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1.
Over application of fertilizer N to cotton is not only a potential threat to environment but also leads to increased costs of cultivation. The study aimed to establish the indicator leaf and its critical greenness for in-season management of fertilizer nitrogen (N) in Bt cotton using chlorophyll (SPAD) meter and leaf color chart (LCC). The response of three varieties and N treatments viz. 0, 30, 60, 90,120, 150 and 180?kg N ha?1 applied in two splits {(50% at thinning and 50% at first flowering) and three splits (50% at thinning, 25% at first flowering and 25% at boll formation)} was studied through split plot design. SPAD values and LCC scores of first, second, third and fourth fully opened leaves from the top of the main stem was recorded at first flowering and boll formation. The physiological efficiency and harvest index was highest for 90?Kg N ha?1 applied in two splits. Beyond 120?kg N ha?1, the N use efficiency parameters were higher for the N treatments applied in three split compared to the respective two split N treatments. The fourth leaf from the top in terms of SPAD values and LCC scores correlated best with N concentration compared to other leaves at all growth stages. The calculated critical SPAD values for the fourth leaf were 45 and 41 at first flowering and boll formation, respectively. Critical score of fourth leaf was 4.1 and 4, respectively at first flowering and boll formation, respectively. It is suggested that color of the fourth leaf from the top of Bt cotton can well indicate N supply from the soil and can help in need based N management. 相似文献
2.
Sanjay Kumar Chaudhary Shankar Jha Yogeshwar Singh 《Communications in Soil Science and Plant Analysis》2018,49(14):1739-1749
Two field experiments were conducted to optimize the days for decomposition of dhaincha (Sesbania aculeata) with different nitrogen (N) levels and scheduling in transplanted rice in calcareous soil in a split-plot design with three replications. Incorporation of dhaincha one day before transplanting (1-DBT) obviated the need for allowing N gap. Nitrogen scheduling as 50% at active tillering + 40% at panicle initiation + 10% at flowering recorded the maximum grain yield (59.05 q ha?1) and N–?phosphorus (P)–?potassium (K) uptake. The different N fractions in post-harvest soil were in the order of total N> total hydrolyzable N> non-hydrolyzable N> exchangeable ammonium (NH4+)–?N and nitrate (NO3?)–?N. Thus, in calcareous soil, rice may be transplanted immediately after burying the dhaincha without any time gap along with 80 kg N ha?1. Also, application of nitrogenous fertilizer in three splits, delaying N application until active tillering stage, is beneficial for improving rice productivity. 相似文献
3.
Boron (B) is one of the essential micronutrients having a specific role, particularly during reproductive phase, in rice. In a previous experiment on aerobic rice, panicle sterility was noted as one of the major challenges. This experiment was conducted to evaluate the influence of soil-applied B on tillering, panicle sterility, water relations, and grain enrichment in fine-grain aromatic rice cultivars ‘Super Basmati’ and ‘Shaheen Basmati’. Boron was soil applied at 0.50, 0.75, 1, 1.25, and 1.50 kg ha?1 while the control treatment did not receive B. Rate of leaf emergence and elongation and tiller appearance were significantly improved by B application. Likewise, B application also improved the leaf chlorophyll contents and water relations in both rice cultivars. Substantial improvement in kernel yield and yield contributing traits was also observed by B application owing to decrease in panicle sterility. A linear increase in leaf and kernel B contents was observed with increase in B application rate. However, the range for an optimum B application rate is very narrow and increase of B application beyond 1 kg ha?1 was toxic. In conclusion, soil application of B is an effective way to decrease panicle sterility and increase the kernel yield and grain B enrichment in rice. 相似文献
4.
