High-yielding Maize Research Articles

Screening of Maize Genotypes against Maize Leaf Aphid [Rhopalosiphum maidis (Fitch)] under Field Condition at Chitwan, Nepal

Thirty maize genotypes including five hybrids, eight quality protein (QPM) and seventeen full season open pollinated (OP) were screened for their resistance against maize leaf aphid (Rhopalosiphum maidis Fitch) at the research field of National Maize Research Program, Rampur, Chitwan, Nepal during the year 2019 and 2020. The design of the experiment was randomized incomplete block with three replications. The plot size was 2 rows of 5 m long with the spacing of 60 cm × 25 cm. The recommended dose of fertilizer for full season OP and QPM were 120:60:40 and for hybrid maize 180:60:40 N: P2O5:K2O kg/ha with farmyard manure 10 t/ha and seed rate was 20 kg/ha. Data on aphid incidence, severity, yield and yield components were recorded. Maize hybrids RML-95/RML-96 (18%) and Rampur Hybrid-10 (22%), two quality protein maize (QPM) S00TLYQ-AB (22%) and S99TLYQ-A (23%) and two full season OP genotypes TLBRS07F16 (24%) and ZM 627 (26%) were less susceptible to aphid infestation and resulted in higher grain yield. The findings could aid in the selection of maize genotypes for the development of aphid resistant and high-yielding maize varieties.

Multivariate Analysis of Agronomic Traits in Newly Developed Maize Hybrids Grown under Different Agro-Environments.

Developing high-yielding maize hybrids is essential under the fast-growing global population and abrupt global climate change. Planting density is one of the imperative components for enhancing maize productivity. This study assessed newly developed maize hybrids under three planting densities on two sowing dates. The evaluated hybrids were 40 maize genotypes comprised of 36 F1-developed hybrids and 4 commercial high-yielding check hybrids. The developed hybrids were generated from selected maize inbred lines according to their adaptive traits to high planting density, such as prolificacy, erect leaves, short plants, early silking, anthesis-silking interval, and small tassel size. The applied planting densities were high, intermediate, and low, with 95,000, 75,000, and 55,000 plants/ha, respectively, under timely and late sowing. The high planting density displayed the uppermost grain yield compared with the intermediate and low densities at both sowing dates. The developed hybrid G36 exhibited the highest agronomic performance under high planting density at timely and late sowing. Additionally, G38, G16, G37, G23, G5, G31, G18, G7, G2, G20, G29, and G17 displayed high agronomic traits at both sowing dates. Joint regression and AMMI analyses revealed significant genotype, agro-environment, and genotype × agro-environment interaction effects for grain yield. The AMMI biplot displayed that G39 was closest to the ideal stable hybrid, and the hybrids G36, G18, G38, G17, G2, and G37 were considered desirable stable hybrids. Moreover, the GGE biplot indicated that a high planting density at an optimal sowing date could be considered a representative environment for discriminating high-yielding maize hybrids. The designated promising hybrids are recommended for further inclusion in maize breeding due to their stability and high yields.

Selection of high-yield maize hybrid under different cropping systems based on stability and adaptability parameters

Abstract The intercropping of maize with other food crops is a current solution to problems in food crop production and crop failures. The objectives of the study were to (i) select adaptive maize hybrids in intercropping as well as sole-cropping systems, and (ii) test the ideal cropping system to evaluate best hybrids for intercropping. This study used 12 maize hybrids with different genetic backgrounds. Planting was carried out for two seasons using four cropping systems. Hybrids were selected according to their adaptability and stability based on parametric, nonparametric, and multivariate analyses. The results showed that G10 had high yield for all cropping systems. G10 was also selected as an adaptive hybrid for sole-cropping, whereas G9 was selected as an adaptive hybrid for intercropping. The L5 and L4 were ideal environments for evaluating hybrids under different cropping systems. The selected hybrids should be evaluated and disseminated for small-holder farmers in Indonesia.

