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1.
Abstract

A field trial was conducted during the short‐day period of 2004–2005 at Ona, Fl., to study the factorial effect of nitrogen (67, 90, and 134 kg N ha?1) and phosphorus (0, 5, 10, 20, and 40 kg P ha?1) rates on forage dry‐matter yield, quality, nutrient uptake, and leaf pigment concentration of limpograss (Hemarthria altissima). The N and P fertilizers were applied 45 days before each of two harvests. There was no interaction between N and P rates on any of the measured variables. Cool‐season forage yield increased curvilinearly from 137 to 350 kg ha?1 in winter and 237 to 1389 kg ha?1 in early spring, whereas crude protein (CP) concentration increased from 145 to 158 g kg?1, as P was increased from 0 to 40 kg ha?1, but yield and CP were not affected by N rate. There was a decreasing linear relationship between leaf concentration of anthocyanins and P rate of application such that forage obtained with 0 kg P ha?1 had 61% more leaf anthocyanins and purple pigmentation than with 40 kg P ha?1. There was no effect of N on anthocyanins content. It was concluded that increased level of leaf anthocyanins was due to the cumulative stress from cool weather and lower plant‐tissue P levels, which resulted in reduced growth and yield of limpograss. In cool weather, P played a critical role in controlling leaf purple pigmentation and forage yield.  相似文献   

2.
Abstract

The experiment was conducted at Kulumsa, South East Ethiopia, using four levels of nitrogen (N) (0, 50,100 and 150?kg N ha?1) and four levels of phosphorus (P) (0, 35, 70 and 105?kg P2O5 ha?1) fertilizers arranged in 4?×?4 factorial arrangements in randomized complete block design with three replications. The available P was increased after harvest due to the application of N and P fertilizer at the rates of 100 or 150?kg N ha?1 and 70 or 105?kg P2O5 ha?1. More specifically, nutrients concentration and nutrient uptake were significantly (p?<?.01) varied among treatment combinations and nutrient use efficiency was declined by increasing N and P after optimum rates. The higher physiological efficiency of N (53.47?kg kg?1) and P (580.41?kg kg?1) and the highest apparent recovery of N (19.62%) and P (2.47%) was recorded from application of 50?kg N ha?1 and P at 70?kg P2O5 ha?1 and the highest agronomic efficiency of N (10.78?kg kg?1) and P (15.25?kg kg?1) was recorded from N at the rate of 50?kg N ha?1 and P at 35?kg P2O5 ha?1, respectively. The combination of N at 100?kg N ha?1 and P at 70?kg P2O5 ha?1 was promising combination that generated highest net benefit 488,878.5 ETB (Ethiopian birr) ha?1 with the highest marginal rate of return (36638%) and gave the highest seed yield (1858.82?kg ha?1) with yield increment of about 57.72% over the control.  相似文献   

3.
Abstract

Sweetpotato is an important tuber crop for the food security in Island countries of the South Pacific. The allometric relationship between tissue nitrogen (N) concentration and aerial dry matter is unknown. We determined critical N (Nc) content from vegetative stage to harvesting, and estimated the range of variation in N nutrition index (NNI) from two field experiments with varied rates of N (0, 25, 60, 125 and 180?kg N ha?1 in 2015 and 0, 50, 125, 175 and 250?kg N ha?1 in 2017). A unified critical N curve (Nc = 3.338?W?0.307) where W?=?aerial dry matter with W?≥?1.38 t ha?1, was constructed based on the N concentration in the aerial dry matter. The calculated NNI ranged from 0.69 to 1.23 in 2015 and 0.54 to 1.17 in 2017. The preliminary Nc dilution curve and NNI determined could potentially be used as a parameter for N management.  相似文献   

