Comparison of Machine Learning Regression Methods to Simulate NO₃Flux in Soil Solution under Potato Crops

Nitrate (NO3) leaching is a major issue in sandy soils intensively cropped to potato. Modelling could test the effect of management practices on nitrate leaching, particularly with regard to optimal N application rates. The NO3 concentration in the soil solution is well known for its local heterogeneity and hence represents a major challenge for modeling. The objective of this 2-year-study was to evaluate machine learning regression methods to simulate seasonal NO3 concentration dynamics in suction lysimeters in potato plots receiving different N application rates. Four machine learning function approximation methods were compared: multiple linear regressions, multivariate adaptive regression splines, multiple-layer perceptrons, and least squares support vector machines. Input candidates were chosen for known relationships with NO3 concentration. The best regression model was obtained with a 6-inputs least squares support vector machine combining cumulative rainfall, cumulative temperature, day of the year, N fertilisation rate, soil texture, and depth.

基于RegNet网络的马铃薯病害识别研究

为克服传统网络模型结构固化、对马铃薯病害识别率低的问题,以PlantVillage数据集中的五类马铃薯病害为研究对象,对图像进行随机放大缩小、水平翻转、垂直翻转等操作进行数据增强。使用一种基于网络设计空间思想设计出具有高度灵活性的RegNet网络模型,利用PoLy损失函数对RegNet进行改进,并加入注意力机制,对数据增强后的马铃薯病害图片进行预测,再与传统网络模型AlexNet和GoogLeNet进行对比。试验结果表明:改进后的RegNetX在马铃薯识别方面具有良好的性能,最高准确率可达99.8%,模型准确率超过AlexNet与GoogLeNet,可为马铃薯病害识别作参考。

不同连作年限马铃薯根际土壤细菌群落特征研究

采用长期定位试验,设马铃薯连作1~7 a(CP1~CP7)和轮作(RT)8个处理,通过高通量测序探究不同连作年限对马铃薯根际土壤细菌群落多样性的影响。结果表明:供试土壤中,放线菌门、变形菌门、厚壁菌门为主要的优势菌门。随连作年限的增加,土壤细菌数量表现出波动变化趋势,连作年限影响细菌群落结构。RT、CP1、CP2、CP3处理土壤细菌相似度较高,CP4、CP5、CP6、CP7处理土壤细菌相似度较高。马铃薯连作7 a土壤中的放线菌门相对丰度降幅最大,较RT降低10.47%;厚壁菌门相对丰度在连作6 a土壤中显著降低,较RT减少22.07%;类诺卡氏属相对丰度在连作7 a显著减少,较RT减少2.34%;芽孢杆菌属相对丰度在连作6 a时最低,较RT减少9.18%;连作7 a较RT减少5.14%;芽单胞菌属相对丰度在连作7 a土壤中达到最高(16.54%),较RT增加5.26%。长期连作改变了马铃薯土壤细菌群落结构,连作4 a土壤细菌群落种类开始变化,土壤细菌群落结构也随之改变。土壤中预防病害的菌类减少,增加了马铃薯染病风险。

荞麦轮作对云南栽培马铃薯根际土壤酶活和微生物的影响

为探讨连作和与苦荞(KQ)轮作对云南省3个马铃薯主栽品种根际土壤酶活性、微生物数量和产量的影响,以马铃薯主栽品种‘合作88’(HZ88)、‘丽薯6号’(LS6H)、‘青薯9号’(QS9H)为试验材料,对不同处理下根际土壤的蔗糖酶、蛋白酶、脲酶、纤维素酶活性和微生物数量以及马铃薯产量、品质进行分析。结果表明,KQ-HZ88、KQ-LS6H、KQ-QS9H轮作处理的马铃薯单株产量分别较HZ88-HZ88、LS6H-LS6H、QS9H-QS9H连作处理显著增加76.32%、80.95%、90.91%,还原糖含量显著降低38.71%、18.42%、21.43%。与3年连作相比,HZ88-KQ-HZ88和KQ-HZ88-KQ、LS6H-KQ-LS6H和KQ-LS6H-KQ、QS9H-KQ-QS9H和KQ-QS9H-KQ轮作处理的土壤蔗糖酶活性分别较HZ88-HZ88-HZ88、LS6H-LS6H-LS6H、QS9H-QS9H-QS9H连作处理显著增加8.54%和14.00%、22.73%和34.25%、18.13%和25.12%;细菌数量显著增加19.05%(P>0.05)和92.86%、75.68%和72.97%、67.11%和73.21%。土壤酶活性及微生物数量的变化可能是引起云南地区马铃薯连作障碍的重要原因之一,轮作可有效改善根际土壤酶活性,增加土壤中有益菌数量,缓解连作障碍。

