Better Soil Moisture Conditions Research Articles

Evaluation of pre-emergence herbicides for weed management and rice yield in direct-seeded rice in Cambodian lowland ecosystems

Poor weed management in direct-seeded rice (DSR) at crop establishment stage has led to the need to explore different pre-emergence herbicides to reduce weed biomass and increase DSR yield in Cambodian lowland ecosystems. This study evaluated weed and yield responses to pre-emergence herbicides (pendimethalin, pretilachlor, butachlor, oxadiazon and no application as the control) under different weed management options during the 2018 and 2019 early wet seasons in farmers’ rice fields. All pre-emergence herbicides reduced weed flora and pendimethalin was most effective in controlling the population of mainly grassy weeds. Pendimethalin significantly reduced weed dry biomass by 36.2% (21.3 ​g ​m−2) in 2018 compared with the untreated control. In 2019, weed dry biomass was significantly reduced by 46% (17.9 ​g ​m−2) with butachlor compared with the untreated plot. Pendimethalin increased toxicity in rice plants, which decreased SPAD (leaf greenness) by 44.8% and tiller numbers by 39.3% at 7 days after herbicide application (DAPH) compared with butachlor, but plants recovered from pendimethalin toxicity at 14 DAPH. In 2018, oxadiazon herbicide significantly increased grain yield by 61% (4.6 ​t ​ha −1) compared with the untreated control, but oxadiazon produced similar grain yields as pendimethalin. In 2019, there was no significant effect of pre-emergence herbicides on yield but butachlor produced the highest rice yield (3.2 ​t ​ha−1) followed by pendimethalin (2.8 ​t ​ha−1) and oxadiazon (2.7 ​t ​ha−1). Our study demonstrated that pre-emergent herbicides function differently under varying soil-water conditions in 2018 and 2019, therefore rice growers can use butachlor to control weeds in dryer soil conditions and potentially use pendimethalin to control weeds in good soil moisture conditions. This information is crucial and safe in developing appropriate strategies to manage weeds and enhancing DSR productivity in lowland ecosystems.

A pleiotropic QTL increased economic water use efficiency in bread wheat (Triticum aestivum L.).

Wheat is one of the most important food crops in the world and drought can severely impact on wheat productivity. The identification and deployment of genes for improved water use efficiency (WUE) can help alleviate yield loss under water limitation. In this study, a high-density genetic linkage map of wheat recombinant inbred lines (Ningchun 4 x Ningchun 27) containing 8751 specific locus amplified fragment (SLAF) tags (including 14757 SNPs), with a total map distance of 1685 cM and an average inter-marker map distance of 0.19 cM was constructed by SLAF-seq technology. The economic yield WUE and nine related traits under three water treatments was monitored over four years. The results showed that loci conditioning WUE were also associated with grain carbon isotope discrimination (CID), flag leaf chlorophyll content, plant height, 1000-grain weight, grain weight per spike and grain number per spike. One locus on chromosome 2B explained 26.3% WUE variation in multiple environments. Under good soil moisture conditions before flowering, the high CID genotype QWue.acn-2B Ningchun 27, was associated with WUE, high grain weight per spike, and kilo-grain weight. Under rain-fed conditions, the low CID genotype QWue.acn-2B Ningchun 4 tended to maintain more spike number and was associated with improved WUE and yield. The introduction of good chromosome fragments of QWue.acn-2B into elite lines by molecular marker assisted selection will boost up the cultivation of high-yield and water-saving wheat varieties.

Testing the Effectiveness of the European Cross-compliance Standard 3.1 “Ploughing in Good Soil Moisture Conditions”

A three years monitoring was carried out at 9 sites in Italy to evaluate some physical indicators of soil quality related to soil structure degradation and compaction: bulk density, packing density, surface roughness of the seedbed, and crop yields, and test effectiveness of European cross-compliance Standard 3.1 ‘Ploughing in good soil moisture conditions’. Two plots were set up in each site: low soil moisture (L), with soil main tillage at lower water content, and high soil moisture (H) with soil main tillage at higher water content. The volumetric soil water contents at ploughing in the two treatments were compared with Upper Tillage Limit (θUTL) and Optimum Tillage Limit (θOTL). Grain yields of crops were lower as average when soil was tilled at high moisture content in comparison with the low moisture treatments. The physical parameters adopted as indicators of soil structure degradation proved effective in assessing the differences among the treatments, and could be adopted as a routine scheme in similar researches on the effects of soil tillage on soil degradation.

