This paper seeks to make an exploratory investigation regarding farmers who have been using an innovation for a relatively long period (established users), compared to farmers who have only recently started (recent users). Therefore, the aims of this research were to identify (i) the extent to which intentions, attitudes and social pressure are similar or different between these two groups and (ii) whether comparison of the groups can improve academic understanding and provide insights into what is influencing the uptake of innovations. The study was conducted with 80 farmers who are already engaged with the use of improved grassland. In order to develop an understanding of the differences in drivers of the adoption of new technology, the sample was divided into established users and recent users of the innovation. To identify differences between groups regarding farmer and farm characteristics, 11 quantitative variables were analysed through a dependent t-test. The theory of reasoned action (TRA) was used as a theoretical framework and the Spearman rank-order correlation was used in data analyses. To identify differences in farmers’ perceptions of the components of the TRA, we used the Mann–Whitney U test. The results showed that established users had stronger intention to use improved grassland in the next 12 months, which would be attributed to activity based on milk production as a main source of family income. Advantages of improved grassland included lower animal feeding expenses; increases in quantity, quality and availability of fodder production and increases in milk production. We concluded that established and recent users’ intention to use improved grassland over the 12 months was influenced in different ways. Established users’ intention to adopt was strongly influenced by normative beliefs, i.e. social pressure from salient referents, where the father, uncle and veterinarian played the most important role, whereas recent users’ intention was mainly influenced by behavioural beliefs (positive and negative beliefs regarding the innovation) and the variables that describe the farm characteristics, i.e. the advantages and disadvantages that farmers perceive of the use of improved grassland on their farms, which were also considered as drivers of adoption.

Chemical weed control in six root crops and fourteen vegetable crops, commonly grown in the tropics, is reviewed.

Wheat yield was increased significantly when grown after sorghum intercropped with cowpeas (both for fodder and grain) or with groundnut compared with sole sorghum in the previous season. The nitrogen requirement for the target wheat yield of 4.0 t ha−1 was 108 kg ha−1 after sole sorghum and this was reduced by 87, 61, 83 and 38 kg ha−1 after intercrops of sorghum with fodder and grain cowpeas, groundnut and greengram, respectively. The different levels of nitrogen applied to the sorghum-legume intercropping systems also allowed savings of between 18 and 55 kg ha−1 of fertilizer nitrogen on wheat in the following season.

Non-destructive methods are described for estimating annual above-ground dry matter production by the coconut palm, Cocos nucifera. Leaf dry weight is estimated from the cross-sectional area of the petiole. Trunk dry weight increment is estimated from the volume increment, and a function relating trunk density to palm age. Husk and shell dry weights are estimated from air-dry weights; copra dry weight is measured after oven drying. The weight of inflorescence stalks is small, and is ignored. Leaf area can be estimated from measurement of the length and width of a sample of leaflets. These methods have been applied to two coconut variety trials, and show significant differences between varieties in crop growth rate and harvest index. The trend of leaf area with palm age is described for two varieties and the hybrid between them.

Medida de la producción de materia seca en el cocotero

Application of dimecron to cowpea plants increased grain yield, its effect being more pronounced in widely spaced plants and those planted in March. Dimecron increased grain yield by encouraging greater leaf area development, by increasing the number of flowering inflorescences and the number of pods set per inflorescence, and by decreasing the number of shrivelled pods. March planting encouraged greater dry matter production than January and May planting. Dimecron application decreased the number of Ootheca beningseni, reduced the proportion of leaf damaged by these insects, and reduced the number of plants infested with aphids and Acidodis larvae.

Annual applications of calcium, potassium and nitrogen (as urea) over three years caused significant differences in soil exchangeable cation ratios and in the yields of subsequent groundnut and maize crops. High rates of potassium and nitrogen, combined with low rates of calcium, lowered groundnut yields, and high rates of potassium, enhanced by ploughing in crop-residue ash, seriously reduced the exchangeable Mg: K cation ratio and maize magnesium status. Maize yields were significantly negatively correlated with soil potassium status. The balance between exchangeable cations in these soils is very easily upset by injudicious combinations of fertilizers and management practices.

