Section 3 (Crop Management)

Tripathi
It is necessary to manage acid upland soil of Nepal for sustaining or increasing crop productivity and
maintaining soil fertility. Therefore, the objectives of the study were (I) to manage the marginal maize
production system with the use of organic manure and inorganic fertilizers, (ii) to synchronize nitrogen
requirement through organic and inorganic sources, (iii) to identify limitation of nitrogen, phosphorus and
potassium nutrients in different agro-climatic conditions, and (iv) to select acid soil tolerant maize
germplasms for the acidic areas.
Materials and Methods
Maize-based system
The experiment was conducted in the marginal rainfed upland (bariland) of Agriculture Research
Station, Lumle (1660 m asl). Before starting the experiment in the summer of 1997, wheat crop was
grown in the experimental field in winter of 1996 without applying any manure or fertilizer in order to
create soil homogeneity. The field trial was started in 1997 and continued upto 2000 with maize and
millet was relayed. Millet was grown on the residual nutrients applied to maize. Maize was sown on the
last week of march each year and millet was transplanted 10 to 11 weeks later after maize slowing. Maize
and millet were harvested in second week of September and last week of November respectively. Bean
was grown as mixed cropped with maize and was sown during second week of April (when maize started
germinating). Bean was harvested as fresh vegetable in the first week of August. Similarly, pea was
relayed with millet and was sown in the first week of November. It was harvested during the second to
third week of March. Incorporation of bean and pea residues were done in the last week of August and
March respectively in treatments of plus residues only. The above experiment was carried out in the same
plots and terminated after four years (2000). The site of the experiment was changed from marginal
rainfed upland to medium fertility rainfed upland during 2001 and all the treatments and planting was
followed similar to that of marginal rainfed upland.
The experiment was designed in a randomized complete block with three replications. There were ten
different treatments comprising organic and inorganic nutrients. At the beginning of the experiment,
composite soil samples to a depth of 25cm were collected from all three replications during 1997 and
2001 both from marginal and medium rainfed uplands (Table 1). Soil of marginal upland was very
strongly acidic (pH4.42), total N was low (0.18%), available P was medium (5.61 ppm), exchangeable K
was low (0.15me/100g) and organic carbon was medium (2.22%) but soil of medium fertility has medium
acidity (pH 6.00), total N was medium (0.37%), available P was very high (337 ppm), exchangeable K
was medium (0.3 me/100g) and organic carbon was medium (3.78%). Every-year, the farm yard manure
was analysed before applying in different treatments. Nitrogen content in FYM was 1.63% (on dry basis)
which was applied in the marginal land from 1997 to 2000. However, N, P and K contents in the FYM
applied in medium fertility soil in 2000 were 2.67%, 1.37% and 1.73% respectively on dry basis. The
gross experimental plot size for maize was 9m 2 (3m63m) and net harvested area was 4.5m 2 (3mX1.5m) in
infertile marginal upland trial and 12m 2 (4m63m) and 6.0m 2 (4m61.5m) as in medium fertility trial of
2001. During maize harvest, maize plant population and grain yields were adjusted in per hectare basis.
The moisture content of maize and finger-millet grains were adjusted at 12% moisture.
Analysis of variance on grain of maize and finger-millet were performed by MSTAC and treatment
differences were compared by least significant differences (LSD).
Synchronizing N-requirement with organic and inorganic fertilizer
The field experiment was conducted in a randomized complete block design with three replications in
farmers' field of Lumle during 2000 and ARS, Lumle center during 2001. There were fourteen treatments
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