Environmental effectiveness of GAEC cross-compliance Standard 3.1 Ploughing in good soil moisture conditions and economic evaluation of the competitiveness gap for farmers

Within the MO.NA.CO. Project the environmental effectiveness of GAEC cross-compliance Standard 3.1 Ploughing in good soil moisture conditions was evaluated, as well as the economic evaluation of the competitiveness gap for farmers which conform or do not conform to cross-compliance. The monitoring has been carried out at nine experimental farms with different pedoclimatic characteristics, where some indicators of soil structure degradation have been evaluated, such as bulk density, packing density and surface roughness of the seedbed, and the crop productive and qualitative parameters. In each monitoring farm two experimental plots have been set up: factual with soil tillage at proper water content (tilth), counterfactual with soil tillage at inadequate water content (no tilth). The monitoring did not exhibit univocal results for the different parameters, thus the effectiveness of the Standard 3.1 is contrasting (class of merit B), and there was an evident practical problem to till the soil at optimum water content, even in controlled experimental condition. Bulk density was significantly lower in the factual treatment although in soils with very different textures (sandy-loam and clayey). Packing density (PD) showed a high susceptibility to compaction in soils with low PD and medium texture. The tortuosity index, indicating the roughness of the seedbed, was lower and generally significantly different in the factual treatment. Results showed that the ploughing done in excessive soil moisture conditions is more expensive due to the increased force of traction of the tractor, which causes an increase in slip of the tractor wheels, with a speed reduction and increase in the working times and fuel consumption. Moreover, the crop yield is also reduced considerably according to the cultivated species.

Effectiveness of the GAEC cross-compliance standard Ploughing in good soil moisture conditions in soil structure protection

Researches have been carried out within the framework on the EFFICOND Project, focused at evaluating the effectiveness of the standards of Good Agricultural and Environmental Conditions (GAECs) established for Cross Compliance implementation under EC Regulation 1782/2003. In particular the standard 3.1b deals with soil structure protection through appropriate machinery use, with particular reference to ploughing in good soil moisture conditions. The study deals with the evaluation of soil structure after tillage in tilth and no-tilth conditions at soil moisture contents other than the optimum water content for tillage. The Mean Weight Diameter (MWD) of water stable aggregates was used as an indicator of tillage effectiveness. The study was carried out in the period 2008-2009 at six experimental farms belonging to Research Centres and Units of the Italian Agricultural Research Council (CRA) with different pedo-climatic and cropping conditions. Farm management and data collection in the different sites were carried out by the local CRA researchers and technicians. The comparison of MWD values in tilth and no tilth theses showed statistically significant differences in most cases, depending on topsoil texture. On clay, clay loam, silty clay, and silty clay loam topsoils a general and significant increase of MWD values under no tilth conditions were observed. No significant differences were observed in silt loam and sandy loam textures, probably due to the weak soil structure of the topsoils. Moreover, ploughing in good soil moisture condition determined higher crop production and less weed development than ploughing in high soil moisture conditions.

Yield and water use response of winter wheat to winter irrigation in the North China Plain

With intensifying water shortage, adoption of deficit irrigation strategies is likely to increase around the world. Winter wheat (<i>Triticum aestivum</i> L.) is one of the crops that has successfully been grown with deficit irrigation in the North China Plain. However, irrigating once before winter wheat enters dormancy (simplified as winter irrigation [WI]) is still a popular practice in this region. This study investigated the necessity of this irrigation and its effects on crop performance to provide guidelines for better irrigation management. Field experiments at two sites with up to five irrigation treatments (from rainfed up to three irrigations with or without WI) in a randomized block design with four replications were conducted for two to three winter wheat growing seasons from 2006 to 2009 in the North China Plain. Results showed that with good soil moisture at sowing, winter wheat achieved its maximum grain production with two irrigation applications in dry seasons and one irrigation application in wet seasons, both without WI. Winter irrigation increased evapotranspiration by 20 to 25 mm (0.79 to 0.98 in) and increased drainage from the root zone profile by 20 mm during the long winter dormancy period. With good soil moisture conditions at sowing plus some rainfall, soil moisture before winter wheat enters dormancy would be adequate so WI would have little effect on crop growth. Otherwise, the moisture for the top 50 cm (19.69 in) soil profile might become too dry, which would have a negative affect on winter wheat growth at the recovery stage without WI. However, even under dry conditions, WI didn9t increase yield of winter wheat with a postdormancy irrigation in early spring. With the same number of irrigation applications, the ones with WI produced lower water-use efficiency (WUE) values than the ones without WI. Under limited irrigation application, irrigation in early spring after winter dormancy produced greater yield and WUE than that with WI. Applying WI encouraged root growth at the topsoil profile, while withholding WI enhanced root length density in the deep soil layer. The results showed that WI increased evapotranspiration and drainage and reduced WUE. Thus, WI should be replaced by early or late spring irrigation after winter dormancy depending on soil moisture conditions.

Effects of irrigation frequency under limited irrigation on root water uptake, yield and water use efficiency of winter wheat

AbstractIn the North China Plain, grain yield, water use efficiency (WUE) and root water uptake of winter wheat (Triticum aestivum L.) were investigated for five seasons, under different irrigation frequencies associated with limited water supply. Results showed that, with half of the normal irrigation amount, the combination of different irrigation amounts per application and the total number of irrigation applications did not affect grain production and WUE in most of the seasons during 2002–07. Due to the high soil water‐holding capacity and large root system of winter wheat, crop water use during each season was similar for all treatments. Results suggest that deficit irrigation applications given to crops in several small amounts were no better than applying them in relatively large quantities, typically as two or even one application. Good soil moisture conditions at sowing also played an important role in achieving high yields of this crop under limited water supply. Copyright © 2008 John Wiley &amp; Sons, Ltd.

Effect of Nitrogen Solution on the Germination of Shattercane

Effect of Nitrogen Solution on the Germination of Shattercane