Oat straw

A ready reckoner for the amount of N, P and K removed by certain representative crops is shown in Table 5.2. The requirement for P and K may be expressed in terms of the element rather than the oxide (P205 or K20). P205 contains 0.43 units of P K20 contains 0.83 units of K. The depletion of N, P and K from the grain of wheat, barley and oats is pro rata for yield, but the nutrient composition of the straw is different, oat straw containing very much more potassium than wheat or barley straw. Potatoes and kale are very much more exhaustive of N and K than the cereal crops. 

Phenolic acids have already been discussed as inhibitory compounds. But inhibition of germination requires a concentration of 10 to 10 M phenolic acids. (j ). Such high concentration may locally be achieved if oat straw is accumulated in the fields (4). This could sometimes be a reason for poor plant growth on fields after harvest of oats without removal of straw. We did not find such concentrations in our husk extracts, however they were 100 - 1000 fold smaller than expected from bioactivity. Phenolic acids are therefore not the active compounds in our inhibitory extracts. 

All assays (21) contained C 180 / g protein, 1000 units of Cx (CM-cellulose) activity (26), and 100 units of /3-glucosidase where necessary, /3-glucosidase isolated from the cellulase of F. solani (21) was added. The a-celluloses were the residues left after delignification and extraction with 18% (w/v) NaOH of oat straw, birch wood, and ryegrass. 

Straw is the general term for those parts of a cereal plant left over after the grains or seeds have been removed. It consists largely of the dry stalk or stem, and some leaves. During the harvest of such crops as wheat, rye, barley, com, or oats, straw is usually whatever is left behind in the field. It has historically been used in a variety of ways, and was regarded as an important product of the harvest... 

The scope of work in a first phase of the project included the adaptation of this peat pyrolysis system for conversion of agricultural residues, preliminary testing to identify operating problems, characterization of two feedstocks (oat straw and corn stover) and finally, experiments to determine product yield and composition at various operating conditions. 

Feedstock Characteristics. Feedstock characteristics are presented in Table I. Results of the metal analysis will be considered in Phase II of the project. Calorific values were approximated using Dulong s formula and not actually measured. The oat straw had a lower ash content than the stover and a correspondingly higher calorific value. Calorific values, calculated on a dry basis and including the latent heat of water vapour in the products of combustion (high heat value), were 17.9 MJ/kg for the straw and 16.0 MJ/kg for the stover. 

Pyrolysis of agricultural residue was experimentally assessed as a fuel production process for farm applications. A rotary kiln (3.4 m by 0.165 m I.D.) was used due to its ease of operation, commercial availability, low operating costs and ease of start-up and shutdown. Ground oat straw and corn stover at less than 10% moisture were pyrolysed in an indirectly fired continuous-flow rotary kiln located at the University of Sherbrooke. The principle products were char and gas, less than 1% of the feed mass was converted to tar. Calorific values were about 17 MJ/kg for the feed, 26 MJ/kg for the char, and 12 MJ/m3 for the gas. Calculations indicate that the thermal efficiency of a self-sustaining process would be around 65%. 

Conversely, there are many low nitrogen forages which do not respond to nitrogen supplementation. Under experimental conditions similar to those of Campling et al. (10) supplemental urea had no effect on the digestion ceilings or intake of wheat straw (0.64% N) or oat straw (0.52% N) fed to sheep and steers, respectively (28). 

Effect of Urea Supplementation on the Nutritive Value of NaOH-treated Oat Straw... 

Experiment 7. The Effect of NaOH Level and Dilution on the In Vitro Digestion of Oat Straw Cellulose... 

Table I. The Effect of NaOH Treatment and Pelleting on the Nutritive Value of Oat Straw (Experiment II)...

Methods. Oat straw harvested in 1967 was treated with NaOH according to the method previously described. Eight female Cheviot lambs were used in this experiment which was designed to substantiate the results obtained in Experiments II and III, and to test in addition the effect of supplementation of straw with a soluble carbohydrate (sucrose) source. This experiment was designed as a 2 X 4 factorial with the effect of treatment (untreated vs. NaOH-treated) compared with four different supplementations (none, sucrose, urea, sucrose + urea). One sheep was fed each of the eight treatment combinations in each replicate, with six replicates constituting the experiment. As in the previous experiments, urea was added at a 2.5% level. Sucrose was added at a 3.5% level in three of the replicates, and an approximately equivalent amount of sucrose was supplied from a 7.0% level of molasses in the other three replicates. The percent of supplements added thus varied from 0-9.5% with the remainder of the ration (91.5-100%) consisting of treated or untreated straw. 

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