Chlorophyll meter as a tool for forecasting wheat nitrogen requirements after application of herbicides

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.     

Effects of cotton (Gossypium hirsutum L.) straw and its biochar application on NH3 volatilization and N use efficiency in a drip-irrigated cotton field

Reducing ammonia (NH₃) volatilization is a practical way to increase nitrogen (N) fertilizer use efficiency (NUE). In this field study, soil was amended once with either cotton (Gossypium hirsutum L.) straw (6 t ha^?1) or its biochar (3.7 t ha^?1) unfertilized (0 kg N ha^?1) or fertilized (450 kg N ha^?1), and then soil inorganic N concentration and distribution, NH₃ volatilization, cotton yield and NUE were measured during the next two growing seasons. In unfertilized plots, NH₃ volatilization losses in the straw-amended and biochar-amended treatments were 38–40% and 42–46%, respectively, less than that in control (i.e., unamended soil) during the two growing seasons. In the fertilized plots, NH₃ volatilization losses in the straw-amended and biochar-amended treatments were 30–39% and 43–54%, respectively, less than that in the control. Straw amendment increased inorganic N concentrations, cotton yield, cotton N uptake and NUE during the first cropping season after application, but not during the second. In contrast, biochar increased cotton N uptake and NUE during both the first and the second cropping seasons after application. Furthermore, the effects of biochar on cotton N uptake and NUE were greater in the second year than in the first year. These results indicate that cotton straw and cotton straw biochar can both reduce NH₃ volatilization and also increase cotton yield, N uptake and NUE. In addition, the positive effects of one application of cotton straw biochar were more long-lasting than those of cotton straw.     

Inoculation of rapeseed under different rates of inorganic nitrogen and sulfur fertilizer: impact on water relations,cell membrane stability,chlorophyll content and yield

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.     

Compost and Nitrogen Management Influence Productivity of Spring Maize (Zea mays L.) under Deep and Conventional Tillage Systems in Semi-arid Regions

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.     

Performance and behaviour of Bt cotton hybrids under sub-optimal rainfall situation

Growth behaviour and yield performance of Bt cotton hybrids under sub-optimal rainfall situation is of practical significance, because more than 60% of the cotton area is under rainfed condition in India. A field trial conducted in a sandy clay loam soil during the seasons 2006–2007, 2007–2008, and 2008–2009 to study the growth behaviour and yield performance under scanty rainfall situation revealed that growth in both Bt and non-Bt cotton hybrids significantly differed under these parameters. The crop experienced moisture stress at the early stages of growth and again during boll development phase in 2006–2007 and 2008–2009. However, Bt hybrids (1691 kg ha^?1) produced higher seed cotton yield than non-Bt hybrids (1092 kg ha^?1), while the controlled variety (LRA 5166) performed the average of these two (1399 kg ha^?1). Similar trend was evident in respect of bolls per plant (at 90 DAP) and the final harvested bolls in both Bt and non-Bt cotton. Because of Bt gene, the early formed bolls were protected from the boll worms which led to less damage and higher yield with Bt hybrids. Amongst the hybrids, RCHB 708 Bt (1917 kg ha^?1) performed better over the others.     

Yield,Petiole Nitrate,and Node Development Responses of Cotton to Early Season Nitrogen Fertilization

Abstract

Nitrogen (N) fertilization continues to be of primary importance in the economically successful production of cotton (Gossypium hirsutum L.). Profit margins of producers might be expanded by increasing the uptake efficiency of applied N. Recently, N fertilization of crops grown in the Mississippi River Delta has been suspected to impact water quality in the Gulf of Mexico. Improving efficiency of N uptake could alleviate some environmental concerns by increasing the retention of N at the site of application. The objective of this study was to determine the impact of replacing preplant N applications with postemergent N applications on the growth and yield characteristics of cotton. Delayed applications of the recommended rate of N fertilizer (112 kg N ha^?1) were tested for four years under irrigated and dry land production conditions. The N rate was applied either preplant, after crop emergence, or at first square. Further, 112 kg N ha^?1 was split applied evenly at preplant + first square, and after emergence + first square. The five 112 kg ha^?1 N treatments were compared to an unfertilized control. Yield tended to be maximized with N treatments that included a first square application. Yields were usually lowest in the unfertilized control and the 112 kg N ha^?1 preplant treatments. Not surprisingly, both yield and plant growth was influenced more by irrigation than N fertilization. Years when drought conditions caused water stress and limited plant growth, dry land cotton had only limited response to the N fertilization treatments. Irrigated cotton responded to N treatments all years with increased growth and yield. Optimizing agronomic considerations, the best N fertilization timing was an after emergence + first square split application.

