The first factor affecting dryland winter wheat grain yield under various mulching measures: Spike number

Water is the key factor limiting dryland wheat grain yield.Mulching affects crop yield and yield components by affecting soil moisture.Further research is needed to determine the relationships between yield components and soil moisture with yield,and to identify the most important factor affecting grain yield under various mulching measures.A long-term 9-yearifeld experiment in the Loess Plateau of Northwest China was carried out with three treatments:no mulch (CK),plastic mulch (M_(P)) and straw mulch (M_(S)).Yield factors and soil moisture were measured,and the relationships between them were explored by correlation analysis,structural equation modeling and significance analysis.The results showed that compared with CK,the average grain yields of M_(P) and M_(S) increased by 13.0and 10.6%,respectively.The average annual grain yield of the M_(P) treatment was 134 kg ha^(–1) higher than the M_(S) treatment.There were no significant differences in yield components among the three treatments (P<0.05).Soil water storage of the M_(S) treatment was greater than the M_(P) treatment,although the differences were not statistically signifiant.Soil water storage during the summer fallow period (SWSSF) and soil water storage before sowing (SWSS) of M_(S) were significantly higher than in CK,which increased by 38.5 and 13.6%,respectively.The relationship between M_(P) and CK was not statistically significant for SWSSF,but the SWSS in M_(P) was significantly higher than in CK.In terms of soil water storage after harvest (SWSH) and water consumption in the growth period(ET),there were no signi?cant differences among the three treatments.Based on the three analysis methods,we found that spike number and ET were positively correlated with grain yield.However,the relative importance of spike number to yield was the greatest in the M_(P )and M_(S) treatments,while that of ET was the greatest in CK.Suifcient SWSSF could indirectly increase spike number and ET in the three treatments.Based on these results,mulch can improve yield and soil water storage.The most important factor affecting the grain yield of dryland wheat was spike number under mulching,and ET with CK.These findings may help us to understand the main factors influencing dryland wheat grain yield under mulching conditions compared to CK.

Can soil organic carbon sequestration and the carbon management index be improved by changing the film mulching methods in the semiarid region?

Plastic film mulching has been widely used to increase maize yield in the semiarid area of China.However, whether long-term plastic film mulching is conducive to agricultural sustainability in this region remains controversial.A field experiment was initiated in 2013 with five different film mulching methods:(i) control method, flat planting without mulching (CK),(ii) flat planting with half film mulching (P),(iii) film mulching on ridges and planting in narrow furrows(S),(iv) full film mulching on double ridges (D), and (v) film mulching on ridges and planting in wide furrows (R).The effects on soil organic carbon (SOC) content, storage, and fractions, and on the carbon management index (CMI)were evaluated after nine consecutive years of plastic film mulching.The results showed that long-term plastic film mulching generally maintained the initial SOC level.Compared with no mulching, plastic film mulching increased the average crop yield, biomass yield, and root biomass by 48.38, 35.06, and 37.32%, respectively, which led to the improvement of SOC sequestration.Specifically, plastic film mulching significantly improved CMI, and increased the SOC content by 13.59%, SOC storage by 7.47%and easily oxidizable organic carbon (EOC) by 13.78%on average,but it reduced the other labile fractions.SOC sequestration and CMI were improved by refining the plastic film mulching methods.The S treatment had the best effect among the four mulching methods, so it can be used as a reasonable film mulching method for sustainable agricultural development in the semiarid area.

Spectral purification improves monitoring accuracy of the comprehensive growth evaluation index for film-mulched winter wheat