Nitrogen accumulation and nitrogen substitution effect of maize under straw returning with continuous cropping

<p id="C3">Crop straw resources in Northeast China are rich, but burning and discarding are serious, and nutrient utilization rate is very low. We explored the feasibility of the substitution of straw returning to nitrogen fertilizer and its effects on nitrogen accumulation under continuous cropping in cold region. A frame culture and continuous positioning experiment was carried out in the experimental site of Northeast Agricultural University from 2017 to 2019, with ¹⁵N labeled urea. A three-factor split-plot design was adopted in this experiment, the main plot was straw returning method with no straw returning (S0) and straw returning (S1), and the sub-plot was nitrogen application levels with 0 (N0), 175 (N1), and 350 (N2) kg hm^-2. Two application methods were set for each fertilizer application amount, one ratio of base fertilizer and top dressing applied was 1:1, and the other ratio of base fertilizer and top dressing applied was 1:0. The results were as follows: When the straw returning amount was 12 t hm^-2, the returning straw could replace 36.8 kg hm^-2 pure nitrogen. The average amount of maize straw was 46.50 million tons in Heilongjiang Province from 2017 to 2019, and straw returning could replace 142,700 tons pure nitrogen. The replace amount of pure nitrogen in the ratio of base fertilizer and top dressing (1:1) was 26.88% higher than that in 1:0. Straw returning was negatively correlated with nitrogen use efficiency in maize. The average nitrogen use efficiency of maize in S0 treatment was 6.09% higher than S1 treatment, and the yield of S1 treatment was 4.66% higher than S0 treatment when the urea application amount was 350 kg hm^-2 (161 kg hm^-2 pure nitrogen). The highest yield of maize was 268.22 g frame^-1 in the treatment of straw returning and topdressing with commonly fertilizer applied in local agriculture. In conclusion, the nitrogen substitution effect was remarkable under maize straw returning in Northeast China. Long-term combined application of crop straw and nitrogen fertilizer significantly improved the biomass, yield, and nitrogen accumulation of maize, which was a cultivation mode for increasing yield and efficiency of maize in Northeast China.

CHALLENGES OF MAIZE BREEDING UNDER TROPICAL CONDITIONS OF BRAZIL

Tropical maize production represents 49% of the global maize harvested area. In terms of productivity, the annual increase rate in tropical regions is twice as higher as the increase rate in temperate regions. The increase in maize grain yield was expressive in the last 41 years in Brazil. Such achievement was possible due to the joint efforts of many areas of science, especially, plant breeding. Although maize breeding success, many are the challenges faced by the maize breeders to develop high-yielding maize hybrids. Tropical conditions provide more intense challenges in terms of pests and diseases pressures, and above all, water deficit conditions. In addition, the constant increase of breeding programs costs requires the development and application of new techniques to improve the genetic gain per time unit, increasing the maize breeding programs’ efficiency. This review discusses the main challenges faced by maize breeding programs under tropical conditions, highlighting topics related to the development of maize hybrids for first and second growing seasons; breeding for biotic and abiotic stresses conditions; specialty maize breeding; use of transgenic in maize; and genomic tools to maximize the efficiency of maize breeding programs under tropical conditions.

Organic substitutions improve soil quality and maize yield through increasing soil microbial diversity

Organic substitution is beneficial to sustainable agricultural development. In order to determine the proper fertilization strategy, it is necessary to evaluate the effects of partial substitution of nitrogen fertilizer with organic amendments on soil quality and crop yield, as well as their decisive factors. A five-year organic substitution field experiment was set up to investigate the effects of partial substitution of chemical fertilizer with stover, cattle manure and biochar on soil quality, soil microbial and nematode diversities and crop yield in a maize (Zea mays L.) field of Northeast China. Our results showed that organic substitutions increased soil quality and manure substitution increased maize yield through changing the composition and functional group of soil biota. Bacteria played important roles in determining the maize yield, but the beneficial effects were contingent on the different types of organic substitution. Stover substitution improved soil quality through increasing bacterial diversity but may lead to the competition of nitrogen between microorganisms and crops. Compared with conventional fertilization, manure substitution provided resources with suitable C/N ratio (6.82) and resulted in the higher maize yield, but the soil quality improvement was weaker under manure substitution than under stover substitution. Biochar substitution reduced the relative abundance of plant-parasitic nematodes but caused an increasing of potential pathogenic fungi for maize. Comprehensively, stover substitution is the most promising fertilization regime for maize in Northeast China from the perspective of soil quality and soil biodiversity.

