Comparison of several weed control and tillage techniques in suppressing weeds and increasing maize production for integrated weed control

The use of herbicides has received attention due to its effects on human health, sustainability, and biodiversity due to toxic chemicals in herbicides. Repeated use of herbicide active ingredients over a long period of time can result in the emergence of resistant weeds. One strategy to reduce the herbicide use without decreasing productivity is integrated weed control. This study aims to compare the effectiveness of several weed control techniques in integrated weed control and their role in suppressing weeds and increasing maize crop production. This study used a Randomized Group Design with 2 factorials. The first factor was weed control technique (W) with levels: no control (W0), cover crop (W1), pre-emergent herbicide (W2), post-emergent herbicide (W3), and weed-free (with weeding) (W4). And the second factor was tillage technique (T), namely: no tillage (T0) and conventional tillage (T1). The results showed that post-emergent herbicides were more effective in controlling weeds and the highest crop production with weed control techniques with pre-emergent herbicides. The tillage technique had no significant effect on weeds and maize crop production.


Introduction
Nowadays, based on volume, 60% of pesticides used worldwide are herbicides, and the majority of large-scale agricultural production systems mostly depend on artificial chemicals to control weeds [1].Weeds have been managed mostly with chemical techniques with herbicide over 70 years [2].Many developed countries used herbicides effectively to control weed in no-tillage and no-cropland areas [3].
Since of the harmful chemicals in herbicides, weed management with them has drawn attention since it is thought to have an impact on biodiversity, human health, and the sustainability of agricultural land.As a result, the EU set a goal to cut the usage of pesticides, including herbicides, by 50% by 2030 in the EU Green Deal.This is done to achieve a resilient and sustainable agricultural system [4].The effect of using herbicide extensively and intensively is evolution and/or spread of herbicide resistant [3].Based on this, a strategy is needed to reduce the herbicides used, without decreasing the agricultural yield.Reducing herbicide use can be done by reducing the quantity or frequency.
One strategy for inhibiting weed growth is integrated weed control, which is a part of a sustainable agroecosystem [5].new cultivation techniques (intercropping, false seedbeds, field reduction, crop rotation and diversification, adjustment of planting density and date), new technologies and precision agriculture tools (Decision Support System, robots, remote sensing, UAVs, omics, and nanotechnology), and new non-chemical tools such as burning, seed coating, beneficial microorganisms, biocontrol agents, mechanical weeding, and natural herbicides) are all part of non-chemical integrated weed management [3].
Cover crop (CC) as one of the ways in integrated weed management through plant competition, by suppressing the weeds emergence on the soil surface.The CC suppressing the emergance of weed by competing in light, water, nutrinets, and, space [6].In addition, CC produces allelopathic substances that can suppress the emergence of weeds or control the weeds [7].
CC plays a multipurpose role.CC plays a role as a suppressor of weed growth, but also plays a role to improve the soil quality.According to Adetunji et al. [8], that CC can help in improving the physical, chemical, and biological characteristics in soil quality such as total soil nitrogen, soil bulk density, soil organic carbon levels [9], as well as an increase nutrient for the soil that come from the CC biomass's breakdown.A plant that can be utilized as CC is the cowpea or Vigna unguiculata.Among the benefits of using this cowpea plant as CC is its ability to thrive in tropical climes and on soils with varying degrees of fertility.[8].
It is expected that the use of CC to improve the quality of soil will lessen the amount of tillage that is done on agricultural land.Reduced biological activity and biodiversity (particularly natural enemies of pests and weed seeds), increased soil erosion, degraded soil structure, loss of organic matter, and nutrient leaching are some of the ways that conventional tillage intensification can lower the quality of the soil [10]; [11].This has an impact on sustainable farmland as well.Furthermore, increasing the depth of tillage can offer a high chance for soil-stored seed banks to rise above the surface and germinate.
Based on the description above, it is necessary to compare several weed control and tillage techniques in suppressing weed growth and increasing corn crop production in support of integrated weed control.

Time and place
This research was conducted from July 2022 to January 2023.This research was conducted at the Technical Implementation Unit of Palawija and Horticulture Tanjung Selamat, Pancur Batu District.

