为实现精准智能水肥管理,减少灌溉施肥量,提高果实品质,本研究构建基于光照、基质水分和回液电导率的灌溉决策和控制系统,以樱桃番茄作为试验对象,设置3个田间应用参数,对决策系统进行应用效果验证,对樱桃番茄的生物量、产量和品质进行综合评价.试验结果表明,该灌溉决策控制系统在樱桃番茄生长期间运行正常,可以有效代替人工进行水肥管理,当苗期、开花期、结果期光辐射分别达到200、400、100 J/cm2时启动灌溉,由基质相对含水量上限80％与实时相对含水量差值计算单次灌溉量,当灌溉液与回液EC差值大于1.0 mS/cm时,灌溉量上调1.3倍.该处理番茄植株较为粗壮,灌溉施肥量最少,提高了水肥生产效率,果实品质得到提升,适宜椰糠栽培樱桃番茄田间应用.

2021年为北京市冬小麦历年播种持续时间最长年份,晚播比例达87.1％.为探明晚播及过晚播对冬小麦生长发育及产量的影响,分别调查了多穗型品种'航麦247'和大穗型品种'济麦22'在5个自然播期下的表现.结果表明:晚播及过晚播小麦生育期缩短,单株干质量降低、株高降低、基部节间变短、穗子变短、不孕小穗数增多、穗粒数、千粒质量及产量下降;与适期早播相比,'航麦247'推迟播种4、11、20、28 d,减产7.9％、21.3％、28.1％、34.1％;'济麦22'推迟播种7、17、20、21 d,减产6.42％、23.9％、28.9％、40.2％.正常年份北京地区播种冬小麦不宜晚于10月10日,如无法避免晚播或过晚播,选择'航麦247'更易获得较高产量.

为推广应用抗旱丰产型小麦品种,解决北京市农业用供水不足的问题,采用种子萌发期、苗期和全生育期干旱胁迫 3 种方法,分别对北京地区 11 个小麦主栽品种进行抗旱性评价,将抗旱级别HR、R、MR、S和HS分别赋值 5、4、3、2、1,并分别给予 3种鉴定方法下的抗旱结果以 20%、10%和 70%的权重,计算出综合抗旱指数,同时结合籽粒产量,综合比较参试品种的抗旱性和丰产性.结果表明,综合抗旱指数在 3.0 以上、抗旱性优于或等于对照农大 212 的品种有农大 3486、京麦 8 号、中麦 415、农大5181、中麦 175.结合胁迫后各品种的产量表现,农大 3486、农大 5181 可作为北京地区抗旱丰产冬小麦首选品种,京麦 8 号可作为备选品种.

引进新型 2BF-20 谷物精量播种机,从播种机性能、播种质量、小麦生育进程、不同时期小麦个体和群体性状、小麦成熟期产量及产量三因素等方面,与传统 2BY-24 谷物联合播种机进行了比较,结果表明,应用 2BF-20 谷物精量播种机,小麦出苗株数、行距合格率、播种深度合格率、播种均匀度合格率更高,平均缺苗率和平均断条率降低,每 667 m2 穗数显著增加;产量较传统的 2BY-24 谷物联合播种机增加 5.6%,在生产中具备推广应用的价值.

为了解决草莓冬季生产灌溉水温偏低而影响草莓生长、产量和品质的难题,以"圣诞红"草莓为试材,采用简单经济的方法,即在灌溉系统首部安装蓄水桶,利用太阳光照对灌溉水进行加温.结果表明:加温灌溉系统可以将灌溉水温提高1～2℃,灌溉土壤温度比未加温灌溉平均提高了1.2℃,有效促进了草莓生长.相比未加温灌溉,加温灌溉的草莓单果质量显著提高了11.12%(12月),果实糖度显著提高了1.24%(1月),总酸度显著降低了44.19%(2月),糖酸比显著提高了59.74%(2月),产量提高了14.17%,水分生产效率提高了13.89%,667 m2产值增加了6 240元.综合来看,加温灌溉系统具有一定的推广应用价值.

