Research

Feeding Utilization of Rice straw

The feeding utilization of rice straw could relieve the environment pollution caused by burning straw in China and could also provide ample roughage for ruminants while to solve the shortage of roughage in agricultural area. Ensilaging could efficiently preserve nutrients of fresh straw and improve its palatability. In recent years, we have been doing research on feeding utilization of rice straw, including selection of double-purpose rice variety, improvement of feeding quality by changing cultivation methods, bale ensilaging technology and feeding safety, so as to promote utilization of rice straw as feed.

 

1. The feeding quality of different parts of rice plant

The nonstructural carbohydrates (NSC) content in the top 3rd stem, and the crude protein (CP) content in the top 1st leaf were higher than that in other parts of the plant (p<0.05). However, the content of acid detergent fiber (ADF) in sheath and the hemicelluloses content in leaf were higher than that in stem (p<0.05). The in vitro dry matter digestibility (IVDMD) of stem was significantly higher than that of leaf and sheath (p<0.05).

 

2. Selection of double-purpose rice variety and their morphological traits

The good quality and double-purpose rice varieties had relatively low plant height and large green leaf area per tiller at harvest; and they also had more wall thickness, high parenchyma area and low vascular bundle area percentage of the top 3rd internode, and high starch particle quantities in the parenchyma of the 3rd internode.

3. Suitable harvest time for different double-purpose rice varieties

In order to get high feeding quality of rice straw, not significantly decreasing grain yield, we concluded that the optimal harvest time of Liangyoupeijiu (late maturing medium indica) should be 6-day earlier than that of theoretical whole growth period (TWP), Nanjing 44 (early maturing late japonica) and Wuyujing 3 (late maturing medium japonica) should be 3-day later than that of TWP, and Nanjing 46 (medium maturing late japonica) should be 6-day later than that of TWP.

 

4. Bale ensilaging technology

By selecting special microflora in silage, inventing equipments for baling and automatic spraying lactic acid solution, the quality of rice straw silage was improved and could be made TMR for dairy cattle.

        

 

5. Feeding safety of rice straw silage

The slathering and over committing of pesticide during rice growth period would have potential risk for rice straw to be used as feed. The degradation rate of pesticide in straw of silage was significantly lower than that of natural withering. According to the analysis of residue pesticide in rice straw whether by natural withering or ensilaging, the feed for animals was of all at safe level after 35 days from harvest.

 

6. Isolation and identification of lactic acid bacteria in rice straw silage

The diversities of cultivable microorganisms in both pre and post-ensiled straws were investigated; and two strains of lactic acid bacteria from post-ensilage straw were isolated. There were not only spoilage organisms (Bacillus), but also pathogenic bacterium (Enterobacter) in pre-ensiled straw. After ensiled, the main putrefication bacterium is Bacillus and corruption fungi consist of Penicillium and Fusarium. Two strains of isolated 1actic acid bacteria are Lactobacillus casei and Pediococcus ethanolidurans. There is still spoilage organism in post ensiled straw. Therefore, fermentation process should be improved to prevent aerobic deterioration.

 

Relevant publication:

 

The feeding quality of rice (Oryza sativa L.) straw at different cutting heights and the related stem morphological traits

Authors: Chen Fei Dong, Yi Xin Shen, Cheng Long Ding, Neng Xiang Xu, Yun Hui Cheng, Hong Ru Gu.

Abstract: This study was to investigate the feeding quality of rice (Oryza sativa L.) straw at different cutting heights and the related stem morphological traits. Wuyujing 3, Yangfujing 8 and Liangyoupeijiu in 2010, and Wuyujing 3, Nanjing 44, Nanjing 46, and Liangyoupeijiu in 2011 were used in this study. In 2010, the feeding quality related traits (such as nonstructural carbohydrates (NSC), crude protein (CP), hemicelluloses and acid detergent fiber (ADF) contents) of rice straw among three cutting heights 10 cm, 20 cm and 30 cm were investigated. In 2011, the nutrient contents (such as NSC, CP, hemicelluloses and ADF contents and in vitro dry matter digestibility (IVDMD)) of leaf, sheath and stem in the top 1st, 2nd and 3rd nodes and the stem morphological characteristics by free hand sections were investigated. The results in 2010 indicated that the NSC content of rice straw at 10 cm cutting height was higher than that at 20 cm and 30 cm cutting heights, CP content of rice straw at 10 cm cutting height was lower than that at 20 cm and 30 cm cutting heights, hemicelluloses and ADF contents were not significantly different among 3 cutting heights. The results of 2011 indicated that the NSC content in stem of the top 3rd node was much higher than that in the 2nd and 1st node, and higher than that in leaf and sheath of the same node. CP content in leaf was much higher than that in stem and sheath. Hemicelluloses content in leaf and sheath was higher than that in stem, and ADF content was higher in sheath than that in leaf and stem, but all not significantly (p > 0.05). IVDMD of stem was higher than leaf and sheath. Those results could explain the feeding quality differences of rice straw at different cutting heights. Wall thickness (WT) and the parenchyma area percentage of stem were significantly positively correlated with NSC content and IVDMD (p < 0.05), which could be used as selection traits for more digestible rice straw.

