Rizki Maulana Ishaq

The 2014 eruption of Mount Kelud substantially reduced vegetation cover and litter input, resulting in habitat degradation for soil organisms, including earthworms. As sensitive bioindicators of habitat quality and landuse change, earthworms were used to assess ecosystem recovery. This study evaluated earthworm density, diversity, and Importance Value Index (IVI) across five landuse systems: Pine–Elephant Grass Agroforestry (APR), Mahogany–Elephant Grass Agroforestry (AMR), Complex Agroforestry (CAF), Simple Agroforestry (SAF), and Annual Food Crops (MOS). Measurements were conducted in four different replicate plots within each LUS. Earthworms collected using the hand-sorting method of three soil depth of 0-10, 10-20, and 20-30 cm. Across all landuse systems, earthworm density was highest in the 0–10 cm soil depth. Among the evaluated landuse systems, AMR had the lowest overall earthworm density. Shannon–Wiener diversity, evenness, and richness indices were consistently low, indicating that earthworm communities remain in the post-eruption recovery stage. Pontoscolex sp. dominated in APR, CAF, SAF, and MOS, whereas Metaphire sp. predominated in AMR. Principal Component Analysis (PCA) revealed that soil moisture was the primary factor associated with earthworm density and biomass, while canopy cover was stronger related to litter quality than to earthworm community attributes.

The spread of Imperata cylindrica in agricultural lands is often associated with a decline in soil fertility, causing crops to be outcompeted by Imperata cylindrica. This study aimed to evaluate land cover, litter biomass, and soil infiltration rates in lands previously occupied by Imperata cylindrica that had been reclaimed with coffee-based agroforestry in Nagari Sirukam, Solok Regency, West Sumatra. The survey on volcanic soils was conducted in July-August 2024. The results showed that natural remnant forests (HT) had the highest canopy cover at 69%, while multistrata agroforestry (AFMT) had a canopy cover of 37%. The highest standing litter was found in multistrata agroforestry (3.1 Mg ha-1), while at HT had 0.6 Mg ha-1 only. The highest infiltration rate was found in Imperata cylindrica grassland (AF0) with 0.072 cm sec-1, due to the dense rhizomes, while multistrata agroforestry had an infiltration rate that was 73% lower (averaged 0.02 cm sec-1). Although the infiltration rate was lower, agroforestry combined with fire control was effective in maintaining soil stability, reducing erosion, and improving soil quality sustainably, providing long-term benefits for soil and water conservation.

Sweet corn production in Batu city is lower than in other districts/cities. This is thought to be due to a decrease in land area and deterioration of land conditions. In addition, intensive agricultural practices in the long term can reduce soil pH which will have an impact on the low availability of essential nutrients such as Mg, S, and P. Kieserite fertilizer application can be used as an effort to overcome these problems. This study aimed to evaluate the application of various doses of kieserite fertilizer combined with a single inorganic fertilizer on the efficiency of nutrient uptake and production of sweet corn plants. The research was conducted in Junrejo Village, Batu City in September 2023 - May 2024. The research used Randomized Group Design (RGD) with Kieserite fertilizer doses (0; 26.92; 53.85; 80.77 kg ha-1). The parameters observed and analyzed were plant height and number of leaves, corn production (quantity and quality), soil chemical properties (pH, Mg-dd, SO42-, P-available), nutrient uptake efficiency (Mg, S, P), and phosphate solubilizing bacteria (BPF) population. The research data were analyzed by ANOVA then DMRT further test at 5% level, correlation and regression tests using R-Studio. The results showed that the application of Kieserite fertilizer at a dose of 50% (~26.92 Mg ha-1) combined with inorganic fertilizer (N,P,K) at a dose of 75% shown in treatment A6 significantly increased the efficiency of Mg nutrient uptake by (RE=7.7%), S nutrient by (RE=2.9%), and P nutrient by (RE=49.9%). This increase in nutrient uptake efficiency certainly affected the level of sweet corn productivity. The correlation test between nutrient uptake efficiency (Mg, S, and P) and sweet corn production showed a positive and strong relationship (r=0.5-0.7), where the higher the nutrient uptake efficiency, the higher the sweet corn production. This study confirms the importance of efficient use of Kieserite fertilizer in order to get optimum production results.

Coffee agroforestry systems have great potential in optimizing the dual function of carbon and biodiversity conservation, especially in areas with high land use pressure. However, although coffee agroforestry has been widely practiced in Indonesia, the specific relationship pattern between carbon stocks and vegetation biodiversity is still not well understood. This study aimed to evaluate (1) the role of coffee agroforestry in maintaining vegetation diversity and carbon sequestration compared to disturbed forests (HT) and (2) the relationship between carbon stocks and biodiversity at various plant growth stages. Three land use systems were selected such as HT and complex (AFM) and simple (AFS) coffee-based agroforestry systems. The number of trees, species richness (R), Shannon-wiener index (H’), species evenness (E), and carbon stocks were measured in 12 plots (100 m x 20 m) for each vegetation growth stages (seedlings, saplings, poles, and trees). The results showed that the H index in coffee agroforestry was generally low to moderate (0.57-2.05), with the highest diversity in the tree category. The diversity level of AFM could mimic HT. In terms of carbon stock, HT had the highest stock (82±19 Mg ha-1), while total carbon stock showed a positive relationship with H index in all vegetation stages (R2=0,13-0,57). In contrast, the relationship between soil carbon stock and H index tended to be weak (R2=0,10). This study emphasizes the importance of maintaining total carbon stock through diverse vegetation in agroforestri systems to support climate change mitigation and biodiversity conservation.