陇东旱塬区复种马铃薯栽培模式筛选

为研究陇东旱塬区冬油菜收获后复种马铃薯不同栽培模式对其产量及经济效益的影响,采用单因素试验区组设计,以陇薯7号原种马铃薯品种为试验材料,共设计8种栽培模式。通过对不同模式下马铃薯农艺性状、商品率、产量及经济效益的比较,筛选出最佳的冬油菜茬复种马铃薯栽培模式。结果表明,秸秆带状覆盖、平作起垄、垄沟种植3个栽培模式表现较好,667 m^(2)产量分别为2292.81、1917.63、1655.46 kg,比对照露地平作分别增产41.27%、18.15%和2.00%。

A Sustainable Production Model for Potato at Low Latitude Plateau in Winter in Yunnan Province

[Objectives]To find a sustainable production model for potato at low latitude plateau in winter in Yunnan Province.[Methods]Xuanshu 2 potato variety was tested in prefectures of Yunnan Province.Soil covering experiment was conducted in two trials(open field experiment and green house potted experiment).Impacts of three cultivation factors were analyzed:(i)three cultivation models(T1,T2 and T3),(ii)planting density(T1,T2 and T3),(iii)soil covering(T1,T2,T3,T4)on plant growth,and yield production.[Results]The soil moisture content,temperature,roots growth,stems development,leaf area index,and number-weight of tubers per plant and per plot(g)have significantly increased with commercial yield average of 45 t/ha.[Conclusions]The combination of this method with modern agriculture mechanization should be further popularized and applied in large scale planting in regions with climatic conditions similar winter season in Yunnan Province,so as to make contribution to the satisfaction of the world population potato consumption.

双牌县红薯连作栽培藤薯两收高产技术

双牌县适宜夏秋红薯生长,配合红薯连作栽培藤薯两收高产技术的应用,能大量采摘红薯藤蔓,立冬后还可收获红薯,经济效益大幅提高。结合当地推广的藤薯两收高产栽培经验,介绍了双牌县红薯连作栽培藤薯两收高产技术,为相关人员提供参考。

再谈1511年之前美洲作物传入中国的可能性

近年有学者认为至少在13—14世纪南太平洋波利尼西亚人即抵达美洲,因为在前哥伦布时代,不少美洲作物便传入中国。他们言之凿凿,主要依据是以《饮食须知》《滇南本草》为代表的古文献以及波利尼西亚的番薯遗存等。其实关于中国方面的文献均可以证伪,波利尼西亚的番薯问题是一个不可复制的特殊案例,所谓的“花生”并非花生,“蕃茄”也不是番茄。近代以来提出的美洲作物是葡萄牙、西班牙等西方殖民者传入亚洲的观点,并非想象建构,不仅最符合逻辑,而且有大量事实佐证。

Soil nutrient loss due to tuber crop harvesting and its environmental impact in the North China Plain

Soil loss due to crop harvesting （SLCH） is a soil erosion process that signiifcantly contributes to soil degradation in crop-lands. However, little is known about soil nutrient losses caused by SLCH and its environmental impacts. In the North China Plain area, we measured the losses of soil organic carbon （SOC） and nitrogen as wel as phosphorus due to SLCH and assessed their relationship with soil particle size composition, agronomic practices and soil moisture content. Our results show that the losses by harvesting potato of SOC, total nitrogen （TN）, available nitrogen （AN）, available phosphorus （AP） and total phosphorus （TP） were 1.7, 1.8, 1.8, 15.9 and 14.1 times compared by harvesting sweet potato, respectively. The variation of SOC, N and P loss by SLCH are mainly explained by the variation of plant density （PD） （17–50%）, net mass of an individual tuber （Mcrop/p） （16–74%）, soil clay content （34–70%） and water content （19–46%）. Taking into account the current sewage treatment system and the ratio of the nutrients adhering to the tubers during transportation from the ifeld （NTRP/SP）, the loss of TN and TP by harvesting of potato and sweet potato in the North China Plain area amounts to 3% N and 20% P loads in the water bodies of this region. The fate of the exported N and P in the sewage treatment system ultimately controls the contribution of N and P to the polution of lakes and rivers. Our results suggest that a large amount of SLCH-induced soil nutrient export during transportation from the ifeld is a potential polutant source for agricultural water for vast planting areas of tuber crops in China, and should not be overlooked.

