Nitrogen topdressing at the jointing stage affects the nutrient accumulation and translocation in rainfed waxy maize

Timely and fitting nitrogen (N) application decreases costs and pollution risk in maize cultivation. To explore the accumulation and remobilization of dry matter (DM), N, phosphorus (P), and potassium (K) in waxy maize under various N topdressings (0?kg ha^?1, LN; 150?kg ha^?1, MN; 300?kg ha^?1, HN) at the jointing stage, a field trial involving two waxy maize varieties (Suyunuo 5 and Yunuo 7) was conducted in 2013–2016. The highest grain yield was obtained under MN mainly due to the highest grain numbers and grain weight. The increase in grain yield under MN was mainly due to the high DM accumulation post-silking, as well as high N, P, and K accumulation and remobilization pre-silking. Generally, the plants had high harvest index (HI) of DM (N, P, and K), partial N fertilizer productivity, and moderate N utilization efficiency (NUE) under MN.     

Synergetic use of biochar and synthetic nitrogen and phosphorus fertilizers to improves maize productivity and nutrient retention in loamy soil

Abstract

This study was designed to investigate the effect of biochar on maize production and nutrient retention with recommended full and half dose of nitrogen (N) and phosphorus (P) nutrition in loamy soil. In the first study, maize was grown in pots with four levels of biochar (0, 2, 4, and 6?t?ha^?1) under two levels of NP fertilizer, viz. recommended (200–150?kg?NP?ha^?1) and it’s half (100–75?kg?NP?ha^?1) dose. The prominent improvement in plant roots traits, leaf area, plant growth, morphological and yield-related parameters were observed with addition of biochar at 2 and 4?t?ha^?1; while, plant height, number of grains per cob, grains and biological yield decreased with biochar addition 6?t?ha^?1 along with full dose of NP nutrition. In subsequent field studies, two levels of biochar along with control (0, 2, 4?t?ha^?1) were investigated. The more improvement in root growth, leaf area and crop growth was observed when biochar was applied at 2?t?ha^?1 with full NP nutrition. Biochar application at 2?t?ha^?1 with full NP nutrition produced the highest grain yield (6.64?t?ha^?1); however, biochar addition (2?t?ha^?1) with half NP nutrition resulted in better grain yield than full dose of NP to enhance maize production as compared with full dose of NP without biochar. Therefore, biochar addition (2?t?ha^?1) with half-recommended dose of NP prominently improved the maize productivity in loamy soil and serve as better in replacement of full dose of NP fertilizer.     

Foliar K application to rainfed wheat in a soil testing high K as an option to improve K use efficiency,grain yield and yield components

Abstract

Granular application of potassium (K) in soils testing high is generally not recommended. However, the effect of foliar K on rainfed wheat (Triticum aestivum L.) under these soil conditions is largely unknown. The objective of this work was to identify the effect of K fertilizer on K use efficiency (KUE), grain yield and yield components of wheat. The data were collected until 2017 in an ongoing trial established in 2007 with eight treatments; two granular K rates (0 and 50?kg K ha^?1); two foliar N rates (0 and 3?kg N ha^?1); and two foliar K rates (0 and 3?kg K ha^?1) in a split-split plot arrangement. Treatments were applied to the same plots each season. Treatment with foliar K resulted in the highest KUE response but the effect size varied according to the accumulated precipitation during the reproductive stage. On average, KUE was enhanced in crop seasons with water constrains (<179?mm) during the growth period but the converse was true as the amount of precipitation increased. In contrast, granular K had no effect on KUE irrespective of precipitation conditions. Application of foliar K increased grain yield as compared to granular K from 2988 to 3089?kg ha^?1. This enhancement was attributed to an increased number of grains per head. Therefore, foliar K application to wheat is suitable in a soil testing high K to enhance KUE and grain yield, overall in crop seasons with water constrains.     