为解决水肥一体化应用中施肥流量随着灌溉管道工作压力变化而波动导致施肥浓度不均匀的问题,设计了一种额定流量为300 L/h、最大工作压力为1.0 MPa的柱塞式注肥泵,对柱塞泵进行不同行程比例和电源频率下的工作流量试验,建立了工作流量与电源频率、行程比例及灌溉管道压力的拟合公式.结果表明:研发的柱塞泵工作流量与电源频率、行程比例均呈极显著的线性正相关,与灌溉管道压力呈显著负相关,以相对标准偏差RSD表示的流量测量精度范围为0.09％～1.43％;行程比例为100％、电源频率为50 Hz时,当灌溉管道压力由0.1 MPa增至0.5 MPa,柱塞泵工作流量下降14.22 L/h,占平均流量的4.58％,RSD最大值仅为0.38％,表明柱塞泵工作流量很稳定,可以适应喷灌和微灌水肥一体化系统不同工作压力的需求.以研发的柱塞泵为核心,提出了仅改变电源频率实现精准施肥的控制策略,具有控制算法简单、流量调节精准、投资成本低等优势,适合于水肥一体化精准施肥.

为明确冬小麦-夏玉米轮作种植模式中,不同耕作整地方式对小麦播种质量、产量和效益的影响,设置旋耕2次、深松+旋耕、重耙+旋耕、翻耕+轻耙、翻耕+旋耕、重耙+翻耕+轻耙和重耙+翻耕+旋耕(CK)共7种耕整地方式.结果表明,在夏玉米为籽粒玉米的地块,7种耕作整地方式中CK处理的秸秆含量较少,地表及0～20cm 土层平均秸秆含量较其他处理减少27.5％和28.6％,土壤与秸秆混合较均匀,0～20cm 土层中每5cm 土壤平均容重较其他处理变化减小30.5％,播种深度适宜,平均3.9cm,出苗质量好,缺苗断垄较其他处理降低25.7％,苗间离散度均匀,平均极差减小39.0％,穗数最多(670.5万/hm2)、产量最高(7966.5kg/hm2)、效益最高(9051.0元/hm2),与其他处理达显著性差异.在夏玉米为青贮玉米的地块,除旋耕2次和深松+旋耕的整地处理产量较低外,其余处理间产量差异不显著,其中翻耕+旋耕处理的产量和效益最高,分别为8133.0kg/hm2和9894.0元/hm2,效益显著高于其他处理.

为了筛选适宜的抗蒸腾产品,提高黄瓜抗旱性,选用2种代谢型、2种成膜型和1种生长调节剂型共5种抗蒸腾产品进行叶面喷施处理,以喷施清水作为对照,测定黄瓜植株生长、植株生物量和产量品质指标,将熵权法和TOPSIS法相结合,对11个评价指标及6个评价方案进行综合分析.结果表明,代谢型国光抗蒸腾剂处理后黄瓜株高比CK提高1.64％,叶片SPAD比CK提高7.37％,地上部和地下部含水率比CK分别提高2.7和9.7个百分点,黄瓜维生素C含量比CK提高25.70％,利用基于熵权的TOPSIS模型分析,代谢型国光抗蒸腾剂处理与最优值的相对接近度为0.9918,在所有处理中最高.黄瓜整个生育期叶面喷施3次代谢型国光抗蒸腾剂,可以有效提高抗旱能力,促进生长和产量品质提升.

为了检验活性水在草莓育苗生产上的应用效果,于2019和2020年分别设置活性水和普通水2个处理,对比分析了母株生长发育情况以及繁育草莓苗的质量、数量和移栽成活率,结果表明:2019年和2020年活性水处理繁苗数量分别较普通水处理增加了13.2％和15.8％,水分利用效益分别增加了16元/m3和15元/m3,子苗移栽成活率分别提高了1.5、3.0个百分点.说明活性水有利于草莓母株匍匐茎和分蘖的生长以及繁苗数量和质量的提高.

为筛选设施黄瓜适用的抗蒸腾剂,提高抗旱能力,以'北农佳秀'和'津优35号'为材料,采用田间试验方法,选择腐植酸型国光抗蒸腾剂和成膜型神润抗蒸腾剂,分别设置国光抗蒸腾剂稀释1000倍(T1)、国光抗蒸腾剂稀释500倍(T2)、神润抗蒸腾剂稀释20倍(T3)、神润抗蒸腾剂稀释40倍(T4)4个处理,以喷施清水作为空白对照(CK),在坐瓜后进行叶面喷施,研究不同抗蒸腾剂对黄瓜长势、生物量和产量品质的影响.结果表明,'津优35号'叶片喷施抗蒸腾剂后,9月11日T1、T2和T3处理的叶片SPAD值比CK分别提高了4.8％、7.4％和9.4％,T1、T2、T3、T4地下部含水率分别比CK提高6.4、17.2、7.1和3.7个百分点;T2处理黄瓜Vc含量比CK提高了25.76％,可溶性蛋白提高了11.54％.'北农佳秀'叶片喷施抗蒸腾剂后,T4整个生育期叶片SPAD值平均比CK提高1.1％,地上部鲜重提高84.6％,单株产量提高27.2％,可溶性蛋白含量提高50％.研究表明,'津优35号'黄瓜选择国光抗蒸腾剂稀释500倍、'北农佳秀'黄瓜选择神润抗蒸腾剂稀释40倍叶面喷施效果较好.

