The small amount of on-farm research that has been carried out with fodder trees in Africa has mainly involved exotic species selected by researchers rather than farmers. In this study, farmers who had participated in a pre-planting survey chose, during feedback meetings, seedlings of indigenous, naturalized and some exotic fodder trees from a nursery. They planted them on-farm, where the planting niches, management, biomass production, and animal response were evaluated over a short period, and compared with the results of the earlier survey. The farmers came from three agro-ecological zones in central Kenya with respective mean annual rainfall totals of 775, 950 and 1300 mm. Data were collected at two months, one year and two years after planting. The feedback meetings proved important to the understanding of discrepancies between the earlier survey results and farmers' practices. Survival and growth of seedlings, manure application by farmers, and percentage of trees pruned for fodder, differed among species. The farmers showed a strong interest in experimenting with and actively cultivating local fodder trees.

On-farm experiments were conducted between 1990–91 and 1996–97 in the Indian districts of Jalandhar (Punjab) and Ghazipur (Uttar Pradesh), on rice-wheat cropping systems. The aim was to compare yields and net returns from three treatments: (i) farmers' nutrient management practices; (ii) integrated use of organic manures and fertilizer; and (iii) NPK fertilizer inputs alone. Productivity of the rice-wheat systems, in terms of grain yield per unit area, was greater in Jalandhar district than in Ghazipur district. In Jalandhar, a high productivity zone, greatest yields were achieved with integrated use of green manure and fertilizer NPK inputs, while in Ghazipur, a low productivity zone, yields were highest with inputs of fertilizer NPK alone. Increases in yield due to these improved practices, over farmers' practice, were 6.98% in Jalandhar and 46.6% in Ghazipur. At both locations, net returns were greater with the use of fertilizer NPK alone. However, benefits from NPK alone over farmers' practice were 6.96% in Jalandhar and 79.6% in Ghazipur. After 11 years of a long-term experiment, at Ludhiana (Punjab) and Faizabad (Uttar Pradesh) soil organic-C and available phosphorus contents have increased, and available potassium content decreased compared with the initial levels.

The general principles of leaf analysis as a diagnostic method and as a guide to plant nutritional status are outlined and discussed. Factors, other than nutrient supply, that affect leaf composition are mentioned and methods of leaf sampling, preparation and storage are described. The practical application of leaf analysis to fruit, flower, vegetable, tree and miscellaneous economic crops is reviewed and suggestions are made for its use as an advisory aid.

Farmers in the mid-hills of Nepal have a mix of rainfed land on which millet is grown in relay after maize (maize/millet), and irrigated land on which wheat is grown sequentially after rice (wheat–rice). Double cropping is the norm but the diminishing quantities of organic materials, coupled with the trend towards increased use of inorganic fertilizers, have raised questions about the long-term productivity and sustainability of the cropping systems. The aim of this work was to examine the long-term effects (eight years) on grain yield of additions of manure and fertilizer either singly or in combination. Maize/millet and wheat–rice rotations were established on a Dystochrept at Pakhribas Agricultural Centre at about 1450 m altitude. Manure and fertilizer applications were applied to the maize (eight combinations in May) and the wheat (different rates in seven combinations in November) every year with the succeeding crops (millet and rice) utilizing residual nutrients. Yields of maize, millet and rice were greater when manure rather than fertilizer was applied but yields of wheat were less. The combined application of manure and fertilizer significantly increased yields of maize and wheat compared with applications of either manure or fertilizer alone. However, for the subsequent crops (millet and rice) there was either a small residual benefit of the combined application when compared with fertilizer alone, or no benefit when compared with manure alone. Overall, the combined application increased total grain yields by about 35% in the maize/millet rotation and by 16% in the wheat–rice rotation. There was no trend in yields in response to treatment with time.

A continuous non-limiting soil water supply, or a non-limiting supply from 120 to 180 days after planting, significantly increased (P = 0.01) female flower production of banana cv Robusta compared with continuous soil water stress. Relieving stress after 120 days produced a significantly higher (P = 0.05) average number of female flowers per inflorescence than when adequate water was supplied throughout. Female flower production is positively correlated with the average growth rates at floral initiation and early floral differentiation and with the final pseudostem girth.

The effect was investigated of seasonal differences between winter and spring on the development of parthenocarpic and fertilized fruits in two squash cultivars, Zucchini Elite F1 and Bushy White. The former had stronger parthenocarpic characteristics than the latter. The effect of night temperature on growth of the parthenocarpic fruits was most pronounced, both rate of growth and final weight increasing with decreasing temperature. Whereas long days inhibited development of parthenocarpic fruits, the heaviest and longest fruits were obtained under normal day-length conditions.

