|Title: ||Potassium balance as influenced by farmyard manure application under continuous soybean–wheat cropping system in a Typic Haplaquept|
|Citation: ||Geoderma, 137(1-2): 155–160|
|Issue Date: ||2006 |
|Additional Links: ||http://www.elsevier.com/wps/find/journaldescription.cws_home/503332/description#description|
|Abstract: ||The effect of 30 years of continuous cropping, fertilization and manuring on the potassium (K) balances, the soil K pools and the nonexchangeable K release in a Typic Haplaquept soil from Almora, India under a rainfed soybean–wheat cropping system were investigated. The apparent K balance was measured as the difference between the total K added and that removed by the crops. The results showed that the total removal of K by the crops exceeded the amount of total K applied to the soil in all the treatments showing a net negative K balance. This ranged
from 3.7 in the plots under NK to 81.7 kg ha−1 year−1 in the N+FYM treated plots. Continuous annual application of recommended doses of NPK+10 t FYM (NPK+FYM) to soybean resulted in an accumulation (+56 kg K ha−1) of exchangeable K (1 N NH4OAc extractable K) in the 0–45 cm soil depth over the study period, despite the highest average annual uptake of K by the system (150.8 kg ha−1 year−1). However, there was a net depletion of exchangeable K (−80 kg K ha−1) in that soil depth under the NPK treated plots. The results also revealed that the content of
non-exchangeable K decreased substantially from 3482 kg ha−1 to 2677 and 2896 kg ha−1 in the 0–45 cm soil layer after 30 years of cropping in the plots under NPK+FYM and NPK treatments, respectively.
There was a significant decline in total soil K with the removal of non-exchangeable soil K in the surface (0–15 cm) soil layer (R2=0.526,Pb0.001, n=36). Thus, long-term application of non-revised recommended fertilizer rates may threaten sustainability of the rainfed continuous soybean–wheat system.|
|Description: ||Metadata only|
|Keywords: ||Soybean based cropping system|
K balance sheet
Long term cropping
Soil K status
|Appears in Collections: ||Plant and Environmental Research Group|
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