Effective Weed Control Research Articles

Assessing varietal tolerance and weed control effectiveness of metribuzin-based herbicide mixtures in wheat (Triticum aestivum)

A field experiment was conducted during 2014–15 and 2015–16 at Research Farm of Department of Agronomy,CCSHAU, Hisar. The experiment comprised five wheat (Triticum aestivum L.) varieties (WH 1105, HD 2967, DPW621-50, WH 1124 and DBW 17) in main plots and six weed management practices, viz. metribuzin (210 g/ha),metribuzin + fenoxaprop (150 + 100 g/ha), metribuzin + pinoxaden (150 + 40 g/ha), metribuzin + clodinafop (150+ 45 g/ha), weed free and weedy check in sub-plots was conducted in split-plot design with three replications. Thepopulation and dry matter accumulation of weeds were not affected by wheat varieties. Wheat variety WH 1105resulted in maximum grain yield and remained at par with HD 2967 and DPW 621-50, but statistically superior toDBW 17 and WH 1124. Minimum population of grassy and total weeds and dry matter accumulation by them wasobserved with metribuzin + fenoxaprop, being at par with other two combinations of metribuzin. But, the densityand dry matter of broad leaved weeds was minimum with metribuzin alone (210 g/ha). Among herbicidal treatments, metribuzin + fenoxaprop (150 + 100 g/ha) remained superior with maximum grain yield.

Transcriptome analysis and the identification of genes involved in the metabolic pathways of fenoxaprop-P-ethyl in rice treated with isoxadifen-ethyl hydrolysate

Fenoxaprop-P-ethyl (FE) is a highly effective weed control agent for rice fields, but it causes phytotoxicity in crops. A whole-plant bioassay has revealed that isoxadifen-ethyl hydrolysate (IH) can significantly improve the tolerance of rice to FE, but the molecular mechanisms underlying this phenomenon are still unclear. In this study, we performed RNA-Seq analysis using rice seedlings treated with FE and IH to determine the IH-regulated candidate genes involved in metabolic resistance to FE. We also analyzed spatiotemporal expression using quantitative reverse transcription polymerase chain reaction to reveal the expression patterns of these genes under different treatments. The results showed that genes encoding metabolic enzymes, such as cytochrome P450 monooxygenases, glutathione-s-transferases, UDP-glycosyltransferase, carboxylesterase, and ATP-binding cassette transporter, were influenced by the application of IH. Most of these genes were upregulated, and their products were involved in various stages of FE metabolism. Tolerance to FE was primarily mediated by CarE15, CYP86A1, GSTU6, GST4, UGT13248, UGT79, and ABCC4, all of which played a vital role in regulating the detoxification process of FE. Our findings elucidated the protective mechanisms of IH, which can help alleviate the phytotoxic effects of FE and expand its potential for application in agriculture.

Spray Deposition on Watermelon Crop in Aerial and Ground Application

The quality and quantity production of watermelon requires the effective control of pests, diseases, and weeds, which is directly related to spraying techniques. The method of application of phytosanitary products is essential, but, most of the time, emphasis is given mainly to the applied product and little attention to the application technique. The objective of the present study was to characterize the ejected spray in the aerial and terrestrial spraying of watermelon crops, with the use of adjuvants in a liquid solution. The experiment was carried out in two commercial plantations, in an entirely randomized design, employing a 6 × 2 factorial scheme, with six forms of application and two liquid compositions. The droplet spectrum was assessed employing water-sensitive card imaging. Smaller drop sizes and relative amplitudes were produced by aerial applications. In turn, the largest droplet diameters and the lowest percentage of drops smaller than 100 μm were obtained when using air induction flat double-jet nozzles. The adjuvant did not interfere in the numerical and volumetric median diameters, the relative amplitude, or the volume rate of droplets smaller than 100 μm.