The effects of drought and plant density on fractional interception (f), radiation-use efficiency (RUE) and dry matter accumulation and partitioning to seeds in cowpea (Vigna unguiculata) need to be quantified in order to calibrate cowpea simulation models for West Africa. Accordingly, a short duration cultivar of cowpea, IT84S-2246-4, was grown at a range of plant densities in well-watered and drought conditions in 1990–91 at two contrasting locations in Nigeria, Ibadan (7°N) and Kano (12°N). Fractional interception of radiation (f) and total above-ground dry matter accumulation (TDM) were measured throughout the growing season and TDM and seed yield (SY) were measured at maturity. At Ibadan drought had no effect on phenology while at Kano drought increased the duration of the vegetative phase (by 5–6 days), but not of the reproductive phase. Drought reduced f and radiation-use efficiency (RUE), and hence TDM, and there were significant interactions between RUE and plant density at both Kano and Ibadan. Average SY in the well-watered treatments at Kano and Ibadan were 1600 and 700 kg ha⊃−1&/sup; respectively and drought reduced SY by 50% at both sites but did not interact with plant density. Across locations, plant densities and drought treatments SY was strongly correlated (r = 0.96) with TDM production between flowering and maturity. These data suggest that partitioning of dry matter during the reproductive phase is not affected by location, drought or plant density and the SY of cowpea can be predicted from dry matter accumulation.

An experiment to determine weed spectrum, weed seedling numbers, temperature and nutrient changes in manure heaped for one to five months was undertaken over two seasons. Weed seedling numbers in manure heaped for one to five months decreased significa ntly by 65–70%. The weed spectrum comprised 17 broadleaf weed species of which Amaranthus hybridus, Leucasmartinicensis and Nicandra physalodes were most prevalent. There were six grasses with Eleusine indica and Cynodon dactylon being dominant. Temperature increased from 20 °C in the unheaped manure to averages of 34 and 42 °C in manure heaped for three and five months respectively in the two seasons. In both season s nitrogen and potassium became more available as the period of manure heaping increased while phosphorus decreased. It was concluded that heaping manure for three months significantly reduces weed seed viability and enhances the availability of some nutr ients.

Application of S, alone or in combination with P, significantly increased the number, yield and nitrogen content of root nodules on pigeon pea and guar. Sulphur, applied at different levels with NPK, increased the methionine content and yield of plants significantly but had no significant effect on the N content. Sulphur at 20 p.p.m., alone or in combination with P, increased the methionine content of pigeon pea significantly but the effect decreased at higher levels of S. In general, higher values of methionine were obtained in the presence of S than when it was absent.

Soybean yields on smallholder farmers’ fields in Malawi are constrained by poor soil fertility, limited application of external inputs and poor crop husbandry. We tested crop management practices through on-farm experimentation and participatory technology evaluation. Two agronomic soybean trials were established in 2009 and 2010 in three contrasting agro-ecologies resulting in 72 replications per trial. Treatments in the first trial included several combinations of inoculation with Bradyrhizobium japonicum, inorganic fertiliser application and compost manure. In the second trial, farmers tested an improved variety, optimal weeding regime, increased plant population and chemical pest and disease control. A combination of inoculation, inorganic fertiliser (10 N, 8 P, 20 K in kg ha−1), and 6 t ha−1 compost manure increased yields from 0.86 t ha−1 under farmers’ practice to 1.56 t ha−1 and resulted in average profits of US$222 ha−1. Increased plant populations and biocide spraying also resulted in substantial yield increases. Inoculation and increased plant population resulted in an average value to cost ratio (VCR) > 2. Low investment costs make inoculants, compost manure and increased plant populations interesting options, whereas adoption of inorganic fertiliser application in soybean may be limited due to high costs and low VCR. The farmers ranked eight technologies in descending order of preference as: (i) early planting, (ii) plant population, (iii) variety choice, (iv) compost manure, (v) weeding, (vi) inoculant, (vii) fertiliser and (viii) spraying. Our participatory research approach demonstrated that there is a wide range of technologies with different levels of human and financial investment costs that smallholder farmers can adopt to enhance their soybean yields and profits.