Biofortified staple crops, amongst them cassava, are being developed to reduce problems of micronutrient malnutrition. In 2006 new cassava varieties with increased levels of provitamin A were released. For the purpose of enhancing adoption of the new cassava varieties, two strategies were used: (1) a participatory research approach and (2) public awareness raising activities. This paper attempts to evaluate the results of these two diffusion strategies. Within the first strategy, the factors found to enhance adoption rates were: awareness of the new varieties' advantages, public entities as the main information sources and involvement in participatory research. Within the second strategy, trends were found between adoption rates and producer characteristics including: ownership of land, middle-level income, advanced education level and use of information media, namely the Internet. In both strategies, a lack of seeds was one of the main factors limiting the adoption process.

In order to ensure sustainability of maize production in short-season environments of Nigeria, the Sudan savanna taskforce of Kano–Katsina–Maradi (KKM) Pilot Learning Site promoted short-season maize varieties in 2008 via Innovation Platforms (IPs). In the light of the promoted varieties, we evaluated the adoption and net benefits (productivity and income) of the maize varieties. We used cross-sectional household data elicited from 600 sampled households, double-hurdle model and propensity score matching. There was a remarkable increase in the adoption of short-season maize varieties in 2014 compared to what was obtained in a baseline conducted in 2008. Our empirical findings revealed that the adoption of the short-season maize varieties promoted through the IPs had significant productivity and income increasing effects. This implies that policy interventions to ensure sustainable maize intensification in the face of environmental limitations, such as early and late season drought, should intensify the promotion of short-season varieties in Sudan savannas. This will require well-concerted agricultural extension that can leverage IPs in view of its potentials.

More than 10 Sub1 rice varieties carrying the submergence-tolerance gene have been released for flood-prone environments in tropical Asia. Improved management practices have been shown to enhance yields of these varieties. The objective of this study was to dissect the growth response of IR64-Sub1 to integrated crop management in a flash flood at the late vegetative stage. Field experiments were conducted at the International Rice Research Institute, Philippines in the dry and wet seasons of 2013. Complete submergence was imposed for 14 days starting at 37 days after transplanting. Integrated management practice (IMP) consisting of: (i) application of fertilizer (compared with no fertilizer use in conventional practice), (ii) use of lower seeding rate (400 vs. 800 kg ha−1) in the nursery bed, (iii) use of slightly older seedling for transplanting (30 vs. 18 day-old), and (iv) higher planting density (33.3 vs. 25.0 hills m−2) gave yields higher by 8–87% compared with the conventional practice (1.3–2.4 t ha−1) in both seasons. This was attributable to higher shoot biomass after water recession, more tillers m−2, greater leaf area expansion and shoot biomass accumulation during the recovery period, and higher filled-grain percentage at maturity. The improved management had no positive effect on panicle formation, spikelets panicle−1, and harvest index since stress was imposed at the transition period between vegetative and reproductive phases. Our results suggest the appropriate nursery management, for submergence-resilient seedlings to further alleviate damage caused by flash floods and increase the yield of Sub1 varieties in flood-prone rainfed lowlands.

The introduction of forage or hay crops into fallow land represents a means of increasing feed supplies for small ruminants in north Africa and west Asia. Such fallows lie between zones planted with food crops and traditional grazing areas. Mixtures of vetch with barley, oats or triticale, and peas with barley, were cut at the 10% flowering, 100% flowering (100F) and full pod (FP) stages of the legume component. Effects of crop maturity, weather conditions and cutting height on yield, the chemical composition of the standing crop and re-growth were measured. Barley–vetch mixtures yielded 8147 kg dry matter ha−1 of standing crop at the FP stage in 1983 but only 2283 kg dry matter ha−1 in 1984 under drought conditions. Hay yields were 4377 and 1640 kg dry matter ha−1, respectively. The highest yielding mixture, grown in 1983, was oat–vetch which yielded 8670 kg dry matter ha−1 of standing crop and 4285 kg dry matter ha−1 of hay at the FP stage. Cutting at the 100F or FP stage maximized dry matter yield and minimized the risk of rainfall prolonging hay making. Rain caused slight damage to some hays cut at early stages of maturity. Voluntary intakes and digestibilities of field-cured hays were determined. The voluntary intakes of triticale–vetch hay at the FP stage and all barley–pea hays were low compared with other hays. Hays contained sufficient estimated metabolizable energy (ME) for use in sheep diets during pregnancy and middle or late lactation. ME values averaged 9.2 megajoules per kg dry matter in both 1983 and 1984.