N. D. Yogendra B. H. Kumara N. Chandrashekar N. B. Prakash M. S. Anantha H. E. Shashidhar 《Journal of plant nutrition》2017,40(9):1277-1286
Leaf color chart (LCC) guides fertilizer nitrogen (N) application to rice as per requirement of the crop on the basis of a critical leaf color. Two field experiments were conducted to evaluate the effect of silicon (Si) and LCC based N management in aerobic rice. Following LCC-based N management, from 60 to 90 kg N ha?1 and 75 to 100 kg N ha?1 with 10–40% and 25–30% less fertilizer N was used without any reduction in yield as compared to the package of practices of 100 (50 kg N ha?1 as basal + two split of 25 kg N ha?1) kg N ha?1 respectively, during both the seasons. The highest grain yield was noticed with 90 kg N ha?1 (30 kg N ha?1 as basal + LCC-3) and 100 kg N ha?1 (50 kg N ha?1 as basal + two split of 25 kg N ha?1) along with the application of calcium silicate (CaSiO3) at 2 t ha?1 as sources of Si and on par with 60 kg N ha?1 (no basal + LCC-3) and 75 kg N ha?1 (30 kg N ha?1 as basal + LCC-3), respectively, during the season in 2008 and 2009. Higher fertilizer N use efficiency was recorded with Si and need-based N management using LCC-3 rather than recommended dose of fertilizer N. 相似文献
5.
华北地区采用无机氮测试和植株速测进行夏玉米氮肥推荐 总被引：2，自引：0，他引：2
A field experiment with a split-plot design was carried out at Dongbeiwang Farm in Beijing Municipality to establish reliable N fertilizer recommendation indices for summer maize (Zea mays L.) in northern China using the soil Nmin(mineral N) test as well as the plant nitrate and SPAD (portable chlorophyll meter readings) tests. The results showed that Nrnin sollwert (NS) 60 kg N ha^-1 at the third leaf stage and N rate of 40 to 120 kg N ha^-1 at the tenth leaf stage could meet the N requirement of summer maize with a target yield of 5.5-6 t ha^-1. Sap nitrate concentrations and SPAD chlorophyll meter readings in the latest expanded maize leaves at the tenth leaf stage were positively correlated with NS levels, indicating that plant nitrate and SPAD tests reflected the N nutritional status of maize well. Considering that winter wheat subsequently utilized N after the summer maize harvest, the 0-90 cm soil Nmin (74 kg N ha^-1) and apparent N loss (12 kg N ha^-1) in the NS60＋40 treatment were controlled at environmentally acceptable levels. Therefore NS60＋40, giving a total N supply of 100 kg N ha^-1, was considered the optimal N fertilizer input for summer maize under these experimental conditions. 相似文献
6.
Sangita Mohanty C. K. Swain Rahul Tripathi S. K. Sethi P. Bhattacharyya Anjani Kumar 《Archives of Agronomy and Soil Science》2018,64(4):465-479
A field study was conducted in the sub-humid tropical region of India to examine the effect of different nitrogen (N) management strategies on nitrate leaching, nitrous oxide (N2O) emission and N use efficiency in aerobic rice. Treatments were: control (no N), 120 kg N ha?1 applied as prilled urea (PU) in conventional method, 120 kg N ha?1 applied as neem coated urea (NCU) in conventional method, N applied as PU on the basis of leaf colour chart (LCC) reading, N applied as NCU on the basis of LCC reading, and 120 kg N ha?1 applied as PU and farm yard manure (FYM) in 1:1 ratio. Results showed that 3.4–16.1 kg NO3-N ha?1 was leached below 45 cm depth and 0.61–1.12 kg N2O-N ha?1 was emitted from aerobic rice during the growing season. NCU when applied conventionally reduced nitrate-nitrogen (NO3-N) leaching and N2O emission by 18.6% and 21.4%, respectively However when applied on the basis of LCC reading NCU reduced NO3-N leaching by 39.8% as compared to PU applied in conventional method. NCU when applied on the basis of LCC reading synchronized N supply with demand and reduced N loss, which resulted in higher yield and N use efficiency. 相似文献
7.