     

Effect of seed rate and nitrogen fertilizer on weed species composition,density and diversity in two sesame varieties

To evaluate the effect of seed and nitrogen rates on weed species composition, density, biomass and diversity in two sesame (Sesamum indicum L.) varieties, a field experiment was conducted in 2009, 2010 and 2011 rainy seasons at Samaru, Nigeria. Four seed rates, 2, 4, 6 and 8 kg ha^?1, four nitrogen rates, 0, 30, 60 and 90 kg N ha^?1 and two sesame varieties NCRIBEN 01M and E8 were arranged as factorial in a split plot design. Weeds with the highest important values in sesame field were Dactyloctenium aegyptium, Ludwigia decurrens, Ageratum conyzoides and Cyperus esculentus. Year had a significant effect on weed density, biomass, diversity, evenness and richness. Weed density, biomass, diversity and richness were lowest in the 2011 trial and weed species evenness in 2009. Variety E8 reduced weed biomass better than NCRIBEN 01M. Averaged over years, weed diversity and evenness were lowest at 4 kg seeds ha^?1. Seed × nitrogen rates effect of 4 kg seed ha^?1 and 30 kg N ha^?1 produced the lowest weed species diversity and evenness. The result suggests that variety E8 at 4 kg seed ha^?1 and 30 kg N ha^?1 with hoe weeding at 3 and 6 WAS may provide better weed control, and it is recommended in sesame production.     

Validation and Recalibration of a Soil Test for Mineralizable Nitrogen

Abstract

A soil test for mineralizable soil N had been calibrated for winter wheat in the Willamette Valley of western Oregon. Seventy‐eight percent of the variation in spring N uptake by unfertilized wheat was explained by N mineralized from mid‐winter soil samples incubated anaerobically for 7 days at 40°C. Mineralizable N (Nmin) ranged from 10 to 30 mg N kg^?1 and was used to predict N fertilizer needs. Recommended rates of N were correlated (R²=0.87) with maximum economic rates of N fertilizer. Subsequent farmer adoption of no‐till sowing and a high frequency of soil tests>30 mg N kg^?1 prompted reevaluation of the soil test. Four N fertilizer rates [0, 56, G, and G+56 kg N ha^?1] were compared in 12 m×150 m farmer‐managed plots. Grower's N rates (G) ranged from 90 to 180 kg N ha^?1 and were based on N_min and NH₄‐N plus NO₃‐N soil tests. Averaged across ten no‐till and five conventionally tilled sites, grain yield and crop N uptake were maximized at the recommended rate of N. Results demonstrate that N fertilizer needs for winter wheat can be predicted over a wide range of mineralizable soil N (10 to 75 mg N kg^?1) and that the same soil test calibration can be used for conventionally sown and direct‐seeded winter wheat.     

