The first number of the Empire Journal of Experimental Agriculture, of which this journal is the immediate successor, appeared in April 1933. It was part of a significant collaborative trend which included the Empire Marketing Board, the Commonwealth Agricultural Bureaux, and the International Wheat Pool, and led in time to the Commonwealth Secretariat and, indirectly, to FAO. The new journal was intended to serve agricultural progress in all the countries of the world which were connected with Britain, including South Africa and the Sudan. In the subsequent half-century of great change many new general and specialist journals have arisen, particularly in the more developed countries, in the Commonwealth and elsewhere; and this journal has come to be concerned mainly with production-oriented agricultural research in tropical, sub-tropical and winter-rainfall environments.

A technique for leaf area measurement utilizing water spray as an inexpensive substitute for electronic equipment was developed and tested with leaves of potato (Solanum tuberosum L.). The leaf areas measured by the spray method were highly correlated with those measured by an electronic area meter. Measurements of leaf area obtained by the spray method were significantly more highly correlated with those obtained by the area meter than were the measurements of dry weights. The main advantages of the new method are precision, accuracy and immediate results at a low cost.

A series of grazed and cut experiments were conducted in Bali and North Sulawesi, Indonesia, between 1992 and 1994, to evaluate a range of selected forages for both intensive and extensive ruminant production under mature, tall coconuts. Yield, botanical composition and persistence of grass–legume mixtures were assessed under regular grazing and cutting regimes.

In North Sulawesi, total dry matter yields of most grass–legume treatments were relatively stable over the two-year period but yields of legume components within treatments declined sharply. In Bali, the grazed plots maintained stable yield and legume components over the experimental period but yield and legume components of cut plots declined sharply. Paspalum malacophyllum and Setaria sphacelata cv. Splenda were productive and persistent grasses and formed weed-free swards but did not combine well with prostrate legumes. The erect growth habit of these grasses may limit their suitability in coconut production systems by impeding nut collection. The prostrate species Brachiaria humidicola and Stenotaphrum secundatum were slightly less productive but equally weed-free and persistent, and established rapidly from cuttings. S. secundatum also formed stable associations with prostrate legumes under grazing. Arachis pintoi cv. Amarillo and A. glabrata CPI 93483 were the most persistent of a range of prostrate legumes. The tree legume, Calliandra calothyrsus, showed promise as a productive cut-and-carry species.

A survey of barley and barley-based farming systems was carried out in Palestine during the 2000 growing season to assess traditional cultivation methods and to analyse developments in the production systems. Seventy-six farmers in the three barley growing agro-ecological zones in the West Bank were included in the study. The research area encompasses a range of agro-ecological conditions, from high to low potential environments, strongly related to precipitation. Estimated grain yields varied from below 1000 kg ha−1 in the driest part of the Eastern Slopes zone to above 4000 kg ha−1 in the more fertile areas in the Central Highlands and Semi-Coastal zones. Barley was found to be closely linked to the dominant crop-livestock farming systems. Thus 84% of the farmers interviewed grew barley as a feed for their own livestock during the dry season. In the more fertile agro-ecological zones, the traditional farming system is shifting towards more intensive production methods with increased mechanization, mainly for land preparation, sowing, harvesting and use of fertilizer. Here animal production is becoming more intensive and a larger proportion of the farm products, including barley, is now produced for the market. Despite the relatively high yields, in comparison to other barley growing areas in the region, local barley landraces, particularly 6-rowed types, persist well and were preferred by 86% of the farmers interviewed. However attempts to modernize agriculture may result in the replacement of traditional barley landraces, and even the barley-livestock cropping system in the more fertile agro-ecological zones. An effort should therefore be made to conserve this valuable genetic resource.

The effects of nematodes on root morphology and the association of root characteristics with resistance to nematodes of seven banana varieties were investigated in two experiments. Banana plants were grown in controlled conditions within polytunnels and harvested on three occasions for the measurement of root morphology and biomass. Varieties differed in their resistance to nematodes, from resistant (Yg Km5, FHIA 17, FHIA 03) and partly resistant (FHIA 01, FHIA 25) to not resistant ((FHIA 23, Williams). Nematodes reduced the root dry weight of FHIA 01, FHIA 17 and FHIA 23 at some harvests. Primary root number was on average 9.5% lower in nematode-infected plants than controls, with no differences among the varieties. Thus, there was no simple association between the resistance of these varieties and their tolerance to nematodes. Varieties differed in root morphology. Root dry weight was greatest for resistant varieties Yg Km5 and FHIA 03, and least for non-resistant varieties FHIA 23 and Williams. Thus, resistance to nematodes was associated with varieties with greater root mass and more and larger primary roots.

Field trials were carried out using an aerial spray of Magniosan 55 (55 per cent magnesium nitrate) for the correction of severe magnesium deficiency in a Valencia orange orchard. Two treatments were applied, in autumn and spring respectively, each containing 50 l. Magniosan 55 solution in 200 l. water per hectare. The spray did not cause damage to fruit or leaves, penetrated satisfactorily into the lower and interior part of the canopy, and increased the Mg content of the leaves of treated trees from 0·095 to 0·190 per cent.

