Comparison of different fertilization rates on yield, evapotranspiration, and water use efficiency of sweet corn under drought-salinity stresses

Reducing P fertilization to address water quality problems has raised concerns among producers regarding crop yield and quality. A 3 yr study was conducted at three sites to examine whether reduction in P fertilization rate and/or use of a preceding rye cover crop affect the yield and quality (sugar concentration and ear weight) of sweet corn (Zea mays L.) grown on soils with “excessive” plant-available P. The experimental design was a split plot with four replications conducted on Norfolk soils. The main plots were no cover crop and a rye cover crop. The subplots were five P fertilizer treatments ranging from 0 to 60 kg P ha-1 at 15 kg P increments. With or without a preceding rye cover crop or P fertilization, postharvest soil test P (Mehlich-1) levels remained “excessive” to a depth of 40 cm. Also, yield of sweet corn was not affected by P fertilization and/or use of a preceding rye cover crop. Without cover cropping, sugar content and ear weight response to P fertilization was positive on site 2 for sugar, and on sites 2 and 3 for ear weight. Utilization of cover cropping positively influenced sweet corn sugar and ear weight sampled at early milk stage without affecting the final yield. In processing sweet corn production, profitability is determined mainly by the yield of marketable ears. Therefore, the small, inconsistent increases in sugar content and ear weight in response to P fertilization, without an increase in yield is not of a major significance to the farmer. On high P soils, P fertilization is unnecessary for the production of quality, high-yield processing corn. The use of a rye cover crop is suggested as a method of reducing the risk of P loss into the surrounding watershed. Key words: Sweet corn yield, sweet corn quality, P fertilization, rye cover crop, phosphorus management, high P soils

A field experiment was conducted to study the effect of intercropping and fertility level on yield and economics of sweet corn at the Department of Agronomy, College of Agriculture, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha during rabi season of 2022-23. The experiment was conducted with split plot design having three main plots and five sub plots with three replications. The main plots were sole sweet corn, sweet corn + radish and sweet corn + beans; whereas the sub plots include the fertility levels of 0:0:0, 40:20:20, 80:40:40, 120:60:60 and 160:80:80 kg N:P2O5:K2O ha-1. Observations were taken on plant growth, yield attributing factors, yield and economics. There was reduction in growth and yield of sweet corn due to competition from intercrops. The highest green cob yield of 10.07 t ha-1 was obtained from sole sweet corn, which was statistically superior over yield obtained from sweet corn taken with any of the intercrops. However, maximum green cob equivalent yield of 12.66 t ha-1 was obtained in sweet corn + radish intercropping system. In case of fertility levels, optimum yield of green cob (10.61 t ha-1) was recorded with application of 120 kg N, 60 kg P2O5 and 60 kg K2O ha-1. The green cob equivalent yield attained the optimum value (14.32 t ha-1) with application of 120 kg N, 60 kg P2O5 and 60 kg K2O per hectare. Maximum net profit of ₹ 111.3 thousand per hectare was obtained when radish was intercropped with sweet corn. From the findings of this experiment, it can be inferred that application of 120 kg N, 60 kg P2O5 and 60 kg K2O per hectare to sweet corn and sweet corn + radish intercropping system is suitable to obtain optimal yield of sweet corn, green cob equivalent yield and net profit.

