An experiment was carried out in the glasshouse to determine the availability of P, and utilization of added phosphate fertilizers from three fertilizer materials, applied by two different methods to sugar cane grown in four diverse soil systems. Phosphorus was applied at the equivalent rate of 175 pounds P (400 pounds P2O5) per acre. A larger response from added P in terms of plant yields was obtained from an aluminous ferruginous latosol and least from dark magnesium clay. Differences in yields of sugar cane were evidently associated with differences in P content in the cane plants and, in certain cases, with a reduction in Al content in plant tops, and the less soluble superphosphate increased yields more than the highly soluble NH4H2PO4. Phosphate fertilizers applied as foliar spray greatly increased the P content in the plants, and plants contained twenty times more P when sprayed with NH4H2PO4 than when the same fertilizer was applied to the soil. However, increased P content in the plants did not necessarily indicate that the P was translocated within the plants or that the added P participated in metabolic processes. The evidence indicated that in soils where the ‘A’ value was high the P status of the sugar cane tops was not correspondingly high.

An on-farm study was carried out at 17 different sites within the Western Hills of Nepal during the spring and summer seasons of 1993 and 1994 in order to monitor the plant population density dynamics of the maize (Zea mays L.) crop under farmers' management. Five farmers were selected randomly at each site and a 20-m2 plot was demarcated just after maize sowing. The maize stands within the 20-m2 plots were first recorded 20 d after sowing, and then at 10-d intervals until harvest. Farmers were allowed to perform all cultural practices on their own. On average, the initial plant stand across all locations and over two seasons was 69 100 ± 1800 plants ha−1, which resulted in 37 300 ± 1700 plants ha−1 at harvest, a 46% reduction from the initial stand. At most locations, the population declined by 30–40 × 103 plants ha−1 between emergence and harvesting and in no cases were the recommended plant populations achieved at harvest. Populations varied across sites and seasons. The rate of population decline was higher in the low and mid hills compared to high-altitude areas. Thinning which is carried out between 30 and 60 d after sowing at most sites was the major cause of population reduction, and delay in thinning was intended to increase fodder production from the thinned maize. In addition, the removal of barren plants at the silking stage and of smutted, lodged and damaged plants attributed to about 12% of total reduction in plant population. The larger the initial stand, the larger was the proportion of barren plants to be removed. No clear relationships were observed between soil fertility and final plant stand at harvest.

Application of zinc to six high-yielding rice varieties in calcareous soils produced significantly higher grain yield and interactions between varieties and Zn levels were significant. Yields of varieties IR 20, Jaya, Sita and Jayanti at 2.5 and 5.0 ppm Zn were similarly affected, but Archana produced significantly higher grain yield at 5 ppm Zn than at 2.5 ppm. Effects of Zn on straw yield were similar. Zn application invariably resulted in a higher Zn concentration in plants at all stages of growth and in grain in all varieties. Maximum Zn contents were observed at the tillering stage and minimum at harvest.

In trials over 2 years at five locations in Northern Nigeria single inputs were removed from a package of maize practices. The improved variety was most important and increased the yield of the otherwise complete package by 86%. Early sowing and high plant population were not important in all trials. The high fertilizer treatment (125–50–50 kg NPK/ha) consistently exceeded the half rate, with a mean increase of 31%. It was suggested that, with clean weeding, priority should be given to the improved variety, high fertilizer and early sowing. High populations, involving changes to traditional techniques, may be introduced gradually.

The yield potential of a highly productive non-commercial Type IV bean cultivar was determined under optimum field conditions, grown in monoculture at 1 plant/m2 on trellises 3 m high. Canopy growth was analysed by dividing the stand into 25 cm horizontal strata. The main components of yield were number of inflorescences and number of pods per stratum. Daily yield for the growing period was 4.9 g dry weight/m2. Although a high yield per plant was recorded (823 g/plant) drop of young pods and seed abortion were the major factors reducing the potential yield.

Four sesame varieties were tested at three plant populations to study varietal and population effects on some attributes of vegetative growth. Significant differences between varieties were detected and planting density was found to modify both areas and dry weights of leaves.

The time and method of placement, and the distance from the plant at which fertilizers should be placed, was studied on sole-crop cowpeas. The development and yield of both early and late season crops were highest where fertilizers were applied at planting. It is suggested that it might be more advantageous to plough the fertilizers under before planting, so that the nutrients will become available to the seedlings from the time they emerge. Application of fertilizer in two bands gave the highest yields, but was not significantly superior to a less laborious method of application in one band. The distance at which the fertilizer was placed, and treatment interactions, did not show any definite trends.

The productivity of climax and serai grassland in South Africa was compared at three stocking rates with steers. On climax grassland, over nine years, gains per head at one steer per morgen (= 2·12 acres = 0·86 hectare) were not significantly greater than at two steers per morgen. Liveweight gains per morgen were 70 per cent higher at the heavier stocking rate and were 162 lb and 273 lb at one and two steers respectively. On serai grassland, over three seasons stocked at two steers and three steers per morgen, the liveweight gains per steer were significantly less at the higher stocking rate but there was no significant difference in the gains per morgen, which were 366 lb and 318 lb at two and three steers respectively. The liveweight gains on the seral grassland were significantly higher than on the climax grassland at the same stocking rate Calculation of the total digestible nutrients (T.D.N.) has shown that with heavier stocking more T.D.N. per morgen may be harvested on both grassland types. However, with heavy grazing the efficiency of conversion of T.D.N. into liveweight was less. The quality of the sward, measured in per cent crude protein, P2O5 and crude fibre was better at the heavier stocking owing to delayed maturity of the grass when it is continually grazed short.

Twenty strains of Eragrostis curvula, together with E. plana, Chloris gayana and Digitaria smutsii, have been compared on the basis of (a) herbage yields and (b) nitrogen, phosphate and potash composition and yield, from broadcast stands in a randomized block experiment over two seasons. The strains of E. curvula were grouped into types for which the names Curvula, Robusta Blue, Robusta Green, Robusta Intermediate, and Chloromelas were used. Significant differences were demonstrated in herbage yield between certain of these types, but there were no clear differences in nitrogen content. Chloris, Digitaria and the three Robusta types had the highest phosphate and potash content, whereas the Chloromelas type and E. plana were intermediate and the Curvula type was lowest in these constituents. Robusta Green, Robusta Intermediate and Curvula types had the highest nitrogen yield, Robusta Green and Robusta Intermediate types the highest phosphate yield, and Robusta Intermediate and Robusta types the highest yield of potash. The superiority of types other than Curvula (Ermelo and Tanganyika strains), and the need for research on the types, has been demonstrated.

Pests and diseases cause appreciable loss to tea in north-east India, but their incidence and intensity of attack vary widely from district to district, and within districts with variation in climate, elevation and the jat (seed-source) of tea. For example, blister blight is a serious disease in Darjeeling and looper catepillar is mainly localized in certain tea estates of the Assam valley. Thus recommendations regarding pesticides and their application in a particular region must be based on a thorough knowledge of the distribution of the diseases or pests in the region. This can best be obtained through sample surveys, planned in representative estates of the region and carried out with the help of trained investigators. Such surveys will also provide basic data on jat, environment and disease, as a guide to experimentation.