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In tropical developing countries farmers tend to grow a wide range of crops in a small area for subsistence or sale. To make full use of often limited resources a good understanding of how environmental conditions affect the characteristics and performance of these crops is essential. This book considers the response of tropical food crops to environmental factors such as climate, soil and farming system. Three types of crop are considered; cereals, legumes and non-cereal energy crops, with individual chapters on the four most important crops in each group. This material is set in context by introductory chapters on tropical farming systems, tropical climates and tropical soils. This updated edition retains the successful formula of the first edition, and will serve the needs of advanced students of tropical agriculture, as well as professionals engaged in research and extension work in tropical crop production.

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ABSTRACT. Many rural communities are vulnerable social-ecological systems (SES) that must do more than become resilient to future environmental and social shocks: they must transform to achieve sustainability. We aimed first to conceptually explore the proposition that SES characteristics (identity, feedbacks, structure, and functions) necessary for transformation may be distinct from those necessary for adaptive maintenance or resilience, and second, to propose metrics that may be used to assess these two types of system changes. We did this by interrogating literature and by investigating two rural towns in Australia using a combination of quantitative methods and focus groups to interrogate community social networks, capitals (human, natural, built, and social) and future scenarios. Results indicated that (1) it is practicable to carry out a holistic assessment of SES characteristics (identity, feedbacks, structure, and functions), and (2) purposeful, positive transformation is supported by vision, identification with place, unhappiness (with the status quo), high personal contribution to social capital, open social networks, and latent capital(s). We conclude that rural communities possess capacities for adaptive maintenance (resilience) and for system-wide transformation, and that the metrics used to assess each are sometimes discrete, sometimes common.

The challenges facing grassland agronomists are becoming increasingly complex, with environmental and ethical issues assuming a greater significance alongside more conventional technical aspects. This new expanded edition, with an increased emphasis on systems thinking, has been revised to reflect current concerns, knowledge and practice. As such it addresses the need for a different approach to grassland agronomy, providing novel and provocative material to instruct, stimulate and enthuse the reader.

The diurnal pattern of nitrate uptake by Capsicum annuum L. cv. California Wonder in a constant environment is described by a Fourier harmonic, with the maximum uptake in the middle of the photoperiod and the minimum in the middle of the dark period. Comparison of the uptake pattern with that of nitrate reductase (EC 1.6.6.1.) activity suggests against a direct control of one process by the other. This was confirmed by the observation that the pattern of nitrate reductase activity was not altered by restricting nitrate uptake to one hour per day. Translocation of (15)N from the roots is much greater in the lightperiod than in the dark period. Reduction of (15)N in the leaves occurs in the lightperiod but very little is reduced in the dark period. Amino acid levels showed marked daily fluctuations but in the roots neither amino acids, sucrose, fructose, glucose nor malate showed fluctuations. The amino acid composition of roots and leaves differed: glutamine+glutamate were relatively more important in leaves than in roots whereas alanine was a more important constituent of roots than of leaves.