Dry-matter partitioning and leaf area of winter wheat grown in a long-term fallow tillage comparisons in the US Central Great Plains

Abstract

Crop management practices (tillage, residue management, fertilization, etc.) define the soil environment to which crops are exposed and through these environmental conditions control crop growth. The purpose of this paper is to report the response of winter wheat (Triticum aestivum L.) to long-term (10 years) application of fallow tillage practices (plow, sub-till, and no-till) and N fertilization in terms of above-and below-ground dry-matter partitioning. During 1978, less winter wheat root tissue was produced in the sub-till treatment compared to the average of the plow and no-till treatments. However, in 1979, all treatments produced the same amount of root tissue. Averaged over all treatments, root tissue was ca. 7% of the above-ground dry-matter production. During 1979, less above-ground dry matter was produced at late grain fill (27 June) with addition of N fertilizer (929 g mp2) than when N was not applied (957 g m-2). In contrast, during 1980 (at about the same stage of development), application of N resulted in more above-ground dry-matter production in the plow and no-till treatments, but addition of N reduced production in the sub-till treatment. Grain yield followed similar trends. Nitrogen application also increased tiller production and number of tillers surviving to maturity. Nitrate reductase activity was measured to determine if the reported lesser levels of nitrate-N in soils under reduced tillage management changed N metabolism of the plant. Nitrate reductase activity differed among N rates (when measured after N application), but did not differ among tillage treatments.

Incorporation of crop phenology in Simple Biosphere Model (SiBcrop) to improve land-atmosphere carbon exchanges from croplands

“…Considering a 45% carbon in dry matter, this converts to 834 g m −2 dry matter. This falls within the range of total dry matter weights given by Wilhelm (1998) for winter wheat under different tillage and nitrogen fertilization rates (i.e. between 636 and 848 g m −2 dry matter).…”

Nitrogen use efficiency in spring wheat: genotypic variation and grain yield response under sandy soil conditions

“…High N supply resulted in higher net assimilation rate (Sage & Pearcy 1987), more productive tillers (Wilhelm 1998), increase in the number of spikes per unit area (Ayoub et al 1994), number of grains per spike (Ibrahim et al 2014), biological yield (Karrou & Maranville 1993) and grain yield (Al-Abdulsalam 1997). Five N levels effectively differentiated genotypes with varying responsiveness to N fertilization, exhibiting a clear significant linear response for most of the traits under investigation.…”

New concepts for dynamic plant uptake models

“…It was assumed that at early growth phases the ratio between stem and leaf dry mass is approximately 1:1, and at the ripening phase the dry mass of the leaves is only 1/10 of the total dry mass of the above-ground plant [31,40]. Curves for stem and leaf mass as a function of time were fitted by adjusting k (with M 0 = 0.00125 kg for stem and leaf; M max = 0.45 and 0.05 kg for stem and leaf, respectively; mass stem plus mass leaf = mass shoot).…”