 

Double-purpose rice (Oryza sativa L.) variety selection and their morphological traits

Authors: Chen Fei Dong, Cheng Long Ding, Neng Xiang Xu, Yun Hui Cheng,Yi Xin Shen, Hong Ru Gu

Abstract: This study was to investigate double-purpose (grain as human food and straw as roughage) rice (Oryza sativa L.) variety selection and their morphological traits at harvest. Eight japonica cultivars and one indica cultivar grown in 2011, and nine japonica cultivars and two indica cultivars grown in 2012 were used. At harvest, the grain yielding related traits such as 1000-grain weight and one-panicle weight, and the feeding quality related traits of straw (such as nonstructural carbohydrates (NSC)) ,crude protein (CP) and acid detergent fiber (ADF) contents and in vitro dry matter digestibility (IVDMD)) were investigated in two years from 2011 to 2012. The grain yielding (GY) and straw yielding (SY) of 10 plants, the fermentation quality related traits (pH, lactic acid (LA) and NH3-N concentration) of straw, plant height (PH) and green leaf area per tiller (GLA) at harvest were analyzed in 2012. The top 3rd internodes of stem were used to make free hand sections to visualize the morphological traits of stem. The results indicated that Wuxiangjing 14, Wuyujing 3 and Nanjing 44 had good straw feeding quality (with high NSC content, IVDMD and good fermentation quality such as low pH and NH3-N concentration and high LA concentration) and were suitable for double-purpose use. The good-quality double-purpose rice varieties were of relatively low plant height and large green leaf area per tiller at harvest and were of thick culm diameter and wall thickness, and high-percent parenchyma and low-percent vascular bundle area for the top 3rd internode in stem.

 

Isolation and identification of lactic acid bacteria, analysis of cultivable microbial diversity in rice straw silage

Authors:WANG Yan-su , ZHANG Yi-fan , YAN Zhen-ya , DING Cheng-long, DAI Chuan-chao

Abstract: The diversities of cultivable microorganisms in both pre and post-ensiled straws were investigated and two strains of lactic acid bacteria from post-ensilage straw were isolated.According to morphological characteristics of bacteria1 colonies, bacterial strains subjected to amplified ribosomal DNA restriction analysis(ARDRA ). Then 1actic acid bacteria were separated and identified from rice straw silage by ARDRA and RAPD-PCR technology. The results show that the number of aerobic bacteria decreases from 7.6×107 cfu.g-1 to 2.43×106cfu.g-1, the populations of fungi significantly decrease from 4.43×105 cfu.g-1 to 86 cfu.g-1, whereas the number of lactic acid bacteria increases from 4.16×105 cfu.g-1 up to 6.61×106cfu.g-1 after ensiled. There are not only spoilage organisms (Bacillus), but also pathogen pathogenic bacterium (Enterobacter) in pre-ensiled straw. After ensiled, the mainly putrefying bacterium is Bacillus and corruption fungi consist of Penicillium and Fusarium. Two strains of isolated 1actic acid bacteria are Lactobacillus casei and Pediococcus ethanolidurans. There are still spoilage organisms in post ensiled straw. Therefore, fermentation process should be improved to prevent aerobic deterioration.

 

Study on the harvest time of different rice (Oryza sativa L.) varieties for grain-straw-dual-use

Authors:DONG Chen-fei, DING Cheng-long, XU Neng-xiang, CHENG Yun-hui, SHEN Yi-xin, GU Hong-ru

Abstract: Investigation of the optimal harvest time to obtain high feeding quality rice (Oryza sativa L.) straw would be useful to increase the utility of rice straw as roughage. In this study, we used four rice varieties Liangyoupeijiu (late maturing medium indica), Wuyujing 3(late maturing medium japonica), Nanjing 44 (early maturing late japonica), and Nanjing 46(medium maturing late japonica), and set five harvest times (6d before the theoretical whole growth period(TWP), 3d before TWP, TWP, 3d after TWP, 6d after TWP), and investigated the grain and straw yielding, the rice straw feeding quality related traits such as nonstructural carbohydrates (NSC),crude protein (CP), acid detergent fiber (ADF) contents and in vitro dry matter digestibility (IVDMD) and the fermentation quality of straw silage (pH, lactic acid (LA) and NH3-N content).The results indicated that the grain yielding increased with the delay of harvest time; NSC content in rice straw of Liangyoupeijiu 6 d before TWP, Nanjing 44 3 d before TWP, Wuyujing 3 3 d after TWP and Nanjing 46 6 d after TWP were the highest among their 5 harvest times; CP content in rice straw decreased with the delay of harvest time. The change trends of straw yielding, IVDMD and the fermentation quality were consistent with that of NSC content. In order to get high rice straw feeding quality, not significantly decreasing grain yielding, we concluded that the optimal harvest time of Liangyoupeijiu was 6 d before TWP, Nanjing 44 and Wuyujing 3 were 3 d after TWP, and Nanjing 46 was 6 d after TWP.