Trials to determine the optimal rate and time of nitrogen application to cotton were conducted at three sites for three seasons. The results indicate that nitrogen is used most efficiently when applied at relatively low rates, with at least half the application delayed until flowering. Early application leads to the incorporation of a greater proportion of the nitrogen into the vegetative structures which, at lower rates, may leave insufficient for fruit development. With late application a greater proportion of the nitrogen is utilized in reproductive growth, although full utilization may not be achieved at higher rates.

The effects of irrigation and spraying of transpiration suppressants on growth and nutrient uptake by spring sorghum (CSH 6) have been investigated. Crop growth, measured by plant-height, leaf area index and dry matter production, and uptake of N, P and K increased with more frequent irrigation and in response to the spraying of transpiration suppressants. Foliar applications of atrazine at 200 g ha−1 and CCC at 300 ml ha−1 proved to be the best in this NW Indian location.

Increments of fibre, sucrose and reducing sugars per cane were estimated for 12 varieties of sugarcane for successive periods in plant and ratoon crops. Sucrose production increased only as that of fibre and reducing sugars fell. Dry matter production per unit fresh weight of leaf blade was negatively correlated with an estimate of gram days of leaf per gram fresh weight of cane. In a further study the net assimilation rate of one variety was found to remain fairly constant over a period of six months at 0·55g/dm2/week. It is suggested that breeding should seek to reduce leaf area ratio while maintaining sucrose percentage cane.

Sisal showing symptoms of parallel streak developed more slowly than symptomless plants, both leaf length and number of leaves unfurled being reduced. In streaked areas of the leaf, ground tissues surrounding the peripheral and internal fibre bundles collapsed; decortication of streaked leaves was difficult and fibre quality was adversely affected by reduction in length and discoloration. Parallel streak was seen only in vegetatively propagated Agave sisalana, in leaves lacking marginal spines. The condition was observed only where the mean minimum temperature fell below 16°C; symptoms appeared five months after the onset of a period of low temperature. Apparently every A. sisalana plant in Kenya is affected, but the condition is masked in coastal regions due to high mean minimum temperature. The disease seems not to be due to bacterial or fungal pathogens, or to nutritional factors, but may be caused by a virus, or a genetic ‘disease’ similar to June Yellows of strawberries.

Optimum transplanting age and relative growth rate in three groups of rice varieties differed with types and maturity periods. Transplanting 52 day old seedlings reduced the shoot number, and the magnitude of reduction was higher in early than in mid-early and medium varieties. Early transplanting reduced the number of days to flowering in all three groups compared with transplanting later. Senescence was much earlier in early types transplated as 52 day old seedlings. Grain production in early types was more sensitive to late transplanting than the mid-early and medium types. Medium varieties outyielded the early and mid-early ones when transplanted at 38 days after seeding.

Papaver bracteatum Lindl., a potential source for codeine production, is a perennial species which is known to flower from the second year of growth. Through selection and early planting date, a high flowering rate (96%) was achieved during the first growing season. The flowering response and yield of capsules were very sensitive to planting date and seedling type. Delaying planting markedly decreased both flowering rate and yield of capsules in the first year. Direct sowing was more advantageous than transplanting. A yield of 36 g/m2 of dry de-seeded capsules was obtained during the first growing season by direct sowing in late summer.

This review gives a historical perspective of the development of Farming Systems Research (FSR) in India over the past 60 years, as India changed from a traditional, subsistence oriented agriculture to one based on science and technology. The first period relates to the years 1930–50, when the Government of India created the Indian Council of Agricultural Research (ICAR) and initiated research on dryland agriculture.

The second period relates to the development of coordinated agronomic trials and simple fertilizer experiments on farmers' fields during the years 1950–65. This development was a forerunner of networks of coordinated applied agronomic research relevant to farmers' cropping systems and adaptive research with farmers' participation. The development of a soil conservation research network in the same period strengthened research on the natural resource base countrywide. The third period started with the reorganization of ICAR, the establishment of State Agricultural Universities and the introduction of coordinated research programmes on high-yielding varieties (HYVs). At the same time the coordinated dryland agricultural research programmes, and subsequently the Central Research Institute for Dryland Agriculture (CRIDA), were established, leading to the development of a national system of FSR for rainfed agriculture.

The fourth period of FSR started with the establishment in 1972 of ICRISAT, an international agricultural research centre that accepted FSR as its mandate and developed the concept of integrating the management technologies for various components of climate, soil, water and crops with a farmers' perspective. ICRISAT's work was complementary to that of CRIDA and helped to bring about conceptual changes in Indian FSR through research aimed at understanding principles and processes of semi-arid tropical (SAT) farming systems. Following this, mechanisms for strengthening on-farm research were emphasized so as to provide stronger linkages between researchers, extension workers and farmers.

Today, FSR with a farmers' perspective occupies pride of place in India's agricultural research agenda. Yet it is a long way from bridging the gap between the generation of technology and its adoption by farmers, who have shown a preference for its components rather than for the full package of technology.

