Identification of Soil Fertility Constraints and Response of Sorghum to Varying Doses of Nutrients Based on Soil Test in a Selected Micro - Watershed in Northern Transition Zone of Karnataka
Loading...
Date
2012
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
UAS, Dharwad
Abstract
Surface soil samples (0-20 cm) on grid points of ten seconds interval were
collected from the Neeralakatti micro-watershed near Dharwad for the assessment of
soil fertility status. The samples were analyzed for pH, electrical conductivity, organic
carbon, available nitrogen, phosphorus, potassium, sulphur, calcium, magnesium,
zinc, iron, copper, manganese and boron following standard procedures. Soil fertility
maps were prepared for each of the nutrients using GIS technique. Major portion of
micro-watershed was low (83%) in available nitrogen, high in available potassium
(61%) and medium (72%) in available sulphur. Available phosphorus was low in 39%
and medium in 45% of watershed area. Nearly half of the micro-watershed was
deficient in available zinc (52%) and boron (56%). The entire micro-watershed was
found to be sufficient in available iron, copper and manganese. A field experiment
was conducted at Neeralakatti village, Dharwad to study the response of sorghum to
varying doses of nutrients based on soil test. The results revealed that application of
150% RD N and P2O5 + 50% RD K2O + 10 kg Zn + 0.4 kg B (150: 112.5: 12.5: 10:
0.4::N: P2O5: K2O: Zn: B kg/ha) (T8) recorded significantly higher grain and straw
yield of 63.17 and 155.92 q/ha, respectively, compared to 42.37, 123.75 q/ha in RDF
(100:75:25::N: P2O5: K2O kg/ha) and 44.82, 130.17 q/ha in T2-RDF modified as per
soil test (112.5: 87.5: 25::N: P2O5: K2O kg/ha), respectively. T8 recorded significantly
higher number of leaves (10.5), dry matter yield (243.65 q/ha) and ear length (30.08
cm), compared to T1 (9.7, 194.54 q/ha and 26.93 cm respectively) and T2 (9.8, 202.34
q/ha and 27.32 cm, respectively). Net return was highest in T8 (` 76,166) compared to
T1 (` 46,674) and T2 (` 52,192). The B:C ratio was also highest in T8 (3.80) compared
to T1 (2.97) and T2 (3.07).