Modeling of Soil-Plant-Fertilizer Relationships for Optimizing Fertilizer Doses for Different Levels of Finger Millet Yield under Semi-Arid Alfisols

Experiments were conducted to test the superiority of treatment combinations of nitrogen (N; 0, 50, 100, 150, 200 kg ha^?1), phosphorus (0, 30, 60, 90 kg ha^?1) and potassium (0, 30, 60 kg ha^?1) for finger millet during 2005–2007. Application of 200-90-60 kg ha^?1 gave maximum yield of 1666, 1426 and 1640 kg ha^?1 in 3 years, respectively. The yield regression model through soil and fertilizer nutrients gave predictability of 0.98, 0.97 and 0.98, with sustainability yield index (SYI) of 50.4, 49.4 and 52.5 in 2005, 2006 and 2007, respectively. Optimum nitrogen, phosphorus and potassium (NPK) doses for attaining yields of 800 and 1200 kg ha^?1 were derived at soil nitrogen, phosphorus and potassium of 75–400, 10–70 and 150–750 kg ha^?1. Fertilizer nitrogen, phosphorus and potassium ranged from 30–128, 3–19, 13–25 kg ha^?1 and 105–203, 4–32, 27–39 kg ha^?1 for attaining 800 and 1200 kg ha^?1 yield, respectively. The doses could be adopted for attaining sustainable yields under semiarid Alfisols.     

Nitrogen requirement of fodder and sugar beet (Beta vulgaris L.) cultivars under high-yielding conditions of northwestern Europe

This study provides current data on plant nitrogen (N) uptake required for maximum sugar yield (PNUp_max) and the corresponding fertilizer N dose (ND) (optimum N dose [ND_opt]) for high-yielding beet crops (sugar yield up to 20 Mg ha^?1). In 2010 and 2011, field experiments were conducted with four cultivars from Beta genus differing in dry matter composition, and six mineral NDs (0–200 kg N ha^?1) at three sites (The Netherlands, Germany, Denmark). Differences between cultivars in PNUp_max and ND_opt were small; however, environments (defined as combination of site and year) substantially differed from each other: highest PNUp_max and lowest ND_opt occurred at environments supplying high amounts of N from soil resources, and vice versa. The level of maximum sugar yield (SY_max) was related neither to PNUp_max (200–270 kg N ha^?1) nor to ND_opt. However, N dose and plant N uptake required for 95% of maximum sugar yield was 50–80 kg N ha^?1 lower than for maximum sugar yield. To conclude, accepting a slight reduction in sugar yield might allow for a substantial decrease in the ND. Cultivar choice and yield level need not to be taken into account at present.     

Response of Chickpea Cultivars to Application of Boron in Boron‐Deficient Calcareous Soils

Abstract

This study was conducted to investigate the effects of four boron (B) doses (control, 0 kg B ha^?1; B₁, 1 kg B ha^?1; B₂, 3 kg B ha^?1; and B₃, 6 kg B ha^?1) in soils deficient in available B (0.19 mg B kg^?1) and lime (CaCO₃) content (20.7%) on yield and some yield components of five chickpea (Cicer arietinum L.) genotypes, namely Akçin‐91, Population, Gökçe, ?zmir‐92, and Menemen‐92 in central Anatolian Turkey in the 2002 and 2003 growing seasons. Plant height, pods per plant, grain yield, protein content, protein yield, thousand seed weight, and leaf B concentration were measured. Grain yields in all genotypes (except for Gökçe) were significantly increased by 1 kg ha^?1 B application. Application of 1 kg ha^?1 B increased the yield by an average of 5%. Genotypes studied showed significant variations with respect to their responses to additional B. Akçin‐91 gave the highest grain yield (1704.8 kg ha^?1) at 3 kg B ha^?1, whereas Population, ?zmir‐92, and Menemen‐92 yielded best (1468.2 kg ha^?1, 1483.0 kg ha^?1, and 1484.7 kg ha^?1, respectively) at 1 kg B ha^?1. Interestingly, Gökçe reached to the highest level of grain yield (1827.1 kg ha^?1) at the control. Gökçe was a B deficiency B tolerance genotype. The other genotypes appeared to have high sensitivity to B deficiency. This study showed that B deficiency could result in significant yield losses in chickpea under the experimental conditions tested. Thus, B contents of soils for the cultivation of chickpea should be analyzed in advance to avoid yield losses.     

