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1.
This study evaluates the effects of different nitrogen (N) rates (0, 50, 100, 150, and 200 kg ha?1) and sources (ammonium sulfate, urea, and ammonium sulfonitrate with a nitrification inhibitor, Entec®) applied either as a single application during sowing (next to the planting rows) or as side dressing (stage 3.2 on Zadok scale), on production components and grain yield of irrigated wheat grown under no-till in a low-elevation Brazilian cerrado and Dark Red Dystrophic Latosol with clayey-texture. It was adopted a randomized block design (5 × 3 × 2) in factorial scheme with four replications. The N sources provided similar grain yields and chlorophyll contents. Increased nitrogen rates increased grain yield up to the 120 kg N ha?1, regardless of application time and N source. Nitrogen fertilization as side dressing can be recommended based on leaf chlorophyll readings. Early application of all nitrogen fertilizers at sowing time was viable.  相似文献   

2.
Nitrogen and sulfur play an important role in maize production. The aim of this study was to evaluate the effect of nitrogen (N) and sulfur (S) levels applied in various ratios on maize hybrid Babar yield at Peshawar in 2011 and 2013. Four N levels (120, 160, 200 and 240 kg N ha?1) and four S levels (20, 25, 30 and 35 kg S ha?1) were applied in three splits: a, at sowing; b, V8 stage; c, VT stage in ratios of 10:50:40, 20:50:30 and 30:50:20. Grains ear?1, thousand grain weight, grain yield ha?1 and soil pH were significantly affected by years (Y), N, S and their ratios, while no effect of N, S and their ratios was noted on ears plant?1. Maximum grains ear?1 (390), thousand grain weight (230.1 g) and grain yield (4119 kg ha?1) were recorded in 2013. N increased grains ear?1 (438), thousand grain weight (252 g) and grain yield (5001 kg ha?1) up to 200 kg N ha?1. Each increment of S increased grains ear?1 and other parameters up to 35 kg S ha?1, producing maximum grains ear?1 (430), thousand grain weight (245 g) and grain yield (4752 kg ha?1), while soil pH decreased from 8.06 to 7.95 with the application of 35 kg S ha?1. In the case of N and S ratios, more grains ear?1 (432), heavier thousand grains (246.7 g) and higher grain yield (4806 kg ha?1) were observed at 30:50:20 where 30% of N and S were applied at sowing, 50% at V8 and 20% at VT stage. It is concluded that 200 kg N ha?1 and 35 kg S ha?1 applied in the ratio of 30% at sowing, 50% at V8 and 20% at VT stage is recommended for obtaining a higher yield of maize hybrid Babar.  相似文献   

3.
Because limited information is available about the validated use of a chlorophyll meter for predicting nitrogen requirements for optimum growth and yield of wheat after application of herbicides, field experiments were carried out in the winter seasons of 2011/2012 and 2012/2013 under different weed and N fertilization treatments. Five weeded treatments, application of herbicides 25 days after sowing (DAS), hand pulling once at 55 DAS and a weedy check were combined with four N application rates. Weeds were completely absent in the non-fertilized plots, either with metribuzin or hand pulling as well as in isoproturon-treated plots fertilized with 190 or 285 kg N ha?1. The grain yield was similar in the treatments of isoproturon × 190 kg N ha?1, isoproturon + diflufenican × conditional N treatment (113.9) or 190 kg N ha?1, hand pulling × conditional N treatment (104.8) or 285 kg N ha?1 and metribuzin × 190 kg N ha?1. Under weeded practices, conditional N treatment recorded the maximum nitrogen use efficiency and almost equaled the grain protein content of the 190 kg N ha?1 application rate. N application based on SPAD readings saved about 40.0% and 44.8% N with isoproturon + diflufenican or hand pulling, respectively, compared to the recommended rate (190 kg N ha?1) without noticeable yield loss.  相似文献   