In order to further improve the utility of unmanned aerial vehicle(UAV)remote-sensing for quickly and accurately monitoring the growth of winter wheat under film mulching, this study examined the treatments of ridge mulching,ridge–furrow full mulching, and flat cropping full mulching in winter wheat.Based on the fuzzy comprehensive evaluation (FCE) method, four agronomic parameters (leaf area index, above-ground biomass, plant height, and leaf chlorophyll content) were used to calculate the comprehensive growth evaluation index (CGEI) of the winter wheat, and 14 visible and near-infrared spectral indices were calculated using spectral purification technology to process the remote-sensing image data of winter wheat obtained by multispectral UAV.Four machine learning algorithms, partial least squares, support vector machines, random forests, and artificial neural network networks(ANN), were used to build the winter wheat growth monitoring model under film mulching, and accuracy evaluation and mapping of the spatial and temporal distribution of winter wheat growth status were carried out.The results showed that the CGEI of winter wheat under film mulching constructed using the FCE method could objectively and comprehensively evaluate the crop growth status.The accuracy of remote-sensing inversion of the CGEI based on the ANN model was higher than for the individual agronomic parameters, with a coefficient of determination of 0.75,a root mean square error of 8.40, and a mean absolute value error of 6.53.Spectral purification could eliminate the interference of background effects caused by mulching and soil, effectively improving the accuracy of the remotesensing inversion of winter wheat under film mulching, with the best inversion effect achieved on the ridge–furrow full mulching area after spectral purification.The results of this study provide a theoretical reference for the use of UAV remote-sensing to monitor the growth status of winter wheat with film mulching.

Effect of Different Mulch Materials on Yield and Nutrition Profile of Common Capsicum (Capsicum annuum) Cultivars in Bangladesh

Capsicum is a nutritious vegetable and its cultivation in farms is getting popular in Bangladesh. Although many efforts have lain to explore better yielding and nutritionally rich cultivars with suitable modern cultivation techniques but still have to find the desired outcome. Thus, it’s necessary to conduct further research to identify the high-yielding and nutritious capsicum cultivars in Bangladesh. An experiment was conducted from July 2021 to June 2022 at the Bangladesh Institute of Research and Training on Applied Nutrition (BIRTAN) research field with three cultivars of capsicum: B0 = California Wonder, B1 = BARI Misti Morich-1 and B2 = BARI Misti Morich-2 and three mulching: T0 = No mulching, T1 = Water hyacinth, T2 = Poly Mulching in randomized complete block design with three replications to identify better quality capsicum cultivar and suitable mulching material. Among cultivars the BARI Misti Morich-2 (B2) showed increased agronomic parameters like number of branches and effective branches per plant, leaves length and width, consequently yield and yield contributing traits were also enhanced like fruits per plant, fruit length, fruit diameter and yield per plant (25.97%, 4.54%, 3.64% and 21.43%, respectively). Poly Mulching (T2) increased agronomic traits, yield traits and yield (0.61 kg) than BARI Misti Morich-1 (T1). The combined effect of B2T2 increased the number of branches per plant, effective branches per plant, leaves length and breadth by 40%, 90%, 15.57% and 26.22%, respectively, hence resulting in an increased yield of 20%. BARI Misti Morich-2 cultivar showed an increase in Fe, Zn and Vitamin-C content of 26.24% and 23.10%, 8.82% and 5.14%, and 6.03% and 5.74% than B0 and B1 cultivars, respectively. Therefore, BARI Misti Morich-2 exhibited the improved agronomic, yield and nutritional traits of capsicum under poly mulching among other cultivars in Bangladesh.

Effect of Different Mulching Materials on Growth Parameters and Yield of Okra (Abelmoschus esculentus) Production in Minna, Nigeria

During the 2022 growing season (August to November) at the Federal University of Technology, Minna School farm, Niger State, an experiment was conducted to investigate the influence of mulching on Okras growth, yield, and moisture content was examined across four distinct growth stages (initial, development, mid, and late) and at varying soil depths (0 - 30 cm and 30 - 60 cm). The study employed a randomised complete block design with four replications, encompassing control (T0), groundnut shells mulch (T1), black polythene mulch (T2), and white polythene mulch (T3) as treatments. The highest average Okra fresh pod yield, amounting to 23.4 t/ha, was achieved by implementing white plastic mulch, contrasting with the control treatment, which yielded the lowest at 22 t/ha. Notably, the control plots exhibited yield reductions of up to 32% compared to the plots employing white plastic mulching. The utilisation of mulch had a notable impact on the overall crop yield, with the superior quality evident in the treatment employing white plastic mulch (26 t/ha). The control treatment exhibited the lowest quality at 24.3 t/ha. Groundnut shell mulch influenced moisture conservation, but no significant variance was observed compared to the control plots. Therefore, the study suggests that polythene mulch may be the most suitable type to enhance the quality of okra production by conserving soil moisture. Among the biodegradable and non-biodegradable mulches used in this study, white polythene mulch was the most effective.

