around forests [2,3].Forest destruction and land degradation will have a direct impact on the people who live in these villages.Moreover, the area of paddy fields and agricultural land tends to decrease.The paddy harvested area in 2021 decreased by 245.5 thousand hectares (2.3%) compared to the previous year, which resulted in the decrease in rice production by 140.7 thousand tons (0.45%) to around 31.4 million tons compared to the year 2020 [4].This condition can trigger the conversion of forest land into primarily plantation and agricultural land which can lead to deforestation and land degradation.
Addressing these national food problems, and in accordance with Government Regulation (PP) Number 17 of 2015 concerning Food Security and Nutrition, the forestry sector plays a role in sustaining food security through the utilization of potential forest resources.This included utilization of less productive forest lands, which can be done by developing food crops-based agroforestry.The multi 1315 (2024) 012013 IOP Publishing doi:10.1088/1755-1315/1315/1/012013 2 benefit of agroforestry including overcoming land and forest degradation by optimizing land cover, increasing people's welfare through diversification of productive plant species, supporting Social Forestry programs and Forestry Multi-Businesses as well as achieving Indonesia's Forestry and Other Land Use (FOLU) net sinks.Furthermore, the implementation of agroforestry is expected to be an effort to mitigate and adapt to climate change through a planting woody plants program to rehabilitate critical lands with plants that have the potential to be carbon sinks and have high economic value.
Smart agroforestry is a knowledge and practices of agriculture and silviculture that is addressed at not only enhancing profits for farmers and their resilience but also improving environmental conditions, including biodiversity enhancement, soil and water conservation, climate change mitigation and adaptation, while assuring sustainable landscape management.It can be a solution for land management systems to minimize the rate of deforestation, and a smart effort to overcome the food crisis, which is prospectively applied primarily in the social forestry area [5].
In agrisilviculture 'one of agroforestry models', it is necessary to know the biomass production and plant productivity on the land that receives tree litter and organic fertilizer input.The availability of soil nutrients will be affected by the litterfall from the shade trees and the application of organic fertilizers.Currently, organic farming has an important role in relation to environmental and food safety issues.One type of nutrient-rich organic fertilizer is Bokashi manure.Bokashi is "fermented organic matter", and also stands for Organic Material Rich Biological Sources, which can be produced independently by the community by utilizing the surrounding forest resources.Bokashi contains the microbial group having the ability to perform a variety of useful functions including the breakdown of hazardous chemicals and wastes as well as the ability to create beneficial bioactive substances and enzymes [6].
Sengon (Falcataria moluccana) is one of fast-growing legume tree species which has multipurpose potential, while the potential food and medicinal plants to be developed include arrowroot (Maranta arundinacea) and cardamom (Amomum cardamomum).These species have a high level of community adoptability, economic value and good prospects for the future, as well as adaptable and able to grow in various soil conditions.Sengon is a shade tree that is mostly demanded by farmers because of its fastgrowing, is able to provide nitrogen (N) which helps maintain soil fertility, is able to grow on marginal land, and is easy to cultivate and market [7].
Arrowroot is a potential functional food crop with a low glycemic index and a gluten-free, alternative carbohydrate source that has great potential to support food security programs [8].Arrowroot rhizome is rich of phosphorus, potassium, sodium, calcium, zinc, iron, and magnesium as well as phenylalanine in medium content and low amounts of oligosaccharides [9].It has various health benefits, including as an immunostimulant and prebiotic food , nourishes the digestive tract, be able to inhibit degenerative diseases and prevent stunting in children [10].Cardamom is a potential biopharmaceutical species that is a native Indonesian spice which is currently prospective, because its selling value is quite high.Several studies have found that the 1,8-cineol content in cardamom has antiviral, anti-inflammatory, antioxidant and antimicrobial activities [11,12].Cardamom is also an increasingly popular component of agroforestry practice in Indonesia, as it offers multiple benefits to both of the environment and farmers' income.Cardamon could contribute to some efforts to address at least two of the main challenges of our era, including rural poverty and climate change.Its combination with other component of agriculture and forestry practices, enable the farmers to preserve the ecological environment which helps protects soils from erosion, preserve biodiversity, and sequesters carbon while producing cardamom under a shade trees' canopy [13].
Another study stated that 86% of the agroforestry components were found to be food sources, in the form of fruits, vegetables, grains, tubers, spices and livestock.This fact shows that combining different components as a food source in agroforestry has the potential to support food security while maintaining biodiversity [14].This research aims to provide smart agroforestry model of sengon with arrowroot and cardamom, to analyze the sengon growth, the arrowroot and cardamom biomass productivities under the agroforestry models.It is needed to investigate these two annual plant species' growths under sengon stands in agroforestry system, to address the above problems and challenges in order to support food security and spice production in promoting the development of smart agroforestry.

