Twenty-one genotypes of pigeonpea were evaluated for their alley cropping potential in two environments differing in soils and climate on the island of Oahu/Hawaii. All entries were planted in hedgerows in August 1988 and were cut 1 m above ground level 229, 290 and 342 days after sowing. Dry matter yields for seven selected genotypes from the three cuttings combined ranged from 691 to 4083 g m−2, with significant differences between genotypes and significant genotype × environment interactions. Genotypes rarely combined more than two desirable alley cropping characters, suggesting a distinct role for selected genotypes in different alley cropping environments. None of the effects influencing growth and yield were constant over levels of the other factors studied, indicating a need for multi-locational testing and standardized sampling intervals in future genotype evaluations with perennial pigeonpea.

Evaluación de genotipos de Cajanus cajan para cultivo en hileras

Through years of research, the Ethiopian Agricultural Research Organization has recommended a number of improved bread-wheat varieties for production in the different climatic zones, along with accompanying technology packages. In areas such as the Jijiga plains, however, adoption of these varieties by the farmers has been very limited. The principal objective of the study was, therefore, to investigate the reasons why farmers are reluctant to adopt high-yielding improved wheat varieties, and to identify farmers' preferences. An assessment study followed by participatory evaluation of the performance of five improved bread-wheat (Triticum aestivum) varieties and a local control was carried out under farmers' management practices. The trial was conducted at 10 locations (across three districts) on the Jijiga plains for two consecutive years (the 1999 and 2000 cropping seasons) and involved 30 farmers. Farmers' preferred varieties were identified using preference ranking. The results showed that farmers refrained from the adoption of some ‘improved’ varieties of bread wheat that were provided through the extension services because the varieties performed poorly under farmers' conditions. The study also showed that farmers do have multiple criteria for evaluating the varieties apart from yield, though the latter was the major parameter for recommending and releasing varieties for multi-locations. Farmers identified earliness, yield, and quality as the main criteria for adoption of wheat varieties. Accordingly, variety HAR-710 stood first in terms of yield (2.56 t ha−1) and other parameters, followed by PAVON -76 (2.49 t ha−1). Though its grain yield was relatively lower than the improved ones, the local control was preferred to some improved varieties used in this study for other quality parameters. The study highlighted the need for re-orienting agricultural research towards involving farmers at the appropriate stages of technology identification.

The Land Equivalent Ratio (LER) has been generally accepted as an agronomically sound index for assessing yield advantages derived from an intercropping practice. However, LER takes no account of the fact that, in subsistance agriculture, it is usually important to maintain a certain minimum percentage of the pure stand yield of the staple crop component in an intercropping system. A new measure ‘Staple Land Equivalent Ratio’ (SLER) is proposed in this paper which takes account of this requirement. Yield data from intercropping experiments are used to show how SLER can be effective in comparing the yield advantages of intercrop treatments in agronomic experiments.

Major changes to the global environment and their impact upon statistical requirements are presented. The need for extensive yet accurate datasets is stressed and the difficulties of achieving appropriate sampling strategies are described. Examples are presented of environmental studies in use in diverse field such as global warming, sustainability, agroforestry and intercropping, and local community studies. The history of the use of environmental statistics is highlighted as is the need for modern methods to handle large, multivariate datasets likely to be subject to both spatial and temporal variability.

Field trials are described in which sesame varieties maturing in 125 days at 2 m high, were grown in alternate rows with sorghum maturing in 175 days at 4 m. Compared to sowing both crops together, the yield of sesame sown 10, 14 and 28 days after sorghum fell by 53, 68 and 100%, respectively, but sorghum yield was not consistently affected. Improved sesame varieties, despite being shorter and less branched, performed better than the local variety, and nitrogen fertilizer applied to one or both components of the mixture did not appear to favour one crop at the expense of the other.