Use of substituted phenoxyacetic acids as yield stimulants for Hevea brasiliensis has been mainly limited to applications below the tapping cut rather than above. Although the above-cut application of these stimulants has exhibited some advantages with respect to yield, its use has been limited due to undesirable bark renewal characteristics. This paper describes studies with a method of above-cut application of stimulant which appears to eliminate the previous disadvantages. Reduced concentrations of growth regulator, applied at frequent intervals in combination with a disease preventive measure, resulted in favourable yield responses, bark renewal characteristics and application economics. Subsequent bark renewal was apparently directly proportional to the concentration of stimulant applied and it was thus possible to control the degree of bark regeneration. The above-cut method shows promise of being particularly effective with systems of reduced intensity tapping on certain clones.

Factorial treatment structure and, in particular, confounded designs are important methods of using experimental resources efficiently. Confounded experiments are not used, and possibly not understood, by experimenters. However, the construction and analysis of confounded designs is logically extremely simple, and can be expressed in terms of simple principles. Modern computing facilities can make confounded designs even more useful.

The range, mean, genotypic and phenotypic coefficients of variation, heritability and genetic advance for various characters, of forty-seven varieties of ragi (Eleusine coracana) showed a wide range of variation and highly significant varietal differences. The genetic advance was highest for yield of straw and genotypic coefficients were higher than phenotypic coefficients for most characters. Path coefficient analysis indicated that the number of productive tillers and grain weight of main ears were the major components for seed yield.

An investigation was carried out to study the effects of boron (0, 1, 2 and 3 kg/ha) and nitrogen (0, 50, 100 and 200 kg/ha) on the growth and yield of radish cv Pusa Rashmi. Various growth characters such as number, fresh weight and dry matter content of leaves, and length, girth, fresh weight and dry matter content of roots increased with increase in boron and nitrogen levels, the highest application of both nutrients giving the best results. Treatment combinations showed significant effects on fresh weight of leaves and roots, with the best results from 3 kg boron + 200 kg of nitrogen/ha.

The relationship of leaf weight ratio (LWR), leaf area ratio (LAR), stomatal frequency and dry matter (DM) production with yield and with photosynthetic efficiency, as reflected by 14CO2 fixation rate, was studied in fox-tail millet (Setaria italica) for three consecutive years. Several genotypes were identified which combined small leaf area and/or low stomatal numbers per plant with productivity under rain-fed conditions equal to that of genotypes with large stomatal numbers. 14CO2 studies in these genotypes showed that the rate of carbon fixation by the leaves was greater, at any canopy position, than in the corresponding large LA/large DM types. Genotypes with consistently small stomatal numbers per plant, associated with good dry matter accumulation and productivity, may also show small transpirational water loss under rain-fed or drought conditions. It is concluded that such genotypes are desirable for better productivity under these conditions.

A method is described of inducing many ‘eyes’ on yam tubers to sprout, and of using the sprout-bearing segments as propagules for establishing yam fields. The number of such propagules obtainable from a tuber depends on its size, but the method greatly increases the rate of propagation and holds special promise for both breeding and commercial production of yam.

Simultaneous deficiencies of nitrogen (N) and phosphorus (P) which limit crop production in western Kenya can be overcome through a combined application of organic and inorganic fertilizers. An experiment was conducted with maize (Zea mays) for two seasons to compare two methods of applying inorganic P fertilizer (broadcast versus spot) in a factorial combination with three N sources, i.e. farmyard manure (FYM), Tithonia diversifolia green manure (tithonia) and urea. Net financial benefits of the tested practices were computed using partial budgeting. Maize yield was not significantly affected by the P fertilizer application method in the first season, but the broadcast method was generally superior to spot application in the second season. The three N sources produced maize yields that were comparable in both seasons. FYM integrated with P fertilizer applied using the broadcast method, however, had the highest cumulative net benefit and was therefore the most economically attractive input combination.

The dry matter yield, nutritive value and persistence of three legume species (Stylosanthes hamata Taub., S. capitata Vog. and Centrosema pascuorum Mart. ex. Benth.) cut at different frequencies during the growing season or only once at the end of the growing season were compared. The shorter cutting intervals enhanced regrowth, but very frequent cutting reduced total dry matter and seed yields. A defoliation interval of three to six weeks is recommended. Generally, S. hamata gave the best performance.

Efecto del deshoje en tres legumbres

Sugarcane yields and smut incidence levels were observed in three successive crops. The effect of pathogen upon host was primarily one of stress, as smut infection was shown to increase sucrose content of cane whilst depressing yields in tonnes of cane per ha. Where infection levels were high, roguing was shown to increase disease incidence. However, smut whip removal was confirmed as the best roguing treatment for commercial fields. Disease control and yield responses related to roguing effort were much better in NCo 376 than NCo 310; and, therefore, continued cultivation of NCo 310 fields with high smut incidence was concluded to be a major hazard to the industry.

The response of sesame to fertilizer was studied in 11 trials at four different sites, in which phosphorus was applied at rates from 0 to 26 kg ha−1 to the seed bed and nitrogen at rates from 0 to 60 kg ha−1 after thinning. Yield responses, found only to the main effects of nitrogen and phosphorus, are discussed in relation to soil type and previous cropping history of the sites and used to calculate gross cash returns from fertilizer use. Seed oil content was affected by environment, but responses to nitrogen and phosphorus were inconsistent.