The efficiency of fertilizer N uptake by wheat, as affected by time and rate of application, was studied in the field using N15 labelled ammonium nitrate. Splitting the application was only beneficial at the maximum rate but two top dressings at tillering and boot stage were better for grain production than a basal dressing or single top dressing at stem extension stage, but uptake of fertilizer N was maximal from a single top dressing. The calculated effective rate of application (E.R.A.) was useful in evaluating the effect of time and rate of application and N availability to plants.

On unlimed Malaysian peat (pH 3.5), flue-cured tobacco produced negligible leaf yields and showed no response to urea. Liming up to pH 5.25 (32 t/ha lime) linearly increased leaf yield. Tobacco responded linearly without reduced leaf quality to 90 k/ha N at pH 4.01 (8 t/ha lime), but to 45 kg/ha N at pH 4.40–5.25 (16–32 t/ha lime), higher N rates at the respective liming levels producing leaves of lower quality. The optimum rates of P and K for flue-cured tobacco appeared to be 26 and 186 kg/ha respectively, with linear responses up to those rates.

Research institutes in Africa have had limited success in producing new technologies appropriate to the needs of small farmers because of an inadequate understanding of small farmers' goals and resource limitations and over-reliance on the transfer of technologies from other regions. Farming systems research (FSR) is an effective way of improving the focus of scientists on the problems farmers face. Vertically segmented thematic research programmes make institutionalization of FSR difficult within multi-commodity research centres, particularly the International Agricultural Research Centres. The Farming Systems Research Group has proved effective at overcoming such difficulties at the International Institute of Tropical Agriculture. Its organization, operation and effects on the performance of the research programmes are described.

On some estates in Malaya the incidence of Marasmius bunch rot reaches serious proportions through causes other than poor sanitation or pollination. In such areas fungicidal sprays may be of value in both therapy and prophylaxis. In laboratory tests, using the paper disc diffusion and liquid culture methods, 32 fungicides were tested for activity against Marasmius palmivorus to provide an indication of promising formulations for field trials. A number of compounds showed strong inhibition of fungal growth in both series of tests, and amongst these the organo-mercury preparations were outstanding, especially Antimucin WBR. Other promising fungicides included Fylomac 90, Seprisan, Hyamine, Izal, Thiram and PCNB. In field trials in which Antimucin WBR and Verdasan were used for treatment of partially-infected immature bunches, these fungicides checked disease development, with a significant reduction in losses through disease. The value of fungicidal sprays formerly recommended in estate practice, and their potential value in prophylaxis, are discussed.

Seeds of 50 sorghum genotypes were tested for emergence after imbibition in water for different times followed by up to 30 days of drying. The emergence of a large number of sorghum genotypes was then tested after 40 h imbibition in water followed by 10 h drying. Genotypes selected as resistant to 45 hours imbibition and 10 days drying regained turgor in the radicle and plumule when exposed to imbibition and drying injury. Genotypes showed significant difference both for emergence and seedling dry weight after exposure to this stress. The genotypes resistant to imbibition injury and drying had a specific protein of 33.0 KDa which was absent from those which were susceptible to such stress.

La adaptación del sorgo a la siembra seca

The results of a two year field study to determine the effect of iron on the yield of maize in the forest and savanna zones of Nigeria have indicated that new and old fields in the savanna, and old fields in the forest zone, require additional iron. The optimum iron requirement for maize in both zones is 3 kg ha−1.

A shortage of available labour early in the growing season, when effort is directed to the weeding ofcereal crops, appeared to be a primary constraint to increased forage cropping by smallholder farmers in the semi-arid zone of central Mali. In experiments with millet, the labour requirement for weeding was reduced by an average of 45% when the crop was weeded at two rather than four weeks after emergence. A combination of weeding by hand and by ox-drawn plough or harrow only slightly increased labour productivity compared with hand weeding alone. Both lablab and cowpea produced good yields of forage when sown in mid July, but average yield declined by 71 kg ha−l for each day's delay in sowing between mid July and mid-August. Green gram was also productive over a two month growing period and appeared to have potential as a late-sown forage crop.

Measurements are reported on the influence of mulch on the chemical and physical characteristics of the soil and the chemical composition of the crop, together with growth measurements on an indicator crop in the greenhouse and on mature coffee in the field. Mulch reduced soil acidity; increased organic carbon, Kjeldahl nitrogen, exchangeable potassium and available phosphorus; and decreased exchangeable calcium and manganese. It increased total pore space, free-draining pore space and rate of rainfall acceptance in the top soil. Effects on the coffee were to increase phosphorus, potassium and in some cases nitrogen in the leaf, but reduce magnesium and calcium levels. Potassium and calcium levels were increased in feeder roots, whereas in the ripe cherry the phosphorus level was increased but nitrogen, calcium and magnesium levels were reduced. The soil effects were reflected in increased growth of the indicator crop and mulch improved the growth of the coffee tree in a year of seasonal drought.