Electricity as an effective weed control tool in non‐crop areas

AbstractWhile weed management is often thought of as an agricultural issue, weeds are also problematic for homeowners, public space managers and utilities. In these situations, weeds are typically hand‐pulled, mechanically treated or managed via herbicides. Hand pulling and mechanical treatments are labour‐intensive, and all control methods may have unintended off‐target impacts, necessitating new alternatives for weed control. We have developed a method of using electricity to effectively manage unwanted plants. A series of experiments was conducted with the aim of developing operating protocols with consideration to specific scenarios: we tested a system on Morus alba (mulberry) and Ulmus pumila saplings, determined the response of Tamarix spp. (tamarisk) to different electricity doses, evaluated electricity as pre‐emergent weed control in xeriscaping, and tested the ability of electricity to prevent climbing growth by the vine Convolvulus arvensis (field bindweed). Tests on M. alba and U. pumila demonstrated that low doses of electricity applied over several days are effective in killing trees up to 20 cm in diameter. The Tamarix experiment showed that the plants displayed typical dose–response characteristics with higher doses leading to less plant growth. Results of the pre‐emergent weed control experiment demonstrated the excellent ability of electricity to prevent weed growth, with treated plots having a mean weed cover of 4% compared to 94% in control plots after 4 months. Finally, electricity was shown to be 100% effective in preventing C. arvensis from climbing poles. Our results indicate that electricity is a viable alternative to manual, mechanical or chemical methods for small tree control, pre‐emergent weed control in xeriscaping, and prevention of climbing weeds.

A Review of Chemical Weed Control Practices in Christmas Tree Production in the United States

Christmas trees are sensitive to weed competition, especially during establishment. In initial stages of the tree crop, weeds can utilize available soil moisture and trees may succumb to drought stress. In later stages, weeds can even interfere with production practices. Non-chemical weed control methods alone may not provide effective weed control. Chemical weed management strategies involve the use of preemergence and postemergence herbicides at the right timing and application rates. There are many herbicides that are used in Christmas tree production in the United States, and each has specific application guidelines and weed control spectra. Moreover, crop trees vary in tolerance by species and tree age. Growers need to be careful while applying herbicides as many of these chemicals can cause injury to Christmas trees. Repeated application of herbicides with the same mechanism of action has resulted in development of herbicide resistance among several weed species. Managing herbicide resistance has now become an important issue. More research is required on identifying and managing herbicide resistance among weed species in Christmas tree production. Future research needs to focus on herbicide and mulch combinations, herbicide rotations, and tank mixing different herbicides with different mechanisms of actions and how these affect Christmas tree varieties.

Allelopathic Potential of Hemp: Implications for Integrated Weed Management

Evolved resistance to herbicides necessitates alternative weed control strategies. Allelopathic crops show promise as an alternative to exogenous herbicides and could be used to reduce establishment, growth, and reproduction of weeds. Individual cannabinoids and terpenes found in hemp (Cannabis sativa L.) show allelopathic potential, but allelopathic effects of plant residue have not been characterized. A laboratory assay found that crude, acetone-soluble hemp extracts diluted to 2.5 mg mL−1 reduced the germination of a bioindicator species. However, tested concentrations below 2.5 mg mL−1 were not more effective than the no-extract control treatment at reducing germination. A greenhouse study found that soil-incorporated hemp residue was not more effective than a maize (Zea mays L.) residue treatment comparison in reducing plant growth. However, a simulated chaff line experiment in the greenhouse showed that the equivalent of 378 g m−2 hemp residue on the soil surface can effectively reduce and delay the germination of waterhemp [Amaranthus tuberculatus (Moq.) Sauer] in comparison to bare-soil, or a maize residue treatment comparison. Together, these results show that incorporated hemp residue will likely not be an effective weed control practice. However, chaff lining hemp residue may be an effective practice for the control of certain weeds and warrants further research in a field setting.

Dose–response screening of industrial hemp to herbicides commonly used in corn and soybean

