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.     

Nitrogen application effects on forage sorghum production and nitrate concentration

Abstract

Forage sorghum (Sorghum bicolor (L.) Moench) is an important annual forage crop but prone to high nitrate concentration which can cause toxicity when fed to cattle (Bos taurus and Bos indicus). Two field experiments were conducted over six site-years across Kansas to determine the optimum nitrogen (N) rate for no-till forage sorghum dry matter (DM) yield and investigate the effect of N fertilization on sorghum forage nitrate content. A quadratic model described the relationship between sorghum DM and N rate across the combined site-years. Maximum DM yield of 6530?kg ha^?1 was produced with N application rate of 100?kg N ha^?1. The economic optimum N rate ranged from 55 to 70?kg N ha^?1 depending on sorghum hay price and N fertilizer costs. Crude protein concentration increased with N fertilizer application but N rates beyond 70?kg N ha^?1 resulted in forage nitrate concentrations greater than safe limit of 3000?mg kg^?1. Nitrogen uptake increased with N fertilizer application but nitrogen use efficiency and N recovery decreased with increasing N fertilizer rates. In conclusion, forage sorghum required 55–70?kg N ha^?1 to produce an economic optimum DM yields with safe nitrate concentration.     

Effects of Biozyme (Ascophyllum nodosum) Biostimulant on Growth and Development of Soybean [Glycine Max (L.) Merill]

Field experiment was conducted to investigate the effects of Biozyme^TM on soybean. Application of Biozyme granule and crop-plus spray with half of recommended nitrogen, phosphorus, and potassium (NPK) showed significant effects on all the growth and yield parameters of soybean. The greatest value for the number of trifoliate leaves (29.95 leaves plant^?1), leaf area (1818.21 cm2 plant^?1), leaf area index (5.946), total chlorophyll content (1.995 mg g^?1 leaf fresh mass), number of nodules (35.086 plants^?1), fresh and dry weight of nodules (0.664 and 0.1592 g plants^?1), dry weight of root (8.564 g plants^?1), pods plant^?1 (69.0), seeds pods^?1 (3.25), straw yield (3.122 t ha^?1), biological yield (6.349 t ha^?1), and grain yield (3.277 t ha^?1) was observed with Biozyme crop-plus spray at 500 mL ha^?1 plus half of recommended NPK and were significantly greater than control values. Biozyme crop-plus spray at 500 mL ha^?1 plus half of recommended NPK performed better compared to other treatments.     

Utilization of industrial waste aqueous ammonia for irrigated forage sorghum production

Sorghum is one of the water- and nutrient-use efficient crops raised in dry regions worldwide. A 3 × 3 split-plot experiment in randomized complete block design was conducted to study the effects of petroleum refinery waste aqueous ammonia (NH₃) on irrigated fodder sorghum for two consecutive growing seasons. The main plots consisted of 0 (control), 40, and 80 kg N ha^?1, respectively, and the injection depths (surface 15 cm, and 20 cm depth) were assigned to sub-plots. A significant effect of NH₃ on both fresh and dry biomass production was observed where the highest yield was recorded from the 80 kg N ha^?1 than the control and 40 kg N ha^?1, respectively. Sorghum biomass yield increased most when NH₃ was injected at 20 cm depth as compared to other depths. Biomass nutrient content and nitrogen-use efficiency were increased when 80 kg N ha^?1 was applied as compared to the control. The critical limit of K:(Ca+Mg), above which the tetany risk increases, did not exceed in sorghum biomass by NH₃ fertilization. Results suggested that industrial waste NH₃ equivalent to 80 kg N ha^?1 injected at 20 cm depth can be a sustainable approach to fertilize irrigated sorghum growing as a forage crop.     