4.
For 7 years (1997–2003), five nitrogen (N) rates (0, 60, 120, 180, and 240 kg N ha?1) were applied to sugar beets arranged in randomized complete block (RCB) design experiments with six replications and grown on light soils (sand content >50 g kg?1) in northern Greece. The aim of this work was to identify soil characteristics that affect yield, quality, and sugar beet response to N fertilization. Before sowing, soil analyses were conducted in control plots (0 kg N ha?1) at two depths (0–30 and 30–60 cm). Soils differed in their physical and chemical properties and especially in sand content, which ranged from 500 to 732 g kg?1. Quantitative (root number, RN; root yield, RY; and sugar yield, SY) and qualitative (percentage sucrose content in fresh root weight, SC; potassium, K; sodium, Na; and α-amino N) traits of control plots were used as soil fertility index. The RN was positively affected by clay content, and RY and SY were positively related with sand and negatively with silt content. The SC was negatively affected by soil (NO3)-N and sodium (Na) concentrations. Also, soil (NO3)-N concentration was positively related with root impurities (K, Na, α-amino N). In combined data over years, N rates had a negative effect on the RN. The RY was the only trait affected by years, N rates, and their interaction. The SC and SY differed significantly between years, and N rates affected significantly the former but not the latter. In combined data over years, N rates were curvilinearly related with Na concentration in roots, whereas a strong, linear relationship was found between α-amino N concentration and N rates. To study the significant years × N rates interaction evidenced for the RY, the relative response (RR) of the RY to N was introduced. Actually, the RR expresses the increase or decrease of the RY for a 150 kg N ha?1 rate compared to the control (0 kg N ha?1). The RR was strongly related with soil K concentration at the 0- to 30-cm depth (y = –0.00002x2 + 0.0082x + 0.5085, r2 = 0.92, P < 0.01, n = 7) and with total N concentration at the deeper layer (y = 1.8335x2 – 3.5312x + 2.6614, r2 = 0.88, P < 0.05, n = 6). Thus, the RY response to a rate of 150 kg N ha?1, which is the commonly applied to the sugar beet crop in Greece, can be predicted reliably by soil characteristics (K and total N concentration) determined before sowing. The strong relationship between soil K concentration and sugar beet response to N merits further research.  相似文献   

5.
ABSTRACT

The study was aimed to determine the appropriate nitrogen (N) rate to combine with liming for enhanced maize yield and nitrogen use efficiency (NUE). Two maize varieties [Ikom White (IKW) and Obatanpa-98 (Oba-98)], two lime rates (0 kg ha?1 and 500 kg ha?1) and three N rates (0, 90 and 180 kg ha?1) were used. The treatments were laid as a split-split plot in a randomized complete block design with three replications. The growth attributes, photosynthetically active radiation (PAR), harvest index, dry matter, and grain yield increased (P ≤ 0.05) with increases in N rates, especially in plots amended with lime. Oba-98 was better yielding (2.12 versus (vs) 1.88 t ha?1) and absorbed more (P ≤ 0.05) radiation (442.06 vs 409.54 μmol m?2s?1) than IKW. The efficiency indices and partial factor productivity were best optimized at the 90 kg ha?1 N rate with Oba-98 having higher values than IKW. Therefore, liming (500 kg ha?1) plus N at 180 kg ha?1produced the best yield of the hybrid maize, Oba-98.  相似文献   

