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SOIL HYDRO-PHYSICAL CHARACTERISTICS AND PLANT WATER AVAILABILITY IN WHEAT UNDER LONG-TERM TILLAGE AND RESIDUE MANAGEMENT PRACTICES

KrishiKosh

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Title SOIL HYDRO-PHYSICAL CHARACTERISTICS AND PLANT WATER AVAILABILITY IN WHEAT UNDER LONG-TERM TILLAGE AND RESIDUE MANAGEMENT PRACTICES
M Sc
 
Creator SURAJIT MONDAL
 
Contributor R.K. Tomar
 
Subject tillage, crops, irrigation, zero tillage, layering, agreements, wheats, land resources, infiltration, soil water content
 
Description T-8262
Increasing crop residue levels by reducing tillage have been invoked as one of the alternate
method for increasing the sustainability of agricultural cropping systems as against conventional
method, where most of the residues are normally removed through intensive tillage operations.
There is little information concerning the combined impacts of tillage systems and residue
application on soils and water availability to crops in India. A study was conducted on a sandy
loam soil (Typic Haplustept) at experimental farm at Indian Agricultural Research Institute to
determine the effects of no till (NT) and conventional tillage (CT) on soil hydro-physical
properties under pigeon pea (Cajanas cajan L.) - wheat (Triticum aestivum L.) cropping system.
The treatments [no till (NT), no till with residue as mulch (NTRM), conventional tillage (CT) and
conventional tillage with residue incorporation (CTRI)] were laid out in a randomized block
design replicated thrice. The selected key parameters evaluated after 6-years of continuous
experiment were bulk density (BD), soil resistance to penetration (PR), aggregate size distribution,
soil moisture retention characteristics, various size pores like macro-, transmission, storage and
residual pores, infiltration rate and total organic carbon (TOC). The effect of these parameters on
the soil moisture content (SMC), soil temperature (ST), leaf area index (LAI), specific leaf weight
(SLW), root weight density (RWD) and grain and biological yields were monitored in succeeding
wheat crop in 2009-10. Residue application affected BD and PR considerably, which was
significantly lower in CTRI (1.52 Mg m-3). Soil compaction was greater under NT and residue
retention could reduce both BD and PR in NTRM. Although a hard layer (cone index 1.7-1.9
MPa) was observed in all plots irrespective of tillage, omission of tillage for last 6 years (NT and
NTRM) indicated marginal reduction in PR at this layer. Aggregate size distribution was better in
NT, NTRM and CTRI than CT. The pore size distribution was significantly affected by tillage and
residue management. Macropores (0-0.2 m soil layer) were 30-40% higher in NT and NTRM
plots, which facilitated for significantly higher water infiltration (~2-3 times that of CT and 1.5
times that of CTRI) and also could aid in root extension to deeper layer, as evidenced by higher
RWD at 0.45-0.60 m layer in these treatments. Residue could significantly improve pore spaces as
well as transmission pores, which could contribute to better water retention in soils. The TOC was
significantly higher in CTRI and NTRM, but it was at par between CT and NT.
Both NT and NTRM resulted in higher (10-11% than CT/CTRI) moisture content during
initial two weeks after sowing. This effect continued up to second irrigation (CTRI as effective as
NTRM), thereafter it eased out. The soil moisture content showed appreciable variation mostly in
0-0.25 m, but no tillage treatments resulted in higher moisture depletion in 0.45-0.60 m, might
contributed to a greater uptake by roots, which on 70 DAS were significantly higher in mass in
these treatments. Although some intermittent variations could be detected, the moisture depletion,
considering the 0-0.90 m soil profile, did not show any significant difference for the entire growth
period. Moderation of ST was achieved mostly under NTRM, which was most significant during
35-71 DAS, coinciding the active growth phase of wheat. The effect of residue was clearly visible
in both LAI and SLW values, which were significantly higher in CTRI and NTRM plots, though
the effect of omission of tillage were not clear. Roots in surface 0-0.1 and 0.1-0.2 m layers were
substantially higher in both CTRI and NTRM compared to CT or NT, but in deeper layers RWD
was higher in both NT and NTRM, possibly indicating the role of a continuous pore (macro-pores)
system in untilled soil, created by earthworms and the roots from preceding crops, which was
utilized by wheat roots as passages through the compact layer zone (at 0.1-0.2 m) to extend to
deeper layers. Maximum grain as well as biological yield was obtained in conventional tillage
along with residue incorporation but it was at par with no tillage and residue retention
 
Date 2016-09-30T17:15:01Z
2016-09-30T17:15:01Z
2010
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/79667
 
Format application/pdf
 
Publisher IARI, DIVISION OF AGRICULTURAL PHYSICS