《Communications in Soil Science and Plant Analysis》2012,43(17-18):2816-2832
The critical leaf and the threshold values of leaf color chart (LCC) and chlorophyll meter (SPAD‐502) for cassava have been evaluated. The nitrogen (N) rates and cultivars had a significant effect on LCC score, SPAD values, and leaf N concentration of leaf 1 in most cases. Among the three leaf positions studied, the youngest fully expanded leaf (YFEL) blade (leaf 1) had significant, positive correlation of tuber yield with LCC score, SPAD value, and leaf N concentration. The regression between LCC score and leaf N concentration of leaf 1 was LCC = 0.358 (Leaf N) + 0.78 (r2 = 0.81) and that between LCC score and SPAD value was SPAD = 10.981 (LCC) – 3.51 (r2 = 0.82). A threshold LCC score of 2.65 and threshold SPAD value of 25 were suitable to determine the optimal timing of N top‐dressing for cassava. 相似文献
8.
A field investigation was conducted at the Indian Agricultural Research Institute's Research Farm during the kharif (wet) seasons of 2002 and 2003 in a split plot design with three replications, consisting of 27 treatments, namely, main plots: three varieties (PRH-10, Pusa Sugandh-3 and Pusa Basmati-1) and three plant spacings (20 × 10, 20 × 15 and 20 × 20 cm2) and sub-plots: three levels of nitrogen (0, 80 and 160 kg N ha?1). The research results indicated that aromatic rice hybrid PRH-10 produced 33 and 6%, respectively, more grain yield than that of Pusa Sugandh-3 and Pusa Basmati-1. The appreciable higher grain yield of PRH-10 over Pusa Sugandh-3 and Pusa Basmati-1 was due to considerable improvement in most of the yield attributing characters. Application of 160 kg N ha?1 recorded 23.7 and 26.1% more grain yield over no nitrogen application whereas it was 6.4 and 6.1% more over 80 kg N ha?1, respectively, during first and second year of the experimentation. Wider plant spacing of 20 × 20 cm2 and application of 160 kg N/ha recorded significantly higher hulling, milling and head rice recovery compared to closer spacing and zero nitrogen application. 相似文献
9.
不同施氮量下缺钾对水稻叶片营养及生理性状的影响 总被引：2，自引：2，他引：0
10.
Kazunori Minamikawa Huynh Cong Khanh Yasukazu Hosen Tran Sy Nam Nguyen Huu Chiem 《Soil Science and Plant Nutrition》2020,66(1):225-234
ABSTRACT Livestock production plays a leading role in agricultural land-use change. Producing biogas from livestock waste and subsequently using the biogas effluent as fertilizer for crops is a promising option to solve environmental problems resulting from expanding livestock production. However, it is difficult to promptly and accurately measure the nitrogen (N) concentration of effluent for farmers in developing countries, making precise N management difficult. The objectives of the current study were (1) to evaluate the feasibility of variable-timing, fixed-rate application of cattle biogas effluent using a leaf color chart (LCC) for rice (Oryza sativa L.) and (2) to determine the optimum LCC threshold for grain yield. We conducted two microcosm experiments in the Mekong Delta of Vietnam in 2018 using eight treatments of N-fertilizer application. In the Zero treatment, we applied no N. In the Estd treatment, we split-applied N as effluent (E) at fixed rate and timing as the standard method. In E2.75, E3.00, E3.25, E3.50, and E3.75, we applied effluent whenever the LCC value went below 2.75, 3.00, 3.25, 3.50, and 3.75, respectively. In U3.25, we applied N as urea (U) whenever the LCC value fell below 3.25. The total effluent-N application rate ranged from 90 to 210 kg N ha?1 season?1. Rice growth was normal but there was a substantial yield gap between the two microcosm experiments due to the seasonal difference in solar radiation. Rice yield tended to increase with increasing LCC threshold. There was a positive linear relationship between LCC and chlorophyll content (SPAD) values (R 2 = 0.73–0.79). Grain yield was well explained (R 2 = 0.70–0.89) by the seasonal mean LCC or SPAD value. Plant total N uptake increased with increasing LCC threshold, but the three calculated indices of N use efficiency (NUE) – apparent N recovery, agronomic NUE, and internal NUE – were not always improved with a higher LCC threshold. Our results showed that the tested variable-timing, fixed-rate strategy for the application of cattle biogas effluent was feasible and the optimum LCC threshold for grain production was 3.75 under the current microcosm conditions. 相似文献
11.