Review on the fully mulched ridge–furrow system for sustainable maize production on the semi-arid Loess Plateau

The fully mulched ridge–furrow(FMRF) system has been widely used on the semi-arid Loess Plateau of China due to its high maize(Zea mays L.) productivity and rainfall use efficiency. However, high outputs under this system led to a depletion of soil moisture and soil nutrients, which reduces its sustainability in the long run. Therefore, it is necessary to optimize the system for the sustainable development of agriculture. The development, yield-increasing mechanisms,negative impacts, optimization, and their relations in the FMRF system are reviewed in this paper. We suggest using grain and forage maize varieties instead of regular maize;mulching plastic film in autumn or leaving the mulch after maize harvesting until the next spring, and then removing the old film and mulching new film;combining reduced/notillage with straw return;utilizing crop rotation or intercropping with winter canola(Brassica campestris L.), millet(Setaria italica), or oilseed flax(Linum usitatissimum L.);reducing nitrogen fertilizer and partially replacing chemical fertilizer with organic fertilizer;using biodegradable or weather-resistant film;and implementing mechanized production. These integrations help to establish an environmentally friendly, high quality, and sustainable agricultural system, promote highquality development of dryland farming, and create new opportunities for agricultural development in the semi-arid Loess Plateau.

Mulching broad ridges with a woven polypropylene fabric increases the growth and yield of young pear trees ‘Yuluxiang' in the North China Plain

Unlike traditional ridging, mulching broad ridges with a woven polypropylene fabric (WPF) can reduce soil evaporation during the drought season and avoid long saturation time in the root zone of pear trees during the rainy season. In this study, field experiments were conducted from 2017 to 2020 in a pear orchard in the North China Plain to investigate the effects of mulching broad ridges (0.3 m in height and 2 m in width) with WPF on soil temperature and moisture, nitrogen leaching, vegetative and reproductive growth of young pear trees(Pyrus bretschneideri Rehd.‘Yuluxiang’). The experiments involved two treatments, namely, control (traditional no-ridge planting without mulching) and mulching broad ridges with WPF (RM treatment). The results showed that the RM treatment increased soil moisture and temperature and decreased nitrogen leaching, resulting in vigorous growth of the young pear trees. Moreover, the RM treatment increased the tree trunk cross-sectional area and height of the young pear trees by 37%and 8%in 2020, respectively. The nitrate nitrogen content at the soil layer depth of 0-30 cm was significantly higher in the RM than that in control. Furthermore, the RM treatment significantly increased the fruit yield due to larger tree size. In addition, compared with control, significantly higher fruit soluble solid content of RM treatment was detected in 2020. High precipitation (423 mm) occurred during fruit enlargement stage in 2020, RM treatment decreased the rainfall infiltration in the ridge and the soil moisture in root region, resulting in the improvement of fruit quality, compared with control.Therefore, mulching broad ridges with WPF can be implemented to increase soil moisture during drought season, soil temperature, and nitrate nitrogen content, thereby improving the growth and fruit yield of young pear trees. Additionally, it can reduce soil moisture in the root zone during the rainy season and improve the fruit quality of the trees. Finally, it can reduce nitrate nitrogen leaching, thereby reducing environmental pollution.

Better tillage selection before ridge–furrow film mulch can facilitate root proliferation, and increase nitrogen accumulation,translocation and grain yield of maize in a semiarid area