6.
ABSTRACT

Grain yield in many soybean experiments fails to respond to fertilizer nitrogen (N). A few positive responses have been reported when soybean were grown in the southern U.S., when N was applied near flowering and when biosolids were added. In a previous study, low N concentrations of soybean forage in north Texas on a high pH calcareous soil were reported and thus, we suspected a N nutrition problem. Consequently, we initiated this study to determine whether selected preplant N sources broadcast and incorporated into a Houston Black clay (fine, smectitic, thermic Udic Haplusterts) might increase forage N concentration, forage yield, or soybean grain yield. In 2003, N was applied as ammonium nitrate (NH4NO3, AN) up to 112 kg N ha? 1 and dairy manure compost (DMC) was applied at rates of 4.9, 9.9, 15.0, and 19.9 Mg ha? 1. The DMC contained 5.9, 2.6, and 6.7 g kg? 1 of total N, P, and K, respectively; thus DMC added 29 to 116 kg N ha? 1. In 2004, AN was applied at rates of 112 and 224 kg N ha? 1 and DMC was applied at 28 and 57 Mg ha? 1; thus, DMC added 168 to 335 kg N ha? 1. In another 2004 test, biosolids, a biosolids/municipal yard waste compost mixture (BYWC), and AN were compared. The biosolids contained 31, 18, and 2.9 g kg? 1 total N, P, and K, respectively. The BYWC mixture contained 8.8, 6.1, and 3.4 g kg? 1 of total N, P, and K, respectively. Biosolids were applied at 10 Mg ha? 1 (310 kg N ha? 1), BYWC was applied at 58 Mg ha? 1 (510 kg N ha? 1), and AN up to 224 kg N ha? 1. None of the soil treatments increased soybean grain yield or forage yield although AN slightly increased forage N concentration in 2003.  相似文献   

7.
Balanced plant nutrition is essential to achieve high yields of canola (Brassica napus L.) and get the best economic return from applied fertilizers. A field study was conducted at nine site‐years across eastern Canada to investigate the effects of nitrogen (N), sulfur (S) and boron (B) fertilization on canola nutrient uptake, nutrient balance, and their relationship to canola yields. The factorial experiment consisted of four N rates of 0 (N0), 50 (N50), 100 (N100), and 150 (N150) kg ha?1, two S rates of 0 (S0) and 20 (S20) kg ha?1, and three B treatments of 0 (B0), 2 kg ha?1 at preplant (B2.0P), and 0.5 kg B ha?1 foliar‐applied at early flowering stage (B0.5F). Each site‐year used the same experimental design and assigned treatments in a randomized complete block design with four replications. Fertilizer S application greatly improved seed yields at six out of nine site‐years, and the highest N use efficiency was in the N150+S20 treatment. Sulfur application generally increased seed S concentration, seed S removal, and plant total S uptake, while B fertilization mainly elevated straw B concentration and content, with minimal effect on seed yields. At the early flowering stage, plant tissue S ranged from 2.2 to 6.6 mg S g?1, but the N : S ratio was over or close to the critical value of 12 in the N150+S0 combination at five site‐years. On average across nine site‐years, canola reached a plateau yield of 3580 kg ha?1 when plants contained 197 kg N ha?1, 33 kg S ha?1 and 200 g B ha?1, with a seed B content of 60 g B ha?1. The critical N, S, and B values identified in this work and their potential for a posteriori nutrient diagnosis of canola should be useful to validate fertilizer requirements for canola production in eastern Canada.  相似文献   

8.
A potato field experiment was conducted for 2 consecutive years to determine the effects of nitrogen (N) and potassium (K) fertilization rates on the yield and quality of potato cv. Spunta cultivated on soil low in N and K. A 3?×?4 complete factorial experiment was used with three rates of nitrogen (330, 495, and 660 kg N ha–1) and four rates of potassium (112, 225, 450, and 675 kg K2Ο ha–1). An additional treatment without fertilization was used as the control. On soils low in N and K, potatoes showed low yield response to K fertilizer. The greatest tuber yields for both years were achieved at 495 kg N ha–1 and 112 kg K2O ha–1 (29.81 t ha–1) and 225 kg ha–1 (27.13 t ha–1), respectively. Differences in mean fresh weight due to treatment application were not significant. Application of 495 kg N ha–1 significantly reduced harvest index (the ratio of tuber dry weight to the total dry weight at harvest) compared to 330 kg N ha–1, but at 660 kg N ha–1 harvest index achieved the greatest significant value. Potassium fertilization had no significant influence on harvest index. Nitrogen rates positively influenced the number of tubers. The addition of 450 kg K2O ha–1 significantly enhanced the number of tubers compared to the lower K rates, and the number was significantly decreased by the application of 675 kg K2O ha–1. Tuber dry-matter concentration was significantly promoted by N fertilization in both cultivation years, but it was negatively affected by K fertilization in the first year of cultivation. There was no change in tuber N with N application, but N application strongly increased nitrate (NO3) concentration, which fluctuated between 360 and 1382 mg kg–1 wet mass. Tuber NO3 was negatively correlated with tuber yield, indicating that high levels of NO3 in tubers can adversely affect yield. Tuber response to K fertilization was not in accordance with the rate of applied nutrient.  相似文献   