Boron Nutrition Studies with Cotton and Sunflower in Southern Turkey

Wide variations in boron (B) contents are typical of Turkish soils and plants, and most of the variation, 84% of the plant-soil B values are within the “normal.” Boron application on low B soils can make a contribution to yield in cotton and sunflower crops. Field experiments were carried out on clayey and medium-textured soils, which are Chromoxererts, Haploxererts, Xerochrepts, and Xerofluvents in Southern Turkey to study the effects of boron fertilization on irrigated cotton and rainfed sunflower growth, yield, and yield components. Four levels of boron—0, 1, 2, and 3 kg ha^?1—were applied at planting and the experimental design was completely randomized block design with four replications. There was a 31% and 31.9% increase in seedcotton yield at 3 kg and 2 kg ha^?1 of B, compared to the control only two out of four sites. There was an average increase of 61.4% in boll weight with 2 kg B ha^?1 application compared to the control. Effect of different application rates of B was not significant for fiber length, fiber strength, and fiber length uniformity. All levels of boron produced higher head diameters over control only one out of four sites. Boron applied at the level of 3 kg ha^?1 produced the highest 1000 seed weight of 47.5 g representing an 18% increase over the control. Boron applied at the level of 1 kg ha^?1 produced the highest seed yield, representing a 25% increase over the control only at one out of four sites. Boron was no value as a fertilizer for sunflower under given experimental conditions even though some uptake of boron was occurred. Boron fertilization may be regarded as effective in improving cotton yields.     

Effect of Combined Use of Organic and Inorganic Sources of Nutrients on Sunflower Yield,Soil Fertility,and Overall Soil Quality in Rainfed Alfisol

Abstract

To study the response of inorganic and organic nitrogen (N) sources both alone and in conjunction and their influence on soil quality, a field experiment was conducted during kharif and rabi seasons using sunflower (MSFH‐8) as test crop. The experimental site soil was Typic Haplustalf situated at Hayatnagar Research Farm of Central Research Institute of Dryland Agriculture, Hyderabad, India, at 17° 18′ N latitude, 78° 36′ E longitude. The experiment design was a simple randomized block design with 11 treatments replicated four times. Among all the treatments, vermicompost (VC)+Fert at 25+25 kg N ha^?1 recorded the highest grain yields of 1878 and 2160 kg ha^?1 during both kharif and rabi seasons, respectively, which were 43.9 and 85.1% higher than their respective control plots. Apparent N recovery varied from as little as 38.30% (FYM at 50 kg N ha^?1) to 62.16 (25 kg N ha^?1) during kharif and 49.65 (75 kg ha^?1) to 83.28% (VC+Fert at 25+25 kg N ha^?1) during rabi season. Conjunctive nutrient treatments proved quite superior to other set of treatments in improving the uptake of N, phosphorus (P), potassium (K), sulfur (S), and micronutrients in sunflower and their buildup in the soil. Highest relative soil quality indexes (RSQI) were observed under VC+Fert at 25+25 kg N ha^?1 (1.00) followed by VC+Gly at 25+25 kg N ha^?1 (0.87). Considering the yield and relative soil quality indices (RSQI), conjunctive applications of VC with either inorganic fertilizer, FYM, or Gly at 25+25 kg N ha^?1 could be a successful and sustainable soil nutrient management practice in semi‐arid tropical Alfisols. Besides this, the fertilizer N demand could be reduced up to 50%.     

Response of red pepper to deficit irrigation and nitrogen fertigation

The main objective of this investigation was to evaluate the response of red pepper grown in a subhumid climate to different irrigation and nitrogen levels. Open-field trials were conducted in the Marmara Region, Turkey. Plants were subjected to three water levels [full irrigation (FI) = 100% crop evapotranspiration (ETc) and two deficit irrigations (DIs)= 66 and 33% ETc restoration] and four levels of N (0, 80, 160, and 240 kg N ha^?1) during the 2012, 2013, and 2014 growing seasons. A split-plot experimental design was used. The highest values of biomass and marketable yield (MY) were observed under FI. DI significantly increased the fruit soluble solids content. The biomass yield, MY, and fruit weight significantly improved with increasing nitrogen levels. The 240 kg N ha^?1 treatment under FI provided the maximum net income. Increasing N supply under DI conditions enhanced the water-use efficiency based on both biomass yield and MY. These results indicate that with respect to the yield, the net income, and the water productivity of red pepper, the FI with a nitrogen supply of 160–240 kg ha^?1 is recommended for drip irrigated and N-fertigated red pepper under subhumid climate conditions.     