Plastic film mulch systems are used widely in arid areas, and the associated tillage measures affect soil properties, root and crop growth, and nutrient uptake. However, much debate surrounds the most suitable tillage method for plastic film mulch systems. We conducted a two-year field experiment to explore the impact of three tillage treatments-rotary tillage before ridge–furrow plastic film mulch(MR), no-tillage before ridge–furrow plastic film mulch(MZ), and plow tillage before ridge–furrow plastic film mulch(MP)-on soil total nitrogen, available nitrogen, root stratification structure,nitrogen transfer and utilization, and maize yield. The results showed that MP had better soil quality than either MR or MZ over 2019 and 2020, with higher nitrate-nitrogen and total nitrogen in the 0–40 cm soil layer. MP improved the soil physicochemical properties more than the other treatments, producing significantly higher root numbers and root biomass for the aerial and underground nodal roots than MR and MZ. At harvest, MP had the highest root biomass density,root length density, and root surface area density in the different soil layers(0–20, 20–40, and 0–40 cm). Significant correlations occurred between root biomass and aboveground nitrogen accumulation during maize growth. During grain filling, MP had the greatest nitrogen transfer amount, significantly increasing root and aboveground nitrogen transfer by 19.63–45.82% and 11.15–24.56%, respectively, relative to the other treatments. MP significantly produced 1.36–26.73%higher grain yields and a higher grain crude protein content at harvest than MR and MZ. MP also had higher values for the nitrogen harvest index, nitrogen uptake efficiency, and partial factor productivity of nitrogen fertilizer than MR and MZ.In conclusion, plow tillage combined with a ridge–furrow plastic film mulch system facilitated maize root development and improved nitrogen utilization, thereby increasing maize yield more than the other treatments.

Improving maize growth and development simulation by integrating temperature compensatory effect under plastic film mulching into the AquaCrop model

Temperature compensatory effect, which quantifies the increase in cumulative air temperature from soil temperature increase caused by mulching, provides an effective method for incorporating soil temperature into crop models. In this study, compensated temperature was integrated into the AquaCrop model to investigate the capability of the compensatory effect to improve assessment of the promotion of maize growth and development by plastic film mulching(PM). A three-year experiment was conducted from2014 to 2016 with two maize varieties(spring and summer) and two mulching conditions(PM and non-mulching(NM)), and the AquaCrop model was employed to reproduce crop growth and yield responses to changes in NM, PM, and compensated PM. A marked difference in soil temperature between NM and PM was observed before 50 days after sowing(DAS) during three growing seasons. During sowing–emergence and emergence–tasseling, the increase in air temperature was proportional to the compensatory coefficient, with spring maize showing a higher compensatory temperature than summer maize. Simulation results for canopy cover(CC) were generally in good agreement with the measurements, whereas predictions of aboveground biomass and grain yield under PM indicated large underestimates from 60 DAS to the end of maturity. Simulations of spring maize biomass and yield showed general increase based on temperature compensation, accompanied by improvement in modeling accuracy, with RMSEs decreasing from 2.5 to 1.6 t ha^(-1)and from 4.1 t to 3.4 t ha^(-1). Improvement in biomass and yield simulation was less pronounced for summer than for spring maize, implying that crops grown during low-temperature periods would benefit more from the compensatory effect. This study demonstrated the effectiveness of the temperature compensatory effect to improve the performance of the AquaCrop model in simulating maize growth under PM practices.

Green High-yield and High-efficiency Cultivation Techniques of Integrated Management of Water and Fertilizer for Maize under Mulch Drip Irrigation

The green high-yield and high-efficiency cultivation techniques of integrated management of water and fertilizer for maize under mulch drip irrigation are described from the aspects of high yield target of maize and its component factor indexes,pre-sowing preparation,sowing,post-sowing management,field management at the seedling stage,integrated management of water and fertilizer for target yield of maize,rational application of micro-fertilizer,comprehensive prevention and control of diseases and pests,timely harvest,etc.,in order to provide a reference for agricultural technicians,maize farmers and maize industry development in northern Xinjiang.

不同覆盖措施对寒地苹果园土壤物理特性和树体生长的影响

为探索适合东北寒地雨养苹果园幼树生长的土壤覆盖技术,以当地主栽苹果品种龙丰为试材,连续2年采用稻草、玉米秸秆、食用菌菌渣和园艺地布覆盖,以清耕为对照,研究不同覆盖处理对苹果园土壤温度、含水量、容重、孔隙度以及树体生长的影响。结果表明:覆盖可显著影响表层土壤温度,与清耕对照相比,覆盖稻草显著降低了土壤温度,覆盖玉米秸秆和覆盖食用菌菌渣能够稳定土壤温度;覆盖处理显著提高了土壤含水量,以覆盖食用菌菌渣最佳,5—10月平均土壤含水量较对照提高40.5%;覆盖有机材料可降低土壤容重,增加土壤孔隙度,在成熟期与对照差异显著,以覆盖玉米秸秆最佳。覆盖促进了龙丰幼树生长,春梢长度和新梢长度、粗度增加,干径增加,促进了叶片生长。综合比较,覆盖园艺地布促进树体生长效果最佳,覆盖玉米秸秆和覆盖食用菌菌渣对改善土壤环境效果最好,同时也能够促进树体生长。