This study reports the results of model simulations of the potential yield of tea in north-east India. The CUPPA-Tea model, developed using data from a high-altitude site close to the equator in East Africa, was validated against the yield data from irrigation experiments conducted on contrasting soil types at Siliguri and Tezpur in the tea growing region of north-east India. The close correspondence between observed and predicted yield and yield distribution suggests that the model is applicable in north-east India. The model was used to simulate the yield response of tea to drought and irrigation using daily weather data for seven years (1983–89) at Siliguri and 14 years (1974–85) at Tezpur. On a clay loam soil at Siliguri, with an available water capacity of about 200 mm m−1, the predicted mean reduction in yield was 1.5 kg ha−1 for each 1 mm reduction in evapotranspiration. However, there appeared to be no reduction in evapotranspiration until the soil water deficit reached about 240 mm. By contrast, at Tezpur on loamy sand, with an available water capacity of about 100 mm m−1, evapotranspiration was reduced once soil water deficits exceeded about 85 mm. There was then a mean reduction in yield of 2.2 kg ha−1 for each 1 mm reduction in evapotranspiration. At both sites, even when soil water deficits were not limiting, the predicted year-to-year variation in yields was about 500 kg ha−1. The results highlight the soil-related differences in response to irrigation and the benefits of using process-based simulation models to investigate the potential yields over long periods.

In this study, different levels of defoliation were imposed on a determinate species (maize) and a relatively indeterminate species (cotton). The aim was to quantify the effects of defoliation on plant growth and production, under either optimum or water-stressed conditions. Under well-watered conditions, 33% defoliation twice (conducted 28 and 35 days after emergence) resulted in a 16% reduction in grain yield of maize while 67% defoliation once (conducted 28 days after emergence) had no significant effect on yield. Under water stress, the grain yields of maize plants with 33% (twice) and 67% defoliation were 13.5% and 25% greater than that of non-defoliated control plants, respectively. For cotton, the reproductive yields (seed and lint) with 33% and 67% defoliation (conducted 43 days after emergence) were reduced, under well-watered conditions, by 28% and 37% of that of the non-defoliated control, respectively. Defoliated cotton plants lost less fruiting forms (squares and young bolls) than non-defoliated plants during water stress. Therefore, under water stress the harvestable product of cotton plants with 67% defoliation was double that of non-defoliated control plants. In non-defoliated cotton plants, a second flush of flowering after release from water-stress permitted further compensatory fruit set and boll harvest. Defoliated plants did not show such levels of compensation. Defoliation significantly reduced water use by maize and cotton. The relative yield advantage of defoliated plants under water-stress conditions can be attributed to defoliation-induced improvement in water status as reflected in measures of photosynthetic rate and stomatal conductance. Under anticipated drought stress, defoliation could be an important management practice to reduce drought-induced yield decrease, but this needs to be tested under field conditions.

During the past two decades or so, rural population in Africa has increased slowly while urban population has grown dramatically. The hugely increased urban demand for cereals and pulses (which produce crop residues for livestock) and for livestock products is now the main force stimulating mixed farming systems in the semi-arid and sub-humid areas of sub-Saharan Africa. Grazing land has diminished, crop residues are becoming a more important element in raising livestock and fattening penned livestock has become profitable. The changes in land use, land tenure and the shift of livestock raising southwards in West Africa are illustrated. Farmers' adaptation to rapidly changing markets for their products and the factors of production are illustrated with examples from Senegal, Nigeria, Niger, and, by way of contrast, Kenya. The main challenges this sets to agricultural scientists are described. The livestock element in mixed farming system now requires careful economic analysis and participative research if scientists are to meet the evolving needs of farming as the urban sector enlarges.

The extent by which fertilizer nitrogen (N) may be reduced by the use of drip-fertigation in sugarcane was determined using 15N-labelled fertilizer in a field experiment in Mauritius. The data showed that, under the soil and climatic conditions that prevailed at the study site, fertilizer N could be reduced by 30%. Indeed, with 80 kg N ha−1 a−1 by drip-fertigation, total or fertilizer N recovered, growth pattern (as reflected by tiller density and leaf area development) and sugarcane yields were not inferior to those obtained with the standard practice of burying 120 kg N ha−1 a−1 along the cane rows. Applying more N than needed by the sugarcane in anticipation of a higher yield with drip irrigation would be wasteful of fertilizer N resources.