AbstractRecent legalization of industrial hemp in the United States has led to increased interest among stakeholders to produce hemp for grain and fiber. However, owing to the lack of herbicides registered for use in hemp, producers are left with limited weed management strategies. Moreover, much of the agricultural land that could be used to cultivate industrial hemp may be prone to carryover of previously applied residual herbicides or physical drift from herbicides sprayed nearby. Industrial hemp sensitivity to herbicides is not well documented. Dose–response studies were conducted under controlled conditions in Madison, WI, screening two industrial hemp grain cultivars for tolerance to 44 preemergence and postemergence herbicides commonly used in corn and soybean. Treatments consisted of herbicides applied at 0×, 0.125×, 0.25×, 0.50×, 0.75×, 1×, 2×, and 4× the recommended maximum labeled rates based on soil type. Preemergence applications were delivered immediately after planting, whereas postemergence applications took place when hemp plants reached 5 to 10 cm in height. Nontreated plants served as the control and were used to estimate percent biomass reduction; dose–response curves were generated. Biomass reduction was >50% for rates under the suggested label rate for 23 preemergence and 21 postemergence herbicides tested. All herbicides tested resulted in >25% biomass reduction at the 0.125× rate, except for clopyralid applied preemergence and postemergence and saflufenacil applied preemergence. This is concerning, as the label rates are determined for effective weed control and the mitigation of herbicide resistance. Overall, these results indicate that industrial hemp is very sensitive to most herbicides tested. Growers should consider herbicide use history and surrounding crops when determining industrial hemp field selection to prevent significant plant injury due to herbicide carryover and drift. Further research into alternative methods of weed control will be vital to establishing hemp as a dominant crop once again.

Effect of Crop Establishment Methods and Weed Management Practices on Productivity and Profitability of Clusterbean under Semi-arid Region of Rajasthan

Background: Adequate tillage checks and delays the emergence of weeds and provides a more favourable environment for early crop establishment. Slow growth of crop plant provides favourable environment for emergence of weeds. Cultural as well as mechanical practices such as hand weeding and intercultural are effective but unavailability of labour and continuous rainfall in rainy season does not permit for timely management of weeds Chemical weed control is effective weed management option which provides effective control of weeds. It is well known that weeds are ubiquitous but their presence in cropped area particularly in rainy season crops like clusterbean act as major limiting factor in achieving high potential yield. The current study aimed to study the impact of crop establishment methods and weed control practices on productivity and profitability of clusterbean. Methods: A field experiment was carried out to find out suitable method of crop establishment methods and weed management practices in clusterbean during kharif seasons of 2018, 2019 and 2020. The experiment was conducted in spilt plot design with three replications. The treatments were four crop establishment methods viz., conventional sowing, zero tillage sowing, broad bed sowing, zero tillage sowing with mulch as main plots and four weed control practices viz., weedy check, pendimethalin+imazethapyr 1000 g ha-1, T3- Imazethapyr 40 g ha-1, T4-Imazethapyr+imazamox 40 g ha-1 as sub plot treatments . Result: The broad bed sowing of clusterbean along with pre-emergence application of pendimethalin+ imazethapyr 1000 g ha-1 was found effective to achieve higher productivity and farm profitability.

Evaluation of Different Weed Management Strategies in Clusterbean [Cyamopsis tetragonoloba (L.) Taub] under Rainfed Conditions of Punjab

Background: Generally, farmers cultivate clusterbean [Cyamopsis tetragonoloba (L.) Taub] on rainfed area but seldom adopt weed control practices in it. It becomes very difficult and uneconomical to maintain weed free environment throughout crop period in the field under rainfed conditions. Therefore, the current study was aimed to find an effective weed control practice in clusterbean under rainfed conditions. Methods: Effect of weed management practices of clusterbean with T1: Pendimethalin @ 1 litre/ha (PE), T2: Imazethapyr @ 0.1 kg/ha at 20 days (POE), T3: Stale bed technology, T4: One hand weeding at 20 DAS (days after sowing), T5: Two hand weedings at 20 and 40 DAS, T6: Imazethapyr @ 0.1 kg/ha at 20 days + hand weeding at 40 DAS, T7: Pendimethalin @ 1 litre/ha (PE) + hand weeding 35 DAS, T8: Pendimethalin @ 1 litre /ha (PE) + imazethapyr 0.1 kg/ha at 30 DAS and T9: Weedy check were investigated under rainfed conditions. Result: Weed control efficiencies of imazethapyr @ 0.1 kg/ha at 20 days + hand weeding at 40 DAS (T6), pendimethalin @ 1 litre/ha + hand weeding at 40 DAS (T7) and pendimethalin @ 1 litre/ha (PE) + imazethapyr @ 0.1 kg/ha at 20 days (PoE) (T8) were statistically similar. Imazethapyr @ 0.1 kg/ha at 20 days (PoE) + one hand weedings at 40 DAS recorded higher growth characters viz., plant height, dry matter and yield attributing characters viz., number of branches, number of pods/plant and seed index than other treatments. The highest seed yield was recorded in imazethapyr @ 0.1 kg/ha at 20 days (PoE) + one hand weedings at 40 DAS (422 kg/ha), being statistically at par with pendimethalin @ 1 litre/ha (PE) + one hand weedings at 40 DAS (390 kg/ha) and pendimethalin @ 1 litre/ha (PE) + imazethapyr @ 0.1 kg/ha at 20 days (PoE) (392 kg/ha) which was significantly higher than other treatments. Imazethapyr @ 0.1 kg/ha at 20 days (PoE) + one hand weedings at 40 DAS recorded 27.9 and 33.9 per cent higher seed yield than imazethapyr @ 0.1 kg/ha at 20 days (PoE) and one hand weedings at 40 DAS, respectively. The net returns and benefit-cost ratio were maximum for imazethapyr @ 0.1 kg/ha at 20 days (PoE) + hand weeding at 40 DAS (T6). It is inferred that imazethapyr @ 0.1 kg/ha at 20 days (PoE) + one hand weedings at 40 DAS was found the most effective and economic approach for weed control in clusterbean under rainfed conditions.