The effect of Ethrel on the yield and sugar content of coconut (Cocos nucifera) inflorescence sap and sustainability of productivity was investigated on forty-year-old tall coconut palms (var. typica) at Bandirippuwa Estate, Lunuwila, Sri Lanka. Ethrel was applied at a concentration of 2.5% and the volume and sugar content of the sap were measured. Application of Ethrel consistently increased the yield per day, yield per spadix, yield per palm per annum and sugar content in the sap for a period of four years. The removal of carbon, nitrogen, phosphorus, potassium and magnesium with the sap was greater from Ethrel-treated than from untreated palms, and this was attributed mainly to the enhanced sap yields and sugar concentrations.

Nematode infestation in Sub-Saharan Africa's (SSA) cropping systems, worsened by poor crop rotations, is a major factor contributing to limited utilisation of applied nutrients and water, leading to low maize (Zea mays L.) yields particularly on sandy soils. The effects of nematode infestation on maize productivity were evaluated under conservation agriculture (CA) on granitic sandy soils in sub-humid smallholder farms of Goromonzi district of Zimbabwe. Four treatments were tested for three seasons on six smallholder farmers’ fields in a randomised complete block design, each farm being a replicate: fenamiphos 40EC (a commercial synthetic nematicide), lime + fenamiphos 40EC, lime and an untreated control. Results of the study showed that independent application of fenamiphos 40EC and lime significantly reduced plant parasitic nematode infestations in maize roots by more than 10 times those present in the untreated plots while maize yield also increased significantly. Yield increase from fenamiphos and lime applications amounted to 53 and 42% respectively, compared to the untreated controls. Maize yield was negatively correlated with density of Pratylenchus spp. nematodes. Nematode management strategies involving fenamiphos 40EC or lime could significantly reduce maize yield losses in maize-based smallholder farming systems of SSA under CA. It was more economical to use fenamiphos than lime to control nematodes.

Pre-emergence application of the herbicides fluometuron, oxadiazon, oxadiazon + diuron and norflurazon gave satisfactory weed control, particularly during the early stages of cotton growth, but supplementary hand-weeding 6 weeks after sowing was necessary for control of resistant weed species. The number of man-hours required for supplementary weeding was considerably less than on the untreated control (6–52%). The economic implications of supportive hand-weeding is briefly discussed. No herbicides had any adverse effect on cotton except fluometuron at 0.95 kg/ha and norflurazon at 1.59 kg/ha.

Crosses were made between tea (Camellia sinensis L.) and Wilson's camellia (C. irrawadiensis Barua), using tea as the female parent, but reciprocal crosses were not successful. The F1 hybrids were intermediate in morphological and anatomical characters between the parents. Regular meiosis and high pollen fertility in the hybrids clearly indicate a close relationship between the parental genomes.

Weed management in rice depends on establishment method and proper selection of herbicide. A field experiment was conducted during dry seasons of 2013 and 2014 to develop a robust strategy for effective weed management in aerobic rice system for tropical rice belts. The efficacy of post-emergent herbicides bispyribac-sodium, azimsulfuron and flucetosulfuron were evaluated under different rice establishment methods (row sowing, spot seeding and broadcasting). Grass weed species constituted 58–68% of the total weed density across the establishment methods in the weedy check treatment. The total weed density and weed biomass were lowest in spot seeding with azimsulfuron (35 g active ingredient (a.i.) ha−1) 30 and 60 days after sowing. Among herbicides, use of azimsulfuron caused the highest grain yield (5.2 Mg ha−1), realizing 72% increase in grain yield over the weedy check. Yields in row sowing and spot seeding were similar and the same was verified when comparing yields in plots treated with bispyribac-sodium and azimsulfuron. Based on our findings and considering both weed presence and grain yield, azimsulfuron in spot seeding can be recommended in aerobic rice.

