Problem 1. Infinite Products and Coproducts in Ab. We have seen that finite products and coproducts agree in Ab. However, the same is not true for infinite products and coproducts. Let I be a set and let {Ai}i∈I be a family of abelian groups, each equal to some fixed group A. (a) Show that the set AI := HomSet(I, A) is an abelian group. Furthermore, show that we can think of this group as the i...

Nitrogen (N) is an essential nutrient widely used in maize crop production. The application of a high N rate commonly practiced by growers as "guarantee" optimal growth and yield. However, excessive nitrogen consumption can cause wastage, negatively impact plants, adversely affects the environment. This paper reports on supply leaf characteristics maize. Maize was grown experimental plot Depart...

knowledge of traits associated with drought tolerance would be useful for developing breeding materials fortarget environments. to study these traits, 119 spring durum wheat breeding lines (bls) from the international maize and wheat improvement center (cimmyt) were evaluated along with local checks (one modern cultivar and three landraces) in three experiments under terminal and non-terminal d...

Simple nitrogen (N) input/output balance calculations in agricultural systems are used to evaluate performance of nutrient management; however, they generally rely on extensive assumptions that do not consider leaching, denitrification, or annual depletion of soil N. We constructed a relatively complete N mass balance for the Big Ditch watershed, an extensively tile-drained agricultural watersh...

Interannual variation in plant phenology can lead to major modifications in the interannual variation of net ecosystem production (NEP) and net biome production (NBP) as a result of recent climate change in croplands. Continuous measurements of carbon flux using the eddy covariance technique were conducted in two winter wheat and summer maize double-cropped croplands during 2003-2012 in Yucheng...

The topsoil around Beijing metropolis, China, is experiencing impacts of rapid urbanization, intensive farming, and extensive industrial emissions. We analyzed the concentrations of Cu, Ni, Pb, Zn, Cd, and Cr from 87 topsoil samples in the pre-rainy season and 115 samples in the post-rainy season. These samples were attributed to nine land use types: forest, grass, shrub, orchard, wheat, cotton...

Fodder maize is the most commonly used crop for biogas production owing to its high yields, high concentrations of starch and good digestibility. However, environmental concerns and possible future conflict with land for food production may limit its long-term use. The bioenergy grass, Miscanthus, is a high-yielding perennial that can grow on marginal land and, with 'greener' environmental cred...

Abstract Intensive cropping is considered to contribute negative effects both on soil physiochemical properties and long‐term grain yield, which can be alleviated by appropriate crop rotations. Soil microbial community vary with different rotations, in turn affect quality yield. Therefore, it of great significance elucidate the response rotation. In this study, structural functional changes rot...