4.
On-farm research was conducted to investigate the effects of nitrogen (N) and compost (C) on yield and yield components of spring maize (Zea mays L.) under conventional and deep tillage system (T) at the research farm of the University of Agriculture, Peshawar, Pakistan, during spring 2013. The experiment was laid out in a randomized complete block design with split-plot arrangement, using three replications. Three compost levels (0, 1, and 2 t ha?1) and two tillage systems (conventional and deep tillage) were allotted to the main plot, whereas N levels (60, 90, 120, and 150 kg N ha?1) were allotted to subplots in the form of urea. Nitrogen and compost levels had significantly affected all the parameters. Plots treated with 150 kg N ha?1 increased ear length (31 cm), grains ear?1 (413), thousand-grain weight (240.2 g), grain yield (3097 kg ha?1), straw yield (9294 kg ha?1), harvest index (24.7 percent), and shelling percentage (81.7 percent). Compost applied at 2 t ha?1 increased ear length (32 cm), grains ear?1 (430), thousand-grain weight (242.3 g), grain yield (2974 kg ha?1), straw yield (8984 kg ha?1), harvest index (24.6 percent), and shelling percentage (83.2 percent). Tillage system had significant effect on all parameters except ear length and harvest index. Deep tillage system produced more grains ear?1 (365), thousand-grain weight (233.3 g), grain yield (2630 kg ha?1), straw yield (8549 kg ha?1), and shelling percentage (79.6 percent). It was concluded from the results that application of 120 kg N ha?1 + 2 C t ha?1 under a deep tillage system could improve spring maize yield and yield-contributing traits under semi-arid conditions.  相似文献   

5.
Rising soil salinity has been a major problem in the soils of Egypt in recent decades. Potassium fertilization and salicylic acid (SA) play an important role in promoting plants to tolerate salt stress and increased the yield of sugar beet crop. A field experiment on sugar beet (Beta vulgaris L.) grown on saline soil was carried out during 2014 growing season in Port Said Governorate, Egypt, to study the effect of potassium fertilization of the soil at applications of 0, 100, 150, and 200 kg potassium (K) ha?1 and foliar spray of SA by solution of 1000 mg L?1, twice (1200 L ha?1 each time) on yield and nutrient uptake. Application of 200 kg K ha?1 in combination with salicylic foliar spray gave the highest root length, root diameter, shoot and root yield, sucrose, juice purity percentage, gross sugar yield, and white possible extractable sugar, nitrogen (N), phosphorus (P), and potassium (K) content, and uptake of sugar beet. The highest increase in sucrose (20%) as well as white possible extractable sugar (184%) was obtained by 200 kg K ha?1 in combination with salicylic foliar spray compared with untreated soil with potassium fertilization and without salicylic foliar spray.  相似文献   

6.
Maize (Zea mays L.) is generally low in bioavailable zinc (Zn); however, agronomic biofortification can cure human Zn deficiency. In the present experiment, Zn was applied in pots as ZnSO4 · 7H2O to maize cultivar DK-6142 as foliar spray (0.5% w/v Zn sprayed 25 days after sowing and 0.25% w/v at tasseling), surface broadcasting (16 kg Zn ha?1), subsurface banding (16 kg Zn ha?1 at the depth of 15 cm), surface broadcasting + foliar and subsurface banding + foliar in comparison to an unfertilized control. As compared to control, all treatments significantly (P ≤ 0.05) increased growth, yield and nutritional attributes in maize. Grain Zn and protein concentrations were correlated and ranged from 22.3 to 41.9 mg kg?1 and 9 to 12 %, respectively. Zinc fertilization also significantly reduced grain phytate and increased grain Zn concentration. Zinc fertilization, especially broadcasting and subsurface banding combined with foliar spray decreased grain [phytate]:[Zn] ratio to 28 and 21 and increased Zn bioavailability by trivariate model of Zn absorption to 2.04 to 2.40, respectively. Conclusively, broadcasting and subsurface banding combined with foliar spray is suitable for optimal maize yield and agronomic Zn biofortification of maize grain. This would also be helpful to optimize Zn and protein concentration in maize grain.  相似文献   