Feasibility of early fertilization of maize with 15 N application to preceding cover crop

Early nitrogen (N) application on live cover crops or their residues is a potential alternative for supplying N demand while enhancing the yield of subsequent cash crops in tropical regions. The objective of applying N on live forage grasses or their residues to no-till (NT) systems is to promote the gradual release of N via straw decomposition to the subsequent crop. However, the N use efficiency by the subsequent crop under early fertilization has not been determined in the end of growing season. The aim of this study was to evaluate whether the most cultivated tropical forage grasses can supply the N demand and enhance the grain yields of maize via the N recovery when N is applied with different timings than the conventional method. A 3-year field experiment was performed using palisade grass [(Urochloa brizantha (syn. Brachiaria)] and ruzigrass (U. ruziziensis) as cover crops with four N application timings to agricultural system: (i) no-N, zero N application; (ii) CC+N, 120 kg N ha−1 applied on live cover crops 35 days before maize seeding; (iii) St+N, 120 kg N ha−1 applied on cover crops straw 1 day before seeding; and (iii) Nv4, conventional method of sidedress N application at the maize V4 (four leaf) growth stage. Except control, all N treatments received 40 kg N ha−1at maize seeding, totalizing 160 kg N ha−1. Straw decomposition and cover crop N accumulation were greater in the treatments in which N fertilizer was applied on palisade grass compared with ruzigrass. High maize yields were achieved with N application on palisade grass or its residues or according to the conventional method, with yields of 13.2, 13.2 and 13.6 Mg ha−1, respectively. Similarly, high maize yields were obtained when N was applied on ruzigrass residues or according to the conventional method (12.1 and 11.8 Mg ha−1, respectively). However, regardless of cover crop species, N recovery was highest when N fertilizer was applied via the conventional method. Additionally, most of the N in maize at harvest came from the soil when N fertilizer was applied to live palisade grass. Thus, best recovery of N fertilizer in the grain occurred in maize fertilized using the conventional method. Our results indicate that agricultural systems characterized by high dry matter from palisade grass have the potential to recycle and supply N to subsequent maize. Although palisade grass combined with early N fertilizer application may enhance maize response and yield, the current conventional method of N fertilizer application on maize allows higher recovery from N fertilizer while increasing the maize yield in tropical food production.

Effects of Solar Radiation on Dry Matter Distribution and Root Morphology of High Yielding Maize Cultivars

The root system connects the plant with the soil, which is a key factor in determining the utilization of soil resources and plant growth potential. Solar radiation can change maize shoot and root growth and affect grain formation. In this study, the effects of different solar radiation conditions on root morphology of three maize cultivars XY335, ZD958 and DH618 and their quantitative relationships were studied by conducting shading experiments. This study was conducted in maize high yield region of Qitai and Yinchuan, China, in 2018 and 2019. The planting densities were 7.5 × 104 (D1) and 12 × 104 (D2) plants ha−1. The shading levels were natural light (CK), shading 15% (S1), 30% (S2) and 50% (S3). The results showed that maize responded to the decreased solar radiation through the increase in ratio of shoot dry weight (SWR) to whole plant dry weight and the decrease in ratio of root dry weight (RWR) to whole plant dry weight. As the solar radiation decreased, the root length density (RLD), root surface area (RSA), average root diameter (ARD) and root length ratio (RLR) decreased, while the specific root length (SRL) increased. With 100 MJ m−2 decrease in solar radiation, the RWR, RLD, RSA and RLR each decreased by 1.47%, 0.5 mm cm−3,0.4 m m−2 and 0. 19 m g−1, respectively. Among the cultivars, the changes of DH618 were the fastest followed by XY335 and ZD958 but DH618 maintained the largest root system under any solar radiation condition. After the decrease of solar radiation, RWR, RLD and RLR were significantly positively correlated with the yield. This indicated that large root systems were conducive to the rapid response to decreased solar radiation and important for achieving stable and high yield. Maize cultivars with these type of root systems should be recommended to better adapt low solar radiation induced by regional variation or climate change.