Study site
The research was conducted in October 2021 -September 2022 at the Cikabayan forest, Dramaga sub district, Bogor Agricultural University (IPB), West Java, Indonesia.The research located at coordinates of latitude -6 o 32'48"S and longitude 106 o 42'58"E with an altitude of 155-190 meters above sea level.

Tools and materials
The materials used were 3-year-old sengon stands, arrowroot tubers, cardamom seedlings, bokashi fertilizer and cow manure.The planting space of sengon was of 1.5 m × 1.5 m, and for arrowroot and cardamom were done in a demonstration plot of 9 m 2 at the planting space 1 m × 1 m, under the sengon stands (in the agroforestry system) and monoculture, amounted to 16 arrowroot tubers or cardamom seedlings (or in combination) for each plot.The cardamom seedlings used local red cardamom cultivars from Pamijahan sub district, while the arrowroot tubers used West Java accessions selected (genotype and phenotype) from the germplasm collection in the experimental garden at Subang, National Research and Development Agency (BRIN).The used tools are GPS, lux meter, thermohygrometer, oven, digital scale, phi-band and stationery.

Procedure of research
The tillage/soil loosening is carried out two weeks before planting.Then, the planting hole was prepared and manure was applied as basic fertilizer, amounted 4 kg per planting bed for arrowroot (5 m × 1 m bed with a height of 15-20 cm) and 4 kg for cardamom planting hole (width of 30 cm × 30 × 30 cm).Provision of bokashi fertilizer as a treatment of 0 g (control treatment), 250 g and 500 g were given at 3 months after planting (MAP) and 6 MAP.Weeding, loosening the soil, as well as controlling pests and diseases were applied as silvicultural activities in agroforestry practices, so that yield productivity is optimally achieved.Temperature and humidity measurements were carried out periodically every week, and rainfall data was obtained from the Meteorology, Climatology and Geophysics Agency (BMKG) database center on the website https://dataonline.bmkg.go.id.

Measurement of canopy shade intensity.
The measurement of light intensity to determine the percentage level of canopy shade of sengon was carried out when the intensity of sunlight was already reaching the peak at 11.00-12.00.Measurement using 2 units of lux meter were read simultaneously under the sengon tree canopy and in an open area at several repeat points in the experimental plot.

Measurement of height and diameter of sengon.
The measurements of height and diameter were employed for sengon trees.The height (H) of the tree from the base of the trunk to the highest peak was measured using a haga hypsometer.Diameter at breast height (D) was obtained using phi-band.These parameters were used to estimate the sengon volume (V) by using the formula V = 0.4911D 2 H [15].