减氮施炭对温室膜下滴灌黄瓜土壤呼吸和氮素气态损失的影响

为降低温室蔬菜过量施氮的不利影响,明确减氮施炭条件下温室膜下滴灌黄瓜土壤呼吸和氮素气态排放特征,以不覆膜不施炭(CK)为对照,设置覆膜(M)、覆膜施炭(MB)、覆膜施炭减氮(MBN_(80%))共4个处理,对覆膜条件下减氮施炭处理对黄瓜产量、耗水量、土壤养分动态、土壤呼吸、N_(2)O排放和氨挥发的影响进行探讨。结果表明:与CK相比,M可降低温室膜下滴灌黄瓜全生育期耗水量20.95%,提高水分利用效率41.03%,降低0~20 cm表层土铵态氮48.12%,降低全生育期氨挥发32.35%、N_(2)O排放量14.34%和CO_(2)排放量12.68%(<0.05)。施炭后,与CK相比,MB可降低耗水量28.37%,提高水分利用效率55.60%,降低表层土铵态氮30.0%,提升硝态氮12.37%,有机质56.28%,降低氨挥发36.68%、N_(2)O排放18.64%,但却显著增大了CO_(2)排放4.66%(p<0.05)。同M对比,MB可在M基础上,进一步提升表层土有机质和铵态氮含量,降低氨挥发,但促进了CO_(2)排放。覆膜施炭减氮20%后,与CK相比,MBN_(80%)可增产25.47%,降低耗水量32.43%,提升水分生产率72.67%,降低表层土铵态氮56.33%,增加有机质51.72%,降低氨挥发40.48%、N_(2)O排放20.79%(p<0.05)。CK全生育期全球增温潜势(global warming potential,GWP)和活性氮排放分别为13.57 t·CO_(2)-eq·hm^(-2)和6.54 kg·hm^(-2),M可显著降低GWP(14.15%)和活性氮排放(27.37%);在M基础上施炭,将进一步降低活性氮排放,但导致GWP显著增大;而在MB基础上减氮20%,可同时显著降低GWP和活性氮排放(p<0.05)。与CK相比,MBN80%在通过施炭20 t·hm^(-2),减氮20%条件下,实现增产25.47%,降低耗水量32.43%,增加有机质51.72%,增加收入17.52%,降低活性氮排放35.32%和GWP 2.28%,也可在MB的基础上,进一步实现增产,降低氨挥发,并破解M和MB处理CO_(2)排放增大的问题(p<0.05)。研究揭示了减氮施炭条件下温室膜下滴灌黄瓜土壤呼吸和氮素气态排放特征,为实现温室蔬菜节水增产固碳减排提供理论依据和技术支撑。

Performance Evaluation of Manually Operated Mulch Laying Machine on Different Soil Conditions

A machine with manual operation for mulch-laying machine with a punching arrangement was developed,and its performance was assessed at three different mulch paper thicknesses(15 m,20 m and 25 m),three different disc angles(35 degrees,40 degrees,and 45 degrees),three different punch spacings(250 mm,500 mm,and 1000 mm),and three different forward speeds(1.3 km/h,1.5 km/h,1.7 km/h)to investigate their effects on field capacity,effective field efficiency,and punching efficiency.Utilizing randomised block design and response surface methods,the experimental plan for optimization was created.All of the independent variables’combined effects on the dependent variables were found to be statistically significant.The influence of operating speed and mulch paper thickness was found to be the most significant on the dependent variable.The effective field capacity and field efficiency increased from 0.11 ha/h to 0.19 ha/h and 72.04 percent to 89.51 percent,respectively,by increasing mulch paper thickness from 15μm to 25μm and operating speed from 1.3 km/h to 1.7 km/h,whereas punching efficiency fell from 85.18 percent to 84.40 percent.Mulch paper of 15μm and a disc angle value of 40 degrees were optimised from the independent factors that were chosen for optimal soil covering over the laid plastic mulch sheet.Punching efficiency was maximised with performance optimised at 500 mm punch spacing.Additionally,the machine operated more efficiently at 1.5 km/h.