Effect of 13 Years Long Minimum Tillage Cum Conjunctive Nutrient Management Practices on Soil Fertility and Nitrogen Chemical Fractions under Sorghum (Sorghum bicolour (L.) Moench)–Mungbean (Vigna radiata (L.) Wilczek) System in Semi-Arid Tropical Alfisol (SAT) in Southern India

A long-term experiment was conducted at the Central Research Institute for Dryland Agriculture for 13 years to evaluate the effect of low tillage cum cheaper conjunctive nutrient management practices in terms of productivity, soil fertility, and nitrogen chemical pools of soil under sorghum–mung bean system in Alfisol soils. The results of the study clearly revealed that sorghum and mung bean grain yield as influenced by low tillage and conjunctive nutrient management practices varied from 764 to 1792 and 603 to 1008 kg ha^?1 with an average yield of 1458 and 805 kg ha^?1 over a period of 13 years, respectively. Of the tillage practices, conventional tillage (CT) maintained 11.0% higher yields (1534 kg ha^?1) over the minimum tillage (MT) (1382 kg ha^?1) practice. Among the conjunctive nutrient management treatments, the application of 2 t Gliricidia loppings + 20 kg nitrogen (N) through urea to sorghum crop recorded significantly highest grain yield of 1712 kg ha^?1 followed by application of 4 t compost + 20 kg N through urea (1650 kg ha^?1) as well as 40 kg N through urea alone (1594 kg ha^?1). Similar to sorghum, in case of mung bean also, CT exhibited a significant influence on mung bean grain yields (888 kg ha^?1) which was 6.7% higher compared to MT (832 kg ha^?1). Among all the conjunctive nutrient management treatments, 2 t compost + 10 kg N through urea and 2 t compost + 1 t Gliricidia loppings performed significantly well and recorded similar mung bean grain yields of 960 kg ha^?1 followed by 1 t Gliricidia loppings + 10 kg N through urea (930 kg ha^?1). The soil nitrogen chemical fractions (SNCFs) were also found to be significantly influenced by tillage and conjunctive nutrient management treatments. Further, a significant correlation of SNCF with total soil nitrogen was observed. In the correlation study, it was also observed that N fraction dynamically played an important role in enhancing the availability pool of N in soil and significantly influenced the yield of sorghum grain and mung bean.     

Effect of Primary Biomethanated Spentwash on Soil Properties,Nutrient Uptake,and Yield of Wheat on Sodic Soil

The experiment on the effect of primary biomethanated spentwash (PBSW) on soil properties, nutrient uptake and yield of wheat on sodic soil was carried out at a research farm of Post Graduate Institute, Mahatma Phule Krishi Vidyapeeth, Rahuri, Maharashtra state, India, during the post-monsoon season. The experimental soil was sodic calcareous having Sawargaon series of isohyperthermic family of Vertic Haplustepts. The experiment was laid out in a randomized block design with nine treatments and three replications. The treatments consisted of varying doses of PBSW (100, 200, 300, 400 and 500 m³ ha^?1), absolute control, farmyard manure (FYM) 5 t ha^?1 + RDF-AST (recommended dose of fertilizer as per soil test), FYM 5 t ha^?1 + 50% GR (gypsum requirement) + RDF-AST and FYM 5 t ha^?1 + 100% GR + RDF-AST. The results revealed that the physical properties, namely bulk density and hydraulic conductivity, were improved in sodic soil due to the application of increased doses of PBSW. A significant reduction in pH, calcium carbonate and exchangeable sodium percentage (ESP) and an increase in organic carbon, cation-exchange capacity (CEC) and electrical conductivity (EC) were observed in the soil, due to the addition of PBSW. The available soil nitrogen (N), phosphorus (P), potassium (K) and micronutrient iron, manganese, copper and zinc (Fe, Mn, Cu and Zn) content after the harvest of wheat was the highest in the 500 m³ ha^?1 treatment compared with all the other treatments. The exchangeable calcium (Ca²⁺), magnesium (Mg²⁺) increased significantly and exchangeable Sodium (Na⁺) reduced significantly with increased doses of PBSW. The saturation paste extract analysis also showed the same trend. A significant increase in the EC of the saturation paste of extract of the soil was observed in all PBSW treatments and it was the highest (4.75 dS m^?1) in PBSW application @ 500 m³ ha^?1. The application of PBSW @ 500, 400, 300 and 200 m³ ha^?1 resembled the treatments of FYM + gypsum @ 100 GR + RDF-AST, FYM + gypsum @ 50 GR + RDF-AST and FYM + RDF-AST, respectively, regarding the biological properties of sodic soil. The PBSW application @ 500 m³ ha^?1 had recorded the highest grain (47.33 q ha^?1) and straw (72.72 q ha^?1) yield and the maximum total uptake of N, P, K, Fe, Mn, Cu, and Zn by wheat, which was at par with the treatment of FYM (5 t ha^?1) + gypsum @ 100% GR + RDF-AST.     