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.

Synthesis of Novel Pyrimidinylselenium Compounds as Acetolactate Synthase‐Inhibiting Herbicides

AbstractA series of pyrimidinylselenosalicylic acid derivatives (5 a–5 l) and 4‐selenopyrimidine derivatives (6 a–6 f) were synthesized and evaluated as potential acetylactate synthase (ALS)‐inhibiting herbicides. All synthesized new compounds were characterized by 1H NMR, 13C NMR, and high‐resolution mass spectrometry (HRMS). The compounds were subjected to herbicidal activity, in vitro ALS enzyme inhibitory activity, and crop safety studies. The herbicidal activity study shows that 4‐chloro (5 b), 5‐chloro (5 c), 5‐methoxy (5 e), 4,5‐dimethoxy (5 f), 5‐fluoro (5 h), and 4,5‐difluoro (5 i) substituted 2‐[(4,6‐dimethoxy‐2‐pyrimidinyl)selanyl]benzoic acid exhibit significantly enhanced weed control effect than other new compounds and Pyrithiobac. Most of compounds exhibit enhanced inhibition effect on Cyperus difformis Linn than those on barnyard grass, Portulaca oleracea, Eleusine indica, and Amaranthus retroflexus. Importantly, 5 c, 5 f, and 5 i also exhibit more potent inhibition effect on Escherichia coli ALS enzyme than other new compounds and Pyrithiobac in in vitro ALS enzyme inhibitory activity study. The possible binding modes of 5 c, 5 f, and 5 i with ALS enzyme were studied on Discovery Studio. To test the possibility of 5 c, 5 f, and 5 i as potential herbicides in paddy fields, we performed the crop safety study. The results show that 5 f and 5 i are safer to rice than 5 c. The present work indicates that 5 f and 5 i may serve as new herbicide candidates for weed control in paddy fields.

Effective weed control by tank-mix application of post-sowing soil applied herbicides on dry direct-seeded rice fields in northern Kyushu

Effective weed control by tank-mix application of post-sowing soil applied herbicides on dry direct-seeded rice fields in northern Kyushu

The opportunities and challenges for harvest weed seed control (HWSC) in India: An opinion

Weeds which are escaped during the control measures are one of the source of soil weed seedbank. At the time of crop harvest, several weed species retain a considerable quantity of their seed. These weed seeds are evenly spread across the crop field through various weed seed dispersal mechanisms. By knowing the weed seed retention character of every weed species, their effective weed control can be achieved by the collection and/or destruction of weed seeds during crop harvest using harvest weed seed control (HWSC) methods. Narrow windrow burning, chaff tramlining, chaff carts, chaff lining, the Harrington seed destructor (HSD) and the bale direct system are common HWSC procedures. The crop harvest is a primary contributor to the transmission of weed seeds over the crop fields and with HWSC, we can now skip this process and prevent weed seed spread. This strategy is useful to target weed species that retain a large part of their seed after maturity and was found highly effective in controlling the spread of herbicide resistant weed seeds. HWSC aims to prevent the mature weeds seed from entering the seedbank. Through HWSC, we can prevent the enrichment of soil weed seedbanks and deplete existing soil weed seedbanks in long run. In India, the scope for HWSC is high in organic farming, direct-seeded rice, zero-till wheat, herbicide tolerant rice and high intensive irrigated agriculture while its scope is much limited in rainfed agriculture. However, the efforts on using HWSC are yet to begin in India and should be initiated.