Organic Inputs on Maize (Zea mays) Yield and Chemical Properties of Two Ultisols

Effects of organic inputs (OIs) on maize grain yield and chemical properties of Ultisols were assessed at Msekera and Misamfu Agricultural Research Stations in the medium and high rainfall regions respectively of Zambia. The OIs included biomasses of the leguminous species Cajanus cajan, Tephrosia vogelii, and Crotalaria juncea, in-situ composted native grasses and shrubs called fundikila, modified fundikila using Mucuna pruriens, and composted cattle manure, with chemical fertilizer as a control. After two crop growing seasons, cattle manure significantly increased soil pH, while modified fundikila significantly increased levels of soil organic matter. At Msekera, OIs increased levels of total N by 300%. At Misamfu, fundikila and Cajanas cajan increased total N by 35%. The OIs did not significantly increase available P and K at both sites. In the first season at Msekera, OIs had a higher mean maize yield (6075&amp;plusmn;368 kg/ha) than chemical fertilizer (3567&amp;plusmn;715 kg/ha). Maize yields for OIs in the second season did not differ significantly from those of the first season. At Misamfu the leguminous OIs Cajanas cajan and Tephrosia vogelii, had a lower combined mean maize yield (5405&amp;plusmn;242 kg/ha) than chemical fertilizer (7426&amp;plusmn;430 kg/ha) in the first season. A 70% decline in maize yield occurred on plots with leguminous OIs in the second season compared to the first season. Leguminous OIs generally performed better at Msekera than at Misamfu. At both sites, the traditional OIs, cow manure at Msekera, and fundikila at Misamfu had higher maize yields than leguminous OIs. We concluded that effects of OIs on soil chemical properties and maize yield vary with soil and climatic conditions and that these need to be considered when selecting OIs for use by farmers.

Greenhouse Gas Fluxes from Selected Soil Fertility Management Practices in Humic Nitisols of Upper Eastern Kenya

We quantified the soil carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) fluxes of five soil fertility management practices (inorganic fertilizer (Mf), maize residue + inorganic fertilizer (RMf), maize residue + inorganic fertilizer + goat manure (RMfM), maize residue + tithonia diversifolia + goat manure (RTiM), and a control (CtC)) in Kenya’s central highlands using a static chamber method from March 2019 to March 2020. The cumulative annual soil CH4 uptake ranged from −1.07 to −0.64 kg CH4-C ha−1 yr−1, CO2 emissions from 4.59 to 9.01 Mg CO2-C ha−1 yr−1, and N2O fluxes from 104 to 279 g N2O-N ha−1 yr−1. The RTiM produced the highest CO2 emissions (9.01 Mg CO2-C ha−1 yr−1), carbon sequestration (3.99 Mg CO2-eq ha−1), yield-scaled N2O emissions (YSE) (0.043 g N2O-N kg−1 grain yield), the lowest net global warming potential (net GWP) (−14.7 Mg CO2-eq ha−1) and greenhouse gas intensities (GHGI) (−2.81 Kg CO2-eq kg−1 grain yield). We observed average maize grain yields of 7.98 Mg ha−1 yr−1 under RMfM treatment. Integrating inorganic fertilizer and maize residue retention resulted in low emissions, increased soil organic carbon sequestration, and high maize yields.

Increasing grain yield, nitrogen use efficiency of summer maize and reducing greenhouse gas emissions by applying urea ammonium nitrate solution