Analysis of the Key Challenges Facing Potato Farmers in Oljoro-Orok Division, Kenya

The objective of this study was to evaluate the key challenges facing potato production in Oljoro-Orok division. Primary data were obtained from randomly selected farmers through questionnaires. Purposive sampling was used to select 300 farmers in the division. Proportionate sampling was used to select the sample of farmers in each of the four locations. The data collected were analyzed using descriptive statistics namely frequencies, percentages and means with the?aid of Statistical Package for Social Science (SPSS) version 17.0 and a SWOT matrix computed. Rainfall variations, lack of clean seeds and crop diseases have been found to be the major challenges facing potato production in the division. 45% of the respondents see rainfall variation as the main cause of decreased potato yields, 33% lack of clean seeds and 6% crop diseases. The study found that farmers use crop diversification and off season approaches to adapt to rainfall variability. The study recommends adaptation measure to be applied to cope with rainfall variation. Such measures include irrigation using water available in Jacob, Terracin and Kivindo dams during dry spelt. A lot of emphases on the use of certified seeds should be done by the agriculture field officers to caution farmers from planting the same potatoes they harvested in the previous harvest.

Botanicals and plant strengtheners for potato and tomato cultivation in Africa

This review provides a summary of botanicals and plant strengtheners that have potential uses for disease and pest management in potato and tomato cultivation in African.We discuss their possible use to prevent major diseases and pests which infest potato and tomato,such as early and late blight,bacterial wilt,potato tuber moth,and tomato leafminer.There are several examples of the successful uses of botanicals for pathogen and pest control relevant for different African climatic conditions;however,most of these studies have been conducted in vitro and often lack field verification.Plant strengtheners(substances that induce and improve crop resistance,yield,and quality)are little studied and used in Africa in comparison to North America and Europe.The possible benefits of using botanicals and plant strengtheners instead of conventional pesticides are discussed here in relation to human health and the environment as well as their modes of action and accessibility to farmers.Lack of knowledge of the composition and active ingredients of extracts,environmental concerns,uncertainties regarding stability and formulation,lack of legislation and limited support from governments,hamper the development of botanicals and plant strengtheners for use in sustainable African agriculture.

复种马铃薯田间除草剂的优选及安全性评价

为解决复种马铃薯田间次生油菜、次生小麦及杂草对马铃薯的危害,筛选高效安全的除草剂及施药模式。除草剂在播种后第3天喷施,茎叶除草剂在马铃薯植株8~10 cm后喷施,采用随机区组设计进行田间药效试验。除草剂施用70%嗪草酮WP 30 g/667 m^(2)+10.8%精喹禾灵EC 30 mL/667 m^(2)+33%二甲戊灵EC 35 mL/667 m^(2),施药后25 d对次生油菜等阔叶杂草的防效达84.61%,对次生小麦等禾本科杂草的防效达69.69%;茎叶除草剂施用3%砜嘧磺隆WP 33 g/667 m^(2)+12%烯草酮EC 30 mL/667 m^(2)效果最佳,施药后15 d对次生油菜等阔叶杂草的防效达84.36%,对次生小麦等禾本科杂草的防效达86.86%;2种处理在规范使用剂量下对马铃薯安全。复种马铃薯土壤封闭除草剂推荐选用70%嗪草酮WP+10.8%精喹禾灵EC+33%二甲戊灵EC,在马铃薯播种后3~5 d于地表面喷施;茎叶除草剂推荐选用3%砜嘧磺隆WP+12%烯草酮EC,在马铃薯苗后8~10 cm、杂草3~4叶期喷施。