Influence of Soil and Fertilizer Nutrients on Sustainability of Rainfed Finger Millet Yield and Soil Fertility in Semi-arid Alfisols

Productivity of rainfed finger millet in semiarid tropical Alfisols is predominantly constrained by erratic rainfall, limited soil moisture, low soil fertility, and less fertilizer use by the poor farmers. In order to identify the efficient nutrient use treatment for ensuring higher yield, higher sustainability, and improved soil fertility, long term field experiments were conducted during 1984 to 2008 in a permanent site under rainfed semi-arid tropical Alfisol at Bangalore in Southern India. The experiment had two blocks—Farm Yard Manure (FYM) and Maize Residue (MR) with 5 fertilizer treatments, namely: control, FYM at 10 t ha^?1, FYM at 10 t ha^?1 + 50% NPK [nitrogen (N), phosphorus (P), potassium (K)], FYM at 10 t ha^?1 + 100% NPK (50 kg N + 50 kg P + 25 kg K ha^?1) and 100% NPK in FYM block; and control, MR at 5 t ha^?1, MR at 5 t ha^?1 + 50% NPK, MR at 5 t ha^?1 + 100% NPK and 100% NPK in MR block. The treatments differed significantly from each other at p < 0.01 level of probability in influencing finger millet grain yield, soil N, P, and K in different years. Application of FYM at 10 t ha^?1 + 100% NPK gave a significantly higher yield ranging from 1821 to 4552 kg ha^?1 with a mean of 3167 kg ha^?1 and variation of 22.7%, while application of maize residue at 5 t ha^?1 + 100% NPK gave a yield of 593 to 4591 kg ha^?1 with a mean of 2518 kg ha^?1 and variation of 39.3% over years. In FYM block, FYM at 10 t ha^?1 + 100% NPK gave a significantly higher organic carbon (0.45%), available N (204 kg ha^?1), available P (68.6 kg ha^?1), and available K (107 kg ha^?1) over years. In maize residue block, application of MR at 5 t ha^?1 + 100% NPK gave a significantly higher organic carbon (0.39%), available soil N (190 kg ha^?1), available soil P (47.5 kg ha^?1), and available soil K (86 kg ha^?1). The regression model (1) of yield as a function of seasonal rainfall, organic carbon, and soil P and K nutrients gave a predictability in the range of 0.19 under FYM at 10 t ha^?1 to 0.51 under 100% NPK in FYM block compared to 0.30 under 100% NPK to 0.67 under MR at 5 t ha^?1 application in MR block. The regression model (2) of yield as a function of seasonal rainfall, soil N, P, and K nutrients gave a predictability in the range of 0.11 under FYM at 10 t ha^?1 to 0.52 under 100% NPK in FYM block compared to 0.18 under MR at 5 t ha^?1 + 50% NPK to 0.60 under MR at 5 t ha^?1 application in MR block. An assessment of yield sustainability under different crop seasonal rainfall situations indicated that FYM at 10 t ha^?1 + 100% NPK was efficient in FYM block with a maximum Sustainability Yield Index (SYI) of 41.4% in <500 mm, 64.7% in 500–750 mm, 60.2% in 750–1000 mm and 60.4% in 1000–1250 mm rainfall, while MR at 5 t ha^?1 + 100% NPK was efficient with SYI of 29.6% in <500 mm, 50.2% in 500–750 mm, 40.6% in 750–1000 mm, and 39.7% in 1000–1250 mm rainfall in semi-arid Alfisols. Thus, the results obtained from these long term studies incurring huge expenditure provide very good conjunctive nutrient use options with good conformity for different rainfall situations of rainfed semiarid tropical Alfisol soils for ensuring higher finger millet yield, maintaining higher SYI, and maintaining improved soil fertility.     

Nitrogen fertilizer applications to maize after alfalfa: grain yield,kernel composition,and plant mineral nutrients

Nitrogen (N) is often applied to first year maize (Zea mays L.) after alfalfa (Medicago sativa L.) at rates greater than needed to attain maximum yields. This study explored other potential benefits of excess N fertilizer applications to maize after alfalfa. Effects of N fertilizer (no N fertilizer, 73, or 135 kg N ha^?1) to maize after alfalfa on stalk dry weight, stalk mineral concentrations [N, phosphorus (P), and potassium (K)], grain yield, and kernel components (protein, oil, starch, P, and K) were investigated. Fertilizer N increased stalk N concentration but not stalk dry weight. Grain yields and yields of protein, oil, starch, P, and K kernel components, expressed on a kg ha^?1 basis, were also unaffected by N fertilizer treatments. Thus, there appears to be no advantage, in terms of yield or kernel components, in applying N fertilizer to maize after alfalfa under the environments experienced during this two year field experiment.     