Measurement of the dry weight.
It was employed for the arrowroot and cardamom.Biomass refers to the mass of plant life organs.Plant biomass was measured by weighing the dried plant material.The drying process aims to remove all the water from the material [16].The fresh material was divided according to the type of plant organ: leaves, stems, roots, tuber and fruit bunch.The sub-samples applied if there were too many sample quantities.Previously, all fresh materials were weighed.Then, they are dried at 65-85 o C for 48 hours until the weight remains constant [17].Then, it is weighed with a digital scale (accuracy of 2 decimal places in grams).
Observations for the yield component were carried out on the dry weight of arrowroot tuber and cardamom fruit bunch per clump after harvesting.Arrowroot tuber production was measured at 9 months of harvest, and cardamom fruit bunch production at 10 months of harvest by weighing the dry weight of tubers and fruit bunch per plot in each treatment.Rainfall Intensity monoculture.The dose of bokashi fertilizer is a subplot, consisting of 3 levels (B1 = 0 g, B2 = 250 g, and B3 = 500 g), in 3 blocks/replications.The environmental design used randomized groups with direct planting under sengon stands.Each observation unit was consisting of 16 arrowroot and/or cardamom seedlings, combined with 4 sengon trees in an agroforestry plot.Data analysis used General Linear Model (GLM) with Statistical Analysis System (SAS) version 9.4 software for analysis of variance (ANOVA) in the SAS procedure.Further analysis was carried out using Duncan's Multiple Range Test (DMRT) if the treatment had a significant effect/difference (P < 0.05) on the observed variables [18] to analyze whether there are differences in the growth and biomass caused by variations in planting patterns and doses of biofertilizer.

Environmental condition and research site characteristics.
The shading intensity of 4-year-olds F. moluccana in average is 66%.The Clay texture of soil, average pH of 5.9 (slightly acidic) with a high C-organic content of 3.29% equavalent to soil organic matter of 5.5%.Available phosphorus (P) is 13.95 mg.kg -1 , and available potassium (K) is 141.7 mg.kg -1 .The value of cation exchange capacity (CEC) was 16.1-18.4cmol(+)/kg (categorized as medium), total nitrogen (N) was 0.27% (categorized as medium) and soil porosity amounted to 56.7%.In this study, sengon, arrowroot and cardamom grew well at an altitude of 155-190 meters above sea level, a range of temperature 26.9℃ -32.1℃ (at average 28.8℃) and humidity of 74.5% -89.5%.The average monthly rainfall is high category of 306 mm, with the highest monthly rainfall in October 2021 of 566 mm and the annual rainfall is 3481 mm (Figure 1).

Source: [19]
Figure 1.Monthly rainfall during plant growth The mean value in bold is the highest value among treatments.
Table 1 showed that the intercropping of sengon-arrowroot-cardamom provided the best growth of sengon from the four models tested.

The biomass of arrowroot and cardamom.
The dry weight of leaf, stem, root, tuber and total biomass of nine months-old arrowroot were shown at Table 2 The dry weight of leaf, stem, root, fruit bunch and total biomass of ten months old cardamom were shown at Table 3.The tuber yield of arrowroot and fruit bunch of cardamom for each treatment were shown in Figure 2 and Figure 3.

Environmental condition and research site characteristics.
The planting area is located in a good environmental condition for the cultivation of arrowroot and cardamom in an agroforestry system.In accordance to the other studies that the optimum temperature for sengon growth is 22-29℃, wet climate, with rainfall of 2000-2700 mm [20], arrowroot plants optimally grow at an altitude of 5 -1,351 m asl, temperature 20-36℃, humidity 40-72% and light intensity 12-56% [21], meanwhile cardamom requires a dry but cool climate at temperature 20-30℃ with 30-70% sunlight intensity, and requires shade throughout its life cycle [7], so they are very appropriate to be developed in a smart agroforestry system.The use of organic matter in the form of manure and treatment of bokashi fertilization supported the improvement of soil physical and chemical properties in this research, including the increase of total soil nitrogen, cation exchange capacity and porosity in clay-textured soils, and reduced soil bulk density.The presence of trees in agroforestry systems plays an important role in maintaining soil fertility through root activity and litter input.The increase in N-content was also supported by the litterfall input of sengon leaf.A study revealed that the litterfall of 3 years-old sengon provides nutrient inputs of C, N and P to the soil of 4.29 tons ha -1 , 0.97 tons ha -1 and 1.79 kg ha -1 respectively per year [22].The presence of this legume tree is important in agroforestry, as it increase the nitrogen (N) availability for plants and reduce the risk of nitrogen loss because of leaching [23].Their ability in fixing N is correlation to the presence of Rhizobium as N-fixation bacteria in root nodules of sengon [24].Deep tree roots also play an important role as a 'safety net' to nutrients capture, especially N which is easily leached due to rainfall [25].Another study on tuber-based agroforestry revealed there is a decrease of soil organic carbon content according to soil depth except for agroforestry of teak-arrowroot, which also provide the highest water holding capacity than the two other agroforestry models, teak-taro and teakcassava [26].Agroforestry can improve the physical and chemical soil fertility, including C-organic content and cation exchange capacity [27].The complex agroforestry and natural forest land have similar soil physical qualities [28].