Cotton–wheat is an important cropping system in South Asia. Introduction of BT cotton has caused the time conflict between sowing of BT cotton and wheat harvest in this cropping system. Wheat is harvested in late April but the best planting time of BT cotton is mid-March, which indicates a time conflict of 30–45 days between two crops in the region. However, this conflict can be managed by raising the cotton nursery and transplanting 30–45 days old seedlings in the field after wheat harvest. This two years field study was conducted to assess the economic feasibility of transplanting BT cotton in BT cotton–wheat cropping system at two locations (Multan, Vehari) in the cotton belt of Punjab, Pakistan. The BT cotton–wheat cropping systems included in the study were; flat sown wheat (FSW) – zero-tilled cotton (ZTC), FSW – conventional-tilled cotton (CTC), ridge sown wheat (RSW) – ridge-transplanted cotton (RTC) (30 days old seedlings), RSW – RTC (45 days old seedlings), bed sown wheat (BSW) – bed-transplanted cotton (BTC) (30 days old seedlings) and BSW – BTC (45 days old seedlings). BSW produced more grain yield than RSW and FSW during both years at both locations. Likewise, BTC (45 days old seedlings) had higher production at both sites during both years. The overall productivity of BT cotton–wheat, in terms of net income, benefit: cost ratio and marginal rate of returns, was the maximum from transplanting 45 days old cotton seedlings on beds after BSW during both years at both sites. Sowing cotton as ZTC following FSW was the least productive cropping system. In conclusion, transplanting 45 days seedlings of BT cotton on beds during late April after harvest of BSW wheat may be opted to manage the time conflict and improve the productivity of BT cotton–wheat cropping system in Punjab, Pakistan.

The effects of pollination on set and growth of summer squash var. Zucchini were investigated. In winter, parthenocarpic fruits developed and pollination had no effect, but in summer only pollinated fruits continued to grow. Partial pollination in summer caused ovary abortion of some fruits, and a reduced rate of fruit growth in those which continued to grow. The ovary was 8·8 cm. long at anthesis in winter but only 8·2 cm. long in summer.

The single-liquid infiltration method of measuring stomatal opening was adapted as a practical field method for determining the time of irrigation of cotton. A number of different liquids, leaf positions and times of measurement were tested and the most sensitive method was selected on the basis of the results. No stomatal response was found while soil moisture was depleted to one-third of available water. A steep reduction in stomatal opening was observed with further drying of the soil. Some results are presented from an irrigation experiment where irrigation control by infiltration method was compared with other methods. The practical possibilities in the use of the method in field practice are discussed.

The concentration of nitrate-nitrogen in cotton petioles was directly related to the rate of nitrogen applied and was greatest at the earliest sampling date, decreasing as the season progressed. There was an increase in the degree of association between the level of nitrogen applied and petiole nitrate-nitrogen, and between petiole nitrate-nitrogen and final yield, up to the time of early flowering, when peak correlation coefficients were reached, after which there was a decline. The level of petiole nitrate-nitrogen showed high positive correlations with the rate of nitrogen application as well as with yield. The final yield showed a significant, positive and linear regression on the level of petiole nitrate at the time of early flowering. A close relationship was also shown to exist between a critical concentration, represented by a narrow range of nitrogen levels in the neighbourhood of 2000 parts per million, and final cotton yield. Yield reductions were related to the number of days petiole nitrogen remained below the critical concentration. The use of petiole analysis as a guide in the nitrogen nutrition of cotton, in the evaluation of various experimental treatments and as an aid in interpreting research results, was demonstrated.