Maize grain production,plant nutrient concentration and soil chemical properties in response to different residue levels from two previous crops

ABSTRACT

The incorporation of previous crop residues in agricultural management benefits soil fertility, crop production, and environment. However, there is no enough information about maximum residue application level without negative effect over next crop yield. To evaluate maize (Zea mays L.) yield under short-time conservation management with incorporation and/or importation of different residue levels, a biannual rotation experiment was conducted in ash volcanic soil in south-central Chile. The experiment consisted of two previous crops, canola (Brassica napus L.) and bean (Phaseolus vulgaris L.), and four levels of residue incorporation (0%, 50%, 100%, and 200% of generated residue; from 0 to 21.4?Mg?ha^?1 for canola and from 0 to 19.0?Mg?ha^?1 for bean). Previous crop species and residue level affected some nutrients concentrations in grain and plant and some soil chemical properties, without effect in maize yield, which averaged 16.6?Mg?ha^?1. Bean residue increased Ca and reduced S in maize plant, increasing soil P, Ca, Mg and K (P?<?0.05). Maize grain Ca content was positively and proportionally affected by canola residue level and negatively and proportionally affected by bean residue level. All canola residue levels increased soil pH and Mg, but the highest level reduced soil S; soil P concentration increased proportionally with bean residue level. The highest bean residue level increased soil S. Different crop and levels of residue did not affect maize yield but did some plant nutrient concentration, and also affected some soil chemical properties.     

Dry matter and nitrogen accumulation and remobilization in wheat as affected by genotype and irrigation

To investigate the genotypic differences of dry matter (DM) and nitrogen (N) accumulation and remobilization as well as the photosynthetic characteristics of flag leaf during grain filling under water-limited conditions, nine winter wheat cultivars were planted under two irrigation treatments including W0 (no irrigation applied during spring) and W2 (1500 m³ ha^?1 applied 50% at stem elongation and 50% at anthesis). Results showed that cultivar and irrigation significantly affected the accumulation and remobilization of DM and N as well as the photosynthetic characteristics of flag leaf. No irrigation in spring on average decreased the photosynthetic rate of flag leaf, accelerated leaf senescence, and consequently decreased the accumulation of DM and N, but increased the ear distribution ratio and the remobilization and contribution of DM and N in leaf and stem to grain. Maintaining high photosynthetic activity and promoting DM and N distribution in ear and the remobilization of DM and N in leaf and stem may lead to higher grain filling rate and lower yield loss under water-limited conditions in North China Plain.     

Effect of exogenous proline application on maize yield and the optimum rate of mineral nitrogen under salinity stress

Abstract

Salinity is a negative abiotic stress that produces drastic disorders on soils and plants causing a critical reduction in plant growth and yield parameters, particularly maize plant, which considers a moderately sensitive plant to soil and water salinity. Although proline and nitrogen are well known to protect plants and improve their tolerance against various abiotic stresses including salinity, the interaction between proline and nitrogen fertilizer under saline conditions remained unclear. Two field experiments were conducted, on a clay saline soil in a split-plot design with four replicates. The main plots were arranged to study the effect of exogenous of proline applications at 0, 50 and 100?mM during seedling and vegetative stages, and mineral of nitrogen fertilization rates were 0, 140, 280, and 420?kg N ha^?1 occupied the subplots. A significant response to fertilizer N was observed at 420?kg ha^?1, while the optimum N rate of 50?mM of proline was 410.3?kg ha^?1 and the economic optimum dose was 403.43?kg ha^?1. Therefore, we recommend using 403.43?kg N ha^?1 to get an optimum economic yield of maize, especially in saline soil, when used 50?mM exogenous of proline at seedling and vegetative stages.     