9.
The objective of this study was to examine the effect of nitrogen-fertilization management on soil nutrient distribution at different soil depths under conventional tillage in dryland rain-fed environment. Two nitrogen (N) application methods (single application with all N applied at planting and split application with 35 kg N ha?1 applied at planting and remaining N applied at V6 growth stage) and five N rates (0, 45, 90, 135, and 180 kg N ha?1) were utilized. Increasing soil depth decreased extractable phosphorus (P), potassium (K), and calcium (Ca) contents in the soil. The nitrate (NO3)-N concentration in deeper soil was similar to the top layer as N fertilization was greater than 90 kg N ha?1. It suggests that N application should be less than 90 kg ha?1 to reduce the movement of excess N to deep soil layers and cause a potential negative impact on environment in this area.  相似文献   

10.
A field experiment was carried out in a semi-arid region of Iran during the 2006–2007 growing season to investigate canola seed yield as affected by nitrogen (N) and natural zeolite (Z) rates. This experiment studied N efficiency and N leaching loss in a sandy soil. Experimental treatments consisted of a factorial combination of three N levels (90, 180, and 270 kg N ha?1) and four zeolite rates (0, 3, 6, and 9 t zeolite ha?1). The result showed that the greatest seed yield (2452.3 kg ha?1) was obtained from the N270Z9 treatment whereas the control treatment (N0Z0) produced the lowest seed yield (1038.3 kg ha?1). Moreover, use of 270 kg N ha?1 without zeolite (N270Z0) led to the greatest amount of N leaching loss (144.23 kg ha?1). Zeolite application clearly reduced N leaching loss in all N rates. This justified low N-use efficiency in high N applications. More N uptake and more canola seed yield is attributed to zeolite application.  相似文献   

11.
Abstract

Yield and kernel quality of rainfed maize as affected by N fertilizer has been generally evaluated through the application of granular N sources at high rates. The purpose of this work was to estimate the response of maize yield and quality (kernel hardness—floating index, weight and test weight -, P uptake and protein) to foliar N application and preceding granular N. Data for this report were collected in 2014 and 2015 in a long-term experiment established in 2002 under permanent beds in a split plot arrangement. Main plot treatments were three foliar N rates (0, 4.5 and 9?kg ha?1) laid out on the top of four preceding granular N rates (0, 20, 40 and 60?kg ha?1) applied from 2002 to 2013 as subplots. Weather conditions were relatively wetter in 2014 than 2015. In 2014, test weight and floating index improved over that in 2015. Foliar application of 9?kg N ha?1 enhanced yield and protein. In 2014, yield response to preceding N rates showed an increasing trend whereas in 2015 response was null. Kernel P uptake response to preceding N rates showed a differential reaction among foliar N rates; 9?kg ha?1 showed the greatest uptake. Kernel floating index was associated to kernel P uptake. Apparently, this relationship has not been previously reported. Results suggests that the application of 9?kg N ha?1 to foliage of rainfed maize grown in permanent beds has the potential to substitute the traditional fertilization practice of granular N sources.  相似文献   

