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Nitrogen (N) is an essential but generally limiting nutrient for biological systems. Development of the Haber-Bosch industrial process for ammonia synthesis helped to relieve N limitation of agricultural production, fueling the Green Revolution and reducing hunger. However, the massive use of industrial N fertilizer has doubled the N moving through the global N cycle with dramatic environmental consequences that threaten planetary health. Thus, there is an urgent need to reduce losses of reactive N from agriculture, while ensuring sufficient N inputs for food security. Here we review current knowledge related to N use efficiency (NUE) in agriculture and identify research opportunities in the areas of agronomy, plant breeding, biological N fixation (BNF), soil N cycling, and modeling to achieve responsible, sustainable use of N in agriculture. Amongst these opportunities, improved agricultural practices that synchronize crop N demand with soil N availability are low-hanging fruit. Crop breeding that targets root and shoot physiological processes will likely increase N uptake and utilization of soil N, while breeding for BNF effectiveness in legumes will enhance overall system NUE. Likewise, engineering of novel N-fixing symbioses in non-legumes could reduce the need for chemical fertilizers in agroecosystems but is a much longer-term goal. The use of simulation modeling to conceptualize the complex, interwoven processes that affect agroecosystem NUE, along with multi-objective optimization, will also accelerate NUE gains.

More than 40% of the total oil palm area in Indonesia is owned and managed by smallholders. For large plantations, guidelines are available on so-called 'best management practices', which should give superior yields at acceptable costs when followed carefully. We tested a subset of such practices in a sample of smallholder plantations, aiming to increase yields and profitability. We implemented improved practices (weeding, pruning, harvesting, and fertiliser application) in 14 smallholder plantations of 13–15 years after planting in Jambi province (Sumatra) and in West-Kalimantan province (Kalimantan) for a duration of 3 to 3.5 years. During this period, we recorded yields, measured palm leaf parameters and analysed leaf nutrient contents. Yield recording then continued for an additional two years. In the treatment plots, the yields did not increase significantly, but the size of the bunches and the size of the palm leaves increased significantly and substantially. The tissue nutrient concentrations also increased significantly, although after three years, the potassium concentrations in the rachis were still below the critical value. Because of the absence of yield increase and the additional costs for fertiliser inputs, the net profit of implementing better management practices was negative, and 'business as usual' was justified financially. Some practices, such as harvesting at 10-day intervals and the weeding of circles and paths, were received positively by those farmers who could implement them autonomously, and were applied beyond the experiment. It is challenging to find and implement intensification options that are both sustainable and profitable, that have a substantial impact on yield, and that fit in the smallholders' realities. On-farm experimentation and data collection are essential for achieving sustainable intensification in smallholder oil palm plantations. [ABSTRACT FROM AUTHOR]

Purpose: We assessed cocoa farmers' access to, demand for, and satisfaction with five innovation support services and the factors shaping them. Design/methodology/approach: We used data from 10 focus groups and a survey of 421 farmers in Central Cameroon. Data were analysed using descriptive and inferential statistics, and regression models. Findings: Results showed that farmers mostly receive training and advice whereas inputs, credit, and equipment are the most demanded services. Training and advice obtained the highest perceived quality score. Conflicts around distribution and capture by leaders were relatively frequent regarding inputs and equipment. Farmers' satisfaction with service outcomes increased with the number of services received and any services above training and advice yielded higher outcomes. Location, involvement in certification, seniority, and leadership position in farmers' organisations were significantly associated with access and demand for at least two services while satisfaction with quality was mostly influenced by prior services received and the extent to which they matched expectations. Practical implications: Farmers' demands for services are diverse, hence the importance of providing them with either service bundles or options from which they can choose. Additional efforts are needed from service providers to create an enabling environment for the implementation of the disseminated sustainable management practices. Theoretical implications: Farmers' satisfaction with services can be analysed from different perspectives. Both endogenous and exogenous factors determine access to, demand for, and satisfaction with services. Originality/value: This research is the first to assess the provision of innovation support services in the cocoa sector using an analytical framework that combines demand, access, and satisfaction with five services. [ABSTRACT FROM AUTHOR]