Possibilities of weed control in sugar beet crop after desmedipham withdrawn and possible non-approval of further use of phenmedipham and chloridazone

The field research were carried out in 2019–2020, in Picobella sugar beet. The aim of the study was to develop an alternative weed control program without phenmedipham, desmedipham and chloridazone. The tested mixtures containing metamitron, ethofumesate, triflusulfuron-methyl, and lenacil used in various combinations together with the Atpolan BIO 80 EC adjuvant effectively controlled Fat hen (Chenopodium album) up to phase 1 of a pair of true leaves (BBCH 12). Excluding ethofumesate from mixtures of metamitron (700 g/ha) and triflusulfuron-methyl (15 g/ha) reduces the effectiveness of weed control. In the absence of ethofumesate, the effectiveness of the action is improved by increasing the dose of metamitron (1050 g/ha) and adding lenacil (100 g/ha) to the composition of the mixture. The conducted research proved that it is possible to effectively protect beet crops against Fat hen (Ch. album) after the desmedipham withdrawn and possible non-approval of phenmedipham and chloridazone.

Harvest weed seed control: impact on weed management in Australian grain production systems and potential role in global cropping systems

The introduction of harvest weed seed control (HWSC) techniques and associated machinery has enabled the routine use of an alternative weed control technology at a novel weed control timing in global grain cropping fields. Driven by the significant threat of widespread populations of annual ryegrass (Lolium rigidum) with multiple-herbicide resistance, in the 1990s Australian growers and researchers developed techniques to target, at grain harvest, the seed production of annual ryegrass and other important weed species. The HWSC approach to weed management is now routinely used by a majority of Australian grain producers as an integral component of effective weed control programs. Here we detail the development and introduction of current HWSC systems and describe their efficacy in Australian grain production systems. The use of HWSC has likely contributed to lower annual ryegrass population densities and thus mitigated the impacts of herbicide resistance as well as slowing further evolution of resistance. In addition, low weed densities enable the introduction of site-specific weed control technologies and the opportunity to target specific in-crop weeds with non-selective alternative weed control techniques. With an awareness of the evolutionary potential of weed species to adapt to all forms of weed control, there is an understanding that HWSC treatments need to be judiciously used in grain cropping systems to ensure their ongoing efficacy. The successful use of Australian developed HWSC systems has attracted global interest and there is now a considerable international research effort aimed at introducing this alternative weed control approach and timing into the world’s major cropping systems.

Effects of time and weeding method on the regeneration and growth of Japanese yam (Dioscorea japonica) vines and tubers in tea gardens

For the weed control of Japanese yams, farmers pull out the vines by hand because the chemical control of Japanese yams in tea plantations is difficult as the vines grow from the area below the tea trees, where the herbicides have limited reach. This study compared the regeneration and growth of vines after controlling weeds using the following methods: 1) cutting the vine at 30 cm height, 2) cutting the vine at ground level, and 3) pulling out the vine from the base (at the node of the tuber and vine). All three treatments were performed during three weeding seasons to determine the most effective method and time to control Japanese yams in tea gardens. In addition, we investigated the deterioration of old tubers and the formation of new tubers by studying their weight changes because each old tuber disappears and forms a new tuber each year. However, our results indicated that new tubers were formed before the disappearance of old tubers, and there were no border time periods where both old and new tubers were absent. Furthermore, the new tubers grew in a short period from July to August. Therefore, we recommend repeatedly pulling out Japanese yam vines during July for effective weed control. Moreover, when vines of Japanese yam were not pulled out completely or were cut in May or July, branches grew rapidly and reached the canopy of tea trees after 2–4 weeks. Furthermore, when vines were pulled out at the ground level, 40 % of vines reached the canopy after one month. Therefore, it is difficult to control Japanese yam completely by pulling out vines alone.

