An increase in enzyme concentration resulted in significant rise of hydrolysis rate of rice straw, wheat straw, and bagasse.
Different rates of straw removal did not affect stalk industrial quality.
Seven gradient rates of straw return, including 0%, 25%, 50 %, 75 % and 100of total straw from previous crop returned in rice and wheat seasons, and 100% of stotalreturned only in rice or wheat strawn were set.
Six rates of straw mulching (0, 4.5, 6.0, 7.5, 15.0 and 30.0 Mg/ha) were assigned to the main plots and two irrigation water qualities (i.e. brackish water with salt content of 3.0 5.0 g/L and fresh water with only 1.27 g salt/L) were applied to subplots.
However, the cyclic incorporation of higher rates of straw (3.0 and 6.0 t ha−1) failed to alter the grain yields of II year rice crop significantly in comparison to control.
Fertilizers increased straw-N transfer to these plant parts both with and without mulching due to the increase of plant biomass, showing greater plant utilization rates of straw-N in the N fertilizer addition treatments, while residual rates of straw-N in soil decreased in these treatments.
The rate of the straw degradability was also higher on WCL diet than that in WPL diet after 8, 16, and 24 h of incubation.
In nature, the bioconversion rate of paddy straw is slow and natural microflora participates in degradation of the crop waste.
The worldwide generation rate of rice straw was about 731 million dry tons in 2007.
In the hydrolysis experiment, the initial rate of rice straw hydrolysis was reduced from 2.26 to 1.553 g L−1 hr−1 when cellulase was added at a concentration of 150 U g−1 rice straw.