A field experiment to evaluate the effect of N, K and time of K application on the growth, yield and chemical composition of wheat (Triticum aestivum) grown in saline soil with subsurface drainage, was conducted at the Central Soil Salinity Research Institute, Karnal Research Farm, Sampla during the winter seasons of 1992–93 to 1994–95. The treatments consisted of three levels each of N (0, 120 and 150 kg ha−1) and K (0, 50 and 75 kg ha−1) with the K applied at two different times (full basal and half basal + half top dressed 30 d after sowing). The growth characteristics (plant height, number of tillers and dry matter weight m−2 recorded at 60 d after sowing) and yield-attributing parameters (number of productive tillers and length of spikes) increased significantly with increasing N levels up to 150 kg ha−1 and K levels up to 50 kg ha−1. Similar responses of N and K were also observed on grain and straw yields of wheat. Time of K application had no significant effect on growth and yields. The N concentration in grain and straw increased significantly with the application of 120 kg N ha−1 over control. Application of K had no significant effect on the concentration of N in grain and straw. The K concentration in grain and straw increased significantly due to the application of 50 kg K ha−1 but it was unaffected by the time of K application. Application of K increased the efficiency of utilization of applied N. A trend towards declining salinity of the soil profile due to leaching through the subsurface drainage system was observed from 1992–93 to 1994–95. For three consecutive years the status of available N and K in surface soil (0–30 cm depth) increased due to their respective applications. This field study indicates that 150 kg N and 50 kg K ha−1 should be applied under canal-irrigated conditions to get the sustainable and optimum yield of wheat in saline soils.

This paper aims to determine the influence of family farming features on efficient use of water. The analysis focusses on a random sample of family farms in the province of Almería, southeast Spain. A hierarchical regression model was conducted to determine how the water efficiency is related to environmental awareness and certain characteristics of farmers, decision-makers and the family farm itself. The results show that these family farms strive to be more efficient in their use of water when they are going to be inherited, when there are younger decision-makers who have received a better education, and also when women are involved. Moreover, this efficiency is positively related to more ecological production and to the farmer's habitual behaviour with respect to water economy. The study provides evidence regarding the influences of socio-economic and environmental features of family farming on water use efficiency that may prove useful for other analyses and policy makers on water management in agriculture.

Using the sustainable livelihoods framework to evaluate the impact of a farmer-to-farmer video on the improved rice parboiling technology, women in Benin rated financial, social, human, natural and physical capital stocks for the baseline year (2006) and the impact year (2009) on a 0–5 scale. Women who had watched the video and those who had not, but who lived in the same villages, perceived a significant improvement in four out of five livelihood capitals while processors in control villages did not perceive any significant change. Apart from testing the sustainable livelihoods conceptual framework as a participatory impact assessment tool for video-mediated rural learning, this study shows how farmer-to-farmer training videos helped to improve multiple livelihood assets.

The rainfall erosivity (R) and soil erodibility (K) factors of the Universal Soil Loss Equation (USLE) were determined on two sites in the Colombian Cauca Department over a five year period when rainfall was mostly lower than average. The results showed that the high erosion potential of the soils can be attributed more to high rain erosivity than soil erodibility. The R factor explained between 59 and 81% of the variation in soil loss recorded on continuously clean-tilled fallow plots. The erodibility of Inceptisols in the study region is classified as low. Values for soil erodibility (K) ranged from 0.012 to 0.015 (measured in SI units) in the fifth year of permanent bare fallowing. K factors were higher in the rainy than in the dry season. Soils, previously under grass vegetation, were very resistant to erosion in the first two years of bare fallowing. In the third year erodibility increased sharply and continued to increase steadily until the sixth year. K factors predicted by the USLE nomograph underestimated the empirically-determined erodibility of these highly aggregated clay soils.

Sorghum is the principal foodcrop grown in Northern Nigeria. A survey of local varieties grown during the rains was carried out in 1958 and the 821 samples collected were assigned to seven morphologically distinct races, of which four are important. Varieties belonging to the Guinea race, with loose, open panicles, are mainly cultivated in high rainfall areas south of latitude 11°30′N. Further north, three races, Kaura, Farafara and Chad are grown in the dry Sudan Savanna zone. Varieties of these races have compact panicles and bulging grains. Estimates of the contribution made by each of the four major races indicate that the Guinea race accounts for nearly 50 per cent of the total sorghum production in Northern Nigeria.

The use of cultivation techniques to conserve rainfall, by preventing runoff, and to improve the soil surface infiltration rate, has produced spectacular increases in the yield of cotton on the Loess Plain soils of Northern Nigeria, where yields of the order of 2000 lb seed cotton per acre can now be produced regularly irrespective of the rainfall pattern. As yields of this level had not been obtained previously, it has been concluded that lack of soil moisture and poor soil aeration have in the past set a ceiling to seed cotton yields. The effects of these cultivation treatments on the two other major crops of the area, sorghum and groundnuts, have now been examined, and results from a series of field experiments over six seasons indicate that adequate soil moisture is essential to the production of high yields, but that the other soil conditions which are alleviated by these cultivations are not so critical for these two crops as they are for cotton. Reasons are suggested why spectacular increases in yield in response to the treatments are not generally to be expected with sorghum and groundnuts.