12.
In experimental grasslands, a positive relationship between biomass production and plant diversity has often been found. Here, we compared a moderately species‐rich old sward with its grass‐dominated counterpart (12 vs. 8 species per 2.5 m2, or 8.3 vs. 0.7% yield proportion of dicots at the start of the experiment) established by herbicide application. We hypothesized an increased N, P and K uptake in the diverse sward related to a higher colonization rate with arbuscular mycorrhizal fungi (AMF), the presence of legumes, and complementary nutrient use of plant species. Phosphorus or N fertilizer application (according to contributions of AMF or legumes) were expected to balance the assumed smaller biomass production of the grass compared to the diverse sward. In two experimental years, N, P and K uptake, biomass production, N2 fixation, and intra‐ and extraradical AMF colonization were investigated in an untreated control and plots that were fertilized with P and N in a low (P1: 20 kg P ha?1; N1: 50 kg N ha?1) or a high dose (P2: 100 kg P ha?1; N2: 500 kg N ha?1) in both swards. Biomass production was larger in the grass compared to the diverse sward. The N, P and K uptake, accumulated over three harvests (or 1.5 years), was also larger in the grass sward. The biomass production ranged from 5.3 to 10.0 t ha?1 and accumulated nutrient uptake from 82 to191 kg N ha?1, 19 to 31 kg P ha?1 and 112 to 221 kg K ha?1. Small legume proportions resulted in an accumulated N2 fixation between 0 and 3 kg ha?1. In the second year, the root length colonized with AMF structures was larger in the diverse compared to the grass sward, and the root length colonized with arbuscules and coils was larger in the N2 treatment compared to the control in the diverse sward. There were hints to higher AMF abundance under conditions of limited P availability (low soil P content, high N:P ratio in plant biomass). We conclude that in semi‐natural grassland of moderate species richness several factors may affect the relationship between plant diversity and productivity, i.e., management, plant species identity, and the number of the plant species of the low‐diversity level.  相似文献   

13.
A study was conducted to assess fertilizer effect on pearl millet–wheat yield and plant-soil nutrients with the following treatments: T1, control; T2, 100% nitrogen (N); T3, 100% nitrogen and phosphorus (NP); T4, 100% nitrogen, phosphorus and potassium (NPK); T5, 100% NPK + zinc sulfate (ZnSO4) at 25 kg ha?1; T6, 100% NPK + farmyard manure (FYM) at 10 t ha?1; T7, 100% NPK+ verimcompost (VC) at 2.5 tha?1; T8, 100% NPK + sulfur (S) at 25 kg ha?1; T9, FYM at 10 t ha?1; T10, VC at 2.5 t ha?1; T11, 100% NPK + FYM at 10 t ha?1 + 25 kg S ha?1 + ZnSO4 at 25 kg ha?1; and T12, 150% NPK treatments. Treatments differed significantly in influencing soil-plant nutrients and grain and straw yields of both crops. Grain yield had significant correlation with soil-plant N, P, K, S, and zinc (Zn) nutrients. The study indicated superiority of T11 for attaining maximum pearl millet grain yield (2885 kg ha?1) and straw yield (7185 kg ha?1); amounts of N (48.9 kg ha?1), P (8.8 kg ha?1), K (26.3 kg ha?1), S (20.6 kg ha?1), and Zn (0.09 kg ha?1) taken up; and amounts of soil N (187.7 kg ha?1), P (13.7 kg ha?1), K (242.5 kg ha?1), S (10.1 kg ha?1), and Zn (0.70 kg ha?1). It was superior for wheat with grain yield (5215 kg ha?1) and straw yield (7220 kg ha?1); amounts of N (120.7 kg ha?1), P (13.8 kg ha?1), K (30 kg ha?1), S (14.6 kg ha?1), and Zn (0.18 kg ha?1) taken up; and maintaining soil N (185.7 kg ha?1), P (14.5 kg ha?1), K (250.5 kg ha?1), S (10.6 kg ha?1), and Zn (0.73 kg ha?1). Based on the study, 100% NPK + FYM at 10 tha?1 + Zn at 25 kg ha?1 + S at 25 kg ha?1 could be recommended for attaining maximum returns of pearl millet–wheat under semi-arid Inceptisols.  相似文献   