The Effect of the Timing of Manure Application in Combination with Mineral Fertilizers and Planting Density on the Weediness of Potato Plantings

Potatoes are one of the most responsive crops for grooming techniques since in the period from seedlings before closing rows are easily suppressed by weeds that take away nutrients, water, light from it. The factor that causes high harm to potatoes is weed. By absorbing a large number of nutrients and moisture from the soil, weeds inhibit the growth and development of plants, reducing their potential productivity. The purpose of the study was to establish the effect of the timing of the introduction of bedding manure in conjunction with mineral fertilizers and planting density on the weediness of potato plantings. Studies were provided to identify the impact of the timing of bedding manure together with mineral fertilizers and planting density for weed planting potatoes. Experiments were laid by the systematic method with a tiered arrangement of variants in the experiment with a 3-fold repetition. We used cattle manure on straw bedding for autumn-winter harvesting. The following types of fertilizers were used: ammonium nitrate, double superphosphate, potassium chloride. Determination of the amount and biomass of weeds in potato plantings was carried out in the flowering phase and before harvesting. The application of manure was accompanied by an increase in the number and weight of weeds. Annual weeds predominated in potato plantings: Amaranthus retroflexus L., 1753 and Amaranthus blitoides S. Watson, 1877, Chenopodium album L. Chenopodium album L., 1753, Setaria P. Beauv, 1812 and Setaria viridis (L.) P. Beauv, 1812, Echinochloa crus-galli (L.) BEAUV., 1812 and others, perennials included Cirsium arvense (L.) SCOP. 1772 and Sonchus arvensis L., 1753, (Elytrigia repens (L.) DESV. ex NEVSKI, 1933 and others. Planting density also has a definite effect on the development of weeds. When manure was applied in autumn under the plow, the number of weeds increased in comparison with other options, where only mineral fertilizers were applied. The application of manure over frozen plow and in winter over snow leads to a slight decrease (2.3-2.5 pcs/m2) of weeds. The greatest number of weeds is observed during the spring application of manure for plowing the fall plow. Nevertheless, studies aimed at clarifying the composition and structure of weediness, the number and weight of weeds in potato plantings are of great practical importance for local agricultural producers. These data should contribute to the development of an effective weed control system and high yields of potatoes in the region

Management extensification in oil palm plantations reduces SOC decomposition

Large scale oil palm monocultures are continuously replacing Indonesia's tropical rainforests. The impact of intensive nitrogen (N) fertilization and herbicide application on biogeochemical processes in these monocultures remains unknown. Thus, we aim to understand NPK and herbicide effects on soil carbon (C) cycle. We hypothesize that (1) increased microbial activity due to N fertilization leads to faster soil organic matter (SOM) decomposition and to increased CO2 emissions from soil. Despite this, we expect (2) that herbicide application increases soil organic carbon (SOC) sequestration, as it counteracts the fertilizer's effects by hampering soil microbial activity, by deactivating the same synthesizing pathway as in plants, leading to decreased microbial respiration. We investigated the effects of fertilization (conventional and reduced NPK) and weed control (herbicide or mechanical weeding) on SOC decomposition in the rows between the palms (interrows) and around the palm stems (weeding circles). 14C labelled glucose was added to soil to analyze the response of microbial activity and SOC mineralization during 30-day incubation. Conventional fertilization caused microbial activation and destabilized SOC by priming, resulting in increased CO2 efflux. Glyphosate application plus fertilization further increased microbial activity contradicting our hypothesis. In combination with high fertilizer amounts, glyphosate strongly increased microbial activity. NPK might occupy a greater share of sorption capacities; hence, glyphosate is still available and can act as an additional source of C and possibly N and P. Therefore, SOC decomposition was 1.5 accelerated compared to the control when glyphosate and fertilizer application were combined. In contrast, reduced SOC decomposition, i.e., a strong negative priming effect (−47.9 μg g −1), occurred under reduced NPK fertilization without herbicides suggesting positive effects on C accumulation and storage. Our results emphasize the risk of management intensification and the need for a low-impact management strategy to maintain soil fertility and the function as a C reservoir.