Proper droplet diameter and kinetic energy can effectively reduce the risk of soil erosion during low-pressure sprinkler irrigation. In this study, we comprehensively evaluated the radial distributions of droplet diameter, velocity, kinetic energy, kinetic energy per unit droplet volume, and specific power for three common low-pressure sprinklers, i.e. Nelson D3000, R3000 and Komet KPT, with two operating pressures (103 and 138 kPa) and three nozzle outlet diameters (3.97, 5.95 and 7.94 mm). Additionally, the relationships between these droplet characteristic parameters were analysed. Overall, the maximum values of five characteristic parameters were observed at the end of the jet under various treatments. Although R3000 had a larger droplet diameter (0.10-6.42 mm) and kinetic energy (1.08 x 10(-10)-8.59 x 10(-3) J) distribution range than D3000 and KPT, the D3000 specific power (mean value of 0.4274 W m(-2)) was the highest of the three sprinklers. Therefore, KPT was suggested more in low-pressure sprinkler irrigation than in the other two sprinklers because its application rates were reduced along the radial direction. In addition to selecting a suitable sprinkler type for minimizing specific power, determining a reasonable sprinkler spacing was also significant (P < 0.01). Furthermore, a universal specific power model with an appropriate accuracy (RMSE = 0.011 W m(-2), NRMSE = 29%) was proposed. This study provides a key basis for the selection and combination of low-pressure sprinklers.

The dry-hot wind climate is one of the major agro-meteorological disasters associated with high temperature, low humidity, and specific wind forces, which seriously affects the yield of wheat in the North China Plain. A field experiment was conducted to investigate the field microclimate, net photosynthetic rate, chlorophyll content of flag leaves, grain filling rate, and wheat yield after sprinkler misting under the condition of a dry-hot wind climate in the 2018 and 2019 seasons. Two travel speeds, full and half speed, and the corresponding irrigation amounts of 2.5 and 5 mm were used by a center pivot irrigation system during dry-hot wind conditions. A treatment without irrigation was applied as a control. The results showed that the air temperature and relative air humidity were greatly improved within 60 min after irrigation, especially in the upper part of the canopy. The net photosynthetic rate of flag leaves under 5 mm irrigation was higher than that under 2.5 mm irrigation during the middle and late grain filling periods. The adverse effects of dry-hot wind on the chlorophyll content of the flag leaves were mainly concentrated in the late grain filling stage. In the two years of the experiment, the average 1000-grain weights of 5 and 2.5 mm of irrigation treatments were 4.3 and 2.8% higher, and the grain yields were 5.8 and 3.3% higher, respectively, than those of the non-irrigated yields. Overall, applying a small amount of water between 12:00–14:00 with a center pivot before the occurrence of dry-hot wind is an effective means to regulate the field microclimate and produce more yield in the North China Plain.

为了对比不同类型保水剂的基本性能,以聚丙烯酰胺-无机矿物型、聚丙烯酰胺型、聚丙烯酸型和淀粉-丙烯酸共聚型为试验材料,通过室内试验,探究了不同保水剂的吸水能力、保水能力以及在不同离子溶液中的吸水性能.试验结果表明:保水剂在去离子水中吸水90 min后逐渐饱和,其中淀粉-丙烯酸共聚型吸水倍率为777.43 g/g,在所有处理中最高,经阳光照射24 h后保水率为68.41％,但是烘干重复吸水能力较差,经过七次烘干复水,吸水倍率下降了80.18％,适合短周期抗旱栽培使用;聚丙烯酰胺型经过烘干复水,吸水倍率仅下降了19.51％,吸水性能较为稳定,适合生长周期较长的作物抗旱使用;离子溶液会降低保水剂的吸水性能,各保水剂在不同价态离子溶液中吸水性能均有所下降,变化趋势并不一致,基本上在吸水50 min后趋于饱和.本研究明确了不同类型保水剂的基本性能,有利于旱作农业技术的发展,提高农业水资源利用率.