AbstractThe contradiction between the high grain yield of summer maize (Zea mays L.) and greenhouse gas (GHG) emissions in the field can be resolved by selecting effective nitrogen (N) sources and fertilization methods. In this study, two fertilization methods were used: (a) urea ammonium nitrate solution (UAN) and urea (210 kg ha–1 nitrogen applied) were applied by farmers' traditional fertilization method; and (b) fertigation of four UAN application rates: CK (no N applied), AF1 (126 kg N ha–1), AF2 (168 kg N ha–1), AF3 (210 kg N ha–1). The results showed that both hybrids (DH518 and DH605) applied UAN under the traditional fertilization method increased grain yield by 2.4 and 1.8% and enhanced nitrogen use efficiency (NUE) by 25.1 and 9.9%, respectively, compared with urea. While under fertigation treatment, the grain yield increased by 7.6 and 6.6%, and the NUE increased by 23.2 and 12.4%. Grain yield increased with the increase of UAN application, and the NUE showed a trend of rising first and then falling under fertigation treatment. Both the cumulative N2O emissions and N2O emission factor showed an increasing trend as well. An application rate of UAN at 168 kg N ha–1 (AF2) resulted in a NUE that was 49% higher than urea. Compared with urea, the global warming potential (GWP) and greenhouse gas intensity (GHGI) of AF2 were reduced by 29.5% and 31.2%, respectively. These indicated that optimizing the application rate of UAN through fertigation would achieve better summer maize yield and environmental benefits.

冬小麦-夏玉米轮作&amp;ldquo;双晚&amp;rdquo;种植模式下的品种匹配与资源效率

<p id="C3">It is of great significance that exploring the characteristics of wheat-maize varieties combination suitable for stress resistance, high yield, and stable yield under the “double delay” system and their matching properties with natural resources, for ensuring the high yield and high efficiency production of winter wheat and summer maize in this region. In this study, field experiments were conducted from 2017 to 2019. Eight winter wheat and eight summer maize varieties were the main varieties in the North China Plain under winter wheat-summer maize “double delay” system with different irrigation treatments. Based on the analysis and evaluation of water use efficiency, grain filling characteristics, growth process, annual light, temperature, and water use efficiency, etc., the characteristics of wheat-maize varieties combination and resource use efficiency under the “double delay” system of winter wheat and summer maize were explored. The results suggested that among the tested wheat varieties, the yields of Jimai 325, Shimai 15, Nongda 3486, and Jimai 22 under conventional water-saving irrigation and rain-fed mode were higher than the average yield of the tested varieties druing the two growing seasons. In addition, the drought resistance index of Jimai 325 and Shimai 15 were higher than that of Jimai 22. Meanwhile, the grain-filling rate, grain number per spike, grain weight, and high stability coefficients of Jimai 22, Jimai 325, and Shimai 15 were higher than the mean of the tested varieties under different irrigation modes. Among the tested maize variaties, the yield and high stability coefficients of Denghai 605, Weike 702, MC670, and Nonghua 816 were all higher than the means of the tested varieties. The grain-filling rate of MC670, Denghai 605, and Xianyu 335 were higher than the means of the tested varieties during the two growing seasons. While, Dika 517 and Xianyu 335 had the lowest grain water content at harvest stage but the highest average dehydration rate among the tested varieties. Based on the comprehensive analysis of the yield and yield stability, drought resistance, grain-filling properties, and dehydration characteristics, the variety combination of Jimai 325-MC670 was selected with the highest annual yield and resource use efficiency. Compared with the local control combination of Jimai 22-Zhengdan 958, the annual yield increased by 17.2% and 17.9%, the light, temperature and irrigation water use efficiency increased by 18.6% and 20.0%, 18.1% and 18.9%, 17.4% and 18.1%, and increased economic benefit 8800 Yuan hm ^-2 and 9600 Yuan hm ^-2, respectively; to fit the whole-process mechanized management mode of wheat-maize double cropping system, maize could use varieties with fast dehydration rate and low grain water content when harvest, such as Dika 517 or Xianyu 335. Compared with the current local combination of Jimai 22-Zhengdan 958, this combination could increase the annual yield by 4.7% and 14.4%, and increase the light, temperature, and irrigation water use efficiency by 5.6% and 16.3%, 4.7% and 15.4%, 5.0% and 14.6%, and increased economic benefit by 2080 Yuan hm ^-2 and 7080 Yuan hm ^-2, respectively. In summary, optimizing the wheat-maize variety combination under the “double delay” cropping system can further improve the annual yield and resource use efficiency synergistically compared with the local staple wheat-maize variety combination.

Yield and quality properties of silage maize and their influencing factors in China.