7.
In view of widespread deficiencies, a long-term experiment was started at the International Crops Research Institute for the Semi-Arid Tropics, Patancheru, India in 2007 to identify economically efficient application strategy (full or 50% dose every or every second year) of sulphur (S) (30 kg ha?1), boron (B) (0.5 kg ha?1) and zinc (Zn) (10 kg ha?1). During the fourth year in 2010, balanced fertilization through adding S, B and Zn increased maize grain yield by 13–52% and soybean yield by 16–28% compared to nitrogen (N) and phosphorus (P) fertilization alone. Balanced nutrition increased N and P uptake, utilization and use efficiency for grain yield and harvest index indicating improved grain nutritional quality. The N, P plus 50% of S, B and Zn application every year recorded highest crop yields and N and P efficiencies indices and increased rainwater use efficiency with a benefit:cost ratio of 11.9 for maize and 4.14 for soybean. This study showed the importance of a deficient secondary nutrient S and micronutrients B, Zn in improving N and P use efficiency while enhancing economic food production.  相似文献   

8.
It is important to develop integrated fertilization strategies for various crops that enhance the competitive ability of the crop, maximize crop production and reduce the risk of nonpoint source pollution from fertilizers. In order to study the effects of mineral nitrogen fertilization and biofertilizer inoculation on yield and some physiological traits of rapeseed (Brassica napus L.) under different levels of sulfur fertilizer, field experiments in factorial scheme based on randomized complete block design were conducted with three replications in 2012 and 2013. Experimental factors were: (1) four levels of chemical nitrogen fertilizer (0, 100, 150 and 200 kg N ha?1), (2) two levels of biofertilizer (with and without inoculation) consisting Azotobacter sp. and Azospirillum sp. and (3) two levels of sulfur application (0 and 50 kg S ha?1). Rapeseed yield, oil content of grains and studied physiological traits had a strong association with the N fertilization, biofertilizer inoculation and sulfur (S) application. Higher rates of N fertilization, biofertilizer inoculation and S application increased the grain yield of rapeseed. In the case of physiological traits, the highest value of relative water content (RWC) was recorded in 100 kg N ha?1 that was statistically in par with 150 kg N ha?1 application, while usage of 150 kg N ha?1 showed the maximum cell membrane stability (CMS). Inoculation with biofertilizer and S fertilization resulted in higher RWC and CMS in rapeseed plants. The chlorophyll content showed its maximum values in the highest level of N fertilization, biofertilizer inoculation and S application. The usage of 200 kg N ha?1 significantly decreased the oil content of rapeseed grains, but the highest grain oil content was obtained from the application of 150 kg N ha?1, Azotobacter sp. and Azospirillum sp. inoculation and S fertilization. It seems that moderate N rate (about 150 kg N ha?1) and S application (about 50 kg S ha?1) can prove to be beneficial in improving growth, development and total yield of inoculated rapeseed plants.  相似文献   

9.
Abstract

The objective of this paper was to evaluate the influence of different rates of biosolids on the soil nitrogen (N) availability for maize and its residuality. A field experiment was developed in a typic Argiudol located in the NE of the Buenos Aires Province. Maize was sown for two consecutive years 1997–1999. Biosolids from a sewage treatment plant of Buenos Aires outskirts were superficially applied to the soil and incorporated by plowing. There were eight treatments: Check; 8, 16, and 24 Mg of dry biosolid ha?1; 8 and 16 Mg of dry biosolid ha?1 applied one year before, 100 and 150 kg N ha?1 of calcium ammonium nitrate (CAN). The sampling and determinations were done during the second maize cycle. At presowing (PS), sowing (S), 6 expanded leaves (V6), 12 expanded leaves (V12), and Flowering (Fl) composite soil samples from 0–40 cm depth were obtained to determine ammonium and nitrate contents. At Fl maize plants were sampled in order to determine total biomass and N content. The N‐nitrate content in the soil was significantly increased by the biosolids application (p < 0.05), and varied for each increment depending on the biosolids rates and the phenological stage. After 30 days from the incorporation the increases of 1.19, 1.34, and 2.05% were observed for N‐nitrates for 8, 16, and 24 Mg ha?1, respectively. The contribution of mineral N from the biosolids was 2.48, 6.46, and 5.01 kg N Mg?1 when the rates were incremented from 0–8, 8–16, and 16–24 Mg ha?1, respectively. The nitrogen mineralization followed a release pattern with a maximum value of 296 kg N‐nitrate ha?1 at sowing for 24 Mg ha?1. Since then, the release of mineral nitrogen decreased significantly till Fl. The N‐nitrates values variation with the temperature adjusted to polinomic functions. The mineral N released from the biosolids increased as a response to the increment of soil temperature and then decreased due to the maize nitrogen absorption and the potentially mineralized nitrogen exhaustion. The application of 150 kg N ha?1 as CAN incremented significantly the soil N‐nitrate content and equalized 16 and 24 Mg of dry biosolids ha?1 at V6. But, no synchronism between the high nitrate releasing from biosolids and the increment in the nitrogen absorption by maize was observed. This fact generates a surplus of nitrate that incremented the potential of nitrogen loss by lixiviation. We observed a residual effect from the biosolids that were applied the previous year. This contribution represented the 35% of the maize requirements and was similar to the nitrate content observed in Bio 16. The biosolids might be a valuable source of nitrogen for maize crop if the synchronism between the soil supply and maize demand is observed in order to avoid nitrates surplus.  相似文献   

