The impact of treatment of organic manures on future soil carbon sequestration under different tillage systems in Pakistan | [Pakistan Journal of Agricultural Sciences • 2017]

Author(s):

1. Khuram Shahzad: Department of Agricultural Sciences, University of Haripur-22060, Pakistan; Institute of Biological and Environmental Sciences, School of Biological Sciences, University of Aberdeen,23 St. Machar Drive, Aberdeen, AB24 3UU, Scotland, UK

2. Ayub Khan: Department of Agricultural Sciences, University of Haripur-22060, Pakistan

3. Mark Richards: Institute of Biological and Environmental Sciences, School of Biological Sciences, University of Aberdeen,23 St. Machar Drive, Aberdeen, AB24 3UU, Scotland,UK

4. Jo U. Smith: Institute of Biological and Environmental Sciences, School of Biological Sciences, University of Aberdeen,23 St. Machar Drive, Aberdeen, AB24 3UU, Scotland,UK

Abstract:

Field experiments were conducted at Gujjar Seed and Nursery Farm, Haripur, Pakistan to investigate impact of incorporating differently treated of organic manures using different tillage systems on soil carbon. Maximum increase in soil carbon was observed when the required nitrogen was applied as bioslurry produced from cattle manure by anaerobic digestion. This was significantly greater than when the required amount of nitrogen was applied as composted poultry manure or chemical fertilizer. Minimum tillage also resulted in a significant increase of soil carbon compared to conventional or deep tillage. These experimental measurements were used to evaluate a dynamic simulation model of soil organic matter turnover, RothC, which was then used to estimate future carbon sequestration. The correlation between experimental and simulated values was highly significant and the root mean square error was within experimental error, suggesting that RothC is providing an acceptable representation of the changes in soil carbon that is occurring in this experiment. The uncertainty in simulations was less than 3%. Simulations were done using future weather scenarios; these suggest that addition of the recommended rate of nitrogen in 8.4 t ha-1 y-1 bioslurry every year increases soil carbon sequestration over 100 years (2012-2112) by 24.9±0.74 t ha-1 compared to the control where no organic manure was applied. This sequesters 7.5±0.24 t ha-1 more carbon than if the same amount of nitrogen is applied as poultry manure, requiring an application rate of 7.5 t ha-1 y-1. If the same amounts of bioslurry and poultry manure are applied, carbon sequestration is still significantly greater for bioslurry than for poultry manure (4.5±0.2 t ha-1). Losses of carbon with climate change were highest under climate scenario B2 (environmental protection with regionalization) and B1 (environmental protection with globalization), followed by A1B (economic growth with globalization), with minimum losses from A2 (economic growth with regionalization). These predicted losses are likely to be more than compensated for by application of organic fertilizers at the rates needed to supply sufficient nitrogen to the crops.

Page(s): 277-286

DOI: 10.21162/PAKJAS/17.4486

Published: Journal: Pakistan Journal of Agricultural Sciences, Volume: 54, Issue: 2, Year: 2017

Keywords:

poultry manure , Organic manures , RothC , bioslurry , nitrogen sources , Soil carbon sequestration

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