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.     

Modeling Effects of Soil Fertility of Nutrients and Precipitation of 22 Years on Sustainable Productivity and Profitability of Pearlmillet and Sorghum Rotation in Semi-arid Vertisols

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.     

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.     

<Emphasis Type="Italic">Lotus ornithopodioides</Emphasis> L. a potential annual pasture legume species for Mediterranean dryland farming systems

Twenty-three populations of Lotus ornithopodioides L., collected from different regions of the Mediterranean basin, were investigated for their ecological and agronomic traits in Western Australia. Great variability was found between and within populations for flowering time, forage and seed yield. Flowering time ranged between 75 and 120 days, dry matter production from 2.8 to 4.3 t ha^?1 and seed yield from 284 to 684 kg ha^?1. Other important traits such as non-shattering pods and hard seed were taken into account during the selection to assure an easy seed harvesting and legume persistence in the targeted environments. The high level of hard seed recorded in early winter, associated to the low seedling regeneration, indicates that L. ornithopodioides is best suited to ley cropping systems. Elite lines of L. ornithopodioides characterized by early flowering time, high seed yield and non-shattering pods were selected. Two of them, LOR02.1 and LOR03.2, showed dry matter higher than 4.0 t ha^?1 and seed yield around 700 kg ha^?1 resulting the lines with most potential for Mediterranean farming systems. The results encourage the exploitation of L. ornithopodioides germplasm to develop a new annual self-reseeding legume resource for Mediterranean farming systems for both forage production and crop rotation uses.     

Effect of biochar amendment on soil physical,chemical and biological properties and groundnut yield in rainfed Alfisol of semi-arid tropics

The aim of this study was to evaluate the effect of biochar and organic soil amendments on soil physicochemical and microbial load, carbon sequestration potential, nutrient uptake and yield of groundnut in acidic red soil under rainfed condition. Biochar was prepared from red gram, cotton, maize stalk and mesquite wood using pilot scale slow pyrolysis biochar unit. The above sources of biochar at the rate of 2.5 and 5 t ha^?1 and enriched farmyard manure 0.75 t ha^?1, composted coir pith 10 t ha^?1 and arbuscular mycorrhizae 100 kg ha^?1 were applied as basal with required nitrogen, phosphorous and potassium fertilizer. Biochar amendment at the rate of 5 t ha^?1 reduced the bulk density from 1.41 to 1.36 g cm^?3 and increased the soil moisture 2.5%. With respect to soil chemical changes, it raised soil pH from 5.7 to 6.3; increased the cation exchange capacity 1.4 cmol⁺ kg^?1 and enhanced the carbon buildup 4.4 t ha^?1. The significant differences in bacteria, fungi and actinomycetes population were observed between biochar and control. The nitrogen, phosphorous and potassium were better utilized under biochar and composted coir pith, which was 21, 5 and 20 kg ha^?1 higher than control. The experimental results suggested that application of biochar to acidic red soil favoured good soil physical, chemical and biological environment, and these positive changes influenced growth and yield attributes and enhanced pod yield 29% over control.     

Zeolite influences on nitrate leaching,nitrogen-use efficiency,yield and yield components of canola in sandy soil

With regard to the low cation-exchange capacity and large saturated hydraulic conductivity of sandy soils, a field experiment was carried out in 2006–2007 to determine the impact of zeolite on nitrogen leaching and canola production. Four nitrogen (N) rates (0, 90, 180, and 270 kg ha^–1) and three zeolite amounts (3, 6 and 9 t ha^?1) were included as treatments. The results demonstrated that the highest growth parameters and seed yield were attained with 270 kg N ha^?1 and 9 t zeolite ha^?1. However, the highest and the lowest seed protein percentage and oil content were obtained with 270 kg N ha^?1 accompanied by 9 t zeolite ha^?1, respectively. Nitrate concentration in drained water was affected by nitrogen and zeolite. The lowest and highest leached nitrate values were found in control without N and zeolite (N₀Z₀) and in treatments with the highest N supply without zeolite (N₂₇₀Z₀), respectively. In general, nitrogen-use efficiency decreased with an increase in N supply. Application of 9 t zeolite ha^?1 showed higher nitrogen use efficiency than other zeolite amounts. Also, application of more N fertilizer in soil reduced nitrogen uptake efficiency. In total, application of 270 kg N ha^?1 and 9 t zeolite ha^?1 could be suggested as superior treatment.     