M. Ângelo Rodrigues Sandra Afonso Isabel Q. Ferreira Margarida Arrobas 《Archives of Agronomy and Soil Science》2017,63(5):626-637
The adaptation of stevia to the growing conditions of NE Portugal is assessed, including the tolerance of this species to cold temperatures, and the potential to produce biomass when grown as an annual crop and when subjected to various nitrogen (N) rates and two harvesting regimes. Almost all the plants died during the winter of 2014 (minimum temperatures peaked at ?8.0°C), making it necessary to replant the crop the following spring. With the best cutting regime (double cut) and N rate (150 kg N ha?1), 1514.4 and 2390.0 kg ha?1 of dry leaves were produced, respectively, in 2014 and 2015. Leaf chlorophyll concentrations estimated by the SPAD (Soil and Plant Analysis Development)-502 chlorophyll meter and a NDVI (Normalized Difference Vegetation Index) carried out by the Field Scout CM 1000 spectroradiometer showed significant differences among N rates, proving to be good indicators of plant N nutritional status. Based on the leaf analysis, provisional sufficiency ranges for N are proposed, namely 25–35 g kg?1 for mid-summer and 15–25 g kg?1 for early autumn. The fluorescence of chlorophyll a and the transient fluorescence intensity performed by the OS-30p+ fluorometer failed to show any stress induced by no-N control treatments in comparison to N-treated plants. 相似文献
12.
Esra Ucar Yasar Ozyigit Ahmet Demirbas Dilek Yasin Guven Kenan Turgut 《Communications in Soil Science and Plant Analysis》2017,48(10):1231-1239
With this study, the effect of different nitrogen (N) doses applied to sweet herb (0, 50, 100, 150 and 200 N kg ha?1) on the macro/micro nutrient element content, dry matter ratio and on the chlorophyll amount in the plant leaves is examined. The research was carried out in the research and trial field of Faculty of Agriculture Agronomy department, Akdeniz University, during the 2012–2013 growing season under field conditions for 2 years with four replications according to the randomized block trial design. Chlorophyll amounts were determined and the average was obtained with three readings from each leaf by a chlorophyll meter when the plants were in the beginning of flowering. Post-harvest macro and micro nutrient elements of the sweet herb were also investigated. According to the obtained data, while the highest chlorophyll and N amounts in the leaf for both the first and second years were determined as 46.97 SPAD (Minolta Corp, NJ, USA) and 1.34 N% 44.9 SPAD, 1.42 N%, respectively, under 200 kg ha?1 N application, the lowest chlorophyll and N amounts were determined in the control group. In addition, N application in different doses for both years increased the phosphorus (P) and potassium (K) contents and increased the microelement contents, especially in the second year. At the same time, a correlation between the chlorophyll content in the plant leaves and the N amount was determined and a linear increase was observed in the chlorophyll amount with the increased green part. 相似文献
13.
