Impact of various organic amendments on soil microbial biomass and enzymes activities under different cropping patterns; an incubation study
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Abstract
As nutrients decomposition is an important factor which make the nutrients available to the plants, therefore, a 60-day an incubation study was carried out in the laboratory of Soil Science & SWC to investigate the rate of decomposition of various organic amendments. For this purpose, two organic amendments such as wheat straw and ground nut straw were applied to soils of Kahuta, Kahirimurat and Pindi Gheb areas. Soil samples were collected at days after 2, 4, 7, 14, 28 and 60 days incubation. The results revealed that all the three amendments increased microbial biomass Carbon, nitrogen and phosphorus and enzyme activity particularly after day 2 indicating microbial biomass turnovers. The rate of decomposition in soil of all sites varied in all treatments for microbial biomass carbon, nitrogen, phosphorus, Dehydrogenase and Alkaline Phosphatase. It was observed that maximum rate of decomposition was on 28 days after incubation and then remained stagnant afterward. The groundnut straw (1% on soil weight basis) had more rate of decomposition than wheat straw (1% on soil weight basis). This might be due to availability of suitable environment for enzymes to convert the organic substrate into available nutrient for the growth of crop. It is concluded that organic amendments can stimulate microbial growth and microbes can increase plant nutrient availability. These outcomes will benefit the scientific community for recommending the organic amendments along with synthetic fertilizers for maintain soil health on sustainable basis with concomitant enhance in yield.
Keywords: Enzyme activities; Groundnut straw; Microbial biomass; Organic amendments; Wheat straw