EFFECT OF NITROGEN APPLICATION ON ACCUMULATION AND TRANSLOCATION OF CARBON AND NITROGEN COMPOUNDS IN TWO MAIZE CULTIVARS WITH DIFFERENT SENESCENT APPEARANCE

Field experiments and plant analyses were carried out to investigate the effect of nitrogen (N) application on accumulation and translocation of carbon (C) and N compounds in two maize (Zea mays L.) cultivars with different senescent appearance. Two maize hybrids included “Danyu 13”, an earlier senescent hybrid, and “Simi 21”, a stay-green hybrid. There were four nitrogen treatments: (1) N1: 0 kg N ha^?1, (2) N2: 250 kg N ha^?1 (1/5 N as basal application and 4/5 N as top-dressing at stalk elongation stage only), (3) N3: 250 kg N ha^?1 (1/5 N as basal, 2/5 N as top-dressing at stalk elongation stage and tasselling stage, respectively), (4) N4: 400 kg N ha^?1 (1/5 N as basal and 4/5 N as top-dressing at stalk elongation stage). For Simi 21, a higher percentage of sugar and starch were found in each treatment in root, stem, leaf and grain, in comparison with that for Danyu 13. The highest percentage of sugar and starch, 80% ethanol-soluble N and soluble protein N in each organ could be achieved in N3 treatment for Simi 21 and in N2 treatment for Danyu 13, respectively, which consequently benefited to translocation of C and N from vegetative parts to grain. Excessive N could not produce the highest percentage of sugar and starch, 80% ethanol-soluble N and soluble protein N, but the highest percentage of residue C and N components in each organ for both hybrids.     

Phosphorus,potassium, chloride,and fungicide effects on wheat yield and leaf rust severity

Abstract

Plant nutrition and disease suppression are among the most important management tools for producers of hard red winter wheat (Triticum aestivum L.) in the central and southern Great Plains. This study was conducted to examine the effects of phosphorus (P) (0, 15, and 30 kg ha^?1) and potassium (K) (0, 37, and 74 kg ha^?1) fertilization, foliar fungicide application, and cultivar disease tolerance on wheat yield, yield components, and severity of leaf rust (Puccinia triticina Eriks.). Compared with no P, fertilizing with P increased yield by as much as 60% (>1.3 Mg ha^?1 increase). Yield of cultivars susceptible to leaf rust was nearly 0.6 Mg ha^?1 less without K than with K fertilization. Fungicide application resulted in mean yields of 4.8 Mg ha^?1 for both resistant and susceptible cultivars, however, yield of susceptible cultivars was suppressed more than yield of resistant ones without fungicide. Although P fertilization had a moderately suppressive effect on leaf rust, the increased yield was primarily due to production of about 50% more heads m^?2 apparently from more prolific tillering. Similarly, K fertilization appeared to reduce leaf rust severity and improve yield by increasing kernel weight, but this response may have been related partially to chloride (Cl) in the KCl fertilizer. Correlations suggested that improving dry matter production and N, P, and K uptakes at the boot stage by P and K fertilization can reduce leaf rust severity later in the growing season and increase wheat grain yield. These results indicate that especially P fertilization, but also K fertilization and fungicide application, are important management tools for reducing disease and increasing winter wheat yield.     

Integrated Fertilizer Management: Influence on Soil Nitrogen,Available Phosphorus,Potassium, Nutrient Uptake and Maize Yield

A field experiment was conducted on an Alfisol (kandic paleustalf) in Abeokuta, Southwestern Nigeria, for two seasons to assess the influence of inorganic and organic fertilizers on nitrogen (N), phosphorus (P), potassium (K), nutrient uptake and maize yield. The treatments consisted of three rates of organic fertilizer 0, 5 and 10 t ha^?1 in the form of poultry manure and NPK fertilizer (20:10:10) applied at 0 and 120 kg ha^?1. Maize (Zea mays) was used as the test crop. The results showed that the combined application of 10 t ha^?1 poultry manure and 120 kg ha^?1 NPK fertilizer enhanced the uptake of N, P and K better than other treatment combinations. Application of 10 t ha^?1 poultry manure alone gave the highest grain yield, which was 67.02% higher than the control in the first season. Complementary application of 5 t ha^?1 poultry manure with 120 kg ha^?1 NPK 20–10-10 was recommended for grain yield.     

