The structural characteristics and composition of sorghum grains which are currently grown are reviewed and possible future improvements that may benefit the grain processor are pointed out. Literature data are given for: composition of whole sorghum grain and hand-dissected fractions; amino acid analyses; amino acid composition of sorghum endosperm meal and protein fractions; lipid analysis of grain sorghums; carotenoid content of sorghum grain; 2-dimensional chromatogram of anthocyanogens and carotenoids in yellow-endosperm sorghum cross.

Carrier-free H₃³²PO₄ was injected into a Sharpsburg silty clay loam soil at depths of 15, 30, and 61 cm when corn (Zea mays L., vat. ‘Nebraska 202’) and sorghum (Sorghum bicolor (L.) Moench, var. ‘Nebraska 505’) plants were 23, 39, and 59 days old. At the 23-day age most ³²P was taken up by roots in the upper 15 cm. Corn roots penetrated to a 61 cm depth earlier than sorghum roots. As the season progressed, sorghum lateral root activity at the 30 and 61 cm soil depths became important. Following the radioactive P injections when plants were 59 days old, sorghum took up more ³²P than corn. Plant age or depth of injection had little effect on the ³²P contributed by roots at varying distances from the source. Roots which extended laterally beyond 66 cm contributed little to the P nutrition of either corn or sorghum grain. Both corn and sorghum had root systems that penetrated to a depth of 152 cm and extended laterally 238 cm.

The influence of sorghum (Sorghum bicolor L. Moench), sesame (Sesamum indicum L.) and groundnuts (Arachis hypogaea L.) unfertilized and fertilized with N and P and of bare and weed fallow on the subsequent season's performance of sorghum and groundnuts was studied in 2-year trials. The fertilizer rates of 50 kg/ha of N and 22 kg/ha of P applied to the first season's crops affected the yield of the second season's sorghum but not of groundnuts. Two consecutive years of sorghum or groundnuts was deleterious to the second season's yield. Symbiotic fixation in groundnuts was apparently low due to soil acidity and the absence of recent groundnut cultivation. Bare fallow increased moisture by 7.4 mm in the top 1.0 m of soil as compared to weed fallow, but the increase was not reflected in the yield of either crop.

Atrazine [2-chloro-4(ethylamino)-6-(isopropylamino)-s-triazine] and propazine [2-chloro-4,6-bis(isopropylamino)-s-triazine] were applied to sorghum [Sorghum bicolor (L.) Moench] at 1.12 to 8,96 kg/ha on separate plots in 1960–63, 1965, and 1966 at 11 experimental locations across Nebraska. Winter wheat was seeded 15 months later. Atrazine, when applied to sorghum at recommended rates, did not affect subsequent winter wheat yields at North Platte on Holdrege loam and Holdrege silt loam. Occasionally, there was winter wheat stand reduction following atrazine and propazine at 4.48 and 8.96 kg/ha. At Alliance on Keith very fine sandy loam, winter wheat fall top growth was reduced by atrazine at 4.48 kg/ha in 1962 and 1963. Thinning of stand did not always reduce grain yields because of subsequent tillering. There was an increase in winter wheat grain yields in 1964 on plots treated with atrazine at 2.24 kg/ha in the sorghum in 1962. At Lincoln, on Sharpsburg silty clay loam, winter wheat yields were reduced from atrazine carryover in 1963 but not in 1964. Under most Nebraska conditions, atrazine applied to sorghum at recommended rates will not persist long enough to cause yield losses of winter wheat in a winter wheat-sorghum-fallow rotation.

Since sorghum is grown in wheat producing areas of the USA, a study was made of the possibility of producing satisfactory sorghum flour on wheat milling equipment. Experimental milling of grain sorghum (commercial No. 2 yellow milo, yellow milo hybrid TE-77, white sorghum hybrid Funk G-766) was carried out on a Buhler Automatic Laboratory Mill. The sorghum was tempered to the desired moisture level (in the range 16.5 to 20.5%). During processing it was necessary to remill the shorts to obtain sufficient flour for 70% extraction rate. Shorts remaining after remilling were milled in a pin mill and added to the final flour. The various milled samples were analysed for moisture, protein, crude fat, ash and crude fibre. Results are tabulated and discussed. For No. 2 yellow milo, the extraction limit is ~70% in order to obtain 1% fat or less in the flour. The procedure of Freeman and Watson [FSTA (1969) 1 8M512] was used for peeling hybrid TE-77. The fat and ash contents of peeled and unpeeled grain were similar, but peeled grain contained less fibre (0.9% against 1.7%). The recovery of low-fat, low-ash flour when milling peeled grain was 10% more than that obtained when milling whole grain. Contents of moisture, fat and ash, colour, and flavour and odour scores of both commercial and lab.-prepared flours were compared. Fat and ash contents were approximately the same in all samples, and flavour and odour scores indicated no extreme differences between samples. White sorghum hybrid flour had the least colour, the other samples had a slight pink colour. Uses of sorghum flour are briefly discussed.

Two varieties of sorghum (Sorghum bicolor L. Moench) and sesame (Sesamum indicum L.) and one of groundnuts (Arachis hypogaea L.) were grown at different population densities with and without nitrogen and phosphorus fertilizers, under 578 mm rainfall in a Sand Sheet (“goz”) soil. Sesame and groundnut yields increased when the maximum plant populations presently utilized in the area were increased by 50%. Further density increases were ineffective for those two crops. Grain sorghum did not respond to any increases in the density. The difference in response between sorghum and the other two crops was attributed to differences in type of root system, which in turn affected the pattern of soil moisture depletion in the soil profile. No interaction between varieties, either unfertilized or fertilized, and population densities was noted. Soil moisture rather than soil nutrients seemed the limiting growth factor in these trials.

The effect of adding urea as a supplemental nitrogen source for rumen microorganisms in a two-stage in vitro digestion technique was determined with shelled corn Zea mays L., corn fodder, sorghum fodder Sorghum bicolor (L.) Moench and alfalfa Medicago sativa L. as substrates. Digestibility in vitro of shelled corn and corn fodder was greatly increased by urea supplementation. Urea slightly increased digestion of sorghum fodder but had no effect on digestion of alfalfa. Some inhibition of sorghum digestion resulted with the highest level of urea supplementation (15 mg urea per 0.25 g substrate dry matter). The optimum amount of urea supplementation, an amount at which highest digestibility was obtained without inhibiting the digestion of any one crop, was 10 mg urea per 0.25 g substrate dry matter. The need for N supplementation to obtain maximum digestion in vitro of substrates containing large amounts of readily-available carbohydrates was clearly demonstrated.

Sorghum, Sorghum bicolor (L.) Moench, was successfully propagated from proliferated spikelets caused by head smut, Sphacelotheca reiliana (Kuehn) Glint. Undetached panicles with proliferated spikelets were surrounded with moist soil until the spikelets developed roots. Removing and transplanting the rooted spikelets resulted in the development of normal plants.