Abstract
Phosphate rock fertilizer has slow solubility; therefore, it is suitable and more effective to be applied on annual crop plantation. To increase the solubility and the effectiveness of phosphate rock application, inoculation of the Arbuscular Mycorrhyzal Fungi (AMF) is required. Experiments were conducted at the Cikabayan Farm, Bogor Agriculture Institute, West Java. The objective was to study the effectiveness of AMF inoculation in increasing the potency of Papuan Crandallite Phosphate Rock to the growth of cocoa seedlings. A factorial experiment was set up in a complete randomized design. The first factor was AMF inoculation, consisting of none AMF, Manokwari indigenous AMF and Mycofer AMF, and the second factor was five dosages of the Papuan Crandallite Phosphate Rock (PCPR), consisting of 0, 0.5, 1.0, 1.5 and 2.0 g P2O5 / seedling. The dosage of 2.0 g P2O5 SP-36 per seedling was used as a comparison. Cocoa seeds of F-1 Upper Amazon Hybrid (UAH) were collected from the Coffee and Cacao Research Center, Jember, East Java. The seedlings were grown in polybags of 20 cm x 30 cm size, with ultisol acid soil obtained from Jasinga (West Java) as the growing medium under 60% of shading net for four months. The media contained 17.03 cmol kg-1 of exchangeable Al. The results showed that increasing the dosages of PCPR at the AMF inoculated seedlings resulted to the linear increase of shoot dry weight and P uptake by 50.14% and 64.88%, respectively; and this was lower than the inoculation of Manokwari indigenous AMF which increased shoot dry-weight by 66.30% and P uptake by 65.45%. Whereas the shoot dry-weight and P uptake of the non-mycorrhizal seedlings increased by 73.56% and 121.94%, respectively. Mycofer inoculants were found to be much more effective in increasing the shoot dry-weight by 127.55% and P uptake by 45.16% than that of the Manokwari indigenous AMF, which increased by 95.97% and 21.29% in shoot dry-weight and P uptake, respectively at the PCPR dosage of 2.0 g P2O5 / seedling as compared to the non-inoculated seedlings.
Highlights
Indonesia is the third biggest country in the world after Ivory Coast and Ghana for the cocoa seed production; 40% of the world’s cocoa seed market is dominated by Ivory Coast (Hartemink, 2005)
The research result showed that the use of Papuan Crandallite Phosphate Rock (PCPR) in several dosages and Arbuscular Mycorrhyza Fungi (AMF) inoculation definitely influenced the growth of cocoa seedling, but there was no significant interaction between PCPR dosage and type of inoculums
The cocoa seedlings which were inoculated by Mycofer AMF (m2) produced the highest height of seedlings, stem diameter and root dry-weight which account for 43.15cm, 7.26 mm, and 2.01 g respectively, and these were different from the seedling inoculated by indigenous AMF (m1) and non AMF inoculation
Summary
Indonesia is the third biggest country in the world after Ivory Coast and Ghana for the cocoa seed production; 40% of the world’s cocoa seed market is dominated by Ivory Coast (Hartemink, 2005). The cocoa plantation in 2006 reached 1,191,742 ha with the production of 779,474 Mg (Dirjen Perkebunan, 2007). The amount of fertile land is becoming somewhat limited todays, development of the cocoa plantation is going to the other directions to the marginal lands located outside Java island such as Sumatera, Sulawesi, Maluku, and Papua. Those lands are dry lands with low fertility level which require high amount of fertilizer. This condition may inhibit the development of cocoa plantation as high inputs of liming and fertilizer are needed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