Crop production impacts on soil phosphorus removal and soil test levels

An 8-year field study documented the impact of tillage, crop rotations, and crop residue management on agronomic and soil parameters at Brookings, South Dakota. The greatest annual proportion of above-ground biomass phosphorus (P) removed was from the grain (78–87% of total) although crop residue removed some P as well. Greater above-ground total biomass P (grain P + crop residue P) was removed from corn than from soybean and spring wheat crops mainly due to the greater corn grain biomass harvested. Cumulative above-ground biomass P removal was greatest for the corn-soybean rotation (214 kg P ha^?1), while it was lowest for the soybean-wheat rotation (157 kg P ha^?1). Tillage treatments within crop rotation or residue management treatments did not influence annual or cumulative P removal rates. Olsen extractable soil orthophosphate-P levels declined consistently through time from a mean of 40 µg g^?1 (2004) to 26 µg g^?1 (2011). Biomass P removal was calculated to be 15.7 ha^?1 yr^?1 to decrease Olsen extractable soil orthophosphate-P levels by 1 µg g^?1 yr^?1 over 8 years of the study.     

Soil management for raising crop water productivity in rainfed production systems in Lao PDR

This study investigated the impacts of organic- and clay-based soil amendments, and their combinations on crop water productivity (CWP) using maize as a test crop. On-station field trials were established over two consecutive years at the Naphok and Veunkham sites in Laos. At each site, 10 treatments were applied in a randomized complete block design with three replications. The treatments were control, rice husk biochar (10 t ha^?1), bentonite clay (10 t ha^?1), compost (4 t ha^?1), clay-manure compost (10 t ha^?1), rice husk biochar compost (10 t ha^?1), bentonite clay + biochar, bentonite-clay + compost, biochar + compost, and bentonite clay + biochar + compost. All treatments were applied in 2011. Significant (p < 0.05) treatment effects in CWP and growing period evapotranspiration were determined. At Naphok, differences between the amended and control plots in CWP varied between 0.1 and 0.6 kg m^?3 in 2011 and from 0.1 to 0.4 kg m^?3 in 2012, whereas differences at Veunkham varied between 0.3 and 1.0 kg m^?3 in 2011 and from 0.05 to 0.29 kg m^?3 in 2012. At both sites, CWP in 2012 was significantly lower than 2011. Our results illustrate that organic- and clay-based soil amendments improve CWP, indicating that soil-based interventions could be suitable options for improving agricultural productivity.     

Evaluation of growth indices and quantitative traits of safflower under organic farming and conventional agriculture

Application of organic fertilizers in sustainable agriculture systems improves yield sustainability of field crop production. The current research has been formed to investigate the effects of various levels of vermicompost (zero, 3, 6 and 9 t ha^?1) in combination with foliar spraying of potassium humate (0, 1, 2 and 3 mL L^?1) on spring safflower, in Iran during 2012–2013. In addition, inorganic fertilization has been considered as conventional agriculture (CA). In the current experiment, growth indices, seed yield, yield components and flower yield were evaluated. The results showed that the maximum leaf area index, total dry weight and crop growth rate have been determined at 9 t ha^?1 vermicompost and 3 mL L^?1 K-humate while the maximum netto assimilation rate has existed in CA at the emergence of flower buds. Likewise, the results indicated that vermicompost leads to a significant increase in seed yield, flower yield and yield components except 1000 seed weight. Flower yield, head number per plant and seed number per head were affected by K-humate concentrations and increased significantly from 1 to 3 mL L^?1. It should be mentioned that 9 t ha^?1 vermicompost and 3 mL L^?1 K-humate produced the highest seed and flower yield.     