In order to assess the response of four popularly grown black gram (Vigna mungo L.) genotypes (T9, PU 19, USJD 113, KU 301) under osmotic stress, the present study was carried out by monitoring the changes in relative leaf water content (RLWC), carotenoid, total soluble protein (TSP), membrane lipid peroxidation (MDA), H2O2 scavenging capacity, and the activities of superoxide dismutase (SOD) and catalase (CAT). Osmotic stress was applied by withholding irrigation for 15 consecutive days at vegetative, flowering and pod filling stages. Under stress condition, several fold increase in the content of MDA, H2O2 scavenging activity and antioxidant enzyme activity was recorded while, RLWC, carotenoid and TSP were found to decrease. Flowering stage was found to be most sensitive in terms of economic yield. The genotype T9 experienced lowest reduction in yield (12.10–33.91%) with maximum value of drought tolerance index (DTI) (7.48) which can be attributed to its higher tolerance capacity to drought. On the other hand, USJD 113 had the highest yield loss (26.48–60.99%) and lowest DTI (6.07) value, indicating its susceptibility towards osmotic stress.

The impacts of long-term warming on soil physical structure and soil organic carbon (SOC) pools are currently disputed and uncertain. We conducted an eleven-year warming experiment in wheatland field in Henan, China. We found that long-term warming significantly increased soil bulk density by 4.5%, and significantly decreased total porosity and non-capillary porosity by 3.4% and 5.0%, respectively. Besides, long-term warming decreased the >2 mm fraction proportion and increased <0.053 mm fraction proportion of dry and wet aggregates. The mean weight diameter value for dry and wet aggregates in long-term warming treatment was significantly decreased by 7.0% and 6.7%, respectively. Moreover, long-term warming significantly decreased the total SOC, very labile pool (F1) and labile pool (F2) content by 10.6%, 30.6%, and 43.6%, and significantly increased the less labile pool (F3) and non-labile pool (F4) content by 94.2% and 21.1%, respectively. Long-term warming increased the passive carbon pool percentage but decreased the active carbon pool (ACP) percentage. Our results suggest that long-term warming negatively affected the soil's physical structure and impaired soil ACP accumulation. The findings of this study help improve our understanding of the response of farmland soils in northern China to climate change and provide scientific basis for establishing carbon management measures in farmland.

Root/shoot relations of two cultivars of pearl millet (Pennisetum glaucum) were studied on a sandy soil at Sadore in Niger using a wet excavation method. For the first 10 days after emergence (DAE), the length of the seminal root showed an exponential growth rate while plant height increased more or less linearly. The maximum rooting depth for millet was 168 cm and the maximum number of root axes and primary laterals, 172 per plant. Root length continued to increase up to 75 DAE, the maximum length exceeding 5000 cm per plant. The proportion of total day matter accumulated in the roots decreased from 30% in the early stages to less than 20% by maturity. The wet excavation method is a promising technique for the rapid removal of intact root systems of pearl millet from the sandy soils of the Sahel.

Nodulated plants of six varieties of Stylosanthes were grown at a constant temperature of 30°C for 21 days in a controlled environment and then for a further 21 days at a range of day/night root temperatures. Dry matter and nitrogen content of S. hamata cv. Verano and CPI40264A were measured after growth at day/night root temperatures of 30/30, 40/30, 50/30, 60/30 and 60/35°C. Similarly, growth and nitrogen content were measured for Verano, CPI40264A, S. gvianensis cv. Oxley and cv. Cook, S. humilis cv. Lawson and S. scabra cv. Seca after growth at root temperatures of 25/20, 25/25, 30/25, 30/30, 35/30 and 40/30°C. There were strong interactions of root temperature with variety and harvest time (31 and 42 days) but all varieties grew well even at the highest temperatures (50–60°C) provided they were supplied with nitrogen. Symbiotically dependent plants of S. hamata cv. Verano were more tolerant of high root temperatures and maintained better growth and nitrogen fixation at 40/30°C than those of CPI40264A, especially after the 31 day harvest. All six varieties responded similarly, but to differing extents, to the lower range of root temperatures. Nitrogen fixation was more severely affected than dry weight by high root temperature.

