Inputs of available nitrogen (N) to ecosystems have grown over the recent past. There is limited general understanding of how increased N inputs affect the cycling and retention of other potentially limiting nutrients. Using a plant-soil nutrient model, and by explicitly coupling N and phosphorus (P) in plant biomass, we examine the impact of increasing N supply on the ecosystem cycling and ret...

Soil amendments can improve the sustainability of agricultural systems by building soil carbon and improving numerous other soil health indicators, including soil structure, water infiltration and retention, bulk density, nutrient availability, and microbial activity. This chapter covers some general considerations relevant to the use of soil amendments followed by a discussion of biosolids, an...

The mathematical methods for optimising the effects of heat processing food products are reviewed in relation to microbial destruction, nutrient destruction, cooking value and loss of quality. Some data are presented for the kinetics of the various thermal effects. The results obtained by various workers are presented with particular reference to nutrient retention.

Ecosystem processes are thought to depend on both the number and identity of the species present in an ecosystem, but mathematical theory predicting this has been lacking. Here we present three simple models of interspecific competitive interactions in communities containing various numbers of randomly chosen species. All three models predict that, on average, productivity increases asymptotica...

The establishment of quantitative relationships between nitrogen (N) retention and energy and protein intake in breeding animals is essential to enable producers to determine the consequences of altering nutrient intake on changes in body composition, reproductive efficiency and lactational performance. Results of an experiment with pregnant gilts revealed that maximum rates of N retention occu...

The functional adjustments of winter-deciduous perennials to Mediterranean conditions have received little attention. The objectives of this study were: (i) to determine whether Amelanchier ovalis, a winter-deciduous shrub of Mediterranean and sub-Mediterranean regions, has nutritional and phenological traits in common with temperate zone deciduous trees and shrubs and (ii) to determine the con...

Nutrients are essential resources for food production but used inefficiently, and thereby they pollute inland coastal waters lost into the oceans. Nutrient conservation by retention consecutive reuse would prevent nutrient losses to atmosphere downstream ecosystems. We present Smart Retention Networks (SNRNs) as a novel management approach achieve across networks of connected waterbodies throug...

The objectives of the current study were to evaluate the effect of an acidifying diet (gypsum) combined with zeolite and slightly reduced crude protein (R) vs. a control diet (C) on nutrient retention in laying hens and compare 3 approaches to estimating nutrient excretion from hens: 1) mass balance calculation (feed nutrients - egg nutrient), 2) use of an indigestible marker with analyzed feed...

Reservoirs are artificial ecosystems with physical, chemical, and biological transitional characteristics between rivers and lakes. Greater water retention time in reservoirs provides conditions for cycling materials inputs from upstream waters through sedimentation, biological assimilation and other biogeochemical processes. We investigated the effects of reservoirs on the water quantity and q...