Sengon growth in agroforestry and monoculture cropping patterns.
The differences in the root type of sengon tree with arrowroot and cardamom root can reduce nutrient competition in sengon trees.Tree roots grow deeper, enabling them to act as a "nutrient safety net" through the absorption mechanism of nutrients that cannot be absorbed by food crops in the lower layers during the growing season.The presence of below-ground root activities and high litterfall contribute to a nutrient security.The deep roots of the tree act as a "nutrient pump" which moves nutrients from the lower layers to the upper layers, so that they can be utilized by annual crops with shallow roots [25].The agroforestry practice can increase biomass production and the rate decomposition of litter [29].Even though tree-crops interactions in agroforestry systems allowed competition among plant components in gaining sunlight, nutrients and other main resources for their growth [30], the above positive interactions in the smart agroforestry system can maintain and increase sengon growth.Sengon is a fast-growing species that relatively absorbs more carbon [31].The best growth of sengon in a smart agroforestry model can be a beneficial way to increase the wood yield and biomass to increase communities' income and to support Indonesia's FOLU Net Sink 2030.The appropriate species selection is one of the determining factors in the success of a smart agroforestry system to support sustainable plant growth.Overall, the land productivity will be better in an agroforestry system, if there is a positive interaction between the selected species combinations.

The biomass of arrowroot and cardamom.
Plant biomass is a parameter used to describe and study plant growth.It is an integration of almost all events that previously occurred in the plant [16].In this research, monoculture planting resulted in the highest production of arrowroot tubers, cardamom fruit bunches and total biomass in these two annual crops compared to their production under shade in the three agroforestry patterns.Light intensity is an important factor for plant growth.Growth and yield productivity including fresh weight and dry weight of plants are significantly affected by an increase in light intensity [32].This condition is supported by plant photosynthesis which takes place optimally under sufficient light conditions at opened area of monoculture plot.The similar result was also expressed by [33] that monoculture system was able to increase the growth including amount of tillers of lemongrass clump in agroforestry system.The other studies also revealed that monoculture cultivation areas allow the highest light intensity received by plants rather than that of agroforestry [34,35].The tree canopy will grow as the plant ages, therefore lowering the light intensity that can be received by the plants under the stands [36].
The arrowroot growth tends to increase along the availability of bokashi fertilizer.It can be seen from its leaf, stem, root, tuber and total biomass that produce the highest yield at the dosage of 500 g bokashi rather than those at 0 g (without bokashi manure).This can be caused by the need for more nutrients for the production of tubers.Biomass weight reflects the level of plant growth which is determined by the adequacy of nutrients, especially nitrogen [16].The growth yield in the form of photosynthate accumulation will increase which causes nutrient uptake to increase as well, and vice versa.A study [37] revealed that liquid organic manure has significantly affected the seedling growth of Anthocephalus macrophyllus by the increase of plant height, diameter and leaf number as well as fresh and dry weight/biomass, as well as can increase plant growth and yield on the other annual crops such as Red Chilli/Capsicum annum [38] and corn [39] .
Unlike arrowroot, the highest leaf, stem and total biomass was found in plots without bokashi fertilizer, and the dosage of 500 g bokashi manure only resulted in the highest fruit bunch biomass.This condition is possible because the C-organic content of the soil is still relatively high (C-org > 3%) at the beginning of planting so that it is still sufficient for the nutritional needs of cardamom growth.Arrowroot tuber yield in this study reached the fresh weight of 1.67 kg per clump (16.7 tons ha -1 ) in monoculture plots (average dry weight 2.38 tons ha -1 ), and 1.04 kg (10.4 tons ha -1 ) in agroforestry plots (average dry weight 1.34 tons ha -1 ).Meanwhile, the production of cardamom fruit bunches per clump with the same spacing (1 m x 1 m) reached 0.26 kg per clump (2.63 tons ha -1 ) in monoculture plots (average dry weight 0.20 tons ha -1 ) and reached 0.21 kg (2.11 tons ha -1 ) in the agroforestry plot A2 (average dry weight 0.17 tons ha -1 ).
