crop rotation affect on crop nitrogen uptake and nitrogen use efficiency (nue). crop rotations with high nue decrease energy use and increase level of sustainability in agro ecosystems. the objectives of this research were to determine the suitable double cropping system for enhancing nue and evaluate the effects of crop rotation, n fertilizer rate and return of crop residue on nue. this study ...

abstract this study was conducted under cold climate condition in khorasan during 2006-2008 growing seasons to evaluation of soil fertility in wheat-based double cropping systems under different rate of nitrogen and return of crop residues. a randomized complete block design with split-split plot arrangement and three replicates was used. main plots were five crop rotations namely: wheat-wheat,...

in order to study the competition ability of amaranth and mungbean in fodder intercropping system under different crop residue management, a field experiment was conducted at two seasons (first planting of wheat and then intercropping management) in agricultural faculty of shahid chamran university of ahvaz during growing season of 2010-2011. the experimental design was split plot based on rand...

satellite imagery was used as a rapid and spatially explicit method to delineate crop residue cover and to estimate the use and intensity of conservation tillage. the potential of multispectral high-spatial resolution of worldview-2 local data was evaluated using 11 satellite spectral indices and linear spectral unmixing analysis (lsua). experimental plots were examined; residue cover was measu...

background and objectives: with regard to the hazards of nitrite, application of natural preservatives in order to reduce the microbial load of meat and meat products is increasing. owing to their anti-bacterial properties, red barberry and the dried residue of red grape could be suitable replacers for nitrite. materials and methods: agar dilution method was employed in order to determine the m...

A prime number p is called b-elite if only finitely many generalized Fermat numbers Fb,n = b 2 + 1 are quadratic residues to p. So far, only the case b = 2 was subjected to theoretical and experimental researches by several authors. Most of the results obtained for this special case can be generalized for all bases b > 2. Moreover, the generalization allows an insight to more general structures...

By a careful analysis of the proofs of Kopparty in fields of characteristic 2, we show that the problem of powering in Fpn requires ACC(p) circuits of exponential size (in n), for any fixed prime p > 2. Similar bounds hold for quadratic residuosity. As a corollary, we obtain non-trivial bounds for exponential sums that express the correlation between the quadratic character of Fpn and n-variate...

We determine the product of the invertible quadratic residues in Zn. This is a variation on Gauss’ generalization of Wilson’s Theorem. From this we deduce that for twin primes p, p + 2, the product of the invertible quadratic residues in Zp(p+2) is ±(p+1), where the sign depends on the residue class of p modulo 4. We examine necessary and sufficient conditions for consecutive odd natural number...

In this paper, we establish a residue theorem for Malcev-Neumann series that requires few constraints, and includes previously known combinatorial residue theorems as special cases. Our residue theorem identifies the residues of two formal series that are related by a change of variables. We obtain simple conditions for when a change of variables is possible, and find that the two related forma...

We present some observations on a restricted variant of unitary Cayley graphs modulo n, and implications for a decomposition of elements of symplectic operators over the integers modulo n. We define quadratic unitary Cayley graphs Gn, whose vertex set is the ring Zn, and where residues a, b modulo n are adjacent if and only if their difference is a quadratic residue. By bounding the diameter of...