14.
ABSTRACT

Long-term fertilization tests evaluated rice (Oryza sativa) productivity in relation to application of nitrogen (N)-phosphorus (P)-potassium (K) (120-34.9-66.7 kg ha? 1, respectively) during 1967–1972 and N-P-K (150-43.7-83.3 kg ha? 1, respectively) during 1973–2000. The comparison treatments (NP, PK, and NK) and the control (not fertilized) were selected for calculating nutrient efficiency. Rice grain yield increased at a 17.78 kg ha? 1 yr? 1 in the control, mainly due to development of improved cultivars. Phosphorus management was found to be important for indigenous fertility and rice productivity in this paddy soil. Yield increased significantly with P fertilization. Without N fertilization (PK), rice productivity increased 56.85 kg ha? 1 yr? 1 from 62% of NPK at the initial stage to 74% after passing 34 years, which might be affected by increasing biological N fixation with P accumulation in soil. In NK treatment, rice yield increased at a relatively low rate (37.82 kg hr? 1 yr? 1) from the same rice productivity with that of NPK in 1967 to 91% after 34 years. In comparison, yield increased at a high rate (62.82 kg hr? 1 yr? 1) without K fertilization (NP) from ca. 90% of NPK and might exceed the yield of NPK after 64 years of long-term fertilization. Therefore, K fertilization level might be readjusted after long-term fertilizing in paddy soil.  相似文献   

15.
Nitrate (NO3) accumulation by spinach was studied under increasing nitrogen (N) levels (60, 120 and 240 kg N ha?1) along with sulfur (45 kg S ha?1) and phosphorus (P; 90 kg P2O5 ha?1) application. Plants were harvested at 50 and 65 days after sowing. Plant samples were analyzed for NO3-N and total N, P, S, potassium (K), calcium (Ca), and magnesium (Mg). Radio assay of 35S was done to estimate percent sulfur derived from fertilizer and percent fertilizer sulfur utilization. Spinach maintained a very high level of NO3-N in its tissue throughout the growing period. NO3-N was increased with increasing nitrogen level and was reduced with phosphorus and sulfur application and also with advancement in growth. Total N, P, S, K, Ca and Mg uptake were increased with increasing nitrogen levels as well as with application of sulfur and phosphorus. Sulfur application caused increase in percent sulfur derived from fertilizer and percent utilization of fertilizer sulfur.  相似文献   

16.
Based on experiments conducted during 1988–2009 on rainfed pearl millet/sorghum with 9 treatments in Vertisols, an efficient treatment for sustainable productivity is identified. Twenty kg of nitrogen (N) from farmyard manure (FYM) + 20 kg N (urea) + 10 kg phosphorus (P) ha?1 in pearl millet and 40 kg N (urea) + 20 kg P + 25 kg zinc sulfate (ZnSO4) ha?1 in sorghum gave maximum yield and rainwater-use efficiency, whereas 20 kg N (FYM) + 20 kg (urea) + 10 kg P ha?1 in pearl millet and 40 kg (urea) + 20 kg P ha?1 in sorghum and gave maximum soil N, P, and potassium (K) over years. The regression model of 20 kg N (crop residue) + 20 kg N (urea) + 10 kg P ha?1 gave maximum R2 for predicting sorghum equivalent yield separately through precipitation and soil variables, whereas 20 kg N (FYM) + 20 kg N (urea) + 10 kg P ha?1 gave maximum R2 under combined model of both variables. Treatment of 20 kg N (FYM) + 20 kg N (urea) + 10 kg P ha?1 was superior for attaining maximum sorghum equivalent yield of 1062 kg ha?1, net returns of Rs. 4805 ha?1, benefit/cost (BC) ratio of 1.50, and 127 kg ha?1 of soil N, 10.3 kg ha?1 of soil P, and 386 kg ha?1 of soil K over years.  相似文献   