生物有机肥配施缓释肥对连作马铃薯提质增产效果研究

针对马铃薯连作障碍问题,探索生物有机肥配施缓释肥对马铃薯连作土壤速效养分、马铃薯养分吸收量、产量及品质的影响。以威芋5号原种为材料,在减施25%缓释肥的基础上,配施不同生物有机肥及组合,测定其出苗率、农艺性状、产量及品质、土壤生化性状等。结果表明,生物有机肥配施缓释肥对马铃薯的农艺性状、出苗率、土壤养分、产量以及薯块品质均有改善作用。生物有机肥的配施可以不同程度地提高土壤中有效养分的含量,调节土壤的酸碱度。其中T4处理增产效果最明显,较单施缓释肥的处理增产16.80%,且马铃薯薯块的养分吸收量最高。从品质来看,T4处理的粗蛋白、淀粉、还原性糖以及Vc含量最高,分别较对照提高26.97%、51.67%、166.94%和39.63%。因此,生物有机肥配施缓释肥可以增加土壤中的有效养分含量,提高连作区马铃薯的产量和品质,其中以混合施用生物有机肥Ⅰ和生物有机肥Ⅱ的T4处理效果最好。

薯豆轮作模式下不同种衣剂对大豆农艺性状及产量的影响

为指导薯豆轮作模式下的大豆生产,选用3种种衣剂,采用田间对比试验方法,以不包衣和连作处理为对照,研究不同种衣剂对轮作大豆农艺性状及产量的影响。结果表明,薯豆轮作方式下3种种衣剂应用效果优于豆豆连作,大豆种子包衣促进了大豆植株生长和发育,使株高、茎粗、节间数、单株有效结荚数、百粒重和产量增加,底荚高度降低,能促进早结荚,使植株重心降低可抗倒伏,同时也促进了根瘤的发生,且对大豆根腐病防治效果明显。其中使用复合微生物菌剂拌种处理大豆的根瘤数最多,防治大豆根腐病效果最好,促进了大豆植株的生长发育,植株粗壮,增加了有效结荚数和产量;精甲·咯菌腈包衣处理的收获株数最多,但对根腐病防治效果最差,发病率最高;阿维·多·福化学药剂处理大豆有效结荚数、百粒重和产量最高,增产效果最好。

Effect of Irrigation Method and Non-Uniformity of Irrigation on Potato Performance and Quality

Potato growth, yield, and quality under improved irrigation methods and non-uniformity of their irrigation applications are important to enhance water management in arid regions. A field experiment was conducted in 2014 spring and fall growing seasons using potato (Solanum tuberosum) grown in northern Egypt at Shibin El Kom, Menofia, Egypt to evaluate potato response to furrow or trickle irrigation. A Randomized Split-Plot Design with irrigation method randomly distributed and non-uniformity of irrigation applications evaluated along either irrigation furrow or trickle lateral as dependent variables measured at the 3rd, 13th, 23rd, 33rd, 43rd and 53rd m along the 55 m irrigation line. Traditional (TF) and partial (PF) furrows as well as trickle point (TP) and line (TL) sources were used as irrigation methods. Each treatment was repeated three times. For a 33rd m treatment, seasonal optimum water use by potato was 328, 234, 269 and 292 mm over 118 days in spring and 200, 164, 178 and 186 mm over 122 days in fall under TF, PF, TP and TL irrigation methods, respectively. Potato tuber yield and quality were significantly affected by growing season (S), irrigation method (I) and non-uniformity of irrigation application (U). Tuber yield, total soluble solid (TSS) and leaf area index (LAI) were significantly affected by I and U, and their interaction I * U;harvest index (HI) was not affected by I but U. Except for TSS by S * I and HI by U * I and S * I, results showed no significant differences. Moreover, tuber weight, number and marketable yield were significantly affected by S, I, U and I * U interaction, except medium tuber size and culls by S. A given 33rd treatment under partial furrow and trickle irrigation, relative to that of traditional furrow, enhanced tuber yield and improved quality in both growing seasons. In non-un- iform irrigation application over two growing seasons, potato crop response was developed under varied irrigation methods. Tuber yields were significantly affected in a linear relationship (r2 ≥ 0.75) by either water deficit or excessive water under irrigation methods.