覆膜对陇东旱地苹果根际土壤化感物质积累与真菌群落特征的影响

【目的】探究果园地膜覆盖对土壤化感物质及真菌群落的影响。【方法】以红富士苹果为研究对象,采用高效液相色谱技术和Illumina高通量测序技术探究了清耕(CK)、覆膜2年(2Y)、覆膜4年(4Y)和覆膜6年(6Y)对苹果树根际0~20 cm和>20~40 cm土层土壤理化性质、化感物质和真菌群落特征的影响。【结果】苹果根际土壤脲酶活性随着覆膜年限的延长而降低。土壤中主要的化感物质的含量总体上随着覆膜年限的延长呈现出降低的趋势。覆膜措施对苹果根际土壤中真菌群落特征具有显著的影响。土壤真菌群落的多样性随着覆膜年限的延长而增高,其中镰刀菌属丰度显著增加。综合对比,覆膜4年的苹果根际土壤中含水量及有机碳、微生物量碳、全氮含量显著增加,较CK分别增加了5.65%~15.00%、3.72%~8.29%、50.16%~64.31%和14.19%~31.44%。β-1,4-木糖苷酶、β-1,4-葡萄糖苷酶和纤维二糖水解酶的活性显著提高,较CK分别增高了78.71%~84.4%、89.01%~97.43%和83.45%~87.68%。并且在0~20 cm的土层中苹果根系的生长量显著提高。与CK相比,根系生物量、根表面积和根体积分别增加了489.84%、533.87%和542.39%。相关性分析结果表明,土壤脲酶、β-1,4-葡萄糖苷酶和香兰素是影响土壤真菌群落的主要环境因子。【结论】覆盖地膜可通过影响苹果根际土壤酶活性和微生物代谢活性,促进土壤碳循环,效果随覆膜年限而异,以覆膜4 a(年)最佳。同时覆膜年限的延长抑制了土壤中植物化感物质的积累,但覆盖年限过长会对土壤真菌群落结构产生不利的影响,因此在生产中,覆膜4 a为西北旱地苹果园适宜的连续覆膜年限。

秸秆覆盖量和施氮量对陇中春小麦的产量效应模拟

为量化分析秸秆覆盖量和施氮量对旱地春小麦的产量效应和协同作用,在APSIM模型中,设置秸秆覆盖量和施氮量2因素5个变化梯度,组合交叉设计25个处理,利用模型模拟25个处理的春小麦产量;于2016—2018年在甘肃省定西市安定区开展小麦大田试验,得到早播(ESW)、正常播(NSW)、晚播(LSW)春小麦产量的实测值,利用APSIM模型模拟2016—2018年春小麦的产量,将模拟值与实测值进行对比,对模型的适用性和模拟精度进行分析;对春小麦产量与秸秆覆盖量、施氮量的耦合关系进行二次多项回归和通径分析,利用Matlab计算春小麦的最大产量及对应的秸秆覆盖量和施氮量。结果表明:不同处理下产量的模拟值与实测值均位于15%置信带内,模型模拟精度较高,归一化均方根误差值为4.64%~12.22%,表明该模型在研究区具有良好的适用性;秸秆覆盖量和施氮量的增长对春小麦的产量效应为正效应,相应关系表现为开口向下的二次抛物线变化关系;ESW、NSW和LSW模拟情景下,春小麦最大产量分别为3548.64、3149.59、2507.58 kg/hm^(2);ESW模式下,最佳秸秆覆盖量和施氮量分别为7062.04、194.91 kg/hm^(2);NSW模式下,最佳秸秆覆盖量和施氮量分别为8211.31、218.81 kg/hm^(2);LSW模式下,最佳秸秆覆盖量和施氮量分别为6215.15、162.01 kg/hm^(2)。