Continuous Cropping,Fertilization, and Organic Manure Application Effects on Potassium in an Alfisol under Arid Conditions

Effects of continuous cropping and addition of organic manures (farmyard manure, FYM, and groundnut shells, GNS) along with inorganic fertilizers on nonexchangeable potassium (K) release kinetics in a K-deficient Alfisol were studied in a 20-year manurial experiment under arid conditions. There was a depletion in available K under continuous cropping without K input (control) as compared to other treatments such as 100% nitrogen–phosphorus–potassium (NPK), 50% NPK + 4 metric tons (MT) groundnut shells ha^?1, 50% NPK + 4 MT FYM ha^?1, and 100% organic (i.e., 5 MT FYM ha^?1). Over 20 years of cropping without K input, available K was reduced from 155 kg ha^?1 (in 1985) to 82 kg ha^?1 (in 2005), showing a negative balance of 73 kg ha^?1. Soil in control plots showed available K in the deficient range (<50 mg kg^?1), whereas four other fertilizer and manurial treatments were greater than the critical limit. Considerable improvements in nonexchangeable K-release parameters such as step K and cumulative K release were observed in manured plots over control. Parabolic diffusion and first-order kinetic equations explained K release from soils. Potassium-release rates were drastically reduced in control plots, and there were increased release rates with continuous addition of manures. Results suggest that soils with groundnut shells or FYM (4 MT ha^?1) along with 50% inorganic fertilizer additions could maintain greater K release rates after 20 years of cropping as compared to cropping without K input.     

System productivity,nutrient use efficiency and apparent nutrient balance in rice-based cropping systems

A 2-year field experiment was conducted to assess system productivity, nutrient use efficiency and apparent balances of phosphorus (P) and potassium (K) in diversified rice-based cropping systems at Gazipur, Bangladesh. Four cropping systems: wheat–fallow–rice, maize–fallow–rice, potato–fallow–rice and mustard–fallow–rice in main plots and four nutrient combinations: NPK, NK, NP and PK in sub-plots were arranged in a split-plot design with three replications. Receiving the NPK treatment, all the component crops gave the highest yield, and omission of N from fertilizer package gave the lowest yield. The maize–rice system removed the highest amount of N (217 kg ha^?1), P (41 kg ha^?1) and K (227 kg ha^?1) followed by wheat–rice, potato–rice and the least in mustard–rice system. The wheat–rice and maize–rice system showed negative K balance of –35.5 and –60.4 kg ha^?1 in NPK treatment, while potato–rice system showed a positive K balance of 31.0 kg ha^–1 with NPK treatment. The N, P and K uptake and apparent recovery by the test crops may be used for site-specific nutrient management. The K rates for fertilizer recommendation in wheat and maize in Indo-Gangetic plain need to be revised to take account for the negative K balance in soil.     

Suitability of Lime,Green Leaf,and Farm Yard Manure and Inorganic Fertilizers for Sustaining Green Gram Yield and Rainwater Use Efficiency Under Moist Sub-Humid Alfisols in India

Field experiments were conducted to assess the effect of nutrients management practices on yield and rainwater use efficiency of green gram (Vigna radiata), and soil fertility under moist sub-humid Alfisols at Phulbani, India, during 2005–2008. Ten treatment combinations of lime @ 10% and 20% of lime requirement (LR) @ 8.3 t ha^?1, farmyard manure (FYM) @ 5 t ha^?1, green leaf manure @ 5 t ha^?1, and nitrogen, phosphorus, and potassium (N–P–K) (20–40–20 kg ha^?1) were tested. The analysis of variance indicated that treatments differed significantly from each other in influencing yield and rainwater use efficiency. Application of lime @ 20% LR + FYM @ 5 t/ha + 40 kg P + 20 kg K ha^?1 was superior with maximum mean yield of 531 kg ha^?1, while lime @ 10% LR + FYM @ 5 t ha^?1 + 40 kg P + 20 kg K ha^?1 was the second best with 405 kg ha^?1 and maintained maximum soil fertility of nutrients. The superior treatment gave maximum sustainability yield index of 67.5%, rainwater use efficiency of 0.49 kg ha^?1 mm^?1, improved soil pH, electrical conductivity, and soil nutrients over years.     