17.
The intensive winter wheat (Triticum aestivum L.)–summer maize (Zea mays L.) cropping systems in the North China Plain (NCP) rely on the heavy use of mineral nitrogen (N) fertilizers. As the fertigated area of wheat and maize in the NCP has grown rapidly during recent years, developing N management strategies is required for sustainable wheat and maize production. Field experiments were conducted in Hebei Province during three consecutive growth seasons in 2012–2015 to assess the influence of different N fertigation rates on N uptake, yield, and nitrogen use efficiency [NUE: recovery efficiency (REN) and agronomic efficiency (AEN)]. Five levels of N application, 0 (FN0), 40 (FN40%), 70 (FN70%), 100 (FN100%), and 130% (FN130%) of the farmer practice rate (FP: 250 kg N ha?1 and 205.5 kg N ha?1 for wheat and maize, respectively), corresponding to 0, 182.2, 318.9, 455.5, and 592.2 kg N ha?1 y?1, respectively, were tested. Nitrogen in the form of urea was dissolved in irrigation water and split into six and four applications for wheat and maize, respectively. In addition, the treatment “drip irrigation + 100% N conventional broadcasting” (DN100%) was also conducted. All treatments were arranged in a randomized complete block design with three replications. The results revealed the significant influence of both N fertigation rate and N application method on grain yield and NUE. Compared to DN100%, FN100% significantly increased the 3‐year averaged N recovery efficiency (REN) by 0.09 kg kg?1 and 0.04 kg kg?1, and the 3‐year averaged N agronomic efficiency (AEN) by 2.43 kg kg?1 and 1.62 kg kg?1 for wheat and maize, respectively. Among N fertigation rates, there was no significant increase in grain yield in response to N applied at a greater rate than 70% of FP due to excess N accumulation in vegetative tissues. Compared to FN70%, FN100%, and FN130%, FN40% increased the REN by 0.17–0.57 kg kg?1 and 0.03–0.34 kg kg?1and the AEN by 4.60–27.56 kg kg?1 and 2.40–10.62 kg kg?1 for wheat and maize, respectively. Based on a linear‐response relationship between the N fertigation rate and grain yield over three rotational periods it can be concluded that recommended N rates under drip fertigation with optimum split applications can be reduced to 46% (114.6 kg N ha?1) and 58% (116.6 kg N ha?1) of FP for wheat and maize, respectively, without negatively affecting grain yield, thereby increasing NUE.  相似文献   

18.
Abstract

Field experiments were conducted to investigate nitrogen use efficiency and performance of maize (Zea mays L.) cultivars as influenced by calcium carbide (CaC2) and nitrogen (N) rates in a derived Savanna (2016 and 2017). Maize cultivars {SUWAN-I [open pollinated variety (OPV)] and OBA SUPER II (hybrid)}, rates of N (0, 60 and 90?kg ha?1) and CaC2 (0, 30 and 60?kg ha?1), were arranged in split-split plot respectively, fitted into a randomized complete block design in three replicates. N Partial factor productivity (PFPN), Agronomic Use Efficiency (both years) and Apparent recovery of N (2017) increased in the order 60?>?90?>?0?kg N ha?1, except N Internal use efficiency which was in the order 0?>?60?>?90?kg N ha?1 (2017). Grain yield increased with increasing rates of N in both years. OBA SUPER-II had significantly higher grain yield than SUWAN-I (2017). Similar pattern was observed on number of grains per cob, dry cob weight, PFPN and plant height (2017). Conversely in 2016, grain, total and shoot N uptakes were significantly higher in SUWAN-I than OBA SUPER-II. Increasing application of CaC2 increased grain N uptake and number of grains per cob. Number of leaves and stem girth increased in the order of 60?>?0?>?30?kg?CaC2 ha?1. Increased grain yield with N rates could be associated with NHI and N use efficiency. These evidences suggested that hybrid maize performed better than OPV in a derived Savanna.  相似文献   

