prediction of seasonal weed seedling emergence patterns is useful in weed management programs. this study was carried out in research fields of islamic azad university – karaj branch in 2009-2010. five crop fields were chosen including: barley, sugar beet and three wheat fields and in each fields between 3 to 5 sites selected randomly. three quadrates were fixed in each sites for studying weeds...

Northeast China (NEC) is one of China’s major rice production areas and has experienced obvious climate warming over the past three decades, similar to other midto high-latitude regions in the Northern Hemisphere. The present study investigates the temporal and spatial impacts of climate warming on rice yield in mid–high latitude regions. In this study, two time series datasets of rice yield an...

Forecast of tree fruit yield requires prediction harvest time size as well number. Mango (Mangifera indica L.) mass can be estimated from correlation to measurements length (L), width (W) and thickness (T). On-tree individually tagged were undertaken using callipers at weekly intervals until the past commercial maturity, judged growing degree days (GDD), for mango cultivars ‘Honey Gold’, ‘Calyp...

The necessary conditions for the existence of a (2 × 4, λ)-splitting GDD of type g are gv ≥ 8, λg(v−1) ≡ 0 (mod 4), λg2v(v−1) ≡ 0 (mod 32). It is proved in this paper that these conditions are also sufficient except for λ ≡ 0 (mod 16) and (g, v) = (3, 3).

We determine a necessary and sufficient condition for the existence of a cyclic {3}-GDD with a uniform group size 6n. This provides a fundamental class of ingredients for some recursive constructions which settle existence of k-rotational Steiner triple systems completely.

We investigate the existence of group divisible designs (GDDs) with block size three, group-type gw and index λ. We prove that the elementary necessary conditions for the existence of such a GDD are also sufficient, which generalizes the result of Colbourn, Hoffman and Rees.

BACKGROUND Although several determinants of global developmental delay (GDD) have been recognized, a significant number of children remain without definitive etiologic diagnosis. The objective of this study was to assess the effect of various prenatal and perinatal factors on the severity and outcome of developmental delay without definitive etiologic yield. METHODS From March 2008 to Februar...

A forward estimate of mango (Mangifera indica L.) harvest timing is required for farm management (e.g., organization labour and marketing). This can be based on accumulated growing degree days (GDD) from an early stage flowering to fruit maturity, with maturity judged a destructive assessment flesh colour dry matter content. The current study was undertaken improve GDD targets Australian cultiv...

Abstract Two species of cleavers, Galium aparine L. and spurium L., are known to inhabit croplands in western Canada. The latter is the more abundant two species. An increased abundance these over most recent decades warrants a comprehensive understanding their developmental phenology cause this increase. This study aimed identify base temperature emergence characteristics spp. across different...

Application of plant growth regulators to hybrid bermudagrass [Cynodon dactylon (L.) Pers. × Cynodon transvaalensis Burtt Davy] putting greens is a common management practice used reduce clipping yield and improve aesthetic functional turfgrass quality. Growing degree day (GDD) models have explored the effects regulator application timing on ultradwarf yield. However, there need for research ev...