Sugarcane yields tend to drop rapidly along with soil fertility level on ultisols r
ecently cleared
from forest conversion if there is no fertilizer input. Ultisols in N. Lampung typically have a low
content of soil organic matter (SOM) N P exchangeable cations and a high concentration of Al and
Mn. Maintaining a high SOM content is considered to be one of the key factors in sustainable crop
production but availability of organic materials in the field is very limited and transferring organic
materials from other places to the plot is too expensive for small farmers. One possibility to solve this
problem is to return the sugarcane
akibat dari usaha pengelolaan BO
harvest residue (trash) to
the soil in stead of burning it after harvest. Another potential source is
Bagas
(sugarcane processing
waste) normally piled up around the sugarcane factory with a high risk of fire.
A field experiment was carried out in 1998-2000 in the area of sugarcane plantation PTPN V
Bunga Mayang North Lampung. The following applications of organic materials were tested on a soil
that had been cropped for more than 10 years after forest conversion: (1) Without organic materials as a
control (2)
Bagas
8 Mg ha
-1
(3)
Bagas
16 Mg ha
-1
(4) Sugarcane trash (harvest residue) 8 Mg ha
-1
.
The treatments were arranged in a randomized block design (RBD) with four replicates. A mixed
legume cover crops (LCC)
Mucuna pruriens
var
. utilis
and
Centrosema pubescens
(1:1) was planted
in the first year followed by sugarcane for another 2 years.
Aim of this experiment is to study the impact of applying organic inputs on the SOM N P
contents biomass of LCC and subsequent yield sugarcane.
Application of
bagas
to the top soil (0-5 cm) lead to an immobilization of N at 8 months after
the start but not for sugarcane trash application. At 5 months after applying trash to the soil the
highest net N mineralization was obtained but it declined for the next measurement. In the soil layer at
5-15 cm depth however application of all sugarcane residues to the soil increased mineral N content at
3 months after the start. No significant effect of application of sugarcane residues was observed on the
SOM content pH and available P level (P-
Bray2
).
Application of sugarcane residues had no significant effect on
Mucuna
biomass production
but significantly (p
Publication year
2003
Authors
Hairiah, D.K.; Purnomosidhi, P.; Nasution, N.; Van, Noordwijk.M.; Lusiana, B.; Khasanah, N.M.
Keywords
Sugarcane, Organic fertilizers, Soil organic matter, Nitrogen mineralization, Cover crops
