Among the processes in orchard fruit production, partial mechanization has done little to reduce the peak demand for labour during the year. The most welcome new machine would be a harvester which, if it is to displace labour, will above all have to be efficient in not damaging the fruit. As regards English apples and pears, a machine that is to replace labour that is no longer available would have to be almost equally efficient. Working back from an economic specification, it seems that an efficient machine will be expensive, and that an expensive machine will have to harvest hundreds of acres to be economic.

An appreciable loss of gaseous N from added urea was recorded in two sub-tropical soils of East Pakistan under laboratory controlled conditions, markedly accentuated by the presence of decomposable organic materials which increased ammonification and tended to decrease nitrate accumulation. The addition of bonemeal to the soils had little effect.

Visual symptoms of deficiencies of manganese, copper, zinc, iron, molybdenum and boron on sisal are described, and compared with those observed previously with deficiencies of macronutrients. The diagnostic value of symptoms is discussed, and tentative suggestions made for micronutrient concentrations in leaves for adequacy and deficiency.

Observations on the relative degree of root nodulation were made for three successive years on tall and short cultivars of Pisum sativum and Phaseolus vulgaris sown at dates appropriate to each cultivar and grown under conditions of ordinary horticultural practice. In P. sativum, it was found that the shorter the cultivar, the greater were the number and weight of nodules per plant and the weight of nodules as a percentage of plant weight; dwarf cultivars also produced a greater weight of nodules per square metre of ground occupied and per square metre per day of crop growth. In Ph. vulgaris, differences in number and weight of nodules per plant between dwarf and climbing cultivars were not consistent between years. In a single comparison between Ph. uulgaris and Ph. multiflorus (scarlet runner beans), numbers and weights of nodules per plant were almost identical. Some agronomic implications of these findings are discussed.

Crop Growth Rate, Leaf Area Index, Net Assimilation Rate and Harvest Index were estimated for oil palms in nine age groups growing on coastal alluvial soils in Malaysia. The mean Crop Growth Rate of mature palms was 29·83 t./ha./yr, with a Leaf Area Index of 3·61, and Net Assimilation Rate was 0·16 gm./dm.2/wk. Photosynthetic efficiency was about 2·2 per cent. Oil constituted about 17 per cent of total dry matter production. Possibilities for improving the yield of oil are briefly discussed.

Incorporation of dry matter of perennial soybean into the soil, alone or with mineral fertilization, resulted in improved vegetative growth of common beans. Fairly high LAI was observed at flowering time where dry organic matter had been added, causing leaf self-shading and decreased growth in the later states of development. In contrast, both the control and mineral fertilized plots showed slower but continuous growth up to 50 days from plant emergence. Only slight differences in grain yield were noticed despite remarkable increases of Crop Growth Rate, Relative Growth Rate, Net Assimilation Rate, and Efficiency of Solar Energy Conversion that resulted from the application of dry organic matter.

The analysis is presented of a 17 variety maize diallel cross grown in Tanzania at 1300, 500 and 200 m. Thirteen of the varieties included Central American material, mainly Caribbean and Flint types, and four were derived from Eastern African Flat-White maizes. Variety cross performance was much affected by environmental conditions. At 200 and 1300 m., four of the top five varieties were the same, and selection of varieties for composite formation was not particularly critcal. At the 500 m. site, order of yields differed markedly from the other sites, and predicted composite yield was much more affected by the choice of varieties included. Criteria are discussed for selection of varieties to be included in composites at the three altitudes.

In upland rice, seed soaked in CCC for 24 hours before sowing or sprayed with CCC 10, 21, 42 and 63 days after sowing, showed severe lodging. Effects of CCC on the number of paniclebearing tillers, number of good grains in 1000 grains, weight of 100 good grains and grain yield were not significant. On the other hand CCC prevented lodging in swamp rice, with the lowest percentage when foliar spray was given 21 days after transplanting. CCC failed to increase the number of panicle-bearing tillers and grain yield in swamp rice.

Water use by maize at three densities was measured by a complete water balance, including soil moisture, rain, applied irrigation and deep drainage in crops irrigated so that relative turgidity at noon remained above 90 per cent (i.e. no-stress conditions). Total evapotranspiration between planting and harvest, 56 cm., was not significantly affected by density, but evapotranspiration was slightly higher at higher densities when ground cover was less than 50 per cent. Actual evapotranspiration rose to 1 cm. per day during anthesis and grain filling. A fifth of the water applied moved beyond the root zone, indicating that work on more permeable soils would be inaccurate if the deep drainage component was ignored.

Young tea plants were grown for eight months in large polythene bags of soil, with provision to prevent rain from running into the soil. After a preliminary period of establishment, in which all plants were kept well-watered, four soil moisture regimes were applied ranging from watering twice weekly to withholding irrigation until plants had been subjected to a soil moisture tension of 15 bar, as determined by gypsum resistance units, for a period of one week before rewatering. Plant survival and growth were significantly better under the wettest compared with the driest regime.

Seedling tests for reaction of tomato cultivars to leaf mould (Cladosporium fulvum) showed that a single race 1·3, or a mixture of races 1 and 3, was present at four sites in the Western State of Nigeria sampled at different times during 1967 and 1968. Vetomold, Vantage, Vinequeen, Astronaut, Floradel, and Tarran were immune and Purdue 135 was resistant. Genetic tests showed that the Cf2, gene conditioned immunity and that the Cf4 gene provided resistance.

The effects of pollination on set and growth of summer squash var. Zucchini were investigated. In winter, parthenocarpic fruits developed and pollination had no effect, but in summer only pollinated fruits continued to grow. Partial pollination in summer caused ovary abortion of some fruits, and a reduced rate of fruit growth in those which continued to grow. The ovary was 8·8 cm. long at anthesis in winter but only 8·2 cm. long in summer.