soil enzyme activities can be used as indicators of soil quality for assessing the sustainability of agricultural ecosystems. the objective of this study was to determine the effects of barley residue input rate, burning, urea fertilizer and tillage management on activities of alkaline phosphatase and urease under field conditions, after a period of 90 days. the experiment was carried out based...

Improving the efficiency of resource utilization has received increasing research attention in recent years. In this study, we explored the potential physiological mechanisms underlying improved grain yield and water-use efficiency of winter wheat (Triticum aestivum L.) following organic fertilizer application. Two wheat cultivars, ChangHan58 (CH58) and XiNong9871 (XN9871), were grown under the...

The structure formation in acid promoted polycondensation and particularly in alkaline post-treatment with urea was studied by 13C NMR spectroscopy in the three-step synthesis of ureaformaldehyde resins. Trishydroxymethyl urea was identified as the constituent of the mixture of hydroxylmethylated urea derivatives obtained in alkaline conditions. The formation of methylenes linked to secondary o...

In order to study the effect of chemical and biological fertilizers on silage corn under different plant densities, a split plot experiment was carried out in a randomized completely block design with three replicates in south western Iran. The main plot included nitrogen fertilizer treatment at three levels (N1: with out chemical and organic fertilizers, N2: 75% chemical fertilizer + 100% orga...

As the saline-alkali paddy area continues to grow, nutrient (e.g., nitrogen (N) and phosphorus (P)) runoff loss is becoming more serious in world. The N-fertilizer application affects risk paddy. Selecting suitable fertilizer types reduce beneficial agricultural sustainability. However, effects of are not clear. This study measured N P concentration surface water paddy, using various N—fertiliz...

abstract the addition of manures and chemical fertilizers as soil amendments for the improvement of soil fertility and quality could affect the seasonal changes in the activity of soil microbes and enzymes. this study aimed at investigating the effect of different levels of nitrogen from broiler litter and urea sources on the trend of urease, alkaline phosphatase and saccharase activities in a ...

Bronchial provocation studies on 15 workers occupationally exposed to formaldehyde are described. The results show that formaldehyde exposure can cause asthmatic reactions, and suggest that these are sometimes due to hypersensitivity and sometimes to a direct irritant effect. Three workers had classical occupational asthma caused by formaldehyde fumes, which was likely to be due to hypersensiti...