10.
Effect of potassium (K) fertilization (0, 20, 40, 60, 80 and 100 kg K ha?1) on yield, nitrogen (N) and K nutrition of Boro (dry season) rice and apparent soil K balance was studied. Experiment was conducted at Bangladesh Rice Research Institute (BRRI) regional station farm, Habiganj, Bangladesh during 2007–2008 to 2009–2010 in a wetland rice ecosystem under haor area. Cropping pattern was Boro–Fallow–Fallow. A popular rice variety BRRI dhan29 was tested in a randomized complete block design with three replications. Results indicated that BRRI dhan29 maintained an average grain yield of 5.19 t ha?1 year?1 without K fertilization. Potassium fertilization significantly increased the grain yield to 6.86 t ha?1 year?1. Quadratic equations best explained the progressive increase of rice yield with increasing K rates. Optimum dose of K in 3 years ranged from 78 to 93 kg ha?1. Internal N use efficiency of rice decreased with increasing K rates. However, K use efficiency was inconsistent. Apparent K balance study revealed that application of 100 kg K ha?1 was not able to maintain a positive K balance in soil under wetland ecosystem with Boro–Fallow–Fallow cropping system. However, K fertilization decreased the negativity of K balance in soil.  相似文献   

11.
This study was designed to observe physiological indices of a spring maize response with the integration of beneficial microorganism, organic and inorganic nitrogen (N) fertilizer, and N levels. Field experiments were conducted in three replications during 2014 and 2015 at Agronomy Research Farm, the University of Agriculture Peshawar, Pakistan. Different beneficial microbes (BM) (with BM and without BM), organic (farm yard manure, FYM) and inorganic (ammonium nitrate) N ratios (0:100, 25:75, 50:50, 75:25, and 100:0), and nitrogen levels (N) (100, 150, and 200 kg ha?1). Beneficial microorganism, 50:50 ratio of organic and inorganic N, and 200 kg N ha?1 seem better in terms of improving SPAD value, plant height (cm), leaf rea (cm2), and leaf area index (LAI) of spring maize. Therefore, the application of BM, 50:50 ratio of organic and inorganic N, and 200 kg N ha?1 were recommended for enhancing crop physiology in agro-climatic condition for Peshawar, Pakistan.  相似文献   