Economic Potential of Compost Amendment as an Alternative to Irrigation in Maine Potato Production Systems

Potato productivity in the northeastern US has been relatively constant for over 50 years, raising questions about what factors are limiting productivity. Research was initiated in 2004 to identify key constraints to potato productivity by evaluating Status Quo (SQ), Soil Conserving (SC), and Soil Improving (SI) cropping systems under both rainfed and irrigated management, and it was found that addition of compost or irrigation substantially increased yield. In this study, we employed partial budgeting to determine cost differences and their impact on net revenue for these cropping systems. Differences in systems were primarily associated with rotation length, tillage operations, compost and application expenses, and water management practices. When compost (as composted dairy manure) was annually applied at 19 Mg haf-1 and evaluated over the entire 3-year crop rotation cycle, the compost-amended rainfed SI system was more expensive to maintain than the irrigated SC system if compost cost exceeded $3.63 Mg-1. Average marketable yields were used to calculate gross and net revenue for each system. Because average potato yield for the irrigated SQ system (28.4 Mg·ha-1) equaled that in the rainfed SI system (28.3 Mg·ha-1), we were able to compare cost of irrigation versus compost for achieving comparable yield. The compost-amended SI system under rainfed management generated more net revenue from the potato crop than the irrigated SQ system when compost costs were less than $7.42 Mg-1. When compared to the commonly used rainfed SQ system, rainfed SI achieved higher net revenue as long as compost cost was less than $22.95 Mg-1. The rainfed SI system achieved higher net revenue than the irrigated SC system when compost cost was $9.43 Mg-1or less, but generated greater net revenue than the rainfed SC system regardless of compost costs, due to substantially higher yields associated with compost amendment. This investigation demonstrates that compost is a potentially viable substitute to irrigation for potato in the northeastern US;however, such potential is highly dependent on suitable compost sources and application costs.

不同肥料和生物菌剂对贵州连作地甘薯产量与土壤养分的影响

【目的】探明不同肥料和生物菌剂对贵州连作地甘薯产量和土壤养分的影响,筛选出适宜贵州地区连作障碍地使用的肥料或生物菌剂,为实现甘薯产业良性发展提供参考。【方法】以常规复合肥、腐殖酸控释肥和腐殖酸复合肥等为研究对象,采用大田试验方法,研究移栽时施用不同肥料和生物菌剂对甘薯薯块商品性、鲜薯和薯干产量及土壤养分的影响。【结果】不同试验点不同处理甘薯的商品性、鲜薯和薯干产量及土壤养分存在一定差异。大、中、小薯的块数和重量贵阳试验点分别为2.00~5.67块和0.62~1.99 kg、3.44~10.33块和0.59~1.80 kg、11.33~25.00块和0.77~1.73 kg。大、中薯块数和重量均以腐殖酸控释肥750 kg/hm^(2)处理最高,小薯以腐殖酸复合肥750 kg/hm^(2)处理最高;紫云试验点分别为0.33~4.00块和0.14~1.46 kg、6.00~11.67块和0.87~1.71 kg、21.00~34.33块和0.67~1.98 kg。大薯块数、中薯重量及小薯块数和重量均以腐殖酸控释肥750 kg/hm^(2)处理最高,其余以农大生物有机肥600 kg/hm^(2)处理最高。贵阳试验点鲜薯和薯干产量分别为32.33~47.71 t/hm^(2)和10.51~15.31 t/hm^(2),均以腐殖酸复合肥750 kg/hm^(2)处理最高,分别较CK显著提高36.46%和29.30%;紫云试验点分别为16.12~19.52 t/hm^(2)和2.77~3.52 t/hm^(2),均以腐殖酸复合肥750 kg/hm^(2)最高,分别较CK提高19.46%和27.04%。贵阳试验点土壤pH、有机质、碱解氮、有效磷和速效钾分别为5.77~7.06、30.93~39.17 g/kg、98.86~113.96 mg/kg、9.21~14.99 mg/kg和106.00~154.00 mg/kg;紫云试验点分别为5.51~6.44、26.33~32.27 g/kg、110.18~132.07 mg/kg、7.53~16.30 mg/kg和62.00~131.00 mg/kg,靠山多霸生物菌肥22.5 L/hm^(2)、30 L/hm^(2)和37.5 L/hm^(2)处理均能提高贵阳和紫云试验地土壤的有机质和碱解氮含量,结合甘薯产量结果看,以靠山多霸生物菌肥30 L/hm^(2)处理的效果最佳。【结论】贵州连作地甘薯种植施用腐殖酸复合肥750 kg/hm^(2)可有效提高甘薯产量,改善甘薯商品性;施用靠山多霸生物菌肥30 L/hm^(2)可提高土壤有机质和碱解氮含量,改善土壤质量。