Silage maize (Zea mays L.) is one of the most important forages in the world, and its yield and quality properties are critical parameters for livestock production and assessment of forage values. However, relationships between its yield and quality properties and the controlling factors are not well documented. In this study, we collected 5,663 observations from 196 publications across the country to identify the relationships between yield and quality properties of silage maize and to assess the impact of management practices and climatic factors on its yield and quality in China. The average dry matter yield of silage maize was (19.98±6.93) Mg ha-1, and the average value of crude protein, ether extract, crude ash, crude fiber, acid detergent fiber, neutral detergent fiber, nitrogen-free extract, and relative feed value was 7.86%±1.71%, 2.53%±1.01%, 5.05%±1.66%, 23.97%±6.34%, 27.62%±7.12%, 51.60%±9.85%, 59.68%±7.72%, and 131.17±31.49, respectively. In general, its nutritive value decreased as its yield increased. Increasing planting density could increase the yield but inhibit the nutritive values, while increasing fertilization could benefit the nutritive values. Geographically, the yield increased and the nutritive value decreased from warm (south) to cold (north) regions. The length of growth duration was a major controlling factor for the patterns of these properties. Our findings provide insights for police-makers to make strategy for achieving high yield and good quality of silage maize and help local people to implement better management practices.

Potentials of straw return and potassium supply on maize (Zea mays L.) photosynthesis, dry matter accumulation and yield

Maize (Zea mays L.) is considered one of the most important grains in the world. Straw return has the effect of reducing soil bulk density and increasing soil porosity. Straw returning and potassium fertilizer can supplement soil potassium content. The improvement of soil structure and the optimization of soil nutrient levels provide a good environment for high yield and high efficiency of maize. Therefore, three field experiments were carried out over a three-year period (2018–2020) to study the effects of straw returning on photosynthesis, dry matter accumulation and yield of maize 'Xianyu 335' under two different fertilization methods and four potassium application levels. The results showed that straw returning and potassium application had significant effects on the above indicators. The above indicators were significantly improved by deep tillage straw returning compared with no tillage straw returning. Increasing potassium supply can promote the effect of straw returning. The photosynthesis, dry matter accumulation and yield parameters of maize treated with straw returning and deep tillage combined with 60 kg/hm2 potassium fertilizer (SFK60) reached the highest in the three harvest seasons. The corn planting profit of SFK45 treatment is the highest, which is $1868.92 per ha. Therefore, SFK45 is an effective way to ensure stable and high yield of corn and maximize farmers' income.

Influence of Soil Fertility Management on Nitrogen Mineralization, Urease Activity and Maize Yield

For studying the effect of soil fertility management practices on N mineralization, urease activity and maize yield, replicated field trials were established in 2015 at Misamfu and Msekera agricultural research stations (ARS) representing two geo-climatic regions of Zambia. The soil at Msekera ARS is a sandy clay loam (SCL) from a Paleustult, while that at Misamfu is a loamy sand (LS) from a Kandiustult. The field trials had three categories of treatments namely legumes, traditional and conventional. The legumes group consisted of researcher-recommended legume-cereal intercrop systems of maize with Cajanus cajan, Crotalaria juncea and Tephrosia vogelii in combination with compound D (10% N, 20% P2O5, 10% K2O) and urea (46% N) at the recommended rate (200 kg ha-1) and half of the recommended rate (100 kg ha-1). Composted cattle manure and Fundikila, a special plant biomass management technique, were the inputs under the traditional category. The conventional category consisted of a treatment to which only chemical fertilizer was applied. Urease activity was determined in surface soil samples (0-20 cm) collected from the field trials after 3 years. For N mineralization, a laboratory incubation study was conducted over 13 weeks. For the laboratory incubation, an additional treatment to which no input was applied was included as control. Application of organic inputs significantly increased the potentially mineralizable N (No) by 127% to 256% on the LS and by 51% to 131% on the SCL in comparison to the control. Similarly, the cumulative N mineralized (Ncum) was twice or thrice higher where organic inputs had been applied in comparison to the control. The No followed the order traditional &amp;gt; legumes &amp;gt; conventional &amp;gt; control, while the mineralization rate constant (k) followed the order legumes &amp;gt; conventional &amp;gt; traditional &amp;gt; control on both soils. The rate of N mineralization was significantly higher on the LS than the SCL. Higher rates of chemical fertilizer resulted in high Ncum and higher maize yield. Maize yield was significantly and positively correlated to Ncum, but inversely correlated to the amount of applied N that was mineralized (%Nmin). Urease activity was stimulated by application of organic inputs and suppressed by higher rates of chemical fertilizers. The type of organic inputs; the rate of chemical fertilizers; and soil texture are factors influencing N mineralization and maize yield. Urease activity was largely influenced by the rate of chemical fertilizer, but not the type of organic inputs or soil texture.

