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.

Poor crop establishment was identified as a major constraint on rainfed crop production by farmers in the tribal villages of Rajasthan, Gujarat and Madhya Pradesh served by the Krishak Bharati Cooperative (KRIBHCO) Indo-British Rainfed Farming Project (KRIBP). On-farm seed priming with water was chosen as a low cost, low risk intervention appropriate to the farmers' needs. In vitro screening of the effects of priming on the germination of seeds of local and improved varieties of maize, upland rice and chickpea provided ‘safe limits’ – the maximum length of time for which farmers should prime seeds and which, if exceeded, could lead to seed or seedling damage. Recommended safe limits were 24 h for maize and rice and 10 h for chickpea, with only minor varietal differences. These recommendations were then tested in on-station trials in Dahod, Gujarat. Farmer-managed trials were conducted for chickpea in three villages in the rabi (post-monsoon) season in 1995–96; for maize and upland rice in eight villages in the kharif (monsoon) season in 1996; and for maize and chickpea in 15 villages in the 1996--97 rabi season. Farmers modified these recommendations to ‘overnight’ for all three crops. Evaluation of the technology by farmers involved focus group discussions, matrix ranking exercises and two workshops.

Direct benefits in all three crops included faster emergence, better stands and a lower incidence of re-sowing, more vigorous plants, better drought tolerance, earlier flowering, earlier harvest and higher grain yield. Indirect benefits reported were earlier sowing of rabi crops because of the shorter duration of the preceding kharif crop, earlier harvesting of rabi crops that allowed earlier migration from the area, with better chance of obtaining off-season work, and increased willingness to use fertilizers because of reduced risk of crop failure. In matrix ranking exercises in four villages in the kharif 1996, 95% of farmers indicated that, even after only one exposure to the technology, they would prime seed in the following season. Similar exercises in four villages in rabi 1996–97 revealed that 100% of collaborating farmers intended to continue seed priming. From 21 villages, 246 farmers attended two workshops to share their experiences of seed priming and resolved to continue with the technology.

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.

Microclimate and soil fertility were measured under and away from the canopies of small and large scattered trees of néré (Parkia biglobosa) and karité (Vitellaria paradoxa) to explain their influence on pearl millet (Pennisetum glaucum). During the rainy season, photosynthetically active radiation under both tree canopies was reduced to 24% of incident radiation but, surprisingly, millet biomass was not significantly different from that in the open. Millet seedlings under the tree canopies experienced only 1–9 h week−1 of supra-optimal temperatures (>40 °C) compared with 27 h week−1 in the open. Reduction in windspeed and soil evaporation was observed under the trees but was unlikely to have a significant influence on millet growth since water was not limiting (rainfall = 920 mm).

Exchangeable potassium, percentage carbon and pH were significantly higher and δ13C lower in soil under trees than in the open. Nitrogen levels were not significantly higher than in the open except for large néré trees. Carbon derived from C3 plants, calculated from δ13C, was significantly higher in soils under trees than in the open and is recommended as a good indicator of the influence of trees on soils. These results show that the combined beneficial effects of temperature modifications and soil fertility could exceed the negative effect of tree shade.

The possibility of growing grasses of higher quality than tall fescue (Festuca arundinacea) in a continental climate with cold winters, hot summers and low precipitation was investigated with and without irrigation at Taigu, Shanxi, China. Tall fescue was compared with perennial ryegrass (Lolium perenne), meadow fescue (Festuca pratensis) and a perennial ryegrass × meadow fescue hybrid cultivar in field swards, managed by cutting, during the year of sowing and in the three subsequent years. Tall fescue persisted satisfactorily throughout the experiment, even without irrigation. With irrigation, the other three grasses persisted satisfactorily to the end of the second harvest year and fairly satisfactorily to the end of the third harvest year. Without irrigation, the other three grasses had incomplete ground cover in the second harvest year and did not recover from the third winter.