Tools and materials
The electric backpack sprayer, measuring cup, trencher, hoe, meter, cutter, treatment tool, analytical balance, plastic and sample envelope, stationery, and camera were among the equipment utilized for this study.The study employed the following materials: corn seeds variety Pioneer 32, cowpea seeds (Vigna unguiculata) used as a cover crop, with white seed color and black hilum (black eye pea) variety Albina IPB, post-emergent herbicides activ.

Implementation
The experimental approach was used to carry out this research.The Randomized Block Design (RBD) approach with two factorials is used in this study.The first factor is weed control techniques (W), specifically: no weeding control (W0), cover crop (W1), pre-emergent herbicide (W2), post-emergent herbicide (W3), and weed-free (with weeding) (W4).And the second factor was tillage technique (T), specifically: no tillage (T0) and conventional tillage (T1).There were three replications (blocks) for each of the ten treatment combinations, for a total of thirty treatments (plots).There were five sample plants each plot, for a total of 150 sample plants, that were to be observed.Analysis of Variance (ANOVA) and Duncan's Multiple Range Test were used to analyze research data.

Land Preparation.
Stakes are erected for every treatment plot, and measurements are taken with a meter.Each plot measured 2.1 by 1.4 meters.Plots were separated by 50 cm, and blocks were separated by 100 cm.This plot will be sown with 40 x 10 cm spacing for cowpeas and 70 x 20 cm spacing for corn seeds.

Weed Dry Weight.
Weeds in the sample plots were identified first in sample plot size 50 x 50 cm, then they will be cut at the base of the stem and then oven dried at 70 o C for 48 hours or until the weed weight is constant.Weeds that have been oven dried and then measured using an analytical balance.The first weed dry weight collection was before applying the treatment and the second weed dry weight collection was after the corn harvest was done.
2.3.3.Tillages.Tillage was done conventionally using a hoe in plots with tillage treatment only.The tillage depth was 15 cm.In the herbicide treatment before emergence and tillage treatment; tillage operations were completed once the cover crop had started to fade.

Planting Cover Crop (CC).
The kind of CC that is utilized is called cowpea, or tolo bean (cowpea).Albina IPB was the cowpea variety that was used.Following tillage or the harvest of the preceding crop, CC planting takes place right away.40 x 10 cm is the planting distance for cowpeas.In every planting hole, there were two cowpea seeds.Furthermore, thinning was done one week after planting (WAP).

Pre-emergent Herbicide Application.
Pre-emergent herbicide which used in this study was herbicide with pendimentalin as the active ingredient.The dose of herbicide applied was in accordance with the label recommendation.Prior to planting the maize, the pre-emergent herbicide was sprayed right away following tillage or clearing the ground.The herbicide was applied in the morning when it wasn't raining outside.
2.3.6.Post-emergent Herbicide Application.Topramezon and atrazine were the active components of the post-emergent herbicides employed in this study.The amounts of herbicides used were in line with what was recommended on the label.When the weeds had three to five leaves, these pre-emergent herbicides were sprayed right after following tillage or area clearance.When the weather is not rainy, herbicide is applied in the morning.

Cover crop termination.
Cutting the CC to the base of the CC stem completes the CC termination process.This termination occurs in the early stages of CC's flowering.It is crucial to make sure that the CC is dispersed equally over the plot following termination.After that, the CC will be left in place for two weeks until soil analysis II and corn planting take place.

Maize Planting.
The corn variety used is Pioneer 32.Planting is done by making planting holes with 2 -3 cm deep.Each planting hole will be filled with 2 corn seeds.The planting distance that will be used in planting this corn is 70 x 20 cm.Thinning will be done at 1 MST by leaving 1 plant to be maintained.

Maize Maintenance.
Watering is done once a day using a watering can.Watering is done in the afternoon.And if there is rain, watering is not done.Fertilization of corn plants uses urea fertilizer at a dose of 250 kg.ha -1 + NPK Phonska fertilizer at a dose of 300 kg.ha -1 + 2 tons.ha - of manure [12].To apply fertilizer, a 10-cm-diameter hole was dug adjacent to the corn plant.Fertilization is done at 4 weeks after planting.Pest control in corn plants can be done manually or with insecticides.Fungal disease control on maize plants will be controlled by using fungicides.These control measures will be adjusted to the realization when this research is conducted.

