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Waxy wheat (Triticum aestivum L.) is grown throughout the world for its specific quality. Fertilization and planting density are two crucial factors that affect waxy wheat yield and photosynthetic capacity. The objectives of the research were to determine the effects of fertilization and planting density on photosynthetic characteristics, yield, and yield components of waxy wheat, including Yield, SSR, TGW, GNPP, GWPP, PH, HI, Pn, Gs, Ci, E and WUE using the method of field experiment, in which there were three levels (150, 300, and 450 kg ha−1) of fertilizer application rate and three levels (1.35, 1.8, and 2.25 × 106 plants ha−1) of planting density. The results suggested that photosynthetic characteristics, yield, and yield components had close relationship with fertilization levels and planting density. Under the same plant density, with the increase of fertilization, Yield, SSR, TGW, GNPP, GWPP, HI, Pn, Gs, E and WUE increased and then decreased, PH increased, but Ci decreased. Under the same fertilization, with the increase of plant density, Yield, SSR, TGW, GNPP, GWPP, HI increased and then decreased, PH, Pn, Gs and E increased, PH and WUE declined. The results also showed that F2 (300 kg ha−1) and D2 (1.8 × 106 plants ha−1) was a better match in this experiment, which could obtain a higher grain yield 4961.61 kg ha−1. Consequently, this combination of fertilizer application rate and plant densities are useful to get high yield of waxy wheat.

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A U.K. field experiment compared a complete factorial combination of three backgrounds (cvs Mercia, Maris Huntsman and Maris Widgeon), three alleles at the Rht-B1 locus as Near Isogenic Lines (NILs: rht-B1a (tall), Rht-B1b (semi-dwarf), Rht-B1c (severe dwarf)) and four nitrogen (N) fertilizer application rates (0, 100, 200 and 350 kg N/ha). Linear+exponential functions were fitted to grain yield (GY) and nitrogen-use efficiency (NUE; GY/available N) responses to N rate. Averaged over N rate and background Rht-B1b conferred significantly (P < 0.05) greater GY, NUE, N uptake efficiency (NUpE; N in above ground crop / available N) and N utilization efficiency (NUtE g; GY/N in above ground crop) compared with rht-B1a and Rht-B1c. However the economically optimal N rate (N opt) for N:grain price ratios of 3.5:1 to 10:1 were also greater for Rht-B1b, and because NUE, NUpE and NUtE all declined with N rate, Rht-Blb failed to increase NUE or its components at N opt. The adoption of semi-dwarf lines in temperate and humid regions, and the greater N rates that such adoption justifies economically, greatly increases land-use efficiency but not necessarily NUE.

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The present study aimed to determine the effect of precipitation and fertilization (NPKCaMg) on the changes in soil organic carbon (SOC) in a long-term field experiment set up in Nyírlugos (Nyírség region, Hungary: N: 47° 41′ 60″ and E: 22° 2′ 80″) on a Haplic Luvisol with popular rotation crops. Over the 40 year period, from 1962 to 2002, SOC pool values ranged between 2.32 and 3.36 mg·kg −1 . On the untreated control plots the values remained nearly constant (3.31 mg·kg −1 : ±0.29 mg·kg −1 and 0.52 mg·kg −1 ). In the 1st 20-year period (1963–1982), there was a significant ( P < 0.001) decrease (16%) on all experimental plots, which may be due to the winter half year (WHY) precipitation (228 mm), summer half year (SHY) precipitation (288 mm), the NPKCaMg fertilizer application rate (64 kg·ha −1 ), and the potato-rye-wheat-lupin-sunflower crop sequence. In the 2nd 20-year period (1983–2002) SOC pool values varied between 3.13 and 4.47 mg·kg −1 . The 16.9% significant ( P < 0.001) increase 16.9% could be attributed to the lower WHY (204 mm) precipitation, higher SHY (320 mm) precipitation, higher NPKCaMg fertilizer rate (213 kg·ha t-1 ), and the sunflower-grass-barley-tobacco-wheat-triticale cropping system. NPKCaMg fertilization resulted in a significant ( P < 0.001) decline (16.6%) in SOC in comparison to the control plots in the 1st 20-year interval, while in the 2nd 20-year period a significant ( P < 0.001) rise (up to 31.9%) was registered. During the 40 experimental years the seasonal correlations (R2) among SOC (mg·kg −1 ), WHY and SHY precipitation (mm) ranged from 0.3343 to 0.9078 (on the P < 0.001 significance level). The correlations (R 2 ) on the influence of NPKCaMg fertilization on SOC (mg·kg −1 ) and precipitation (mm) were significant ( P < 0.001): the means for WHY, SHY and over the 40 years were 0.4691, 0.6171 and 0.6582, respectively. Organic carbon reserves (mg·kg −1 ) in soils decreased linearly as precipitation increased (from 3.22 to 7.27 mm·yr −1 ). In case this trend — increasing precipitation caused by climate change reduces SOC in arable soils — will continue, and is aggravated by warming temperatures and a more altering climate (as predicted by climate change forecasts), the livelihoods of many Hungarian and European farmers may be substantially altered. Thus, farmers must take into consideration the climate (WHY and SHY precipitation), fertilization (NPKCaMg), and cropping (tuber-seed-tobacco-protein-oil-forage) changeability to optimize their SOC pool, soil carbon sequestration, soil sustainability and crop management in the nearest future.

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