Soil-Plant-Fertilizer Relationships in Turmeric Assessment of Soil-Plant-Fertilizer-Nutrient Relationships for Sustainable Productivity of Turmeric under Alfisols and Inceptisols in Southern India

Field experiments were conducted during 2005–2007 to test effects of nineteen treatments on turmeric rhizome yield in Alfisol at Utukur and Inceptisol at Jagtial in India. The treatments were comprised of nitrogen (N) at 0, 60, 120 and 180 kg ha^?1; phosphorus (P) at 0, 40, 80, and 120 kg ha^?1; and potassium (K) at 0, 50, 100, and 150 kg ha^?1. Application of 180-120-100 kg ha^?1 NPK gave maximum yield of 4302 kg ha^?1 in Alfisols, whereas application of 120-80-100 kg ha^?1 gave 4817 kg ha^?1 in Inceptisols. Regression and principal component (PC) models were calibrated through soil-plant-fertilizer variables. The regression model gave significant R² of 0.75 in Alfisols compared to 0.88 in Inceptisols, whereas the PC model explained variance of 66.5 percent in Alfisols and 76.3 percent in Inceptisols. Regression model through PC scores gave R² of 0.54 in Alfisols and 0.47 in Inceptisols. Maximum sustainability yield indexes of 58.8 and 55.5 percent by 180-120-120 kg ha^?1 (Alfisol) and 67.1 and 60.6 percent by 120-80-100 kg ha^?1 (Inceptisol) were attained based on regression and PC models respectively.     

Evaluation of Integrated Nutrient Management Interventions for Cotton (Gossypium hirsutum) on a Vertisol in Central India

Phospho-compost (PC) and poultry manure (PM) were evaluated in field experiments to diversify integrated nutrient management (INM) for rain-fed cotton. Seed cotton yield in the PC (2501–2579 kg ha^?1) was similar to the recommended INM (2673 kg ha^?1) treatment and was significantly better than nitrogen, phosphorus and potassium (100% NPK) (2130 kg ha^?1) and farmers practice (FP) (1886 kg ha^?1). Yield was lower in the PM (2476–2617 kg ha^?1) than in the PC. Nutrient uptake was higher in all INM intervention plots due to an improvement in soil nutrient status compared with those receiving 100% NPK. Soil labile carbon values were higher in the INM treatments (333–452 mg kg^?1), with a greater magnitude in the PC-amended plots (402–452 mg kg^?1). Carbon management index (CMI) values were higher for the INM than treatments NPK and FP. Among INM interventions, PC plots had higher values than the PM.     

Crop Utilization of Nitrogen in Swine Lagoon Sludge

Swine lagoon sludge is commonly applied to soil as a source of nitrogen (N) for crop production but the fate of applied N not recovered from the soil by the receiver crop has received little attention. The objectives of this study were to (1) assess the yield and N accumulation responses of corn (Zea mays L.) and wheat (Triticum aestivum) to different levels of N applied as swine lagoon sludge, (2) quantify recovery of residual N accumulation by the second and third crops after sludge application, and (3) evaluate the effect of different sludge N rates on nitrate (NO₃-N) concentrations in the soil. Sludge N trials were conducted with wheat on two swine farms and with corn on one swine farm in the coastal plain of North Carolina. Agronomic optimum N rates for wheat grown at two locations was 360 kg total sludge N ha^?1 and the optimum N rate for corn at one location was 327 kg total sludge N ha^?1. Residual N recovered by subsequent wheat and corn crops following the corn crop that received lagoon sludge was 3 and 12 kg N ha^?1, respectively, on a whole-plant basis and 2 and 10 kg N ha^?1, respectively, on a grain basis at the agronomic optimum N rate for corn (327 kg sludge N ha^?1). From the 327 kg ha^?1 of sludge N applied to corn, 249 kg N ha^?1 were not recovered after harvest of three crops for grain. Accumulation in recalcitrant soil organic N pools, ammonia (NH₃) volatilization during sludge application, return of N in stover/straw to the soil, and leaching of NO₃ from the root zone probably account for much of the nonutilized N. At the agronomic sludge N rate for corn (327 kg N ha^?1), downward movement of NO₃-N through the soil was similar to that for the 168 kg N ha^?1 urea ammonium nitrate (UAN) treatment. Thus, potential N pollution of groundwater by land application of lagoon sludge would not exceed that caused by UAN application.     