Maize
Harvesting.Maize will be harvested with the following harvest maturity criteria: The leaves and kelobot are yellowish in color and dry, and the seeds are shiny and have no marks when pressed with a fingernail.The harvested maize will be separated between the cob and the husk.

Observed Variable 2.4.1. Weed Emergance Suppressant.
The dry weight of the weeds was measured by cutting them at the root neck before applying weed control treatment and at V10 corn stadiums.The cut weeds were put into envelopes based on each treatment.Next, the weeds will be dried using an oven at 70 o C for 48 hours or until dry and then weighed dry weight.

Maize Production.
The variable that observed in maize production are cob length (cm), cob diameter (mm), weight per cob (g), weight of 100 seeds (g).
Measure the diameter of the cob at the center of the cob using a caliper.This measurement is carried out when the corn has been separated between the cobs and husks.The harvested maize cobs are first dried for a week under direct sunlight to reduce the moisture content of the kernels, so that the kernels do not break when shelled.Next, the corn kernels are shelled and dried again for 3 days.Then the harvested corn kernels per cob per sample will be weighed using an analytical balance.Then 100 were taken randomly per plot and weighed using an analytical balance.

Weed Dry Weight.
Considering the outcomes of the analysis of variance, it is known that the tillage techniques and interaction between weed control techniques does not significantly affect the dry weight of weeds in the first observation (Weed Dry Weight 1) and second observation (Weed Dry Weight 2), but weed control techniques significantly affect the dry weight of weeds in the second observation with weed control techniques in post-emergence herbicide treatment (W3) against the use of cover crops and without control, but not significantly different from other treatments.According to [13], [14], and [15] that between cover crop biomass and weed dry matter there is no correlation.This is because leguminous cover crops not only function as ground cover crops but also provide high quality residues and nitrogen [16].In the treatment of tillage techniques there is a similar pattern to the dry weight of weeds produced.The heaviest weed dry weight was in the no-tillage treatment (T0) both in the first and second observations, and the lowest was in the conventional tillage treatment (T1).This occurred because of the reduction in weed biomass along with tillage.The elimination of established weeds, especially perennial weeds that grow from vegetative elements like store roots, rhizomes, or other underground structures, often requires tillage.Tillage includes weeds being pulled up and their roots and branches chopped [17].The treatment of tillage techniques and the interaction between weed control techniques and tillage techniques had no significant effect on all parameters of maize yield.However, the results of the analysis of variance showed that the treatment of weed control techniques only had a real effect on the cob diameter parameter, while on other corn yield parameters such as cob length, weight per cob, and weight of 100 seeds had no real effect.In light of the outcomes of additional assessments using the Duncan's Multiple Range Test method on the average data of corn cob diameter from the treatment of weed control techniques, it shows that weed control with pre-emergent herbicides (W2) produces corn with the largest cob diameter which is significantly different from no control (W0) and weed-free (by weeding) (W4), but not significantly different from the cover crop treatment (W1) and post-emergent herbicides (W3).Weed control by herbicide application can cause the suppression of weed growth by suppress competition between plants and weeds.High weed competition ability will suppress the ability of plants to absorb nutrients to support plant growth [18].
In the treatment of tillage techniques, the heaviest weed dry weight in the parameters of cob length, weight per cob and weight of 100 seeds was found in the no-tillage treatment, while in the cob diameter parameter was found in the conventional tillage treatment.However, it can be seen in Table 2 that the dry weight results in both the no-tillage and conventional tillage treatments were not much different.The tillage was only reducing soil porosity within soil aggregates but does not affect the soil organic matter content [19]

Conclusion
Weed control techniques had a significant effect on weed dry weight in the second observation with weed control techniques in the post-emergence herbicide treatment.Conventional tillage treatment had a positive effect on reducing the second weed dry weight.Pre-emergence herbicide application had a significant effect on no weed control and weed-free (with weeding) treatments on maize cob diameter parameters.

Figure 1 .
Figure 1.Interaction between Weed Control and Tillage Techniques on Weed Dry Weight 1

Figure 2 .
Figure 2. Interaction between Weed Control and Tillage Techniques on Weed Dry Weight 2

Table 1 .
Weed Dry Weight Data on the Weed Control and Tillage Techniques Treatment The result of maize production parameters can be shown at Table2.

Table 2 .
Average Data on Corn Planting Yields for Weed Control and Soil Tillage Techniques .