Effect of soil compaction and fertilizer placement depth on growth, yield, nutrient uptake of maize (Zea mays L.) and soil properties in tarai soils of Uttarakhand

Soil compaction and placing of fertilizer in undesirable depth in soil are the most serious threat under intensive cultivation system in poorly drained heavy textured soil. In view of this, a field experiment was conducted during kharif season of 2014–15 to understand the effect of soil compaction and fertilizer placement depth on performance of maize crop, nutrient uptake and soil properties. The soil was heavy textured i.e. silty clay loam with poor drainage and receiving about >1400 mm rainfall annually. Root length and root length density of plants in compacted plots (1.54 and 1.63 Mg/m³) decreased remarkably from 1.50–4.60 cm and 0.06–0.11 cm/cm³, respectively, compared with non-compacted soil (1.34 Mg/m³) however root dry weight did not exhibit response against soil compaction. Maximum grain yield of 5613.4 and 5593.0 kg/ha was recorded with non-compacted soil (1.34 Mg/m³) and 0–10 cm fertilizer placement depth, respectively, however at par yields were obtained between 1.54 and 1.63 Mg/m³ compaction levels. Compaction and fertilizer placement depth showed highest adverse effect on Zn uptake (14.70–20.42%) whereas least on P uptake (6.23–11.0%). Non compacted soil (1.34 Mg/m³) and placing fertilizer at 0–10 cm depth maintained favourable oxidizable organic carbon and hydraulic conductivity but reduced with increase in compaction and placement depth. In general, strong negative and non-significant relationships of the compaction and fertilizer placement depth with growth and yield parameters, yields, nutrient uptake and soil properties were estimated.

Soil compaction at 1.54 Mg/m³ and fertilizer placement at 0-20cm depth reduced the maize grain yields by 10.6 and 8.8% over 1.34 Mg/m³ and 0–10 cm depth respectively, and further increase in compaction and depth had less effect.

Uptake of nutrients was affected more between compaction levels of 1.34 and 1.54 Mg/m³ but for fertilizer placement depths between 0–20 and 0–30 cm.

Organic carbon reduced significantly by 9.8% at 1.54 Mg/m³ over non-compacted soil but was at par with 1.63 Mg/m³ however hydraulic conductivity reduced significantly at all compaction levels. Fertilizer placement depth had significant effect on organic carbon, pH and electrical conductivity.