Studies On The Stalk-degradable Microbial Preparation In Main Food Crops And Its Application

In this study the best stalk-degradation combine strains were screened and the stalk-degradation microbial preparation were produced by using the indoor shake flask method. Pot experiments and field trails were conducted to discuss the effect of straw decomposition and plant growing with stalk-degradable microbial preparations applied. The results were as follows: 1.It was found that the degradation of wheat/rice/corn straw in soil showed the periodic degradation characteristics according to the pot experiments and field trails. The decomposition process of straw could be regarded as four stages: initial degradation stage, early degradation stage, middle degradation stage and late degradation stage:(1) In pot experiments, the initial stage is 0~10d, and the straw weightlessness rate of wheat/rice/corn reached about 15%, 20% and 35%; the early stage is 10d~30d, and the straw weightlessness rate of wheat and rice reached about 20%~30%, while the straw weightlessness rate of corn reached about 35%~45%; the middle stage is 30d~80d, and the straw weightlessness rate of wheat/rice/corn reached 30%~50%, 30%~55% and 50%~70% respectively; the late stage is after 80 days, and the straw weightlessness rate of three kinds straw reached over 50%, 65% and 70% respectively.(2) In field trails, to the wheat straw, the initial stage is 0~45d and the straw weightlessness rate reached about 40%; the early stage is 45d~90d and the straw weightlessness rate reached about 40%~50%; the middle stage is 90d~135d and the straw weightlessness rate reached about 50%~60%; the late stage is after 135 d and the straw weightlessness rate reached over 60%. To the rice straw, the initial stage is 0~45d and the straw weightlessness rate reached about 20%; the early stage is 45d~90d and the straw weightlessness rate reached about 25%~30%; the middle stage is 90d~150d and the straw weightlessness rate reached about 30%~55%; the late stage is after 150 d and the straw weightlessness rate reached over 55%. To the corn straw, the initial stage is 0~45d and the straw weightlessness rate reached about 50%; the early stage is 45d~120d and the straw weightlessness rate reached about 40%~50%; the middle stage is 120d~210d and the straw weightlessness rate reached about 50%~70%; the late stage is after 210 d and the straw weightlessness rate reachedover 70%.2. Effects of straw degradation with stalk-degradable microbial preparations applied were studied. Results indicated that it couldn’t change the degradation process of straw in soils with stalk-degradable microbial preparations applied, and the degradation effects were not the same in pot experiments and field trails. In pot experiments, the effects for wheat straw was in the early stage, and for rice and corn were in the initial stage, and the effects for the three kinds of straw were not as obvious as in the middle and the late stage. Compared without stalk-degradable microbial preparations applied, the degradation effects of applying stalk-degradable microbial preparations were as followed: for wheat straw, its straw weightlessness rate, cellulose degradation rate and hemicellulose degradation rate reached 27.65%~30.96%, 27.97%~32.50% and 29.59%~32.85% respectively at 20 d, increased by 36.22%~52.52%, 43.67%~66.90% and 30.86%~45.28% respectively; for rice straw, its straw weightlessness rate, cellulose degradation rate and hemicellulose degradation rate reached 24.74%~26.70%, 30.17%~33.44% and 28.61%~34.48% respectively at 10 d, increased by 33.57%~44.17%, 29.14%~43.17% and 70.37%~105.38% respectively; for corn straw, its straw weightlessness rate, cellulose degradation rate and hemicellulose degradation rate reached 35.24%~41.15%, 17.27%~27.53% and 37.18%~40.63% respectively at 10 d, increased by 11.26%~29.92%, 183.62%~352.13% and 25.99%~37.67% respectively.3. It was studied that effect of different kinds of straw in different periods were not the same with stalk-degradation microbial preparation applied. Similarly, for wheat straw, its straw weightlessness rate, cellulose degradation rate and hemicellulose degradation rate reached 39.14%~45.77%, 41.70%~43.92% and 41.57%~47.11% respectively at 30 d, increased by 6.16%~24.15%, 28.10%~34.93% and 2.54%~16.21% respectively. As to the degradation effects, all the three preparations accelerated the degradation of straw. As to the degradation time, they made 10d~15d in advance in the early stage. For rice straw, its straw weightlessness rate, cellulose degradation rate and hemicellulose degradation rate reached 26.91% and 27.35%, 42.40% and 44.08%, 25.46% and 26.02% respectively at 45 d with preparation A and B, increased by 34.53% and 36.74%, 68.86% and 75.55%, 56.10% and 59.55% respectively. The two preparations could make 10d~15d early in advance in the early stage, but preparation C has no effect. For corn straw, its straw weightlessness rate, cellulose degradation rate and hemicellulose degradation rate reached 53.90%, 17.65% and 26.78% at 45 d with preparation B, increased by 13.35%, 46.00% and 43.50%. It could make 15d~20d early in advance in the early stage, but preparation A and C has no obvious effect.4. Results indicated that it could accelerate the degradable of straw with stalk-degradationmicrobial preparation applied. The content of soil labile carbon was increased obviously, and rate of seedling was increased as well as the plant biomass.