Smart irrigation is one application of digital agriculture that can be used to achieve improved crop yields while saving water and energy. Many variations of smart irrigation can be applied, but there is no consensus among the scientific community as to which method is the best practice. The objective of this research was to evaluate two smart irrigation methods: a soil moisture–based method using sensors and an evapotranspiration- (ET-) based technique. The selected crop was sweet corn. Growth variables (biomass, yield, harvest index, and water productivity) were compared for each of the two methods. Three irrigation regimes were applied for each method: 60%, 90%, and 120% of crop evapotranspiration (ETc) for the ET-based method, and 25%, 30%, and 35% of the total soil moisture for the soil moisture–based method. Corn sap flow was measured in response to the three treatments in the soil moisture–based experiment to measure transpiration. The results showed that the ET-based method is easier to implement with less infrastructure, and it can result in similar yields compared to the soil moisture–based method. Although the fresh yield was 16% higher using the soil moisture–based method, grain yield can be sustained with the ET-based method using 8% less water. Selection of an appropriate irrigation scheduling method should be based on marketable yield: keeping the soil water content near field capacity will result in a higher fresh yield but will not translate into more dry matter. If grain yield is the target, the ET-based method is less expensive and more farmer friendly, but care should be taken to properly estimate irrigation losses to avoid underirrigation. An evaporative stress index (determined using sap flow measurements) of 70% will cause a 22% reduction in fresh sweet corn yield but only a 7% reduction in grain yield. Transpiration peaked when the soil moisture was above 85% of the available water (i.e., at 38% in the calcareous clay soil of the experiment).

In order to study the effects of drought stress and nitrogen (N) levels on grain yield, yield components and water use efficiency of grain corn (SC.704), a field experiment was conducted in 2009 growing season. The experiment was split-plot based on randomized complete block design arrangement and four replicates. Main plots were three irrigation levels included optimum irrigation (I1), moderate stress (I2) and sever stress (I3) (irrigation based on depletion of 50%, 60% and 70% of field capacity soil water, respectively). Sub-plots included three levels of nitrogen (N1=120, N2=180 and N3=240 Kg N ha-1). Results indicated that, drought stress reduced biological yield (BY), grain yield (GY) and other yield components, significantly. Nitrogen imposed a significant effect on GY and yield components. Grain yield reduction in moderate and sever drought stress compared with optimum conditions was 15.4% and 37%, respectively. Nitrogen application had a positive effect in GY and BY under optimum and moderate stress treatments. GY reduction in sever drought stress and low N rates was due to lower grain per ear and 1000-grain weight. The highest and the lowest water use efficiency (economic and biologic) were in optimum irrigation and sever drought stress, respectively. Also the highest water use efficiency was belonged to optimum irrigation and 240 Kg N ha-1 treatments.

Field experiments were conducted to determine the crop losses caused by ascochyta blight in different pea varieties grown in Victoria. For each variety, the reduction in yield associated with disease was determined by comparing grain yields in plots not sprayed with fungicide (disease present) and plots where the disease was controlled with fungicide sprays (no disease). There was considerable variation between pea varieties and lines in disease severity and crop losses. Individual varieties had different levels of tolerance to disease, and there were large differences between varieties in the percentage yield loss caused by the same level of disease. Disease severity was closely correlated with reductions in grain yield, and for most varieties there was a 5-6% reduction in grain yield for every 10% of stem area affected by disease (first 10 internodes on the main branch). Ascochyta blight caused substantial reductions in grain yield of all commercial pea varieties grown in Victoria but was usually most severe on the early-maturing varieties. For 15 varieties, empirical crop loss models to predict the relationship between disease severity and reduction in yield were developed. A disease survey of commercial crops was then conducted and estimates made of yield losses caused by ascochyta blight using the previously developed crop loss models. The estimated yield losses caused by ascochyta blight in commercial crops in Victoria in 1986 ranged from 3.1 to 26.4% and exceeded 15% in over three-quarters of crops surveyed. The results suggest that field pea production in Victoria is seriously retarded by ascochyta blight and that the development of effective strategies to control the disease should be given a high priority.

Simulating on the effects of irrigation on jujube tree growth, evapotranspiration and water use based on crop growth model

