Effects of long-term contrasting lime and phosphorus applications on barley grain yield,root growth and abundance of mycorrhiza |
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| Authors: | Julie Therese Christensen Musibau Oyeleke Azeez Rodrigo Labouriau Sabine Ravnskov Hanne Lakkenborg Kristensen Lars Juhl Munkholm Gitte Holton Rubæk |
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| Institution: | 1. Department of Agroecology, Aarhus University, Tjele, Denmark;2. Department of Mathematics, Aarhus University, Århus C, Denmark;3. Department of Agroecology, Aarhus University, Slagelse, Denmark;4. Department of Food Science, Aarhus University, Aarhus N, Denmark |
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| Abstract: | Lime and phosphorus (P) applications are common agricultural management practices. Our aim was to quantify the effects of long-term application practices on root growth and abundance of arbuscular mycorrhizal fungi (AMF) under field conditions. We assessed the effects of lime and P fertilizer applications on barley yield, root growth and AMF abundance in 2016. Treatments were no, low, medium and high liming rate corresponding to application of 0, 4, 8 and 12 Mg lime ha?1 every 5–9 years since 1942 combined with no or yearly application of 15.6 kg P ha?1 since 1944. At harvest, grain yield, root intensity (core-break) and AMF abundance at different soil depths were estimated. Root development was monitored during early growth with minirhizotrons in treatments receiving low, medium and high liming rates and P fertilization. A quadratic model relating grain yield to liming rate estimated yields to peak at 6.4 Mg lime ha?1 with yields of 4.2 and 3.2 Mg grain ha?1 with and without P fertilization, respectively. Low and medium liming rates resulted in greater AMF abundance, especially in the no P treatments. During early growth in P-fertilized treatments, 77% and 65% more roots developed in the soil profile when treated with medium and high liming rate, respectively, compared to low liming rate. We conclude that long-term application of lime in soils receiving yearly P fertilization improved conditions for root growth in soil layers below 30 cm, but at the high liming rate, this did not translate into higher yield. |
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| Keywords: | core-break method minirhizotron soil penetration resistance soil pH |
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