Intercropping is a common practice in Africa, but the advantage compared to sole cropping depends on the crop plants and local agro-ecological conditions. The potential of intercropping maize (Zea mays) or sorghum (Sorghum bicolor) with watermelon (Citrullus lanatus) was tested in two on-farm trials in southern Mozambique under semi-arid conditions in an area with low and unpredictable rainfall. In the first experiment, plant density, yield and monetary value of sole and intercropping plots of maize with watermelon were determined in 17 farmers' fields in an area where all crops developed to maturity and harvest. There was a significant reduction in yield of both maize (28.8%) and watermelon (57.8%) in the intercrop compared with the sole crop yields. However, the mean land equivalent ratio of 1.13 for yield showed that intercropping had advantages as, on average, an area planted with sole crops would require 13% more land than an intercrop production to generate the same outcome. In the second experiment, carried out in another area with 16 farmers' fields, drought was more pronounced and only watermelon developed to maturity. Intercroppings with maize and sorghum resulted in 70% and 69% yield reduction, respectively. In conclusion, watermelon is a good companion crop for intercropping with cereals to mitigate the risk of total crop failure due to drought.

Prevention of the enormous losses of crop production in the Third World, both before and after harvest, would make a substantial contribution to the survival and well-being of countless small fanners. Many attempts to reduce the scale of pest attacks by facilitating the purchase of pesticides and fertilizers have failed in the face of maladministration, mistrust, primitive conditions and ignorance. Yet, despite the difficulties, these fanners have evolved a pattern and practice of production which incorporates many positive attributes which have only recently been appreciated by western scientists. Attention is drawn to some of these methods and also to the benefits and limitations of both classical and manipulated biological control. It is concluded that further improvements depend on the ability of entomologists to adapt some of the concepts widely used in China to utilize scientific techniques within a socio-economic structure where even the plastic bag must be regarded as high technology.

Cotton varieties differ in their sensitivity to boron deficiency. Breeding for tolerance of deficiency offers some scope for yield increases under the prevailing non-intensive conditions under which most of the crop is grown in northern Nigeria, but cannot be considered a complete solution to the problem.

Over a decade after the forest-savanna transition zone of Nigeria was deemed suitable for production of sorghum (Sorghum bicolor), no research has been undertaken on the crop's tillage requirements in the southeastern part of the zone. This study evaluated the effects of tillage-mulch practices on soil moisture, water use (WU), grain yield and water use efficiency (WUE) of the crop in a Typic Paleustult (sandy loam) at Nsukka during 2006 and 2007 growing seasons. In a split-plot design, no-till (NT) and conventional tillage (CT) treatments were left bare (B) or covered with mulch (M) at 5 Mg ha−1. The ensuing treatments (NTB, NTM, CTB, and CTM) represented four tillage methods, which were replicated four times in a randomized complete block. In the monitored root zone, NTB and CTM significantly (p ≤ 0.05) enhanced the soil moisture status over NTM and CTB, but the main effects of the tillage and the mulch factors were not significant. The crop WU was uninfluenced by the treatments throughout the study. Although the grain yield showed higher values with NT than with CT, the differences were significant (p ≤ 0.05) only in 2007 that was marked with erratic rainfall and relatively low mean yield. Mulch significantly (p ≤ 0.05) enhanced the grain yield in 2006, with greater effect in CT than NT. On average, the mulch plots out-yielded their bare counterparts by about 26%. The tillage × mulch interaction was significant (p ≤ 0.01), and showed higher grain yields in NTB, NTM and CTM than in CTB. In the year-weighted average, yield increments in NTB, NTM and CTM over CTB were 53, 53 and 67% respectively, a pointer to the relevance of mulch with the CT but not the NT. Relative WU showed that the crop's water demand was met under all treatments. Hence, the yield reduction in the CTB was not due to water shortage. The WUE varied among the treatments in the same pattern as grain yield. In summary, NTB and CTM proved superior to NTM only in soil moisture status but to CTB in all measured parameters. From a socio-economic viewpoint, however, NTB would be preferable to CTM for growing sorghum in this area.

The influence of leaf area and inter-plant competition on the growth and yield of a crop of high-yielding dry beans (Phaseolus vulgaris L.) in central Mexico was studied, using density and thinning treatments. The highest seed yield (4210 kg/ha at 14% moisture) was obtained with the highest density (28·8 plants/m2). Thinning showed that pods/plant was sensitive to inter-plant competition between 36 and 78 days after seeding (first flower at 50 days), but seeds/pod, and especially seed weight, were not sensitive. It is suggested that the close positive relation between yield and leaf area duration derives from the influence of photosynthate supply upon pod number.