The possibility of producing herbage of higher quality than that of tall fescue (Festuca arundinacea) in a continental climate with cold winters, hot summers and low precipitation was investigated, with and without irrigation, at Taigu, Shanxi, China. Tall fescue was compared with perennial ryegrass (Lolium perenne), meadow fescue (Festuca pratensis) and perennial ryegrass × meadow fescue in field swards, managed by cutting, during the year of sowing and in the three subsequent years. Perennial ryegrass yielded well in the year of sowing, but was low yielding subsequently; perennial ryegrass × meadow fescue yielded well in the year of sowing and in the following year. Both of these grasses had high rates of leaf appearance and extension and a high proportion of cell content in the dry matter. Tall fescue yielded well, but was low in proportion of cell content.

Photosynthetic rates (Pn) of China-type high quality tea (Camellia sinensis), clone T78, 44–68 months after field planting, were monitored during the different seasons of 1996 and 1997. The maximum value of Pn (11.9 μmol m−2 s−1) was recorded in October when humidity was very high, temperature, sunshine hours and soil moisture were moderate and photosynthetic photon flux density (PPFD) was highest. Low temperature accompanied by low soil moisture reduced Pn during the winter (February). An important limiting factor for Pn was observed to be moisture stress. An apparent relationship between Pn and relative humidity was observed. In general, higher rates of Pn were recorded during periods of low evaporative demand (low VPD).

The adaptation of extra-short-duration (ESD) and short-duration (SD) pigeonpea (Cajanus cajan) genotypes to the short rainy season (late March to late May; yala) was studied in Sri Lanka in 1995 and 1996. Eight ESD and two SD genotypes were sown on two dates in April and May, with and without supplementary irrigation. In addition, pigeonpea ESD genotype ICPL 88039, and SD genotype ICPL 86012, sesame (Sesamum indicum cv. M.I.3), blackgram (Vigna mungo cv. M.I.1) were compared under rainfed zero-tillage conditions after a rice crop at two locations in 1996. Grain yields of the pigeonpea genotypes under rainfed conditions ranged from 0.07 to 0.47 t ha−1 in the early sowings and 0.09 to 0.42 t ha−1 in the late sowings. The irrigated yields reached 1.7 t ha−1 in early sowing and 1.3 t ha−1 in the late sowings. Irrigation differentially influenced the performance of pigeonpea genotypes in both the sowings in 1996. Analysis of pooled data showed highly significant genotype × environment (year–sowing–irrigation combination) interactions. The interaction pattern among genotypes was associated with differences in the length of the reproductive period and the partitioning coefficient of genotypes. ICPL 88039, with the shortest reproductive period and one of the best in partitioning efficiency, recorded maximum mean yield. As a rainfed post-rice crop in farmers’ fields, ICPL 88039 yielded 0.43–1.4 t ha−1 which exceeded yields of SD pigeonpea (0.02–0.88 t ha−1), blackgram (0.03–1.00 t ha−1) and sesame (0–0.09 t ha−1). The results suggest scope for introducing ESD genotypes as a sole crop in the yala season in Sri Lanka since genotypes with short reproductive periods and high partitioning efficiencies are likely to have better adaptation to this season.

Cutting and carrying of mulch from established tree plots is an alternative to in situ mulch in agroforestry systems. Through the cut-and-carry method, the undesirable effects of tree-crop competition characterized by in situ mulching can be avoided. An economic evaluation of the cut-and-carry method of providing nutrients for maize production was carried out based on investigations in south-western Nigeria. The results showed that the use of mulch from multi-purpose trees (MPTs) through the cut-and-carry method contributed to higher maize grain yields than those obtained with fertilizer or in the untreated controls. However, because of high labour requirements and scarcity of land in the study area, providing nutrients for crop production by this method is unprofitable both in the short and the long term. This may serve as a constraint for the adoption of this technology by farmers. Alternative options requiring less labour and land requirements should be investigated in the quest to replace shifting cultivation.