Nutrient deficiencies in export tree and food crops: literature review and field observations

This paper reviews nutrient deficiencies in agricultural crops of PNG using the literature of agronomic trials and field observations made throughout the country. Nutrient deficiencies have been investigated systematically since the mid-1950s, but research has mainly focused on export tree crops and relatively little information is available on food crops. Literature analysis and field observations showed consistent trends, with deficiencies of boron and phosphorus in large parts of the PNG highlands. The review has been useful in delineating areas where nutrient deficiencies occur and these findings could be used for planning nutrient management research and extension activities in food crop

To the hands of the poor: water, trees and land

This paper argues for a shift in rural development strategy in India to place more water, trees and land securely in the hands of the poor. Practical precepts, including political feasibility, are used to identify and assess major potential thrusts. These include water reform on canal irrigation, equitable access to groundwater, tree holdings on forest and common land, agroforestry for resource-poor farmers, and land purchase to settle the landless

Cacao agroforestry systems do not increase pest and disease incidence compared with monocultures under good cultural management practices

Pests and diseases threaten cacao production worldwide. Agroforestry systems are traditionally seen by farmers as one of the causes of increased pest and disease incidence, in contrast with full-sun monocultures. Cultural management practices - e.g. regular tree pruning, frequent pod harvest, regular removal of infested pods, weed management - have been reported to be crucial for pest and disease management. We performed two experiments for the purpose of assessing the effect of (i) different cacao production systems, and (ii) the frequency of harvest and removal of infested pods on the incidence of pests and diseases and on the cacao yield. The first experiment was performed in a long-term system comparison trial in Bolivia, where data on pest and disease incidence were recorded for three years in five production systems: two monocultures and two agroforestry system under organic and conventional farming, and one successional agroforestry system, i.e. a high tree density multi-strata system. Pest and disease management did not differ between systems and relied on cultural management practices. Overall, the incidence of pests and diseases did not differ between production systems, which indicated they were not the driver of yield differences between them. Across production systems, only 14% of the pods were affected by pests and diseases; 70% of these were affected by frosty pod rot. More than 80% of the pods infected by frosty pod rot were removed before the sporulation phase. In the second experiment, the effects of the frequency of harvest and removal of infected pods - every 15 days versus every 25 days - on pest and disease incidence and yield were tested in four farmers’ fields. Fortnightly harvest and diseased pod removal significantly decreased disease incidence and increased cacao yield, by 25% and 46% respectively. Our results show that cacao agroforestry systems do not increase pest and disease incidence compared with monocultures when good cultural management practices are implemented, which, in turn, can increase the productivity of the cacao plantations

Impact of Ponderosa Pine Thinning and Slash Management on the Herbage Production of Selected Soils in Custer State Park

Custer State Park\u27s multiple-use management plan stresses compromise among resource users. The objective of integration of forest, wildlife and recreational resource management is to provide maximum benefits to all sectors of the management plan. Forest management techniques have a marked influence on the unique wildlife populations of Custer State Park. To provide input for individuals making integrated management decisions, an approach was taken to combine forest stand and soil survey information, to assess understory herbage production for deer and elk grazing. Thinning pine stands will increase forage and browse production. Slash left from thinning and timber harvesting operations is suspected of limiting the response of understory vegetation. Overstory and understory production is dependent on soils which contain moisture and nutrient reserves. This study was designed to accomplish the following three objectives: (1) Characterize predominant soils of the Precambrian Crystalline core area of Custer State Park. (2) Evaluate the understory production of these soils under varying forest conditions. (3) Develop prediction models that resource managers can use to assess understory production in different forest environments. Results from this study should enable resource managers to evaluate the effects of current and proposed forest management schemes on wildlife populations. Coupled with the recently completed soil survey of the Black Hills. parts of Custer and Pennington counties, these results should be useful managerial tools for Custer State Park personnel

Late Pliocene lakes and soils: a data-model comparison for the analysis of climate feedbacks in a warmer world

Based on a synthesis of geological data we have reconstructed the global distribution of Late Pliocene soils and lakes which are then used as boundary conditions in a series of model experiments using the Hadley Centre General Circulation Model (HadCM3) and the BIOME4 mechanistic vegetation model. By combining our novel soil and lake reconstructions with a fully coupled climate model we are able to explore the feedbacks of soils and lakes on the climate of the Late Pliocene. Our experiments reveal regionally confined changes of local climate and vegetation in response to the new boundary conditions. The addition of Late Pliocene soils has the largest influence on surface air temperatures, with notable increases in Australia, southern North Africa and Asia. The inclusion of Late Pliocene lakes generates a significant increase in precipitation in central Africa, as well as seasonal increases in the Northern Hemisphere. When combined, the feedbacks on climate from Late Pliocene lakes and soils improve the data to model fit in western North America and southern North Africa