Characterisation of sweet stem sorghum genotypes for bio-ethanol production

In an effort to characterise and select promising sweet stem sorghum genotypes with enhanced biofuel productivity, the present study investigated phenotypic variability present among diverse sweet stem sorghum genotypes based on ethanol production and related agronomic traits. One hundred and ninety genotypes were evaluated. Data were subjected to variance, cluster, correlation, path coefficient and principal component analyses. Significant differences (P?<?0.01) were detected among tested genotypes for all measured traits. Days to flowering varied from 62 to 152 with a mean of 93. Plant height varied from 90 to 420?cm with a mean of 236?cm. Stem diameter ranged from 7 to 31?mm with a mean of 16?mm. Biomass yield varied from 6.668 to 111.2?t?ha^?1 with a mean of 30?t?ha^?1. Stalk dry matter content ranged from 17.2% to 44.2% with a mean of 29.8%, while fibre content varied from 8.92% to 34.8% with a mean of 17.2%. The stalk brix yield varied from 3.3% to 18.9% with a mean of 12.1%. Ethanol productivity ranged from 240.9 to 5500?l?ha^?1 with a mean of 1886?l?ha^?1. The best ethanol producing genotypes were AS203, AS391, AS205, AS251 and AS448. Days to flowering, plant height, stalk brix and stem diameter exerted the greatest indirect effects on ethanol production through higher biomass production. Biomass yield had the greatest direct effect on ethanol production. Therefore, the above traits should be considered during breeding sorghum for bio-ethanol production. Also, the traits had high heritability values, hence selection should provide for good genetic gains. Overall, the above sweet stem sorghum genotypes are useful genetic resources for breeding of sorghum with enhanced bio-ethanol production.     

Water storage,water use and maize yield for tillage systems on a tropical alfisol in Nigeria

Water storage, water use, and maize yields were studied on a tropical alfisol derived from basement complex rocks in Western Nigeria. The objective was to determine the effects of tillage practices on these factors over a long period since a short term yield record may not be a good basis to evaluate the performance of tillage systems.The study, which lasted for five years (1976–1980) with two growing seasons per year, involved four tillage practices, namely: zero-tillage with mulch; conventional tillage (ploughing and harrowing); plough only and “manual” system which was an imitation of the local peasant practice. The experimental design was randomised complete block with four replications.Results show that in the early seasons the cultivated treatments, namely conventional and ploughing, out-yielded the zero-tillage in the first two years of the study (1976 and 1977). Yields ranged from 2639 kg ha^?1 in the zero-tillage to 5240 kg ha^?1 in the conventional tillage. However from 1978, the zero-tillage yields were significantly higher (P < 0.05) than yields from the cultivated treatments with the figures ranging from 4998 kg ha^?1 to 5949 kg ha^?1 in the cultivated plots and zero-tillage, respectively.The late season yields were also significantly higher in the zero-tillage throughout the study period. The late season is usually a period of low rainfall and the plants go through periods of stress, especially during the critical tasseling and silking period.Water use was similar for plants under the different tillage practices but water use efficiency (WUE), which for the early season ranged between 76.34 kg ha^?1 cm^?1 in 1980 to 118.65 kg ha^?1 cm^?1 in 1978, was significantly higher in the zero-tillage most of the time.The leaf stomatal resistances averaged over the measuring periods were 9.2, 9.5, 9.7 and 10.6 s per cm for plants under the zero-tillage, conventional, manual, and plough respectively. These figures were, however, not significant at five percent.There was also no significant difference (P < 0.05) in the flag leaf water potentials. The average values were ?1.39, ?1.42, ?1.49 and ?1.80 MPa for conventional, plough, zero-tillage and manual techniques, respectively.     

