Drying rates of stem internodes of S. 24 perennial ryegrass and S. 37 cocksfoot, some with leaf sheaths and laminae attached, were measured in controlled conditions of air speed, temperature and relative humidity after exposure for 60 sec to dry heat, steam, steam containing petroleum ether vapour, and petroleum ether vapour only. The last treatment was most effective in increasing the drying rate, but a similar effect was obtained by splitting the stem internodes longitudinally or by removing from the larger plant fragments (internodes with leaf) the leaf sheaths and laminae. Observations on leaves with a scanning electron microscope confirmed that the steam and petroleum treatments acted on the surface waxes thus reducing the cuticular resistance to water loss. The presence of internal tissue resistance was demonstrated by anaerobic treatment of ryegrass leaves and stem internodes to disrupt cell protoplasts. The ensuing increase in drying rate was clearest in stems which have a low surface area to volume ratio. The results suggest that the combination of both mechanical damage and thermal or chemical surface treatment could form the basis for more effective methods of increasing the drying rate in the field of crops cut for conservation.

Nine high-oil varieties of sunflower were evaluated for their reactions to salinity during emergence in salinized soil culture ranging from 0 to 12·80 mmhos/cm under controlled temperature of 27±1 °C. The varieties were Louck, Vniimk-8931, Chernianka-66, Record, Armarisky, Peredovik, Orizont, Mhjak and Zarea.

Soil salinity decreased the percentage of emergence in all varieties of sunflower. The rate of decrease in emergence of some varieties was greater than others. Among varieties tested Vniimk-8931 (a tall variety) and Chernianka-66 (a dwarf variety) showed the highest and the lowest tolerance to salinity at 7·60 mmhos/cm, respectively. For electric conductivities above 7·60 mmhos/cm, the nine varieties of sunflower could be classified in three categories. Vniimk-8931, Record, Louck, Peredovik and Armarisky as high salt tolerant, Mhjak and Orizont as medium salt tolerant and Chernianka-66 as low salt tolerant varieties.

In a dry area of Southern Tanzania with a single rainy season irrigation during the six-month-long dry season (May-November) doubled the total annual yield of tea and at the same time evened its distribution over the year to some extent. Other factors including low temperatures limited growth rates during the period June-September despite irrigation, whilst a lull in production in November appeared to be unrelated to external factors. Roots were traced to depths of about 4·3 m and by the end of the dry season unirrigated bushes were drying the soil below 3m. In general total yields decreased with decreasing frequency of irrigation and quantity of water applied but because these plants were deep rooting they could withstand deficits up to 100 mm without a reduction in yield, equivalent to a loss of about 25% of the total available water in the profile. There was some evidence that the most economical use of water occurred when the soil was not rewetted to field capacity at each irrigation, although yields were then less. Irrigation also reduced the incidence of a stem canker, Phomopsis theae. The implications of these results to the tea industry of East Africa are discussed.

The habit of growth of pigeon-pea cultivars was greatly affected by environmental changes. The effect was greatest in the highest yielding cultivar, Pant A2, for the characters plant width, number of pods/main branch, number of pods/plant, grain yield and plant weight. In the late-sown crop the ‘vegetative sink’ was affected more than the ‘generative sink’. T21 was the outstanding yielder under late-sown conditions. It is suggested that a rotation of mungbean–pigeon pea–wheat can be grown in 1 year, with profitable returns.