陇东旱塬区复种马铃薯田蛴螬及金针虫防治药剂筛选试验

陇东旱塬区种植冬油菜和冬小麦后,土地闲置期可复种马铃薯,但蛴螬、金针虫等地下害虫对马铃薯为害严重,科学合理防治蛴螬、金针虫对保证马铃薯产量非常重要。为筛选出陇东旱塬区复种马铃薯田防治蛴螬、金针虫危害的低毒高效的适宜药剂,以马铃薯品种陇薯7号为指示品种,蛴螬、金针虫为防治对象,选用3种高效低毒杀虫剂对各药剂的拌种或喷沟处理进行田间防效试验,调查各处理蛴螬、金针虫虫口基数,出苗期的出苗率、受害率、安全性和成熟期的受害率、安全性。结果表明,35%噻虫嗪种衣剂、60%帮巧时种衣剂防效均达85%以上,且拌种处理和喷沟处理无显著差异。60%帮巧时悬浮种衣剂拌种和喷沟防效均好,分别为88.44%、90.36%;折合产量高,分别为16407.41、17066.14 kg/hm^(2),较空白对照分别增产16.71%、21.40%,较常规药剂对照分别增产12.07%、16.57%;保产效果好,分别为95.39%、96.20%。见于此,60%帮巧时悬浮种衣剂可作为陇东旱塬区复种马铃薯田蛴螬、金针虫防治的候选杀虫剂;并建议用48.00 mL的药量稀释10倍液后拌种薯100 kg,将525.00 mL的药量稀释250倍液,按225 L/hm2喷沟。

连作和轮作对云南三个马铃薯主栽品种根际土壤真菌群落结构的影响

马铃薯连作导致土壤微生物群落结构失衡、土传病害加重以及土壤退化,作物轮作可以缓解这些负面影响。为探讨连作、与苦荞轮作对云南地区3个马铃薯主栽品种(合作88、丽薯6号、青薯9号)土壤微生物群落结构的影响,采用高通量测序技术,对根际土壤真菌群落结构进行研究。结果表明,连作分别增加了合作88土壤中被孢霉门(Mortierellomycota)、子囊菌门中未分类属(unclassified_Ascomycota)、孢霉属(Mortierella)丰度的4.30%、113.82%、1.60%,轮作合作88(HZ88)-苦荞(KQ)和KQ-HZ88分别下降31.06%和45.01%、87.04%和7.14%、40.43%和45.53%;连作增加了丽薯6号土壤中子囊菌门(Ascomycota)丰度的7.57%,轮作丽薯6号(LS6H)-KQ和KQ-LS6H分别下降50.72%和1.22%;连作增加了青薯9号土壤中担子菌门(Basidiomycota)、罗兹菌门(Rozellomycota)丰度的11.35%、50.79%,轮作青薯9号(QS9H)-KQ和KQ-QS9H分别下降22.12%和52.59%、74.22%和22.22%。此外,与HZ88-HZ88、LS6H-LS6H、QS9H-QS9H连作相比,轮作HZ88-KQ和KQ-HZ88、LS6H-KQ和KQ-LS6H、QS9H-KQ和KQ-QS9H土壤中Ascomycota的丰度分别显著降低46.07%和9.11%、53.59%和18.13%、9.44%和-12.87%;癣囊腔菌属(Plectosphaerella)丰度分别显著降低94.27%和17.41%、86.07%和45.17%、63.11%和-427.04%;unclassified_Ascomycota丰度分别显著降低94.64%和74.97%、97.34%和22.97%、85.73%和-32.56%。土壤真菌群落结构的变化可能是引起云南地区马铃薯连作障碍的重要原因之一,轮作可以对此进行有效缓解。