Effect of Continuous Rice–Wheat Rotation on Soil Properties from Four Agro‐ecosystems of Indian Punjab

Abstract

In Indian Punjab, rice-wheat is a dominant cropping system in four agro-ecosystems, namely undulating subregion (zone 1), Piedmont alluvial plains (zone 2), central alluvial plains (zone 3), and southwestern alluvial plains (zone 4), varying in rainfall and temperature. Static and temporal variabilities in soil physical and chemical properties prevail because of alluvial parent material, management/tillage operations, and duration of rice-wheat rotation. A detailed survey was undertaken to study the long-term effect of rice-wheat rotation on soil physical (soil separates, bulk density, modulus of rupture, saturated and unsaturated hydraulic conductivities, soil water content, and suction relations) and chemical (organic carbon, pH, electrical conductivity) properties of different textured soils (sandy clay loam, loam, clay loam, and silty clay loam) in these four zones of Punjab. Soil samples (of 0-to 30-cm depth) from 45 sites were collected during 2006 and were analyzed for physical and chemical properties. The results showed that sand content and pH increased whereas silt and organic carbon decreased significantly from zones 1 to 4. Compared to other textures, significantly greater organic carbon, modulus of rupture, and pH in silty clay loam; greater bulk density in clay loam, and greater saturated hydraulic conductivity in sandy clay loam were observed. Irrespective of zone and soil texture, in the subsurface soil, there was a hard pan at 15-22.5 cm deep, which had high soil bulk density, modulus of rupture, more silt and clay contents (by 3-5%) and less organic carbon and hydraulic conductivity than the surface (0-15 cm) layer. These properties deteriorated with fineness of the soil texture and less organic carbon content. Continuous rice-wheat cropping had a deleterious 2945 effect on many soil properties. Many of these soils would benefit from the addition of organic matter, and crop yields may also be affected by the distinct hardpan that exists between 15 and 22.5 cm deep.

Impact of Temporal Change of Land Use and Cropping System on Some Soil Properties in Northwestern Parts of Indo-Gangetic Plain

“…The lower OC content in the lower layers during 2008 may be blocking of translocation of organic matter due to the formation of impervious layer below the surface having higher bulk density (1.8 g cm 3 ). Similar results were also reported by other studies [23][24][25][26] . Decreasing trend in pH was observed in the surface soils (7.3 Soils occurring on recent flood plain are not fully developed.…”

Dynamics of Hydraulic Properties of Puddled Soils

“…Water retained by different soils at varying suctions in the four agro climatic zones of Punjab where puddling has been continuous from more than 15 years is reported by Singh et al (2009). Water retention was higher in zone 1(undulating sub region), followed by zone 2 (piedmont alluvial plains) and zone 3 (central alluvial plains) and least in zone 4 (southwestern alluvial plains) ( Figure 1a).…”

“…Amongst the textural class, saturated hydraulic conductivity was significantly more in sandy clay loam due to more sand content in the soil (66 per cent) than other classes, where it ranged from 31-55 per cent. Saturated hydraulic conductivity was more in the surface soil (due to more organic carbon and less bulk density) and it decreased with depth and was lowest in 15-22.5 cm soil layer, where bulk density and organic carbon were having reverse trend than the surface soil (Singh et al, 2009 Table 2. Averaged effects of agro climatic zones, textures and soil depths on saturated hydraulic conductivity.…”

“…Saturated hydraulic conductivity of sandy clay loam soil (Fig 3) generally decreased from agro climatic zone 2 to zone 4 in soil depths because of changes in temperature which resulted into decrease of organic carbon content in the surface soil layers and increase in the bulk density of subsoil layers (Singh et al, 2009). Hence better puddling for reducing water flux is difficult to achieve in the soil having high organic carbon leading to high structural stability index.…”

Effect of tillage practices on least limiting water range in Northwest India

“…Studies in Punjab (Kukal and Aggarwal, 2003;and Singh et al, 2009) have shown the presence of a high soil bulk density (ρ b ) layer at 15-25 cm soil depth under this monoculture. Therefore, there is a need to diversify the prevailing wheat-rice cropping system with the wheat-maize system, which will help in preventing the deterioration of soil health as well as restricting the fall of underground water by consuming less water as compared to rice.…”