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.

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.

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.

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.

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.

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 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.

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.

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.

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.

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.

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.