Influence of Organic Residue Recycling on Crop Yield,Nutrient Uptake,and Microbial and Nutrient Status of rabi Sorghum (Sorghum bicolor L.) under Dryland Condition

The field experiment was conducted on black soil (Vertic Ustropept) at Zonal Agricultural Research Station farm, Solapur, for successive 30 years from 1987–1988 to 2016–2017 under dryland condition in a randomized block design with 10 treatments and 3 replications. The pooled results of seven years (2010–2011 to 2016–2017) revealed that the application of 25 kg N ha^?1 through crop residue (CR, byre waste) along with 25 kg N ha^-1 through Leucaena lopping (Leucaena leucocephala) to rabi sorghum gave significantly higher grain and stover yield and Sustainable Yield Index (14.61 and 36.11 q ha^?1 and 0.47, respectively) which was on par with T₇, where 25 kg N ha^?1 through farmyard manure (FYM) + 25 kg N ha^?1 through urea was applied for grain and stover yield (13.95 and 34.46 q ha^?1 and 0.44, respectively). The gross and net monetary returns and benefit–cost ratio were also influenced significantly due to integrated nitrogen management (Rs. 59,796, Rs. 47,353 ha^?1, and 3.13, respectively). This was also reflected in residual soil fertility status of soil after harvest of rabi sorghum. The organic carbon content and available nitrogen content of soil, as well as nitrogen uptake and moisture use efficiency for grain, were also increased. The total microbial count of bacteria, fungi, and actinomycetes was more where FYM or CR addition was done. The count of N fixers and P solubilizers was more under Leucaena application either alone or with CR or urea. Application of CR at 4.8 t ha^?1 (25 kg N ha^?1) along with Leucaena lopping at 3.5 t ha^?1 (25 kg N ha^?1) as green leaf manure is the best alternative organic source for fertilizer urea (50 kg N ha^?1) to increase the production of dryland rabi sorghum.     

Effect of Oil Palm Fly Ash on Soil Properties and Yield of Sweet Corn in the Tropical Zone of Thailand

Disposal of oil palm fly ash (OPFA) into the environment causes environmental pollution. A field experiment was conducted to evaluate the effects of OPFA and mineral fertilizer on soil properties and yield of sweet corn. A total of six treatments were applied that included 2, 4, and 6 t ha^–1 OPFA, 200 kg ha^–1 nitrogen, phosphorus, and potassium (NPK), 100 kg ha^–1 NPK + 2 t ha^–1 OPFA as well as the control. A significant increase in soil pH and available P was observed with the sole OPFA treatments at 2, 4, and 6 t ha^–1, while a significant increase in exchangeable cations [K, magnesium (Mg)] was detected only at the 6-t ha^–1 OPFA treatment. The highest grain yield of 4220 kg ha^–1 was obtained at the 100-kg ha^–1 NPK + 2 t ha^–1 OPFA-treated plots, which was statistically similar with the grain yield of 3800 kg ha^–1 received at the 200-kg ha^–1 NPK-treated plots. The practical implication of this study is that OPFA can be used as a liming material to increase soil pH and it has a synergetic effect in combination with inorganic fertilizer.     

Potassium fertilization and soil diagnostic criteria for forage corn (Zea mays L.) production contributing to lower potassium input in regional fertilizer recommendation

Abstract

Effective soil diagnostic criteria for exchangeable potassium (Ex-K) combined with inorganic potassium (K) application rates were developed to lower K input in forage corn (Zea mays L.) production using experimental fields with different application rates and histories of cattle manure compost. Two corn varieties, ‘Cecilia’ as a low K uptake variety and ‘Yumechikara’ as a high K uptake variety, were selected from among 20 varieties and tested to make diagnostic criteria for K fertilization applicable to varieties with different K uptakes. The K uptakes increased from 96 to 303 kg K ha^?1 for ‘Cecilia’ and from 123 to 411 kg K ha^?1 for ‘Yumechikara’ with increasing Ex-K content on a dry soil basis from 0.11 to 0.92 g kg^?1 with no inorganic K fertilizer application. The K uptake by corn for achieving the target dry matter yield of 18 Mg ha^?1 was estimated to be approximately 200 kg K ha^?1 in common between the two varieties. Yields of both varieties achieved the target yield at an Ex-K content of approximately 0.30 g kg^?1 with no K fertilization, although ‘Yumechikara’ reached the target yield at a lower Ex-K content. At the low Ex-K content of 0.1 g kg^?1, inorganic K fertilizer application at 83 kg K ha^?1 was needed to gain the target yield, and apparent K recovery rate for K fertilizer was calculated to be 70% for both varieties. The K uptakes for gaining the target yield by the K fertilization were lower than that by soil K supply. Based on these results, diagnostic criteria of Ex-K and inorganic K application rates were set up as follows: at an Ex-K content of < 0.15 g kg^?1, inorganic K fertilizer is applied at 83 kg K ha^?1 (100 kg ha^?1 as potassium oxide (K₂O) equivalent); at an Ex-K content of 0.15–0.30 g kg^?1, the application rate is reduced to 33 kg K ha^?1 (40 kg K₂O ha^?1); at an Ex-K content of ≥ 0.30 g kg^?1, inorganic K fertilizer is not applied because of sufficient K in the soil. Additionally, we propose that cattle manure compost be used to supplement soil K fertility.     

