The performance of newly developed extra-short-duration pigeonpea (Cajanus cajan) genotypes and traditional short-duration pigeonpea cultivars was compared in rotation with wheat in on-farm trials conducted in 1996–97 and 1997–98 in Sonepat (28° N) district in Haryana, and in 1996–97 at Ludhiana (30° N) district in Punjab, India. At both locations, a wheat crop (Triticum aestivum cv. HD 2329) followed pigeonpea. At Sonepat, an indeterminate extra-short-duration genotype ICPL 88039 matured up to three weeks earlier, yet gave 12% higher yield (1.57 t ha−1) and showed less susceptibility to borer damage than did the short-duration cv. Manak. At Ludhiana, extra-short-duration pigeonpea genotypes, ICPL 88039, ICPL 85010 and AL 201 gave similar grain yields to the short-duration T 21 in spite of maturing three to four weeks earlier. Yields of wheat crops following extra-short-duration genotypes were up to 0.75 t ha−1 greater at Sonepat and up to 1.0 t ha−1 greater at Ludhiana. The results of the study provide empirical evidence that extra-short-duration pigeonpea genotypes could contribute to higher productivity of pigeonpea–wheat rotation systems. Most of the farmers who grew on-farm trials in Sonepat preferred extra-short-duration to short-duration pigeonpea types for their early maturity, bold seed size, and the greater yield of the following wheat crop.

Cotton (Gossypium hirsutum) is the main agricultural export commodity from Tanzania. The most significant disease of the crop is fusarium wilt caused by Fusarium oxysporum f.sp. vasinfectum. Phytosanitary measures instituted at the cotton ginneries to prevent the distribution, for planting, of seed infected with the wilt fungus have become difficult to apply since economic liberalization and the entry of the private sector into cotton ginning and lint marketing. Surveys of cotton fields, ginneries and cotton buying posts were conducted in order to determine the factors affecting disease incidence and spread. In affected fields, disease incidence was generally less than 5%. Where it was greater than this, wilt symptoms were associated with root damage caused by the root-knot nematode (Meloidogyne incognita). At a number of ginneries, herdsmen were allowed to remove seed husks that accumulate at the ginneries as a byproduct of oil extraction. The husks are used as cattle feed and this was identified as a potential source of disease spread. At the buying posts visited, there was no system for separating cotton varieties or for identifying seed cotton purchased from villages infected with fusarium wilt. As a result, seed subsequently distributed for planting is likely to be a source of infection for the spread of this disease. The implications of economic liberalization in the cotton sector are discussed with respect to seed distribution and management of fusarium wilt.

New varieties are often developed on research stations with limited farmer involvement until the final stages of testing. Recently, farmer participatory approaches have been employed to include farmers' input into breeding objectives at much earlier stages of varietal development. This paper reports on a farmer survey in Uganda to record farmer selection criteria for banana cultivars as a pre-breeding activity. From ranked data, bunch size and crop maturation time were the key selection criteria in the county's most important commercial production zones. Stand longevity, taste and crop maturation time were key factors where banana production is in decline and sale of bananas less important. Principal component analysis revealed that, nationally, stand longevity and tolerance of marginal soils were the most important criteria, probably because the larger part of overall production is for subsistence.

The East African highlands, home to more than 80 cultivated varieties of locally evolved bananas, constitute a secondary centre of banana diversity. Uganda is the leading producer and consumer of banana in the region and also enjoys the highest diversity of a group of bananas uniquely adapted to this region. These East African highland bananas comprise cooking and brewing types. The former is a staple for more than 7 million people and thus important for food security. Little is known about the distribution of the vast germplasm and this study was set up to help determine a distribution pattern and to understand the dynamics of cultivar change using farmers participatory appraisal methods. The study involved a guided interview with 120 farmers, at 24 sites throughout the banana-growing region of Uganda, to reveal cultivar diversity, proportions, distribution and preferences. Cultivar diversity ranged from 18 to 34 (mean = 26) cultivars per site, and from 4 to 22 (mean = 12.3), cultivars per individual farm. Such high diversity was attributed to a variety of end uses, better food security and the perception that each cultivar had a unique range of strengths and weaknesses. Highland banana (AAA-EA) represented 76% of total production while Kayinja (‘Pisang Awak’ subgroup) (ABB) contributed 8%; Ndiizi (’Ney Poovan’ subgroup) (AB) 7%; Kisubi (‘Ney Poovan’ subgroup) (AB) 5%; Gros Michel (‘Bogoya’) (AAA) 2%; and plantain (AAB) 2%. Although 130 highland cultivars were recorded, only 10 constituted 50% of highland banana production while 45 cultivars were found at only 1 or 2 sites. A few cultivars showed more universal distribution and it is proposed that these may be the oldest and best performing local landraces.