East African highland bananas and climbing beans are important crops for food and income in the highlands of Uganda. Intercropping of banana with legume crops is a common practice, yet climbing bean intercropping with perennials has rarely been studied in Uganda. To understand how best to improve the production system, we assessed the effects of pruning of banana leaves on light availability for climbing beans, resulting effects on bean yields and potential differences in shade tolerance between two climbing bean varieties in the eastern and southwestern highlands of Uganda. Measurements of the transmission of photosynthetically active radiation (PAR) through the banana canopy were combined with yield measurements of a local and improved climbing bean variety and with banana pseudostem girth in two seasons (2016A and 2016B). We also compared yields of intercropped with sole-cropped climbing beans. The mean fractions of PAR transmitted through the banana canopy – hence available for beans – were 0.43 on pruned and 0.38 on non-pruned subplots, a significant 15% difference. The improved light availability did not increase climbing bean yield. Although no direct relationship between light interception and bean yields was found, bean yields on the most and least shaded parts of the intercropped fields differed significantly, suggesting that beans do benefit from improved light availability in intercropping. Generally, yields of sole-cropped beans were significantly larger than of intercropped beans, but we could not single out the effects of competition for light, water, and/or nutrients. The bean varieties responded similarly to the pruning treatments. The local variety tended to perform relatively better in intercropping, the improved variety in sole cropping, though differences were not significant overall. Pruning and retention of eight banana leaves over the course of a season did not affect banana pseudostem girths in the mature banana plantations. Although light availability improved, farmers may not expect a major effect on bean yield. Future research may focus on the effects of a lower number of leaves retained, comparing a number of bean varieties for suitability in sole or intercropping, or on other factors influencing the relation between the two crops such as relative plant densities of beans and bananas.

This study analyses the experience and response of farmers within a multi-year collaborative research trial focused on the development of forage-based fallows in eight communities in the central Peruvian Andes. Quantitative data from a rural household survey were used to characterize farming household socioeconomic factors, livelihood strategies and soil and crop management practices of community members belonging to four participation groups with respect to the trials: 1) current participants near the end of the trial; 2.) those who participated early on, but dropped the trials after the first year; 3) those who participated in meetings but not directly in experiments; and 4) those who never participated meaningfully in the process. Furthermore, qualitative interviews of farmers in the four groups were used to examine trends and questions arising from the quantitative survey findings. Analysis of this mixed-methods dataset showed that better resource-endowed households (in terms of human and social capital, more livestock assets, higher levels of farm value production and income, and farm inputs) tended to be more likely to participate compared to households with lower levels of these variables. Our findings suggest that the differences in resource endowment among participation group households may be related to household life cycles, where access to resources change over time, reflecting the changing demography of a household. It was established that farm households with intermediate-age children, that is near the middle of a farm life cycle trajectory, are those with the most wherewithal to participate in trials and likely serve as examples and test cases for other farms with younger parents or older farmers with children moved away. Follow-up interviews indicated that farming households at either end of the farm life cycle trajectory may be using a ‘wait-and-see’ approach to the trials carried out by their neighbours who have more labour and other resources to deploy. In light of these findings, we suggest that participatory research should aim to ensure that the voices, challenges and opportunities of Non-participants are represented in the research process and experimental design. Additionally, greater consideration should be placed on understanding management by context issues in order to better target potential farming innovations such as improved fallows, at multiple levels, from the field to the household and to the community and beyond.

Although soybean is emerging as an important commercial crop in sub-Saharan Africa (SSA), its productivity on smallholder farms is very low. Soybean requires application of phosphorus (P) fertilizer and inoculation with the right rhizobium strains to achieve optimum biological nitrogen fixation and higher yields. However, subsistence farmers in SSA rarely invest in P fertilizers and inoculants due to lack of knowledge of their use and benefits. Most of the early reports on soybean in SSA have been based on work on research stations; hence, information is lacking on the profitability of fertilizer and inoculant use on smallholder farms in SSA. The main hypothesis of the present study was that the combined application of P and inoculants significantly reduces yield risks and increases P use efficiency and profitability compared with P fertilizer alone under smallholder farm conditions. We analyzed a data set of over 2,800 observations from on-farm demonstrations across Ghana, Kenya, Malawi, Rwanda, Tanzania, Uganda, and Zambia. Soybean yields, the partial factor productivity of P (PFPP), agronomic efficiency of P (AEP), and the value cost ratio (VCR) were significantly improved by the combined application of P fertilizer with inoculants than with P fertilizer alone. Combining P and inoculants increased yields over P alone by 17.3% in Kenya, 21.4% in Zambia, 25.7% in Ghana, 56.4% in Tanzania, and 57.1% in Malawi. However, soil organic matter was an important determinant of yield response and P use efficiency. The VCR increased linearly with increasing AEP in P + inoculant (R2 = 0.829) and less so with P fertilizer alone (R2 = 0.672). Net present values were positive in all countries, indicating that investments in P fertilizer and inoculants will generate profits over time. In order to increase uptake of fertilizers and inoculants among subsistence farmers and make soybean production more profitable, appropriate policies and market incentives need to be created.