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close this bookAbstracts on Sustainable Agriculture (GTZ; 1992; 423 pages)
Open this folder and view contentsAbstracts On Traditional Land-Use Systems
Open this folder and view contentsAbstracts on farming systems research and development
Open this folder and view contentsAbstracts on integrated systems
close this folderAbstracts on cropping system
View the documentAcknowledgements
View the document1. Green manure crops in irrigated and rainfed lowland rice-based cropping systems in south Asia.
View the document2. Comparative evaluation of some inter-cropping systems in the humid tropics of southern nigeria.
View the document3. Intercropping improves land-use efficiency.
View the document4. A new maize modernizes savanna farming.
View the document5. Analysis of the environmental component of genotype x environment interaction in crop adaptation evaluation.
View the document6. Climatic analyses and cropping systems in the semiarid tropics.
View the document7. Field crop production in tropical Africa.
View the document8. The cultivated plants of the tropics and subtropics.
View the document9. Software system for plant growth prediction.
View the document10. Flood-tolerant crops for low-input sustainable agriculture in the everglades agricultural area.
View the document11. The physiology of tropical production.
View the document12. Achieving sustainability in cropping systems: the labour requirements of a mulch rotation system in Kalimantan, Indonesia.
View the document13. Grain yield responses in rice to eight tropical green manures.
View the document14. Utilization efficiency of applied nitrogen as related to yield advantage in maize/mungbean intercropping.
View the document15. Effects of two underseed species, medicago polymorpha l. And scorpiurus muricatus l.,on the yield of main crop (durum wheat) and subsequent crop (teff) under humid moisture regimes in Ethiopia.
View the document16. Characterization and environment-management relationships in beans and sorghum intercropped with maize in honduras. (caracterizacion y relaciones ambiente-manejo en sistemas de frijol y sorgo asociados con maiz en Honduras.)
View the document17. Production potential of pigeonpea/pearl millet intercropping system in rainfed diara (floodprone) areas of eastern uttar pradesh, India.
View the document18. Effect of mixed cropping lentil with barley at different seeding rates.
View the document19. Yield performance and complementarity in mixtures of bread wheat (triticum aestivum l.) And pea (pisum sativum l.).
View the document20. Economic feasibility of green manure in rice-based cropping systems.
View the document21. Effect of nitrogen on pigeonpea (cajanus cajan) and rice (oryza sativa) intercropping system.
View the document22. Smallholder cotton cropping practices in Togo.
View the document23. Effect of row arrangement on yield and yield advantages in sorghum/finger millet intercrops.
View the document24. Yield, economics and nutrient balance in cropping systems based on rice (oriza sativa).
View the document25. Mechanisms for overyielding in a sunflower/mustard intercrop.
View the document26. Agronomic modification of competition between cassava and pigeonpea in intercropping.
View the document27. Production and economic evaluation of white guinea yam (dioscorea rotundata) minisetts under ridge and bed production systems in a tropical guinea savanna location, Nigeria.
View the document28. Evaluation of intercropping cassava/corn/beans (phaseolus vulgaris l.) In northeast Brazil.
View the document29. Intercropping of sweet potato and legumes.
View the document30. Cassava in shifting cultivation. - a system approach to agricultural technology development in Africa.-
View the document31. Economic returns from yam/maize intercrops with various stake densities in a high-rainfall area.
View the document32. Performance of three centrosema spp. And pueraria phaseoloides in grazed associations with andropogon gayanus in the eastern plains of Colombia.
View the document33. Barley, lentil, and flax yield under different intercropping systems.
View the document34. Biological potential and economic feasibility of intercropping oilseeds and pulses with safflower (carthamus tinctorius) in drylands.
View the document35. Screening of different tropical legumes in monoculture and in association with cassava for adaption to acid infertile and high al-content soil.
View the document36. Intercropping studies in peanut (arachis hypogaea l.).
View the document37. Intercropping of rainfed groundnut (arachis hypogaea) with annual oilseed crops under different planting patterns.
View the document38. Resource use and plant interactions in a rice-mungbean intercrop.
View the document39. Cassava/legume intercropping with contrasting cassava cultivars. Part I
View the document40. Cassava/legume intercropping with contrasting cassava cultivars. Part II
View the document41. A post-green revolution strategy for the improvement of small farmer-grown common beans.
Open this folder and view contentsAbstracts on agroecology
Open this folder and view contentsAbstracts on agrometeorology
Open this folder and view contentsAbstracts on agroforestry
Open this folder and view contentsAbstracts on homegardens
Open this folder and view contentsAbstracts on seed production
Open this folder and view contentsAbstracts on plant protection
Open this folder and view contentsAbstracts on water management
Open this folder and view contentsAbstracts on soil fertility
Open this folder and view contentsAbstracts on erosion and desertification control
Open this folder and view contentsAbstracts on potential crops for marginal lands

20. Economic feasibility of green manure in rice-based cropping systems.

In: Proc. of a Symp. on Sustainable Agriculture - Green Manure in Rice Farming; IRRI, Philippines, 1988, pp. 11-16

In this paper the authors discuss the key concepts, issues, and methods of determining the economic feasibility of green manure; employ these concepts in a case study of the economics of azolla as a green manure in

Philippine rice production; and draw a number of general conclusions regarding the economic feasibility of green manuring in rice-based farming systems.

Increased use of fertilizer, with development and dissemination of improved varieties and expanded and improved irrigation, has been a key factor in the growth of rice production in Asia and elsewhere.

The increase in fertilizer use has been remarkable by any standard.

Between the first and second halves of the 1970s, average fertilizer consumption grew by 50% in South Asia, 39% in Southeast Asia, and 53% in

East Asia.

The rapid growth in fertilizer use has been due almost entirely to increased use of chemical fertilizers. Organic fertilizers (green manure crops, animal manure, and compost), traditionally important sources of nutrients, declined in relative importance with the rapid increase in use of chemical fertilizers.

Although data on use of organic fertilizers is scarce, there is at least some evidence that their use has declined in absolute, as well as in relative terms.

Despite (or because of) these trends, interest in the potential for expanded use of green manure has been renewed.

Concern also has been rising over possible long-term adverse effects of heavy use of chemical fertilizer on soil structure, crop productivity, and off-farm pollution. Green manure and other organic fertilizers can maintain and improve soil structure.

Increased use of chemical fertilizers may also incur long-term environmental costs. In areas where chemical fertilizers are heavily used, drainage runoff contributes to eutrophication of rivers and lakes.

Green manure and other organic fertilizers have a number of apparent agronomic and environmental advantages.

The case study results suggest that azolla usually is not a cost-effective substitute for urea fertilizer. Green manuring is uneconomic,largely because of the opportunity cost of land used to grow azolla. Use of land for azolla incurs a substantial cost of alternative cropping opportunities forgone. Compared to using N from urea, using azolla as an intercrop is profitable only with good irrigation.

High labour costs, high opportunity costs of land, and poor water control are major constraints to the economic feasibility of green manure. Given the current stage of azolla technology and its relatively poor economic feasibility, policy support for widespread investment in technology dissemination is not appropriate. Instead, strong support should be given to a research program designed to overcome the constraints to economic feasibility. Improvements in azolla technology that increase nitrogen yield and pest resistance or reduce the opportunity costs of labour and land could make azolla economically feasible in a greater number of environments.

1110 92 - 4/153

Cropping systems

Asia, India, study, field trial, intercropping system, pigeonpea, rice, nitrogen economics

MAHAPATRA, P.K. et al.

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