Cocoa (Theobroma cacao L.) is an important crop in Indonesia, but many farmers still face problem in improving bean production. This research aimed to evaluate the effect of humic acid and biofertilizer applications on pod growth and yield of cocoa. The research was conducted at Kaliwining Plantation managed by Indonesian Coffee and Cocoa Research Institute at Jember District, East Java, Indonesia from June 2017 to February 2018. The experiment used mature tree of Sulawesi from one clone. Treatment used were humic acid at level of 0, 1000, 2000, 3000 and 4000 ppm in combination with biofertilizer at level of 0, 500, 1000, 1500 and 2000 ppm that were applied through soil and foliar respectively. Results of this experiment showed that there was an interaction between humic acid and biofertilizer on beans number per plant and photosynthesis rate. Plants treated with 1000 ppm humic acid produced the highest number of small cherelle. Biofertilizer applied at 1500 ppm increased cherelle number, healthy cherelle, number of young pods, number of harvested pods, bean weight per plant and bean yield. The combination of 1000 ppm humic acid and 1500 ppm biofertilizer increased bean production by 39.7%. The high bean production was in line with the high photosynthetic rate. Thus, humic acid and biofertilizer applications could be a way to increase cocoa bean production in this area.

A survey was conducted of Indonesian cocoa farms to assess the extent of yield variation and factors associated with this variation. The survey of 120 farms during the course of 3 years encompassed four provinces in Sulawesi (South, South-East, West and Central), Western Sumatra, Lampung, East Java and West Papua. A high degree of yield variation was observed between farms, the average over 3 years ranged from 39 to 3586 kg ha−1. Overall, yields were greater on farms that were classified as ‘highly managed’, compared to ‘moderately’ and ‘less managed’. Seasonal variability in yields was generally greater in districts with a more pronounced dry season such as South Sulawesi and Lampung. Multiple regression analyses revealed particular husbandry practices that were linked with higher cocoa yields. Specifically, the use of inorganic fertilisers, application of fungicides against blackpod and weeding were all practices that were associated with higher yields. A positive association between rainfall and yield was observed for the years 2014/15 and 2015/16 but not 2016/17, which was a La Niña year (when rainfall totals were higher). Some of the farms surveyed were planted with cocoa at very low densities implying an opportunity for yield improvement through gap filling or replanting at higher densities (although it was noted that some farmers maintained lower planting densities due to the cultivation of companion crops). Given the smallholder status of most cocoa farms in Indonesia (mean area in this study was 0.71 ha) it is important that farmers are able to maximise returns from their land in order to maintain a livelihood. This study illustrated the potential for yield improvement on Indonesian cocoa farms through adoption of best agronomic practice.

Cocoa is one of the agricultural commodities that have important role and are reliable in realizing agricultural development program of Indonesia. The cocoaproduction of Indonesia tends to decrease that caused by in appropriate farming. This research aimed to evaluate the shade management to cocoa productivity and evaluating the correlation between soil quality and the cocoa production with the different shade management. This research was conducted from October 2016 until June 2017 in Kaliwining Experimental Station and Soil Laboratory of Indonesian Coffee and Cocoa Research Institute (ICCRI), Jember, Indonesia. Clones at the trial plots were Sulawesi 1 and Sulawesi 2, 10 years old, and arranged in 3 m x 3 m spacing. The design of this research was conducted by observing parameters of sample trees on cocoa field. This research used three observation plots, with shade trees of leucaena (Leucaena sp.), teak (Tectona grandis), and teak combined with krete (Cassia surithensis) shade. The results indicated that shade species affected the cocoa production. Teak shade gave higher production of cocoa (i.e 3,01 kg.tree-1) compared to other species of shade (1.83 and 1.39 kg.tree-1 for leucaena and teak and krete combination, respectively). The correlation of soil quality with cocoa production showed that soil calcium content, earthworm biomass and soil bulk density were positively correlated with the production of cocoa. Shade species greatly affected the production in combination with the soil quality.

The issue of cadmium in cocoa beans has become one of the primary considerations in setting quality criteria in chocolate-consuming countries. Using rootstock genotypes that are tolerant to cadmium uptake can provide data on the absorption of cadmium into shoots for recovery. This study examined cocoa plants’ growth and physiological response to cadmium (Cd) accumulation. The research was carried out using polybags in the Greenhouse of the Indonesian Coffee and Cocoa Research Center using a half-sib family of cocoa aged 4 months after sowing. The study was designed using a completely randomized split-plot design with 3 replications. The parent plots were the half-sib families of Sulawesi 1, Sulawesi 2, and Scavina 6. The subplots were added with cadmium solution at 0 (control), 2, 4, and 8 ppm. The results showed that adding cadmium up to 8 ppm did not affect the growth and biomass of cocoa seedlings; however, it had a negative effect on plant physiological processes of the net assimilation rate and relative growth rate. Cadmium content in the tissue increased with increasing cadmium concentration in the growing medium. The accumulation of cadmium in roots was higher than that of shoots. Absorption of cadmium in the root tissue of Sulawesi 1 was higher than that of Scavina 6 and Sulawesi 2; genetic factors did not affect cadmium uptake in the shoots. There was a positive correlation between root dry weight and cadmium concentration in the tissue; the higher the dry weight of the root tissue, the higher the cadmium uptake in plants.

Ants are soil macrofauna that plays an essential role in preventing pods of cocoa (Theobroma cacao L.) from Helopeltis antonii and Conopomorpha cramerella attack. However, the method of those pests control primarily using pesticides and that will disturbed ant's life. This research aims to determine the abundance and diversity of ants in cocoa plantations with different shade and to determine the correlation between ant abundance and intensity of pest attack from Helopeltis antonii and Conopomorpha cramerella. Ants sample was carried out using pitfall traps and Berlese funnels based on purposive sampling method. The results showed that five subfamilies were found in cocoa plantations with different shade. Subfamily Myrmicinae was the dominant group in all observation sites. The ant abundance has a strong correlation with intensity of pest attack. This was influenced by a role of the ant as natural enemies from Helopeltis antonii and Conopomorpha cramerella.