Alefsi David Sánchez-Reinoso Mario Felipe Nieto Joanna Dossmann Jesús Hernán Camacho-Tamayo 《Journal of plant nutrition》2013,36(18):2373-2387
AbstractThe objective of this research was to determine the difference on growth between a rice cultivar with Clearfield® technology (Only Rice 228) and a hybrid (Benja 1); to characterize nutrient uptake, distribution, accumulation and removal between these two commercial genotypes. Tests under shade house and field conditions were performed to estimate macro and micronutrient uptake patterns. Plants were sampled at nine growth stages (emergence, initiation of tillering, active tillering, initiation of panicle primordia, booting, flowering, milky, soft dough and mature grain) and divided into different organs for nutrient determination. The results showed that “Benja 1” plants (92 d) had a shorter cycle than “Only Rice 228” (OR 228) plants (118 d). “OR 228” exhibited a greater biomass production (16.575?kg ha?1 vs. 12.621?kg ha?1) in field. The nutrient acquisition was faster in the hybrid Benja 1 between tillering initiation and the milky grain stage in which the N, K, Ca, Mg, Mn, B, and Cu uptake was more evenly and highly distributed throughout these stages in both conditions. “Benja 1” showed a higher nutrient harvest index (HI). HI values above 50% (P (62%), N (61%), Cu (67%), S (55%), and Mg (52%)) were found in Benja 1 under field conditions. The results also highlight Si removal in both rice genotypes, in which Benja 1 stands out. These results provide information on the nutrient uptake and partitioning of modern rice genotypes, and give the knowledge to optimize fertilizer programs and timing recommendations for rice biomass and grain production in Colombia. 相似文献
14.
Christos Noulas Juan M. Herrera Miltiadis Tziouvalekas Ruijun Qin 《Communications in Soil Science and Plant Analysis》2018,49(7):763-781
Four spring wheat genotypes (Triticum aestivum L.) were grown without (N0 = 0 kg N ha?1) and under ample (N1 = 250 kg ha?1) nitrogen (N) fertilizer in field experiments in two seasons. The aim was to assess genotypic variation in N use efficiency (NUE) components and N-related indices during grain filling thus to identify superior wheat genotypes. Leaf chlorophyll (SPAD) readings at crucial growth stages were employed to help differentiate genotypes. Interrelations between yield and N-related indices with SPAD, where also assessed to explain possible pathways of improving NUE early in the growing season. Results showed that genotypic effects on NUE were mostly evident in 2000, a year with drier preanthesis and wetter postanthesis than the normal periods. ‘Toronit’ almost always had the highest biomass yield (BY) and grain yield (GY). Except in 1999 under N0, ‘L94491? showed the highest % grain N concentration (GNC). Genotypes affected SPAD at almost all stages and N fertilization delayed leaf senescence for all genotypes and growth seasons. Correlations between SPAD at different growth stages and GY, N biomass yield at maturity (NBYM) and GNC were significant (P≤ 0.001), positive and strong/very strong (>r = 0.7). N translocation efficiency (NTE) was inversely related to PANU (~r = ? 0.77, P≤ 0.001), suggesting that N after anthesis is being preferentially transported to the ears to meet the N demand of the growing grains. It is concluded that there is still a large potential for increased NUE by improved N recirculation, use of fast and inexpensive crop N monitoring tools and high yielding, N uptake efficient genotypes.Abbreviations: NUE, Nitrogen use efficiency; SPAD, Minolta SPAD-502 chlorophyll meter, NHI, nitrogen harvest index; HI, Harvest index; NTE, N translocation efficiency from vegetative plant parts to grain; DMTE, dry matter translocation efficiency; CPAY, contribution of pre-anthesis assimilates to yield; PANU, Post-anthesis N uptake, d.a.s., days after sowing, N0, zero (0) kg ha?1 applied N fertilizer, N1, 250 kg ha?1 applied N fertilizer. 相似文献
15.