Four extra-short-duration (ESD) lines in 1991 and eight ESD lines in 1992 were grown with adequate soil moisture throughout their growth or subjected to drought coinciding with the vegetative, flowering and pod-filling stages under rainout shelters. In both years, drought stress treatments significantly reduced dry matter accumulation and grain yield. The extent of reduction in grain yield varied with the line and stage of stress imposition. Drought stress at the flowering stage caused greater reduction in total dry matter and grain yield than the stress imposed during the pre-flowering and pod-filling stages. Drought stress coinciding with the flowering stage reduced grain yield by 40–55% in 1991 and 15–40% in 1992 in different lines. ESD genotypes could extract moisture from up to a metre depth during pre-flowering and flowering stage stress but less so during the pod-filling stage stress. Genotype ICPL 88039, followed by ICPL 89021, showed consistently lowest sensitivity to drought stress at flowering. Protracted drought stress commencing from the pre-flowering to flowering or from the flowering to pod-filling stages was more harmful than stress at the individual stages. The reduction in yield under drought stress could be attributed mainly to less total dry matter accumulation, but also increased abscission of plant parts. The results suggest variation in sensitivity of ESD lines in relation to timing of stress, which should facilitate targeted screening for different intermittent moisture stress environments.

Summer cover crops extract soil water and may affect succeeding winter wheat (Triticum aestivum L.) yield and water‐use efficiency (WUE). We examined the effect of summer cover crops and N fertilization rates on soil water storage at wheat planting (SWP) and harvest (SWH), winter wheat yield, evapotranspiration (ET), and WUE from 2017–2018 to 2019–2020 at Changwu and Chang'an in the Loess Plateau of China. Cover crops were soybean [Glycine max (L.) Merr., SB], sudangrass [Sorghum sudanense (Piper) Stapf, SG], soybean and sudangrass mixture (SS), and no cover crop (CK) and N fertilization rates were 0, 60, and 120 kg N ha–1 applied to winter wheat. Soil water was measured to a depth of 2 m at wheat planting and harvest, and grain yield, ET, and WUE of wheat were evaluated. Cover crop biomass was greater for SS than SB at both sites. The SWP and ET were greater for CK than other cover crops at all N fertilization rates, but SWH varied for cover crops, N fertilization rates, years, and sites. Winter wheat grain yield and WUE were greater for SS than other cover crops and increased with increased N fertilization rates in all years and sites. Although SS and 120 kg N ha–1 reduced SWP and ET, wheat yield and WUE were greater than other cover crops and N fertilization rates in the semiarid climatic condition of the Loess Plateau of China where annual precipitation is adequate to reduce the detrimental effect of water stress.

[PHOSPHOROUS AVAILABILITY, ITS UPTAKE AND YIELD OF SWEET CORN UNDER THE APPLICATION OF UREA AND PK FERTILIZERS IN JATINANGOR INCEPTISOLS]. Maize is one of the staple foods cultivated in Indonesia. Low soil fertility causes the low production of maize. Sweet corn requires sufficient nutrients to grow and produce optimally. The application of a combination of Urea fertilizers and PK on sweet corn plants is expected to increase the availability of nutrients and sweet corn crop production. The objective of this study was to determine the effect of Urea fertilizer and PK application on available P, P uptake, and yield of sweet corn (Zea mays saccharata Sturt) on Jatinangor Inceptisols. This research used the Randomized Block Design (RBD) experiment model, consisting of 9 treatments of 1 control treatment (without treatment), 1 standard recommendation of N, P, K fertilizer treatment, and 7 treatments combination of Urea fertilizer and PK. Each treatment was repeated three times. The results revealed that available-P, P uptake, and yield of sweet corn on Jatinangor Inceptisols were affected by the combination of Urea fertilizer and PK. The combination of 300 kg/ha of urea with 215 kg/ha of PK fertilizer increased the available P value until 23,78 ppm, P uptake (0,67 %), and fresh weight of the corncobs (480,27 g plant-1) on Jatinangor Inceptisols.