Effect of nitrogen fertilizer rate and timing on sorghum productivity in Ethiopian highland Vertisols

Sorghum is cultivated on Vertisols in the Ethiopian Highlands. An experiment was conducted in the Gumara-Maksegnit watershed in 2013 and 2014 to assess the effect of rate and timing of nitrogen fertilizer application on the possibility to shorten the maturity period and to improve the productivity of sorghum. The experiment was laid out as Randomized Complete Block Design with three replications. Treatments were nitrogen doses between 0 and 87 kg N ha^?1 as urea applied at planting, at knee-height stage or in split doses at both stages. Results showed that application of 23, 41, 64 and 87 kg ha^?1 N gave a yield increase of 40, 53, 62 and 69% over the control (0 kg N ha^?1), respectively. In addition, split application of 41 kg ha^?1, 64 kg ha^?1 and 87 kg ha^?1 of nitrogen fertilizer, half at planting and half at knee height stage, gave 19%, 15% and 18% increase in sorghum grain yield over a single dose application, respectively. Applying 87 kg ha^?1 nitrogen fertilizer with split application half at planting and half at knee height stage, along with 46 kg ha^?1 of P₂O_5, gave the highest grain yield and income.     

Effect of Graded Levels of Surface Crop Residue Application Under Minimum Tillage on Carbon Pools and Carbon Lability Index in Sorghum (Sorghum bicolor (L.) Moench)-Cowpea (Vigna unguiculata) System in Rainfed Alfisols

A long term experiment (2005–2012) was conducted in rainfed semi-arid tropical Alfisol at Hayathnagar Research Farm of Central Research Institute for Dryland Agriculture, Hyderabad, India. The aim of this experiment was to study the long-term impacts of graded levels of surface crop residue application on carbon (C) pools, aggregate associated C, C lability index and their relationship with crop yield. The experiment was conducted in a randomized block design (RBD) with minimum tillage (MT). Experimental treatments comprised of four levels of surface application of sorghum crop residues (@ 0, 2, 4 and 6 t ha^?1). The test crops, sorghum and cowpea, were grown in rotation yearly. Based on the pooled analysis of long term data (2005–2012), the study revealed that the surface application of sorghum residue @ 6 t ha^?1 and 4 t ha^?1 recorded 21% and 16% higher sorghum grain yields, respectively over control (no residue) whereas, the corresponding increase in the cowpea yield was 50% and 60%, respectively. Besides, the concentrations of soil organic carbon (SOC), inorganic carbon (IC), total carbon (TC), particulate organic carbon (POC) in the top surface soil (upper layer, 0–5cm depth) were found significantly higher than the sub-surface soil (lower layers, 5–15 cm depth) in all the treatments. Storage of soil C was assessed in soil aggregates fractions, and it was found that the smaller size aggregate fractions (0.053mm) contained significantly (p = 0.05) higher content of SOC compared to the large sized fractions (2 mm). The amount of very labile fraction of C extracted with 12 N H₂SO₄ was significantly higher (1.04 g kg^?1) with the application of sorghum stover @ 6t ha-¹ compared to other residue level treatments, in the 0-5 cm soil layer. The Lability Index (LI) increased with the increase in the amount of residues applied and was significantly higher in the surface soils compared to subsurface soil. The results of this study will be highly relevant and of significant value from the view point of managing SOC and its different pools in soil under abiotically stressed semiarid tropical Alfisols soils.