In 2‐years field experiments near Nienstädt (60 km west of Hannover, northern Germany), the effects of rate and timing of nitrogen (N) application on leaf N‐concentration, leaf greenness (SPAD chlorophyll meter readings), canopy greenness (canopy light reflectance), leaf area development, photosynthetic activity of leaves, and yield and quality of sugar beet were studied. In 1999 (pre‐planting soil mineral N: 15 kg ha—1), N fertilizer was applied at rates of 0, 105, 125, 145, 165 and 205 kg N ha—1. In 2000 (pre‐planting soil mineral N: 60 kg ha—1), an N rate of 100 kg ha—1 was applied at planting (100/0/0/0) or split applied at planting and 8 (60/40/0/0), 12 (60/0/40/0), and 16 (60/0/0/40) weeks after planting (WAP), respectively. In both years, canopy greenness as indicated by ”︁sensor values” (a combination of the reflectance of visible and near infrared light) changed with crop age. However, at each time of measurement, sensor values precisely reflected the different N application treatments and were significantly correlated with leaf N‐concentrations and SPAD chlorophyll meter readings. Beet yield and processed white sugar yield increased up to an N supply (fertilizer N + pre‐planting soil mineral N) of 160 kg ha—1. Split N application slightly retarded leaf growth but had no effect on photosynthetic activity per unit leaf area. Beet yield and beet quality were not systematically affected by the timing of N application. Certain application schemes tended to favor either beet yield or beet quality, resulting in similar processed white sugar yields. Our data suggest that moderate N topdressing can be integrated in site‐specific N management systems in sugar beet production. Canopy light reflectance might serve as a useful diagnostic tool to assess the N status and sidedress N demand of sugar beets. However, due to changing sensor values over time, on‐site calibration (using established standard methods or reference plots receiving extra N at planting) will be necessary. The applicability of this approach has to be tested in further field studies.<?show $6#> 相似文献
16.
《Communications in Soil Science and Plant Analysis》2012,43(6):777-784
Alarming climate change, rainfed upland farming, and low resource-use efficiency of conventional fertilizer management practices are major production constraints detrimental to rice productivity in the northwestern (NW) Himalayas. Recent agronomic intervention of direct-seeded rice (DSR) coupled with suitable rice germplasm well suited to rainfed upland ecosystems in combination with appropriate integrated nutrient-management (INM) technology can enhance the rice productivity in the region. Thus, a field experiment with seven treatments replicated three times in a randomized block design was conducted on INM technology in rainfed upland rice cv. HPR-1156 (Sukaradhan-1) to harness the potential of DSR technology in order to boost rice productivity in the NW Himalayas. Results on INM in direct-seeded upland rice revealed that nitrogen, phosphorus, and potassium (NPK) at 90:45:45 kg ha?1 + farm yard manure (FYM) at 5 t ha?1 (oven dry-weight basis) significantly resulted in the greatest magnitude of growth and development (plant height, tillers m?2) and yield-contributing characters (panicles m?2, panicle length, grains panicle?1 and 1000-grain weight), resulting in significantly greatest grain, straw, and biological yield followed by sole use of NPK at 90:45:45 kg ha?1 and NPK at 60:30:30 kg ha?1 + FYM at 5 t ha?1, respectively, in rainfed upland rice. Application of NPK at 90:45:45 kg ha?1 + FYM at 5 t ha?1 again resulted in significant improvement in soil organic carbon and available NPK status over other treatments and initial soil fertility status in an acidic Alfisol. Overall, it is inferred that INM technology with judicious use of NPK at 90:45:45 kg ha?1 + FYM at 5 t ha?1 in rainfed upland rice under DSR technology can enhance the rice productivity and resource-use efficiency in NW Himalayas. 相似文献
17.
《Communications in Soil Science and Plant Analysis》2012,43(21):2833-2851
A field experiment was conducted to investigate the effects of pretransplant basal (surface application, BSF, and incorporation methods, BIC) and split applications of nitrogen (N) on the growth and yield parameters of rice. Using 120 kg N ha?1 except (N0, control), different percentages of N rate were applied at basal, tillering, and panicle initiation in five N split treatments. Growth parameters and dry matter were greater in BIC than BSF until panicle initiation stages. Among N split applications, N2 (25:50:25) using low basal surface N was optimized for maximum dry matter and yield. With large incorporated basal N, N1 (50:25:25) obtained greater dry matter and yield but did not differ from N4 (50:50:0). With omitted N at tillering, N5 (50:0:50) did not increase rice yield or dry matter by either method. This study highlighted that N split-application patterns affect the growth and yield parameters of Manawthukha rice. 相似文献
18.