12.
ABSTRACT

Soil fertility and water use are two important aspects that influence rice productivity. This study was conducted to evaluate the performance of in-situ (sesbania and rice bean) and ex-situ (subabul) green manuring along with zinc fertilization on water productivity and soil fertility in rice under rice–wheat cropping system at Indian Agricultural Research Institute, New Delhi, India. Sesbania incorporation recorded higher total water productivity (2.20 and 3.24 kg ha?1 mm?1), available soil nutrients, organic carbon, alkaline phosphatase activity, microbial biomass carbon and increased soil dehydrogenase activity by 39.6 and 26.8% over subabul and rice bean respectively. Among interaction of green manures and zinc fertilization, subabul × foliar application of chelated zinc-ethylenediaminetetraacetic acid at 20, 40, 60 and 80 days after transplanting recorded highest total water productivity (2.56 and 3.79 kg ha?1 mm?1). Foliar application of chelated Zn-EDTA at 20, 40, 60 and 80 days after transplanting recorded significantly higher water productivity than other Zn treatments, however it was statistically similar with foliar application of zinc at active tillering + flowering + grain filling. Sesbania × 5 kg Zn ha?1 through chelated Zn-EDTA, recorded highest available nitrogen, phosphorus, potassium, zinc, manganese, copper and iron than other green manure and Zn fertilization interactions, although it was statistically similar with rice bean × 5 kg Zn ha?1 through chelated Zn-EDTA as soil application. Sesbania × foliar application of 5 kg Zn ha?1 through chelated Zn-EDTA as soil application recorded highest soil enzymatic activities and microbial biomass carbon.  相似文献   

13.
Maize (Zea mays L.) is an important food crop in the Guinea savannas of Nigeria. Despite its high production potential, drought, Striga hermonthica parasitsim, and poor soil fertility particularly nitrogen deficiency limit maize production in the savannas. Breeders at IITA have developed drought- and Striga-tolerant cultivars for testing, dissemination, and deployment in the region. Information on the response of these cultivars to N fertilization is, however, not available. This study evaluated grain yield, total N uptake (TNU), N uptake (NUPE), N utilization (NUTE), and N use efficiency (NUE) of selected maize cultivars along with a widely grown improved maize cultivar at two locations in the Guinea savannas of northern Nigeria. Maize grain yield increased with N application. The average grain yield of the maize cultivars was 76% higher at 30, 156% higher at 60, and 203% higher at 120 kg N ha?1 than at 0 kg N ha?1. This suggests that N is a limiting nutrient in the Nigerian savannas. Five drought-tolerant cultivars produced consistently higher yields when N was added at all levels. These cultivars had either high NUPE or NUTE confirming earlier reports that high N uptake or NUTE improves maize grain yield. The study also confirms earlier reports that maize cultivars that are selected for tolerance to drought are also efficient in uptake and use of N fertilizer. This means that these cultivars can be grown with application of less N fertilizer thereby reducing investment on fertilizers and reduction in environmental pollution.  相似文献   

14.
Data from a 49-year-long organic–mineral fertilization field experiment with a potato–maize–maize–wheat–wheat crop rotation were used to analyse the impact of different fertilizer variations on yield ability, soil organic carbon content (SOC), N and C balances, as well as on some characteristic energy balance parameters. Among the treatments, the fertilization variant with 87 kg ha?1 year?1 N proved to be economically optimal (94% of the maximum). Approximately 40 years after initiation of the experiment, supposed steady-state SOC content has been reached, with a value of 0.81% in the upper soil layer of the unfertilized control plot. Farmyard manure (FYM) treatments resulted in 10% higher SOC content compared with equivalent NPK fertilizer doses. The best C balances were obtained with exclusive mineral fertilization variants (?3.8 and ?3.7 t ha?1 year?1, respectively). N uptake in the unfertilized control plot suggested an airborne N input of 48 kg ha?1 year?1. The optimum fertilizer variant (70 t ha?1 FYM-equivalent NPK) proved favourable with a view to energy. The energy gain by exclusive FYM treatments was lower than with sole NPK fertilization. Best energy intensity values were obtained with lower mineral fertilization and FYM variants. The order of energy conversion according to the different crops was maize, wheat and potato.  相似文献   