Bio-N® fertilizer is a substance which contains living microorganisms which, when applied to seed, plant surfaces, or soil, colonizes the rhizosphere or the interior of the plant and promotes growth by increasing the supply or availability of primary nutrients to the host plant. This study was conducted to determine the effects of Bio-N® and different levels of inorganic fertilizers on the growth, yield and postharvest quality of sweet corn (Zea mays var. rugosa). The experiment was conducted using a 5m x 4m plot size and arranged as a 2x3 factorial experiment within a Randomized Complete Block Design. Bio-N application (with and without) was designated as Factor A, while the varying levels of inorganic NPK fertilizer (100%, 75%, 50%) were assigned as Factor B. This resulted in six treatment combinations, with each plot containing 108 sweetcorn plants, replicated three times. Sweetcorn plants applied with Bio-N® fertilizer gave a significant growth and yield compared to those plants without fertilizer (Bio-N®) applied. The highest net income and return of investment were obtained from plants applied with Bio-N® with 100% RR of inorganic fertilizer at 284,866.00 and 316.05% respectively.

To investigate the effect of irrigation regime, soil clay content and their combination on growth, yield, and water productivity of rice, a shelter experiment was conduct using Randomized Complete Block Design (RCBD) with a factorial arrangement of treatments with four replications. Irrigation regime was the main treatment investigated, set in three levels as R(30 mm-100%) (100% of saturation and 30 mm flooded), R(30 mm-90%) (90% of saturation and 30 mm flooded) and R(30 mm-70%) (70% saturation and 30 mm flooded), respectively. The sub-treatment was soil type, set in three levels as 40%, 50% and 60% clay content, respectively. Results showed that irrigation regime and soil clay content had significant effects on growth, yield and water productivity of rice. However, their combination showed no significant impact on panicles number, root biomass, harvest index and irrigation water productivity. Higher soil clay content results in increase in growth, yield, and water productivity of rice. The total water consumption during R(30 mm-100%) was higher than that during R(30 mm-90%) and R(30 mm-70%) because the latter two saturation levels led to the cracking of soil and decrease of total number of irrigations. Cracks were consistently getting more serious with the reduction in soil water content and the increase in soil clay content. Cracks in soil will preferentially become the major routes of water losses, thus water percolation during R(30 mm-70%) was higher than that during R(30 mm-90%) and R(30 mm-100%) after each irrigation event. The total water use under R(30 mm-70%) exceeded the water consumption under R(30 mm-90%) due to the great amount of soil cracking as well as the excessive volume of standing water depth. Considering water consumption and grain yield, the following conclusion can be reached: (i) The reduction in water consumption was greater than the reduction in grain yield in the case of drying soil 10% below saturation before reflooding. (ii) The reduction in water consumption was less than the reduction in grain yield in the case of drying soil 30% below saturation before reflooding; (iii) The increase in water use was greater than the increase in grain yield in the case of maintaining soil moisture at 100% of saturation before reflooding. Therefore, the water use efficiency was recorded in the order of R(30 mm-90%) >R(30 mm-100%) >R(30 mm-70%). Keywords: irrigation regime, clay content, combination, growth, yield, water productivity, rice DOI: 10.25165/j.ijabe.20181104.3895 Citation: Hamoud Y A, Guo X P, Wang Z C, Chen S, Rasool G. Effects of irrigation water regime, soil clay content and their combination on growth, yield, and water use efficiency of rice grown in South China. Int J Agric & Biol Eng, 2018; 11(4): 144-155.

The effect of first-generation southwestern corn borers ( Zeadiatraea grandiosella Dyar) on the development and yield of dent and sweet corn was studied at Stillwater, Okla., in 1955. Plants in different stages of growth were manually infested with newly hatched larvae. Plant height was not significantly affected, but the weight of plants was reduced moderately by the borers. There was a greater reduction in yield of grain from small than from large corn plants. Dead heart was also more prevalent in the plants that were smallest at the time of infesting. Since small plants had greater damage than larger ones, the earliest planting consistent with good agronomic practices should avoid the greatest damage by the first generation of this borer. Dissections made at harvest did not give an accurate measurement of first-generation populations.

