Forage cultivation and processing; Feeding utilization of agricultural by-products; Harmless treatment of livestock and poultry manure

The roughage utilization of rice straw

The feeding utilization of rice straw could relieve the environment pollution caused by straw burning in south China where is the main planting area of rice. Feeding utilization of straw could also provide ample roughage for ruminants, so as to solve the shortage of roughage in agricultural area. Ensilaging could efficiently preserve the nutrients of fresh straw and improve its palatability. In recent years, we have been doing research on the roughage utilization of rice straw, including the double-purpose rice variety selection, the cultivation methods to improve rice straw feeding quality, the bale ensilaging technology and the feeding safety of rice straw silage, so as to supply instructions for increasing rice straw utility rate as roughage.

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 other parts of the plant (p<0.05). However, the acid detergent fiber (ADF) content in sheath and the hemicelluloses content in leaf were higher than in stem (p<0.05). The in vitro dry matter digestibility (IVDMD) of stem was significantly higher than leaf and sheath (p<0.05).

2. Double-purpose rice variety selection and their morphological traits

The good quality double-purpose rice varieties had relatively low plant height and large green leaf area per tiller at harvest; and they also had thick 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 rice straw feeding quality, not significantly decreasing grain yielding, we concluded that the optimal harvest time of Liangyoupeijiu (late maturing medium indica) was 6 d before theoretical whole growth period (TWP), Nanjing 44 (early maturing late japonica) and Wuyujing 3 (late maturing medium japonica) were 3 d after TWP, and Nanjing 46 (medium maturing late japonica) was 6 d after TWP.

4. The bale ensilaging technology

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

5. The feeding safety of rice straw silage

The slathering, and even overcommiting of pesticide during rice growth period would bring hidden danger for rice straw used as roughage. The degradation rate of pesticide in straw of silage was significantly lower than that of natural withering. According to the residues of pesticide in rice straw whether by natural withering or ensilaging, the feeding for animals was all at safety level after harvested 35 days.

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 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.