Influence of potassium and magnesium fertilizer application on the yield and nutrient accumulation of maize genotypes under field conditions

The use of maize (Zea mays L.) genotypes that are able to utilize nutrients efficiently is an important strategy in the management of plant nutritional status; it is of particular importance with regard to potassium (K) and magnesium (Mg), due to their high requirement and influence on plant growth. The influence of K and Mg fertilizers on certain growth parameters of maize genotypes TM.815 and KL.72.AA, including length, seed in ear, seed weight growth, and nutrient concentration, was determined under field conditions over two successive years. The aim of the experiment was to study the effect of different rates of K and Mg fertilizers on maize genotype plant growth parameters, grain yield, and nutrient accumulation under field conditions.

A split plot design with three replicates was used and each block contained three treatments of 0, 100, and 200 kg ha^?1 of K₂O and 0, 10, and 20 kg ha^?1 of Mg; K₂SO₄ was used to supply K, and MgSO₄ was used for Mg.

Plants that responded to the K fertilizer had an increase in height, yield, and the concentration of K in the leaves and seeds. The addition of K fertilizer increased the concentration of nitrogen (N), iron (Fe), zinc (Zn), manganese (Mn), and K in the plant leaves and increased seed K concentration. Mg fertilizer increased the concentration of N, Fe, copper, and Mn in the leaves; however, it exerted no significant influence on K concentration. The KL.72.AA maize genotype had a higher mean plant height, number of seeds in ear, yield, and N, K, Fe, and Zn concentrations compared to the TM.815 maize genotype. In the experiment, the K fertilizer exerted a statistically significant effect on the leaf and seed K concentration; however, on a statistical basis, the Mg fertilizer did not affect the Mg concentration.     

Possibilities of using sewage sludge as nitrogen fertilizer for maize

Abstract

The objective of this study was to determine the effects of nitrogen fertilizer sources of ammonium sulphate and municipal sewage sludge on yield, N content and uptake of the maize (Zea mays L.). Nutrient and heavy metals were determined in soil and plant. The experiment with three sludge rates (256, 513 and 1026 kg total N ha^?1 or 9.5, 18.0 and 38.1 t ha^?1 sludge), two nitrogen rates (80 and 160 kg N ha^?1) and zero-N control were conducted on a clay loam soils under irrigated conditions in Eastern Anatolia region in Turkey. Treatments were arranged in a randomized complete block design with four replications. Yield, N content and total N uptake of maize increased significantly with sludge application. 9.5 t and 19.0 t ha^?1 sewage sludge applications did not significantly affect heavy metal content of leaf and grain. However, 38.1 t ha^?1 sludge applications increased leaf Pb and Zn. DTPA-extractable Cd, Cu, Fe, Pb and Zn concentrations of the soil increased at applications of 38.1 t ha^?1 sewage sludge, whereas applications of 9.5 t and 19.0 t ha^?1 sludge only resulted in elevated levels of Cu and Zn, We conclude that if sewage sludge is to be used in production of maize, applications rate up to 19 t ha^?1 could be accepted. However, this means also that the N requirement of maize crop is not covered by the sludge; therefore, the rest of nitrogen could be supplied as inorganic N.     

Combined Application of Potassium and Zinc Improves Water Relations,Stay Green,Irrigation Water Use Efficiency,and Grain Quality of Maize under Drought Stress