Determinants in the Adoption of Alternate Wetting and Drying Technique for Rice Production in a Gravity Surface Irrigation System in the Philippines

Alternate Wetting and Drying (AWD) is a well-known low-cost water-saving and climate change adaptation and mitigation technique for irrigated rice. However, its adoption rate has been low despite the decade of dissemination in Asia, especially in the Philippines. Using cross-sectional farm-level survey data, this study empirically explored factors shaping AWD adoption in a gravity surface irrigation system. We used regression-based approaches to examine the factors influencing farmers’ adoption of AWD and its impact on yield. Results showed that the majority of the AWD adopters were farmers who practiced enforced rotational irrigation (RI) scheduling within their irrigators’ association (IA). With the current irrigation management system, the probability of AWD implementation increases when farmers do not interfere with the irrigation schedule (otherwise they opt to go with flooding). Interestingly, the awareness factor did not play a significant role in the farmers’ adoption due to the RI setup. However, the perception of water management as an effective weed control method was positively significant, suggesting that farmers are likely to adopt AWD if weeds are not a major issue in their field. Furthermore, the impact on grain yields did not differ with AWD. Thus, given the RI scheduling already in place within the IA, we recommend fine-tuning this setup following the recommended safe AWD at the IA scale.

Weed control in maize crops with various schemes of herbicide application

Goal. Carry out a comparative evaluation of the effectiveness of different schemes of application of modern herbicides in maize crops.
 Methods. Field, phenological, statistical. Conducted spraying of corn crops to seedlings (ВВСН 00) with herbicides Adengo 465 SC, hp (thiencarbazone-methyl, 90 g/l + isoxaflutol, 225 g/l + cyprosulfamide, 150 g/l), 0.5 l/ha, Primextra TZ Gold 500 SC, (S-metachlor. 312.5 g/l + terbuthylazine, 187.5 g/l), 4.5 l/ ha, Merlin Flex Duo 475 SC, (isoxaflutop, 50 g/l + cyprosulfamide, 50 g/l + terbuthylazine, 375 g/l, 2.0 l/ha. After germination in the phase of 4—5 leaves (ВВСН 14—15) applied insurance herbicides Milagro 040 SC, (nicosulfuron, 40 g/l), Basis 75 v.g. rimsulfuron, 500 g/kg + thifensulfuron-methyl, 250 g/l), MаisTer Power OD (foramsulfuron, 31.5 g/l + iodosulfuron-methyl sodium, 1.0 g/l + thiencarbazone-methyl, 10 g/l + cyprosulfamide, 15 g/l), Laudis 30 WG, VG (tembotrione, 200 g/kg + isoxadifen-ethyl, 100 g/kg) and Stellar, RK (topramezone, 50 g/l + dicamba, 160 g/k) in the recommended consumption rates. The experimental plots were 1000 m2 in the first experiment, the recurrence of 3-fold and 25 m2 in the second experiment, the recurrence of 4-fold. Observations were made for meteorological indicators. Statistical processing of the results was performed according to computer «Statgraphic plus» programs. 
 Results. Mixed type of segetal vegetation prevailed in the experimental plots. Among the perennial weeds dominated by Sonchus arvensis L., Cirsium vulgare Savi Ten., Convolvulus arvensis L., among annuals — Setaria glauca L., Setaria viridis L., Echinochloa crus-galli L., Polygonum convolvulus L., Calinsoga parviflora L., Stellaria media (L.) Vill.), Chenopodium album L., Raphanus raphanistrum L., Thlaspi arvense L., Amaranthus retroflexus L. The application of pre-emergence herbicides effectively inhibited the growth and development of weeds. 60 days after application, the effectiveness of herbicides was 87—97% against cereals and 89—98% against dicotyledonous weeds, which did not require the application of insurance herbicides. During the critical periods of maize development, a sufficient level of soil moisture was recorded during the research years. After 60 days, the effectiveness of herbicides applied after crop germination was 65—95% against dicotyledonous and 65—92% against cereal weeds. The highest effect in killing weeds was provided by MaysTer Power, 1.5 l/ha, Laudis 30 WG, VG, 0.5 kg/ha + surfactant Mero, 2.0 l/ha and Stellar, RK, 1.25 l/ha + surfactant Metholate, 1.25 l/ha. The application of herbicides has significantly reduced the aboveground mass of weeds and increased crop yields. Maize grain yield from weed-protected areas was at the level of 8.0—9.7 t/ha against 4.1—4.9 t/ha in the control.
 Conclusions. Both herbicide application schemes under favorable weather conditions provide effective weed control of maize crops The efficiency of pre-emergence herbicides was at the level of 87—98%, post-emergence — 65—95%. At the same time, the reduction of aboveground mass of weeds was 75—95%, and crop yields increased by 1.6—2.2 times depending on the drug.