マメ科牧草のアルファルファ,アカクローバ,シロクローバをリビングマルチとして利用し,除草剤を用いずに不耕起栽培したスィートコーンの生育,収量と雑草の発生状況を2ヶ年にわたって調査した.1998年,1999年とも全てのリビングマルチ区で雑草の発生は顕著に抑制された.しかし,スィートコーンの収量はリビングマルチ牧草の種類によって異なり,スィートコーンの株立ち率の高かったシロクローバリビングマルチ区(WC区)では収量,品質とも慣行栽培区(CV区)と有意な差がなかったが,株立ち率の低かったアルファルファリビングマルチ区(AL区)では収量が著しく低かった.WC区のスィートコーン株立ち率が高かった原因は,シロクローバの草高が低く乾物生産量も少なかったため,出芽や初期生育においてシロクローバとの光や養分に対する競合が小さかったことによると推察された.また,株立ち以降もWC区ではシロクローバの草高が低く,シロクローバの窒素吸収量がスィートコーンの生育にともなって減少したことから,スィートコーンとシロクローバとの間に窒素や光に対する競合はほとんどなかったと推察された.これらのことから,シロクローバによるリビングマルチを利用することで除草剤を用いずにスィートコーンを栽培することが可能であると考えられた.

Increasing sweet corn yields in peatland is achieved by fertilizing using organic fertilizer to make it environmentally friendly. Fertilization aims to increase soil fertility and meet plant nutrient needs. The purpose of this study was to ascertain the components of sweet corn growth and yield in peatland by the application of compost made of cattle manure and kalakai. This study arranged in a Randomized Block Design, consisting of 5 treatments i.e. P1 (treatment without cattle manure compost as a control), P2 (10 tons/ha of cattle manure compost), P3 (20 tons/ha of cattle manure compost), P4 (30 tons/ha of cattle manure compost), and P5 (40 tons/ha of cattle manure compost). The components of sweet corn yield and growth were the variables that were observed. According to the study, there was a significant difference in sweet corn plant height and leaves quantity at 45 days after planting across all treatments (P<0.05). At 45 days after planting, all treatments showed significant differences (P<0.05) in ear length, ear circumference, ear weight without husks, number of corn kernel rows, and number of corn kernels per row of sweet corn plants. The P3 treatment gave the best results in this study.

Arid and semi-arid regions in the world that produce wheat (Triticum aestivum) are faced with frequent droughts in recent years. Moreover, wheat production is highly dependent on irrigation and it is essential to increase irrigation water productivity in these regions. Therefore, the aim of this study was to investigate the effects of irrigation methods, planting methods, and nitrogen application rates on yield, water and nitrogen use efficiencies of winter wheat. The experiment arranged in split–split plot with randomized blocks with two surface irrigation methods [ordinary furrow irrigation (OFI) and variable alternate furrow irrigation (VAFI)] as the main plots, two planting methods [on-ridge planting (ORP) and in-furrow planting] as the sub plots, and three nitrogen application rates (N0 = 0, N1 = 150 and N2 = 300 kg N ha−1) as the sub–sub plot. Results indicated that VAFI reduced the winter wheat grain yield, dry matter, grain number per spike, and harvest index as 12, 9, 3, and 4%, respectively; however, these reductions were not significant in comparison with OFI method with a reduction of 33% in irrigation water; as a consequence, the straw nitrogen concentration, grain protein concentration, and also water use efficiencies (WUE), irrigation water productivity (IWP), economic irrigation water productivity (EIWP) and nitrogen use efficiency (NUE) were improved in VAFI as 14, 5, 6, 26, 25, and 8%, respectively. In spite of a slight reduction in grain yield, VAFI method increased EIWP. Economic nitrogen productivity decreased about 50% by increase in N rate, and 150 kg N ha−1 was the optimum rate to apply. Furthermore, VAFI decreased the seasonal ET, thereby improved WUE and IWP. In-furrow planting increased significantly the WUES while it did not enhance significantly WUE for grain. Generally, increasing the nitrogen rate increased the grain yield; whereas, there was no significant difference between the treatments of 150 and 300 kg N ha−1. Results suggest that application of 150 kg N ha−1 combined with in-furrow planting method and variable alternate furrow irrigation is an effective way to improve WUE, yield, yield components and NUE for winter wheat in the study area.