Even though the biomass production of arrowroot tubers and cardamom fruit bunch in the agroforestry cropping pattern was lower than those in the monoculture pattern, the land equivalent ratio (LER) from these tree agroforestry models is > 1 [40], which means overall productivity will be better in an agroforestry system.The ecological/biological productivity is evaluated from the total biomass yield, while the economic productivity is evaluated from the harvested yield.The LER value is the ratio of yields between agroforestry (polyculture) to monoculture crop yields at the same level of land management.The LER value > 1 indicates that the productivity of agroforestry land is higher than that of monoculture [41].LER is a useful indicator to describe productivity gains in promoting smart agroforestry.This is in accordance to another study which revealed that agroforestry systems produced a higher annual mean biomass contribution than that generated in the forest (6.5 Mg ha −1 vs. 3.2 Mg ha −1 ).The leaf as the main contributor that supply the total biomass to the soil [29].Smart agroforestry plays a significant role in sustaining soil fertility by recycling soil nutrients to support plant growth [42].The simple tending, and the low intensity of pest and disease occurrences in the cultivation of these annual crops, will give more advantages to the farmers in obtaining cost efficiency in agroforestry practices.Furthermore, the great health benefits of this functional food plants and the queen of spices will increase food security.Arrowroot tuber can prevent stunting, good for digestion, celiac disease and diabetic diets as well as an immunostimulant that can be obtained by subsistence.A higher protein content of arrowroot than other tubers and arrowroot starch can meet the daily need for folate up to 100%, so that it serves many benefits especially for pregnant women [8].Snack bar with formulation of 70% arrowroot flour were considered has low glycemic index of 25 [43].Recent study revealed that agroforestry practices increase the cardamom leaf essential oil yield and 1.8-cineol content [44] and can maintain the phenolic content of arrowroot tuber [45].This will be an added value for its development in the social forestry (SF) area.The three agroforestry models in the combination of sengon, arrowroot and cardamom are potential to be promoted especially in the SF area, in order to support the Food Security Program, Forestry Multi-Business and Indonesia's FOLU Net Sink 2030.

Conclusions
The three agroforestry models have the potential to support food security, which can be prospective mainstreaming in implementing Social Forestry programs.The higher growth increment of sengon was found in the three agroforestry cropping patterns amounted to 3.0-3.5 m 3 .ha -1 compared to monoculture of 2.1 m 3 .ha - .The highest dry weight of leaf, stem, root, tuber and fruit bunch biomass of arrowroot and cardamom was produced in the monoculture pattern, with the total biomass amounted to 7.69 tons ha -1 for arrowroot and 8.60 tons ha -1 for cardamom.

Note:
Mean values followed by different letters within a row are significantly different (P < 0.05) which indicate that the treatment has a significantly different effect.The mean value in bold is the highest value among treatments.A2 = Intercropping of sengon and cardamom; A3 = Intercropping of sengon-arrowroot-cardamom; A6 = Monoculture of cardamom.

Table 1 .
3.1.2.Growth of sengon on agroforestry and monoculture cropping patterns.The volume increase of sengon for 10 months on various cropping patterns was shown at Table 1.Growth of sengon on various cropping patterns

Table 2 .
. The Remark: Mean values followed by different letters within a row are significantly different (P < 0.05) which indicate that the treatment has a significantly different effect.The mean value in bold is the highest value among treatments.A1= Intercropping of sengon and arrowroot; A3 = Intercropping of sengon-arrowroot-cardamom; A5 = Monoculture of arrowroot.

.
The biomass of cardamom in various cropping patterns and dosages of bokashi fertilizer