水分及秸秆覆盖对夏玉米土壤呼吸及碳平衡的影响

【目的】充分发挥秸秆覆盖与适宜灌溉对作物增产及土壤固碳减排的各自优势及二者协同效应,建立减排增产节水的高效农田管理模式。【方法】以豫东地区夏玉米为研究对象,设置覆盖方式(秸秆覆盖(S)和无覆盖(N))和灌水控制下限(田间持水率(FC)的50%(W1)、60%(W2)、70%(W3)、80%(W4))两因素试验,系统研究水分及秸秆覆盖对土壤碳排放总量、土壤微生物异氧呼吸碳释放量和农田净初级生产力固碳量影响。【结果】秸秆覆盖和灌水增加了土壤呼吸、农田净初级生产力固碳量和土壤微生物异氧呼吸碳释放量,其中SW4处理均最高,与SW3、NW4处理差异不显著。SW3处理净生态系统生产力(NEP)和碳排放效率均最高,分别较其他处理高3.99%~245.74%和2.35%~138.80%。与SW4处理相比,SW3处理在节约灌水的前提下,农田净生态系统生产力提高2.99%,碳排放效率提高2.35%。【结论】综合考虑农田净生态系统生产力和碳排放效率,SW3处理(灌水控制下限为70%FC+秸秆覆盖)可以作为节水、减排、增产的农田管理模式。

地膜覆盖对胶园间种珠芽黄魔芋光合生理特性及产量的影响

为了解不同地膜覆盖对胶园间种的珠芽黄魔芋(Amorphophallus muelleri)叶片光合生理特性、土壤物理性状及产量的影响,本研究设置银色地膜、黑色地膜、白色地膜、防草席、加厚黑色地膜、微孔黑色地膜和无覆盖(CK)共7个处理,测定分析魔芋换头期、膨大期和成熟期3个时期叶片的光合特性参数:净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(T_(r))、胞间CO_(2)浓度(Ci)、电子传递速率(ETR),生理特性参数:可溶性蛋白(SP)含量、可溶性糖(SS)含量、叶绿素(Chl)含量、叶绿素a/b(Chl a/b),土壤原位物理性状参数:土壤含水量(SMC)、土壤电导率(SC)、土壤温度(ST),并测定魔芋地下球茎产量的变化。结果表明:同一时期不同地膜覆盖处理均提高了魔芋叶片的光合参数(P_(n)、G_(s)、T_(r)和ETR),换头期和膨大期防草席处理的P_(n)、Gs和T_(r)均显著高于其他处理(P<0.05),而其他处理间不规律上下变幅,其间有显著差异;除了成熟期,同一时期不同地膜覆盖处理魔芋叶片的SP和Chl均显著高于对照,各处理间无显著差异;同一时期不同处理魔芋叶片的SS和Chl a/b变化趋势稍有不同,成熟期各处理的SS均显著高于对照,3个时期对照的SS均最低,而成熟期地膜处理的Chl a/b较对照均无显著差异;同一时期不同地膜覆盖的SMC和SC均高于对照,加厚黑色地膜处理保水效果最好,膨大期微孔黑色地膜处理和成熟期防草席处理的SC均显著最高,其他处理间的SMC和SC无显著差异。同一地膜覆盖处理不同时期的P_(n)、G_(s)、T_(r)、ETR、SP、和Chl均表现为换头期>膨大期>成熟期,而各处理的SS和Chl a/b表现为成熟期>膨大期>换头期。经所有指标和产量相关性分析的结果来看,除了ST与产量呈负相关外,其他指标与产量均呈正相关。不同地膜覆盖较对照均提高了珠芽黄魔芋产量,银色地膜、黑色地膜、防草席和加厚黑色地膜处理增产效果明显,而白色地膜和微孔黑色地膜处理增产不明显。因此,在实际生产中,采用银色地膜、黑色地膜、防草席和加厚黑色地膜都是魔芋增产增效的可行选择。