15.
Abstract

Nitrogen (N) and potassium (K) fertility management of maize (Zea mays L.) in the humid subtropical Mississippi Delta may differ from a temperate climate because of its use in rotation with cotton (Gossypium hirsutum L.), soil temperatures rarely falling to 0°C, and heavy winter rains that facilitate nutrient losses. An experiment to determine the [N] (concentration=[ ]), phosphorus [P], [K], calcium [Ca], magnesium [Mg], iron [Fe], manganese [Mn], zinc [Zn], and copper [Cu] and their total contents plant?1 of maize grown in rotation with cotton, using N fertility levels of (134, 179, 224, 269, and 314 kg N ha?1) in combination with K fertility levels of (0, 45, 90, and 134 kg K ha?1) was conducted in 2000 and 2001 at Tribbett, MS. Ear leaves, immature ears, and husks collected at growth stage R2 and grain and stover collected 21 days after R6 were dried, weighed, and analyzed for nutrient concentration. Plots were also harvested for yield, kernel weight, grain bulk density, and harvest index (HI). Increased [N] values of about 1.3 mg g?1 occurred in all organs except the stover between 134 and 314 kg N ha?1 N fertility. Stover [N] increased approximately 3.0 mg g?1 within the same N fertility range. Total N content of ear leaves, grain, and stover increased by about 11.0, 550.0, and 730.0 mg plant?1, respectively, with N fertility increased from 134 to 314 kg N ha?1. Yields, kernel weights, grain bulk densities, and harvest indices also increased with added N fertility. Several micronutrient concentrations and contents increased as N fertility increased. Increased K fertility had only limited influence on concentrations of most nutrient elements. The nutrient contents of most elements in the stover increased with added K fertility compared with plots that received no supplemental K fertilizer. These data showed between 139 and 265 kg N ha?1 was permanently removed by grain harvest and suggest that N fertility recommendations for the Mississippi Delta may be low for maize yield goals above 10 Mg ha?1. Added K fertilizer has minimal benefit to maize when soil test levels are adequate but are important to succeeding cotton crops where K uptake during fruiting can exceed the soil's ability to release K for uptake.  相似文献   

16.
The present study aims at identifying potentially high-yielding testcross maize hybrids using different selection indices that consider agronomic traits other than grain yield alone. Forty-one (41) testcross hybrids developed from 20 elite drought-tolerant maize inbred lines and two inbred testers plus three hybrid checks were evaluated in the rainy seasons of 2013 and 2014 in Ogbomoso in the derived savanna agroecological zone of Nigeria. Hybrids were planted in each year in 11 × 4 lattices with two replications. Testcross hybrids and checks exhibited significant differences for all measured traits except ear height, husk cover and number of ears per plant. Grain yield of hybrids and checks averaged over the 2 years varied from 3117 to 8393 kg ha?1 with a mean of 5935 kg ha?1. Top 11 hybrids produced vigorous plants, each yielding >7000 kg ha?1. Base index and multivariate index methods identified EXL11 × 9071 whereas base index and Smith–Hazel selection index methods identified EXL18 × 9071 as superior hybrids at 5% selection intensity. These hybrids will be considered for advanced breeding program and release to farmers as high-yielding drought-tolerant hybrid maize varieties in the increasingly drought-prone derived savanna agroecology of Nigeria.  相似文献   

17.
Understanding differences in grain yield and nitrogen utilization efficiency (NUtE) between barley and triticale could be useful for designing more sustainable cropping systems. Field experiments were conducted to compare grain yield and dry matter accumulation as well as N accumulation, translocation, and utilization in barley and triticale under Mediterranean conditions with two N fertilization rates (0 and 100 kg ha?1). Overall, across years and N application rates, barley out-yielded triticale by 30% (6943 vs. 5339 kg ha?1). Differences in the grain number per m2 explained most of the variation between species in grain yield, with barley showing higher values than triticale. Barley showed higher early growth resulting in greater N accumulation in anthesis, and eventually in higher translocation to the grain than triticale. When no N was applied, barley showed a mean increase of 15% in NUtE. Triticale showed an advantage in biomass production efficiency in anthesis only in the drier year. From a practical point of view, barley could be a better choice than triticale under low availability of N, not only concerning profitability, but also sustainability. In dry areas, triticale might be a sustainable choice as a silage crop because of better N exploitation for biomass production than barley.  相似文献   