INFLUENCES OF DIFFERENT CONCENTRATIONS OF HERBICIDES ON THE GROWTH AND YIELD OF MAIZE AS WELL AS THEIR EFFECTS ON THE ASSOCIATED WEEDS IN NORTH-WESTERN NIGERIA

The field experiment was conducted in the dry season between December 2012 to April 2013 at Bakori, Bakori local government, Katsina (11033’N, 7036’E). The experiment consisted of 8 treatments levels which include 4 different formulations each; viz: ParaeForce(R) at 150ml / 20L and 200ml / 20L,AminoForce(R) at 100mL / 15L and 125mL / 15L applied a day before sowing and 4 weeks after sowing and a weedy control. The treatments were laid out in randomized complete block design (RCBD). The objective was to evaluate resistant weeds to herbicides (ParaeForce(R) and AminoForce(R)) and their effects on the growth and yield of maize. Result shows that 17 weed species from 11 families were encountered which include Cynodon dactylon, Cyperus rotundus, Doctylocterium aegyptium and Eleusine indica that shows signifcant (≥ 0.05) resistance to ParaeForce(R) + AminoForce(R) at 150mL / 20L followed by 100mL / 15L had 91.70, 87.12 and 49.15% weed control efficiencies at 4,8 and 16WAS. Sequential application of ParaeForce(R) + AminoForce(R) at 200ml/20L followed by 125mL/15L recorded significantly (≥0.05) high maize yield of (6.7kg) in all the three blocks and effective weed control with 86.28, 77.58 and 33.55% weed control efficiencies at 4, 8 and 16WAS. This study recommended the application of ParaeForce(R) and AminoForce(R) at 200mL/20L followed by 125mL/15L as an alternative way of reducing weed resistance to ParaeForce(R) + AminoForce(R) formulation and to improved performance of maize yield in the experimental site.

Humic acid modulates growth, photosynthesis, hormone and osmolytes system of maize under drought conditions

With population increasing and global warming, extreme weather events and water resource shortage have become nonnegligible factors restricting maize production. The effects of humic acid (HA) on plant growth and stress tolerance have been extensively studied. However, the underlying physiological and molecular mechanism of how HA influences drought resistance in maize plants remains unknown. In the present study, a pot experiment was conducted with two irrigation levels (W1: drought stress 45–60% of field capacity, W2: well-watered, 75–100% of field capacity), two HA application rates (H0: 0 kg ha−1, H1: 45 kg ha−1), and two maize genotypes (Zhengdan958 and Xianyu335). The results showed that HA applied at 45 kg ha−1 improved the proportion of macro-aggregates in the soil while increasing the soil water content by 5.0% at W1 compared with H0. The availabilities of P, K, Fe, and Mg in soil were improved, and the activities of rubisco and ATP synthase, the content of IAA, and the concentrations of osmotically active solutes (i.e., soluble sugars, betaine, and proline) in maize were increased with HA application. In addition, the expressions of genes involved in primary metabolic processes, especially photosynthesis, carbon fixation, and hormone and osmotic metabolisms in maize leaves, were regulated. Higher maize yields were achieved in the treatments with HA applied by 19.7% in Zhengdan958 and 14.3% in Xianyu335 than without HA applied under drought stress, respectively. And the water use efficiency of Zhengdan958 and Xianyu335 was 2.16 g kg−1 and 2.08 g kg−1 in the treatments with HA applied, respectively. In conclusion, HA application enhanced the drought resistance and growth of maize. The results of this study help to understand the drought resistance mechanism of maize and provide support for crop production in face of water shortage.