ABSTRACT Field experiments were conducted in the major rice growing area of Chile to evaluate the effects of nitrogen (N) fertilization and site on grain yield and some yield components, dry matter production, N uptake, and N use efficiency in rice cultivar ‘Diamante’. Two sites (indicated as sites 1 and 2) and six N rates (0, 50, 100, 150, 200, and 300 kg N ha?1) were compared. Nitrogen fertilization increased yield, panicle density, spikelet sterility, dry matter production, and N uptake at maturity. 90% of maximum yield was obtained with 200 kg N ha?1 in site 1 (12,810 kg ha?1) and with 100 kg N ha?1 in site 2 (8,000 kg ha?1). These differences were explained by lower panicle density, and the resulting lower dry matter production and N uptake in site 2. Nitrogen use efficiency for biomass and grain production, and grain yield per unit of grain N decreased with N fertilization. While, agronomic N use efficiency and N harvest index were not affected. All N use efficiency indices were significantly higher in site 1, except grain yield per unit of grain N. The observed variation in N use efficiency indices between sites would reflect site-specific differences in temperature and solar radiation, which in turn, determined yield potentials of each site. On the basis of these results, cultivar ‘Diamante’ would correspond to a high-N use efficiency genotype for grain yield. 相似文献
19.
Marcelo Curitiba Espindula Valterley Soares Rocha Paulo Cezar Rezende Fontes Raul Carvalho Corrêa da Silva Leandro Torres de Souza 《Journal of plant nutrition》2013,36(11):1956-1964
ABSTRACT The objective of this study was to evaluate the effect of nitrogen (N) and trinexapac-ethyl (TE) rates on the SPAD index in wheat flag leaf. The treatments were five N rates (30, 60, 90, 120, 150 kg ha?1) combined with four TE rates (0, 63, 125, 188 g ha?1). The experiment was carried out in a randomized block design with four repetitions. SPAD index, leaf N content and grain yield showed quadratic response to the increase in N rates, whereas area, wet and dry weight of flag leaf presented linear increase. TE caused linear increase in SPAD index, linear decrease in leaf area, reduction in grain yield with smaller N rates and increase with larger N rates. The N content, and the wet and dry weight of flag leaf were not affected by TE. SPAD calibration to estimate N status in wheat should be specific for each TE rate. 相似文献
20.
Eduardo M. Kawakami Derrick M. Oosterhuis John L. Snider 《Journal of plant nutrition》2013,36(10):1615-1639
The objective of this growth chamber study was to evaluate the effect of adding N-(n-butyl) thiophosphoric triamide (NBPT) and dicyandiaminde (DCD) to urea fertilizer, on the physiology and growth of cotton (Gossypiumhirsutum L.) under normal and high temperatures. Treatments consisted of two day temperature regimes, 30°C and 38°C, and five nitrogen fertilization applications: unfertilized control, 125 kg ha?1 of urea, 93 kg ha?1 of urea, 93 kg ha?1 urea + NBPT, and 93 kg ha?1 urea + NBPT + DCD. The addition of NBPT to urea fertilizer had positive effects on leaf chlorophyll, leaf area, dry matter, nitrogen (N) uptake, and N use efficiency. The absence of a significant interaction effect indicated that N fertilization was not influenced by temperature. Deficiency of N significantly decreased leaf chlorophyll, increased glutathione reductase, decreased protein and increased leaf nitrate reductase. Physiological changes under high temperature included increased plant N uptake, glutamine synthetase, leaf chlorophyll, protein content, plant height and leaf area were due to high N uptake and utilization. 相似文献