玉米秸秆还田下深松年限对土壤有机碳含量及胡敏酸结构特征的影响

为明确不同秸秆还田结合耕作措施下土壤有机碳组分的变化特征,基于6 a秸秆还田长期定位试验,利用三维荧光光谱技术,对CK(不深松+不秸秆还田)、NFG(不深松+每年秸秆还田)、EFG(隔一年深松+每年秸秆还田)、TFG(隔两年深松+每年秸秆还田)和SFG(连年深松+每年秸秆还田)处理下土壤有机碳(SOC)含量及胡敏酸(HA)结构特征进行分析。结果表明:与CK相比,EFG处理0~10 cm土层的SOC、HA含量和PQ值分别显著增加25.23%、16.19%和4.27%,FA含量降低4.55%。10~20 cm土层,EFG处理的SOC含量最高,较CK增加13.18%;SFG处理的HA和FA含量较CK提高最多,增幅分别为13.27%和32.74%。通过HA三维荧光图谱发现,与CK(Ex/Em=270/455,270/460)相比,EFG(Ex/Em=280/455,270/465)处理下0~10 cm和10~20 cm土层中的HA荧光峰波长均有红移现象。土壤胡敏酸中包含两个组分,C1(Ex/Em=270/280)和C2(Ex/Em=440/515)同为类腐殖酸物质,胡敏酸整体腐殖化程度较高,结构较为复杂;其中EFG和TFG处理的C2组分所占比例最高,分别为28.59%和31.38%。各处理的C1和C2组分F_(max)值均较CK有所增加,即腐殖化程度增加。综上所述,EFG处理(隔一年深松+每年秸秆还田)通过提升土壤有机碳及腐殖酸类物质含量,增加腐殖化程度,加强了土壤的供肥能力,为黑龙江黑土区较佳的耕作技术措施。

地膜覆盖对夏直播垄作花生的温度效应和产量的影响

为探究地膜覆盖对夏直播垄作花生的温度效应,以及对花生生长发育和产量的影响,以露地为对照,研究了普通白膜、降解黑膜处理下土壤温度的动态变化以及对花生主要经济性状和产量的影响,并探讨温度效应与气温的关系。结果表明,普通白膜覆盖提高了土下10 cm的日最低温度和日平均温度,降低土下10 cm的日最高温度;降解黑膜覆盖降低土下10 cm的日最低温度,增加土下10 cm的日最高温度和日平均温度。不同气温区间普通白膜处理土下10 cm最低温度均值高于土表1.8~3.2℃,降解黑膜则低0.7~2.0℃;普通白膜处理土下10 cm最高温度均值低于土表1.6~6.0℃,降解黑膜则高3.1~6.3℃。土表和土下10 cm平均温度均值随气温升高而增加,不同气温区间对土表和土下10 cm平均温度均值的影响不同,普通白膜和降解黑膜间也有差异。地膜覆盖的增温效应促进了植株的生长发育,整体上有利于单株叶面积和植株干质量的增加,但生长后期有早衰现象。地膜覆盖对花生主要经济性状的影响不显著,普通白膜、降解黑膜和露地种植的花生产量分别为4286、4247和4028 kg/hm^(2),差异不显著。此外,地膜覆盖对花生根瘤数量也有影响。本研究对夏直播垄作花生高产栽培及地膜覆盖技术的应用具有指导意义。

不同覆盖处理对菠萝园土壤代谢物和细菌群落结构的影响

【目的】探测不同覆盖处理对菠萝园土壤微生态环境的影响。【方法】以未覆盖为对照(CK),比较研究了聚乙烯地膜(PM)、无纺布(NW)和可降解地膜(BF)覆盖下菠萝营养生长期土壤理化性状、酶活性以及细菌群落结构、代谢物的差异。【结果】与CK相比,NW土壤中有效磷以及BF土壤中全氮含量显著提高;3种覆盖下土壤的过氧化氢酶和蔗糖酶活性显著降低,但PM土壤的蛋白酶、BF的酸性磷酸酶活性显著提高。与CK相比,PM土壤的放线菌数量减少;NW的细菌数量增多,放线菌减少;BF土壤的真菌和细菌数量增多,放线菌减少。16S测序表明3种覆盖的细菌菌群多样性均低于CK,其中BF的菌群丰度相对最高。与CK相比,PM、NW、BF土壤共筛选到17种显著差异代谢物,主要包括糖类、有机酸、含氮化合物和醇类代谢物,3种覆盖处理中BF土壤的糖类代谢物积累最高。CCA分析表明,pH影响土壤菌群结构发生分异,土壤养分、酶活性与细菌群落结构存在正相关。【结论】3种覆盖处理中NW有利于维持营养生长期菠萝园土壤相对稳定的微生态环境。