Profitability and Farmer Acceptability of Selected Climate Smart Technologies and Practices for Maize-Beans Production in Drought-Prone Areas, Uganda

Climate change is increasingly affecting farm-level decisions on when to plant and which climate smart agriculture (CSA) options to use. This study was conducted to determine the profitability and farmer acceptability of different CSA options for maize-bean production in drought-prone areas of Uganda. It was conducted on-farm in Rakai and Nakasongola districts during 2020 and 2021. Variables included: planting date (early vs late); varieties (common beans: NABE 4 and NAROBEAN 2, and maize: Longe 5 and Bazooka); intercropping versus pure stand; and fertiliser use (manure, Diammonium phosphate (DAP) or combination). The experimental design was split-split plot, replicated six times. Over two years, early planting caused 16% and up to 46% higher yields of maize and beans, respectively, than late planting, resulting in 14% - 28% and 18% - 43% higher Benefit/Cost (B/C) ratio for maize and beans, respectively. Intercropping reduced maize and beans yield by 16% - 25% and 52% - 57%, respectively. The B/C was highest for sole maize; intercropping was more profitable than sole beans. Fertilizer (DAP) was most profitable when Bazooka was early-planted as sole crop followed by intercrop. For late planted-crop, manure was better. These practices were more beneficial when applied simultaneously for both crops excluding bean variety. Farmers’ lessons stressed the importance of early planting and fertilizer use; however, majority indicated they were to adopt more than two of the practices tested.

Влияние на биовъглен върху добив от царевица и микробиална активност при Алувиално- ливадна почва

A three-year field experiment with maize was carried out on fluvisol. The aim of the present study was to evaluate the impact of biochar on maize yield at different levels of water stress and its effect on the amount of soil microorganisms. The following variants were studied: control with no biochar addition, and variants with biochar. Biochar was applied in 2 t/ha in 2016, produced by pyrolysis of rice straw, then in 3 t/ha in 2017 and 10 t/ha in 2018, both obtained by pyrolysis of oak bark. These variants were divided into three more depending on the irrigation regime: i.e. non-irrigated, irrigation at dT>0 °C, and irrigation at dT<-1 °C. Under non-irrigated conditions, the effect of biochar on maize yield was not pronounced over three years. Under irrigation conditions with water added according to crop water stress, higher yields of maize were obtained in the third year when biochar application to the soil was highest (10 t/ha). Also, yield was higher when faster (at lower water stress dT<-1 °C) irrigation rates were applied. Soil moisture changed slowly in the biochar variants and the best values of the temperature differences were obtained for irrigation at dT<-1 °C in 2018. These results showed that the influence of biochar on soil microbiota was significantly greater, and the most stimulating effect of biochar was obtained for bacterial populations.

Effect of application compost and vermicompost from market waste on soil chemical properties and plant growth

This study was conducted to determine the effect of compost and vermicompost from market organic waste on the soil chemical properties and the growth of maize. The treatments tested were three doses of compost (2.5, 5, and 10 t/ha), three doses of vermicompost (2.5, 5, and 10 t/ha), and one control (without compost or vermicompost). At the time of harvest (10 weeks after planting), maize shoot dry weight, root dry weight, cob length, cob diameter, cob with husk, and cob dry weight, as well as the soil chemical properties organic carbon (C), total nitrogen (N), total phosphorus (P), available P, total potassium (K), and pH were observed. Maize plant height, leaf number, and stem diameter were observed at 2, 4, 6, and 8 weeks after planting. The results showed that the application of compost and vermicompost significantly affected soil chemical properties and the yield of maize. The application of 10 t vermicompost/ha resulted in the highest yield of maize and highest increase of soil organic carbon, total phosphorus available phosphorus, total potassium, and pH by 7.21%, 112.41%, 287.44%, 85.44% and 17.58%, respectively. The application of 10 t compost/ha resulted in the highest increase of soil total N by 44%.