18.
A field experiment was conducted to study the effect of silicon (diatomaceous earth, DE) fertilization on growth, yield, and nutrient uptake of rice during the kharif season of 2012 and 2013 in the new alluvial zone of West Bengal, India. Results showed that application of silicon significantly increased grain and straw yield as well as yield-attributing parameters such as plant height (cm), number of tillers m?2, number of panicle m?2, and 1000-grain weight (g) of rice. The greatest grain and straw yields were observed in the treatment T6 (DE at 600 kg ha?1 in combination with standard fertilizer practice (SFP). The concentration and uptake of silicon, nitrogen (N), phosphorus (P), and potassium (K) in grain and straw were also greater under this treatment compared to others. It was concluded that application of DE at 600 kg ha?1 along with SFP resulted increased grain, straw, and uptake of NPK.  相似文献   

19.
Best nitrogen (N) management practices are most important for increasing maize (Zea mays L.) productivity and profitability in Northwest Pakistan. Field experiments were performed at the New Developmental Research Farm of NWFP Agricultural University, Peshawar during summer 2002 and 2003. Factorial experimental treatments were two plant densities (D1 = 60,000 and D2 = 100,000 plants ha?1) and three N rates (N1 = 60, N2 = 120 and N3 = 180 kg N ha?1) as main plots, and six split N applications in different proportions at different growth stages of maize (cv. ‘Azam’) in two equal, three equal, three unequal, four equal, five equal and five unequal splits at sowing and with first, second, third, and fourth irrigation at two week intervals as subplots. Application of the higher N rate (180 kg ha?1) with 4 to 5 splits significantly increased leaf, stem, ear, and total plant dry weight at silking and physiological maturity as well as grain yield plant?1 at both low and high plant densities. Variation in dry matter partitioning and grain yield in maize due to fluctuation in the rainfall data of the two years suggests zonal specific effective N management practices for sustainable maize production in different agro-ecological zones of Northwest Pakistan.  相似文献   

20.
Maize yield is often limited by zinc (Zn) deficiency. The objectives of this study were to (i) evaluate maize yield response to Zn applied at four different rates, (ii) evaluate the yield response and agronomic efficiency of maize to the application of a complex fertilizer, MicroEssentials SZ (12N–40P–0K–10S–1Zn), compared to different rates of monoammonium phosphate (MAP) + ammonium sulfate (AS) + zinc sulfate (ZnSO4), and (iii) evaluate the association between tissue Zn concentration and soil-test Zn with the maize response to Zn fertilizer. Eleven experiments were carried out during the 2010, 2011, and 2012 growing seasons throughout eight states in the USA. Treatments consisted of four Zn rates of a physical blend of MAP + AS + ZnSO4 (0, 2.24, 4.48, 6.72, and 11.2 kg/ha Zn) and MicroEssentials SZ at a Zn rate of 2.24 kg/ha Zn. Nitrogen, phosphorus (P), and sulfur (S) rates were balanced across treatments (40 kg/ha P, 22 kg/ha S) and fertilizers were broadcast and incorporated immediately prior to planting. Treatment and location main effects were significant (P < 0.001) on corn yields, whereas the interaction treatment × location was not (P = 0.33). Maize responded positively to Zn fertilization; average yields across locations increased from 10,540 kg ha?1 without Zn to 11,530 kg ha?1 with 11.21 kg Zn ha?1 applied as a physical blend. The yield response and Zn agronomic efficiency of maize with the application of the complex fertilizer at a rate of 2.24 kg Zn ha?1 averaged 1004 kg ha?1 and 448 kg maize kg Zn?1, respectively, significantly higher (P < 0.1) than the yield response and Zn agronomic efficiency with the application of a physical blend with the same Zn rate, which averaged 293 kg ha?1 and 131 kg maize kg Zn?1, respectively. The Zn concentration in plant tissue of unfertilized plots varied greatly and was not related to the maize response to Zn fertilizer (r = 0.01; P = 0.98). With respect to soil Zn, a negative but nonsignificant relationship was found between maize response to Zn fertilizer and soil-test Zn (r = ?0.51; P = 0.16).  相似文献   

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