Sustainability of intensive irrigated agriculture in Egypt has become a critical issue, as land and water resources are limited on the one hand and population is increasing rapidly on the other. Salinization, heavy input use, nutrient export and pollution all threaten the health of soils that have been feeding Egypt for centuries. At the same time, the build-up of newly reclaimed desert soils to economically sustainable productive capacity is a major challenge. In a collaborative effort between the Agricultural Research Center (ARC) of the Ministry of Agriculture and Land Reclamation in Egypt and the International Center for Agricultural Research in the Dry Areas (ICARDA), a long-term resource management programme, funded by the European Union, has been developed to address the issue of resource management in a multidisciplinary way. Long-term agronomic trials (with such variables as water quantity, water quality, nutrient inputs and crop rotations) have been set up at sites representing the old lands, the newly reclaimed areas and the rainfed areas. These trials are complemented by extensive long-term monitoring in villages close to the experimental sites. This covers farmers' perspectives, farming practices and the condition of farmers' soils and crops and is aimed at identifying over time the sustainable and non-sustainable production practices and the social and economic factors that underline them. The project activities began with a Preparatory Phase which comprised inventory studies, rapid rural appraisal and multi-disciplinary surveys. This knowledge was used in the planning of the two closely related activities of long-term trials (LTT) and long-term monitoring (LTM). As the programme was implemented, the complementarity of the LTT and LTM approaches became the most important feature of this programme.

During the wet summer season of northern tropical Australia higher yields were attained by introduced weakly photoperiod-sensitive short-duration rice varieties than by locally-bred strongly photoperiod-sensitive varieties resembling traditional tropical indicas. There was no clear relationship between growth durations and yields. Dry season yields were lower, associated with shortened durations (especially of the reproductive phase) and lower cumulative radiation totals in the late phases of growth. Dawn, a variety of U.S. origin imported from the Philippines, outyielded all other varieties. In both wet and dry seasons yields depended largely on panicle weights, which in turn depended on high seed numbers per panicle. Individual seed weights were of less importance. The results tended to confirm a prior interpretation of climatic data, i.e. that there is no environmental factor limiting wet season yields in the region to levels below those obtained elsewhere in the tropics, provided the crop receives a high standard of care and attention.

In their recent paper ‘On-farm trials for development impact? The organization of research and the scaling of agricultural technologies’, de Roo, Andersson and Krupnik report on three case studies, each undertaken by one of the authors, of projects conducting on-farm research. They reach conclusions on the limitations of the projects themselves and the effects of ‘donor dependency’, and propose a strategy to overcome these issues. However, the description of the philosophy, strategies and conduct of the projects reviewed in the southern African case study is incomplete and misleading, and shows that the case study author did not understand or overlooked important project components. Due to this the conclusions reached, insofar as this case study is concerned, are largely either invalid or already contemplated in the project activities. Here, we describe more fully the philosophy and strategies followed by the series of projects on which the case study was conducted, which were designed to facilitate, through the upscaling of project methodologies, the eventual outscaling and widespread adoption of more sustainable farming systems by smallholder farmers in eastern and southern Africa. We propose these methodologies as a valid comprehensive approach to the organization of agricultural research for development for the successful development, scaling-up and scaling-out of agricultural technologies.

A multidisciplinary team has attempted to find a sustainable alternative to slash and burn agriculture in deciduous forest in the Bolivian lowlands for those who do not have access to tractor power. Farm size ranges from 30 to 50 hectares and labour and capital are major constraints to development. Fertilizers are not used because of their high price. The alternative proposed is that the farm should contain an area of not more than one hectare in alley cropping producing the family's requirements in farinaceous foods and vegetables, and an area, limited by labour constraints, of perennial crops for cash income. The balance of the farm would be in a silvipastoral system producing various tree products, beef and cheese for sale and sheep for home consumption.

Cotton is widely grown as a cash crop by subsistence farmers of Northern Nigeria, although it is invariably sown too late to produce yields that would allow economic use of insecticides to control insect pests. This late sowing is because subsistence farmers always emphasize the production of food crops, delaying sowing of cotton until these are established. Experiments are described in which cotton was sown early within the cereal, without affecting cereal yields yet producing significantly greater cash returns than sole cereal.