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20161
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Subject: Soil Science × Author: Harmandeep Kaur × End date: 2017 × Start date: 2011 ×
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    ThesisItemOpen Access
    Interactive effect of deep tillage and irrigation regimes on crop growth and yield of kharif maize
    (Punjab Agricultural University, Ludhiana, 2016) Harmandeep Kaur; Meharban Singh
    Deep tillage responses in maize on coarse textured soils are reported to be related with improvement in root growth and plant water status. In a field study on sandy loam soil at the research farm of Department of Soil Science during Kharif 2015; combinations of two tillage systems i.e. conventional tillage (CT) and deep tillage (DT) and two irrigation regimes i.e. irrigation water/pan evaporation ratios of 0.5 (I1) and 1.0 (I2) were evaluated on two maize hybrids i.e. PMH1 (long duration) and PMH2 (short duration). DT with sub soiler loosened soil in chisel furrow up to 35-45 cm depth. Comparatively higher bulk density i.e. 1.66 and 1.69 Mg m-3 was observed in 15.0-22.5 and 22.5-30.0 cm soil layers, in CT and the reduction in bulk density with DT was maximum in these layers. The penetration resistance (PR) was also lower with DT than with CT; however the magnitude of decrease varied with soil depth and position of measurement. Root length density (RLD) at 70 DAS, was higher under DT than CT in the 15-90 cm depth and increased irrigation level produced higher RLD, under DT but not under CT. Root length index (RLI) in the 90 cm soil profile, did not vary with irrigation level but DT increased RLI. Both leaf area index and plant height were generally higher under DT than CT and with I2 over I1, but the effect was significant only for DT. PMH2 was significantly shorter in plant height than PMH1 at all the growth stages. Leaf water potential (LWP) at 66 DAS was significantly higher with DT and with I2 in both the hybrids. Increase in LWP with I2 over I1 was significant under CT only. Soil temperatures in general were lowered with irrigation & DT and were slightly lower in PMH1 than PMH2. Both DT and higher irrigation caused higher chlorophyll content, but effect was significant for DT only. Fifty percent tassel stage under DT as compared to CT, was 3.3 & 1.8 days earlier in PMH1 and 4.8 & 7.2 days earlier in PMH2; in I1 & I2 treatments respectively. Both grain and biological yields (grain plus stover) were significantly higher with DT over CT and with I2 over I1 in both the hybrids. PMH1 as compared to PMH2, produced significantly higher grain (12.5 %) and biological (17.8 %) yields. Percent increase in grain yield with DT over CT, for I1 & I2 respectively, was 33.8 & 30.6 in PMH1 and 24.5 & 16.8 in PMH2. Significant interaction was observed between tillage and cultivar for biological yield only. Harvest index did not vary significantly with tillage and irrigation treatments, but hundred grain weight varied significantly with tillage and cultivar. Soil profile water use was higher in DT over CT; by 43.5 & 24.5 mm in PMH1 and 31.6 & 22.6 mm in PMH2; for I1 & I2 irrigation regimes respectively. Averaged over other two treatments; water productivity (kg ha-1 mm-1) was higher in DT over CT by 21.2 %; in I1 over I2 by 6.0 % and in PMH1 over PMH2 by 10.9 %.