19.
Boron (B) deficiency hampers cotton (Gossypium hirsutum L.) growth and productivity globally, especially in calcareous soils. The crop is known as a heavy feeder of B; however, its reported plant analysis diagnostic norms for B-deficiency diagnosis vary drastically. In a 2-year field experiment on a B-deficient [hydrochloric acid (HCl)–extractable 0.47 mg B kg?1], calcareous, Typic Haplocambid, we studied the impact of soil-applied B on cotton (cv. CIM-473) growth, productivity, plant tissue B concentration, and seed oil composition. Boron was applied at 0.0, 1.0, 1.5, 2.0, 2.5, and 3.0 kg B ha?1, as borax (Na2B4O7·10H2O), in a randomized complete block design with four replications, along with recommended rates of nitrogen (N), phosphorus (P), potassium (K), and zinc (Zn). Boron use improved crop growth, decreased fruit shedding, and increased boll weight, leading to seed cotton yield increases up to 14.7% (P < 0.05). Improved B nutrition of plants also enhanced seed oil content (P < 0.05) and increased seed protein content (P < 0.05). Fiber quality was not affected. Fertilizer B use was highly cost-effective, with a value–cost ratio of 12.3:1 at 1 kg B ha?1. Fertilizer B requirement for near-maximum (95% of maximum) seed cotton yield was 1.1 kg B ha?1 and HCl-extractable soil B requirement for was 0.52 kg ha?1. Leaf tissue B requirement varied with leaf age as well as with plant age. In 30-day plants (i.e., at squaring), B-deficiency diagnosis critical level was 45.0 mg kg?1 in recently matured leaves and 38.0 mg kg?1 in youngest open leaves; at 60 days old (i.e., at flowering), critical concentration was 55.0 mg kg?1 in mature leaves and 43.0 mg kg?1 in youngest leaves. With advancement in plant age critical B concentration decreased in both leaf tissues; that is, in 90-day-old plants (i.e., at boll formation) it was 43.0 mg kg?1 in mature leaves and 35.0 mg kg?1 in the youngest leaves. As critical concentration range was narrower in youngest leaves (i.e., 35–43 mg kg?1) compared with mature leaves (i.e., 43–55 mg kg?1), B concentration in youngest leaves is considered a better indicator for deficiency diagnosis.  相似文献   

20.
A two-year field study was conducted to determine the effect of two zinc (Zn) levels [0 and 10 kg zinc sulfate (ZnSO4) ha?1] in respect with four potassium (K) levels (0, 20, 40 and 60 kg K2O ha?1) on growth, yield and quality of forage sorghum. The soil of the experimental field was loamy sand (Inceptisol), carrying 70, 08, 77, and 0.51 mg nitrogen (N), phosphorus (P), K, and Zn kg?1 soil, respectively. Increasing K levels significantly improved most of the growth, yield, and quality attributes gradually irrespective of the Zn levels. Zinc applied at 10 kg ZnSO4 ha?1 proved significantly better than no zinc application at various K application rates. The benefit of zinc application increased progressively with increasing K rates for most of the parameters studied, indicating significant response of the crop to positive K × Zn interaction in plants in respect with K and Zn application to the soil. Accordingly, 60 kg K2O ha?1 applied with10 kg ZnSO4 ha?1 boosted most of the attributes maximally. It resulted in about 20–40% increase in growth attributes, 25% increase in fresh matter yield, 36–38% increase in dry matter yield, and 38% increase in protein yield compared to the comparable K level applied without zinc. It also enhanced N uptake by 38%, P uptake by 5–19%, K uptake by 40–42%, and Zn uptake by 114–144%. Across the K rates, application of 10 kg ZnSO4 surpassed no zinc application by 30–35% in N uptake, by 8–15% in P uptake, by 33–36% in K uptake, by 120–140% in Zn uptake, by 19–21% in fresh matter yield, by 29–31% in dry matter yield, and by 30–34% in protein yield.  相似文献   

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