Abstract

Maize (Zea mays L.) plays an important role in the global food security, but its production is threatened by climate change, especially drought stress. Potassium (K) and zinc (Zn) are considered useful to mitigate the negative consequences of drought stress in plants. Therefore, the objective of this two-year study was to identify the best combination of K and Zn application to improve the water relations, photosynthetic pigments, yield, irrigation water use efficiency (IWUE) and grain quality of maize sown under mild and severe drought stress conditions. The consisted of three drought stress levels viz. 1) well-watered as control (WW), 2) mild drought (MD) with 25?mm of potential soil moisture deficit (PSMD), 3) severe drought (SD) with 50?mm of PSMD and six K-Zn treatments: i.e. 125, 100 and 150?kg ha^?1 K with 0 and 12?kg ha^?1 Zn. The results indicated that K-Zn application improved the water relations and chlorophyll contents, biological yield and grain quality, irrespective of water stress treatment. The combined application of K-Zn under mild drought stress produced statistically same biological yield and grain quality as under well-irrigated without K-Zn fertilization and also produced compratively higher IWUE, biological yield and grain quality under sverer drought stress. Hence, the application of K at 150?kg ha^?1 in combination with Zn at 12?kg ha^?1 might be useful to improve the maize production and grain quality under drought stress. As IWUE was low in WW conditions, therefore, irrigation scheduling must be re-evaluated for optimum water use efficiency.     

Soil and nutrients losses under different crop covers in vertisols of Central India

Purpose

Accelerated erosion removes fertile top soil along with nutrients through runoff and sediments, eventually affecting crop productivity and land degradation. However, scanty information is available on soil and nutrient losses under different crop covers in a vertisol of Central India. Thus, a field experiment was conducted for 4 years (2010–2013) to study the effect of different crop cover combinations on soil and nutrient losses through runoff in a vertisol.

Materials and methods

Very limited information is available on runoff, soil, and nutrient losses under different vegetative covers in a rainfed vertisol. Thus, the hypothesis of the study was to evaluate if different crop cover combinations would have greater impact on reducing soil and nutrient losses compared to control plots in a vertisol.

This experiment consisted of seven treatment combinations of crop covers namely soybean (Glycine max) (CC₁), maize (Zea mays) (CC₂), pigeon pea (Cajanus cajan) (CC₃), soybean (Glycine max)?+?maize (Zea mays) ??1:1 (CC₄), soybean (Glycine ma x))?+?pigeon pea (Cajanus cajan) ?2:1 (CC₅), maize (Zea mays)?+?pigeon pea (Cajanus cajan) ??1:1 (CC₆), and cultivated fallow (CC₇). The plot size was 10?×?5 m with 1% slope, and runoff and soil loss were measured using multi-slot devisor. All treatments were arranged in a randomized block design with three replications.

Results and discussion

Results demonstrated that the runoff and soil loss were significantly (p?<?0.05) higher (289 mm and 3.92 Mg ha^?1) under cultivated fallow than those in cropped plots. Among various crop covers, sole pigeon pea (CC₃) recorded significantly higher runoff and soil loss (257 mm and 3.16 Mg ha^?1) followed by that under sole maize (CC₂) (235 mm and 2.85 Mg ha^?1) and the intercrops were in the order of maize?+?pigeon pea (211 mm and 2.47 Mg ha^?1) followed by soybean?+?maize (202 mm and 2.38 Mg ha^?1), and soybean?+?pigeon pea (195 mm and 2.15 Mg ha^?1). The lowest runoff and soil loss were recorded under soybean sole crop (194 mm and 2.27 Mg ha^?1). The data on nutrient losses indicated that the highest losses of soil organic carbon (SOC) (25.83 kg ha^?1), total nitrogen (N), phosphorus (P), and potassium (K) (7.76, 0.96, 32.5 kg ha^?1) were recorded in cultivated fallow (CC₇) as compared to those from sole and intercrop treatments. However, sole soybean and its intercrops recorded the minimum losses of SOC and total N, P, and K, whereas the maximum losses of nutrients were recorded under pigeon pea (CC₃). The system productivity in terms of soybean grain equivalent yield (SGEY) was higher (p?<?0.05) from maize?+?pigeon pea (3358 kg ha^?1) followed by that for soybean?+?pigeon pea (2191 kg ha^?1) as compared to sole soybean. Therefore, maize?+?pigeon pea (1:1) intercropping is the promising option in reducing runoff, soil-nutrient losses, and enhancing crop productivity in the hot sub-humid eco-region.

Conclusions

Study results highlight the need for maintenance of suitable vegetative cover as of great significance to diffusing the erosive energy of heavy rains and also safe guarding the soil resource from degradation by water erosion in vertisols.