Weet corn productivity in Indonesia is still in the low category. One of the causes is the problem of soil with low pH. Soil with a low pH causes the availability of nutrients to decrease, thereby inhibiting plant growth and development. Efforts can be made to add dolomite, because hydrolyzed dolomite can increase nutrient availability in the soil. Therefore, this research was carried out with the aim of analyzing the effect of adding various doses of dolomite on soil chemical properties, plant uptake of Ca, Mg and P, population of phosphate solubilizing bacteria, and sweet corn productivity in the Tegalan Land of Junrejo Village, Batu City, East Java. The research design used a randomized block design (RAK) consisting of 9 treatments with 3 replications. Treatment consisted of: M0 = control; M1 = 100% N, P, K; M2 = 100% N,P,K + 100% Kieserite; M3 = 100% N,P,K + 50% Dolomit; M4 = 100% N,P,K + 100% Dolomit; M5 = 100% N,P,K + 150% Dolomit; M6 = 75% N,P,K + 50% Dolomit; M7 = 75% N,P,K + 100% Dolomit; M8 = 75% N,P,K + 150% Dolomit. The data was analyzed for diversity using R studio software and continued with the DMRT (Duncan Multiple Range Test) test at 5% level. Next, to see the relationship and influence between parameters, correlation and regression tests were carried out. The findings demonstrated that adding 2.8 tonnes of dolomite per hectare might raise soil CEC (50.61%) and pH (13.41%). In addition, the addition of 4.2 tons/ha of dolomite was able to decrease soil P-available (5.65%), increase Ca-dd (26.4%), Mg-dd (85%), Ca absorption (165.12%), Mg absorption (366.67%), P absorption (78.57%), and sweet corn yield (78.04%). The addition of different doses of dolomite did not significantly alter the overall population parameter of phosphate-solubilizing bacteria. Furthermore, the link between sweet corn yield and nutritional absorption was both robust and weak. The increase in sweet corn output was impacted by P, Ca, and Mg absorption by 54.54%, 41.21%, and 42.79%, respectively.

Agroforestry systems have significant potential for development in increasing coffee production in Indonesia. Besides providing economic benefits, agroforestry can also have ecological impacts, such as improving soil structure, reducing erosion, and other environmental services. There is a complex interaction between trees, soil, and crops in agroforestry systems, making modeling a valuable approach to unraveling these processes. We utilized the spatial and temporal explicit model WaNuLCAS to (i) evaluate the model's performance in depicting actual events (through coffee production and soil water content), (ii) assess the dynamic processes influencing coffee production and the environmental impact of management patterns, (iii) formulate and simulate optimal scenarios for coffee production optimization. Data from a one-year period involving five agroforestry management patterns for coffee-pine in UB Forest were used as input for the model. The model validation results showed satisfactory and acceptable outcomes for coffee production and groundwater dynamics. WaNuLCAS simulation results indicated that pruning and thinning management are crucial factors in increasing coffee production and are related to creating optimal conditions for coffee plants (light, humidity, and inter-plant competition). Additionally, fertilization management can be combined as a supporting factor to meet the nutritional needs of coffee plants. WaNuLCAS simulation results also suggested that pruning and thinning can improve soil physical properties, but thinning increases surface runoff within the system. This research provides insights into how modeling can be used as a decision-making tool.

Bromo Tengger Semeru National Park (BTS-NP) in East Java, Indonesia showcases a breathtaking volcanic landscape and cultural allure, drawing hundreds of thousands of domestic and international visitors. Recreational activities involving human and animal trampling and motorized-vehicle traffic caused soil disturbance along their networks of paths, trails, or roads, potentially having a detrimental long-term effect on the tourism industry and environmental services provided by the national parks. However, the extent of the impact of these disturbances on soil properties remains unclear. This study assessed the impact of different disturbance intensities, consisting of undisturbed locations as a control (zone 1), low to medium- (zone 2), and high- (zone 3) disturbance intensities on five different BTS-NP tourism hotspots, including Entrance Wonokitri (EW), Whispering Sand (WS), Parking Temple (PT), Teletubbies Hill (TH), and Entrance Bromo Stairs (EB), on soil properties, including soil compaction represented by soil penetration resistance, and soil infiltration. This study revealed that the higher severity impact of recreational activities on soil compaction was parallel with higher disturbance intensity, particularly in EW and TH. In these particular locations, higher soil compaction is significantly linked to lower soil infiltration, thus needing extra attention and protection. Meanwhile, in WS, PT, and EB, soil infiltration was more controlled by the establishment of a cemented topsoil layer consisting of mixed sand, sulfur, and water. Better management strategies, such as the use of proper trails and road infrastructures, particularly on EW and TH, might be relevant to minimize the impact of recreational activities on these ecologically, economically, and culturally important areas.

In tropical regions, land-use pressures between natural forest, commercial tree plantations, and agricultural land for rural communities are widespread. One option is to increase the functionality of commercial plantations by allowing agroforestry within them by rural communities. Such land-sharing options could address wider societal and environmental issues and reduce pressure on natural forest. To investigate the trade-offs involved, we used InVEST to model the ecosystem services provided by growing coffee under commercial pine plantations in Indonesia against other land-use options. Pine–coffee agroforestry provided worse supporting and regulating services (carbon, sediment and nitrogen retention, catchment runoff) than natural forest; however, it provided greater provisioning services (product yield) directly to smallholders. Converting pine monoculture into pine-coffee agroforestry led to increases in all ecosystem services, although there was an increased risk to water quality. Compared with coffee and root crop monocultures, pine–coffee agroforestry provided higher levels of supporting and regulating services; however, product yields were lower. Thus, opening up pine plantations for agroforestry realises additional income-generating opportunities for rural communities, provides wider ecosystem service benefits, and reduces pressure for land-use change. Lower smallholder yields could be addressed through the management of shade levels or through Payments for Ecosystem Services schemes.