Agriculture Reference
In-Depth Information
7.2.2 EXPERIMENTAL TREATMENTS AND DESIGN
In all four seasons, the experiment was a two-factor experiment arranged
in a randomized complete block design (RCBD) with three replications.
Main plots were assigned to four different fertilizer levels: i) the full rec-
ommended rate (100% RR) of inorganic fertilizer; ii) 50% RR, 25% of
RR, and the Control treatment in which no inorganic fertilizer was applied.
However, the recommended rate changed between seasons and was 120
kg N ha
−1
, 60 kg P
2
O
5
ha
−1
, and 60 kg K
2
O ha
−1
in the DS, and 90 kg N
ha
−1
, and 30 kg P
2
O
5
ha
−1
, 30 kg K
2
O ha
−1
in the WS. The exact N, P, and
K amounts applied are given in Table 2.
Subplots (30 m
2
each) were assigned to the different biofertilizers test-
ed in the experiment. Three different biofertilizers available in the Philip-
pines were used, and an overview of their characteristics is given in Table
3. The products were Bio-N
®
(BN), BioGroe
®
(BG), and BioSpark
®
(BS;
the same product was called BioCon in 2009). In addition, a Control treat-
ment was used in which no biofertilizer was applied. Thus, the total num-
ber of treatment combinations tested was 16.
BN was developed in the early 1980s by Dr. M Umali-Garcia [28].
According to the distributor (BIOTECH, UPLB), it contains
Azospirillum
lipoferum
and
A. brasilense
, isolated from
Saccharum spontaneum
(lo-
cal name is Talahib). BN is available in dry powder form in a 200-gram
package, which can be used for seed inoculation, direct broadcasting on
seeds, or mixed with water as a root dip. The BN product has a shelf-life
of 3 months and the package we used was well before its expiry date. BN
is specifi cally targeted at rice and corn.
The second product tested was BG, developed by Dr. ES Paterno of
BIOTECH at UPLB. It contains unknown plant growth-promoting bacte-
ria (rhizobacteria) that infl uence root growth by producing plant hormones
and providing nutrients in soluble form [28].
The last product tested was BS, developed by Dr. VC Cuevas. Accord-
ing to personal information from her, it contains three different species of
Trichoderma
isolated from Philippine forest soils (including
Trichoderma
harzianum
), and is mass-produced using a pure organic carrier [29]. The
product can be used for seed coating or for soil application in the seedbed.