Population pressure has diminished the role of the traditional bush fallow system in restoring the fertility of depleted soils following several years of cultivation in the derived savanna of southwest Nigeria. The search for alternative fallow systems led to the development of alley cropping using Leucaena leucocephala and cover cropping using Pueraria phaseoloides. These soil-conserving systems also embody the principles of sustainability by ensuring stable crop yields in spite of an increase in land-use intensity. Simulating smallholder farm conditions and based on a split-plot experiment with the three fallow systems as the main plots and four different land-use intensities (LUI) as the subplots, simple direct observation and record keeping were used to collect data on labour use in all farm operations including fuelwood cutting and stacking in alley cropping systems with fallow phases. Data collection covered a period of four years (1993–96), corresponding to one out of the three phases (or complete cycles) of the trial. Partial budget analysis was used to estimate profitability of cassava (Manihot utilissima)–maize (Zea mays) under each LUI. Results based on crop production indicate that each of the cassava-maize enterprises was profitable but the level of profit varied from 10 819 to 50 289 Naira ha−1. Production under cover cropping has a net benefit advantage of 4–25% (over that under bush fallow) and 25–60% (over alley cropping). Profitability increased as the LUI decreased, depicting the overall importance of fallow periods on soil fertility restoration. Results based on crop production plus fuelwood operations indicate that production with cover cropping has a net benefit advantage over that of both bush fallow and alley cropping under both zero-fallow and one-year fallow LUIs. However, results from two- and three-year fallows indicate that fuelwood yield generated sufficient revenue to put alley cropping at a net benefit advantage of 29–42% over bush fallow and 26–37% over cover cropping. From these results, cover cropping is recommended, especially to farmers in areas where, although land shortage is a problem, fuelwood and the other sources of domestic energy are still cheap and easily accessible. However, in areas with abundant land and where farmers can still wait for fallow periods of at least two years, alley cropping is recommended since, in addition to soil fertility improvement, substantial revenue is obtained. However, considerations of yield variability, labour scarcity, as well as risk-aversion behaviour among farmers may alter their technology choice.

Long-term data (20 years) on wheat (Triticum aestivum) grain yield under various fertilizer-nitrogen (N) and water conditions in rainfed and irrigated environments of sub-tropical north India were used to assess the magnitude and economics of N response in relation to amount and timing of irrigation. Treatments comprised combinations of fertilizer N rates (ranging from 0 to 150 kg ha−1) and irrigation regimes (rainfed, supplemental, limited, and adequately irrigated). Regression analysis of wheat yield against available water supply and fertilizer N showed a strong interaction between the two variables for grain yield and input use efficiency. The effect, on grain yield and returns, of increasing the N rate for a given water supply was influenced by the irrigation regimes. Economic optimization of water and N, based on constrained profit maximization technique, showed that optimum amounts of available water (or irrigation) and fertilizer N are related directly to the capital investment. Increased input prices lowered their optimum levels for a given investment. The analysis suggests an approach for resource allocation that relates to capital investment and input prices.

Data from a long-term trial on rates of fertilizer nitrogen (N) application to maize (Zea mays) were used to validate a cropping systems simulation model (APSIM) and then to apply the model to explore the risk associated with N fertilizer use by smallholder farmers and management strategies to minimize that risk. On average, maize growth and development in response to N was simulated with a degree of accuracy that justified its use in analysis of risk associated with N use in these semi-arid regions of Zimbabwe. APSIM was then configured to simulate the response to N over a 46-year climate record in order to assess the long-term risks associated with N use. The simulated long-term distribution indicated that negative responses to N could be expected in 15% of years, whereas no negative response to N was recorded in the experiments at the Makoholi Research Centre. Median responses were 20–30 kg maize grain kg−1 N for observed and simulated results. In terms of return on fertilizer investment, the observed and simulated distributions were also similar: in about 20% of years, a negative return could be expected, while in the best 20% of years a return of $Z5000 or more could be expected given the grain:fertilizer price ratio which, at March 2000, was about 1:7. The model analysis has suggested moderate rates (approximately 30 kg N ha−1) of N fertilizer would give greater responses per unit N applied than smaller rates (15 kg N ha−1). There was no evidence that conditional fertilizer strategies based on early-season rainfall would offer significant benefits over fixed application strategies. Early sowing at recommended population densities gave higher responses to N than were achieved for late sown or low-density crops.

Ranking and scoring exercises are common in participatory research work, for example in determining farmer preferences for crop varieties, tree species or other commodities. However, they rarely involve eliciting opinions of many individual farmers so as to establish the repeatability of study findings. This paper demonstrates ways in which ranking of evaluation criteria can be combined with evaluation scores to produce generalizable results concerning farmers' overall preference for a set of bean (Phaseolus vulgaris) varieties. The use of weighted indices is explored. Results were found to be robust across all indices. However, farmer evaluations for yields did not correlate well with actual yields measured on their own plots. Farmers often gave high evaluation scores for yield performance of new bean varieties, even when they yielded quite poorly in plots in their own fields. Reasons for this are discussed.

Volume 37 Number 3 July 2001

MANURE MANAGEMENT BY SMALLHOLDER FARMERS IN THE KANO CLOSE-SETTLED ZONE, NIGERIA

F. HARRIS and M. A. YUSUF

We would like to point out that as a result of an error during the printing process, parts of Table 1, Table 2 and Table 3 were accidentally removed from the tops of the respective pages. The publishers would like to offer their sincere apologies to the authors and to readers for this mistake. Please find Tables 1, 2 and 3 reprinted in full on the pages overleaf.