Assessment of Environment-friendly Usage of Spent Wash and its Nutritional Potential for Sugarcane Production

Excessive and inappropriate use of fertilizers is a key factor of low sugarcane yield and degradation of soil. A two-year (2013–14 and 2014–15) field study was conducted to assess the impact of combined application of organic and inorganic fertilizers on sugarcane at research farm of Shakarganj Sugar Research Institute, Jhang, Pakistan. Experiment was conducted under randomized complete block design with three replications. Treatments were used as control (no exogenous application), spent wash (160 t ha^?1), (nitrogen, phosphorus and potassium) NPK (168:112:112 kg ha^?1), spent wash (120 t ha^?1) + NPK (42:28:28 kg ha^?1), spent wash (80 t ha^?1) + NPK (84:56:56 kg ha^?1), spent wash (40 t ha^?1) + NPK (126:84:84 kg ha^?1), and spent wash (160 t ha^?1) + NPK (42:28:28 kg ha^?1). Application of spent wash @ 80 t ha^?1 + NPK @ 84:56:56 kg ha^?1 resulted maximum crop growth rate (11.35 g m^?2 d^?1), leaf area index (7.78), and net assimilation rate (2.53 g m^?2 d^?1). Maximum number of millable canes (14), weight per stripped cane (0.90 kg), stripped cane yield (117.60 t ha^?1) and unstripped cane yield (141.25 t ha^?1) were observed with spent wash @ 80 t ha^?1 + NPK @ 84:56:56 kg ha^?1, followed by sole fertilizer application @ 168:112:112 kg NPK ha^?1 and spent wash @160 t ha^?1 + NPK @ 42:28:28 kg ha^?1. Similar trend was observed regarding quality parameters. The maximum benefit–cost ratio (1.80) was achieved with integrated application of spent wash @ 80 t ha^?1 + NPK @ 84:56:56 kg ha^?1.     

Macro-Nutrient Concentration and Content of Irrigated Soybean Grown in the Early Production System of the Midsouth

Macro-nutrients in soybean (Glycine max L. Merr.) have not been extensively researched recently. Concentrations and contents of nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur (N, P, K, Ca, Mg, and S) were determined for three irrigated cultivars grown using the early soybean production system (ESPS) on two soils (a sandy loam and a clay) in the Mississippi Delta during 2011 and 2012. Data were collected at growth stages V3, R2, R4, R6, and R8. No change in macro-nutrients due to soil type or years occurred and modern cultivars were similar to data collected >50 years ago. Mean seed yield of 3328 kg ha^?1 removed 194.7 kg N ha^?1, 16.5 kg P ha^?1, 86.0 kg K ha^?1, 17.5 kg Ca ha^?1, 9.0 kg Mg ha^?1, and 10.4 kg S ha^?1. Increased yields over the decades are likely due to changed plant architecture and/or pests resistance, improved cultural practices, chemical weed control, and increased levels of atmospheric carbon dioxide (CO₂). Yield improvements by genetically manipulating nutrient uptake appear to be unlikely.     

Impact of mineral and organic fertilization on yield,C content in the soil,as well as on C,N and energy balances in a long-term field experiment

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.