Maize is one of the major crops in China. The soil water content (SWC) in the root zone of maize is a critical indicator that guides agricultural production decisions and can affect national food security. However, a daily -scale, high-precision, spatial estimation method for SWC in China's main maize-producing areas has not been well researched. Therefore, we developed a spatial estimation model for SWC with a dynamic parameter opti-mization mechanism termed TPE-CatBoost. It combines the CatBoost algorithm as the core fitting framework with the efficient tree-structured Parzen estimator (TPE) algorithm to achieve a dynamic hyperparameter optimization based on covariate characteristics. Daily measured multi-depth SWC data at 175 stations from 2015 to 2019 were used as the reference truth, and 18 items of information, including soil physical and chemical properties, daily meteorological conditions, and spatial location information, were obtained from Google Earth Engine and considered as covariates. Model training was performed using the leave-one-out cross-validation method. Estimation error differences were investigated in four dimensions: time, space, depth, and the model. Our key results are as follows: (1) by combining all covariates, the highest estimation accuracy could be obtained at any soil depth, with a mean absolute error (MAE) within [6.06%, 6.94%]. The top five mean importance scores of covariates were latitude, soil pH, bulk density, DEM, and dewpoint temperature; (2) the MAE for all years remained within [4.66%, 9.34%], with higher errors in June; (3) the MAE for each province remained within [3.5%, 8.29%], with errors decreasing from north to south; and (4) compared with GIS-based spatial interpo-lation methods (inverse distance weighted, ordinary Kriging, and empirical Bayesian Kriging [EBK]), artificial intelligence (AI) algorithms combining environmental covariates (XGBoost, CatBoost, and TPE-CatBoost) could achieve better estimation accuracy. In particular, TPE-CatBoost performed well, with an improvement of 15.1% over EBK. We also demonstrated that TPE-CatBoost was susceptible to changes in the covariate gain capacity under extreme weather conditions using the SHapley Additive exPlanation (SHAP) algorithm. Visual mapping of single-day spatial estimation results in ArcGIS showed high consistency in distribution trends compared with the Soil Moisture Active Passive (SMAP) product.

以多穗型小麦品种轮选987和农大211为供试品种,设置5个播种密度(基本苗)梯度,研究其对小麦生长发育和产量的影响.结果表明,两个品种成熟期亩穗数随着基本苗的增加而增加,基本苗增加对亩穗数的贡献率逐渐降低,籽粒产量随着基本苗的增加呈先上升后缓慢下降的趋势,基本苗过少或过多均不利于高产,最高产量对应的亩基本苗均是30万,2个品种表现趋势一致.

为了解不同土壤水分传感器的工作性能,以目前国内应用最为广泛的频域反射性(FDR)土壤水分传感器为例,考虑当前新型的探管式结构,选取3种国产主流的FDR(管式)传感器(编号为Q1、Q2和Q3)进行261 d的田间性能测试试验.结果表明:3种传感器监测的土壤含水量曲线变化规律一致,峰值出现在有降雨时,表层土壤含水量曲线波动幅度大于深层土壤.但3种传感器在绝对数值上存在较大差异,土壤含水量变异系数在0.20～0.58之间.3种传感器的观测数值受温度影响较大,表层(0～20 cm)土壤变异系数大于深层土壤,增幅为38％以上,夏季(6月到7月)的土壤含水率变异系数大于其他季节,增幅为16％.通过对传感器观测值和人工观测值进行数据拟合,分别建立了3种传感器土壤水分的原位二次标定方程,有效降低了传感器之间的变异系数,降幅为53％～66％.因此,在农田应用中,应考虑土壤温度、土壤类型因素对FDR传感器原位二次标定的影响,以消除不同传感器工厂标定的差异性.

通过分析北京地区60年间降水年型的分布,解析冬小麦—夏玉米不同生长发育阶段的降水量与需水量关系,分析主要的需水阶段及需水量,为制定冬小麦—夏玉米周年节水灌溉制度提供参考.

笔者针对一家一户小规模设施农业生产者使用沼液滴灌存在灌水器堵塞、烧苗等问题,研发了1套沼液滴灌系统,该系统主要由沼液存贮装置、过滤装置和稀释装置组成,通过三级过滤和沼液原液稀释,解决了沼液原液滴灌造成的灌水器堵塞和烧苗等问题.春大棚黄瓜应用沼液滴灌技术,与对照相比,分别增产20.6％和21.2％,分别增收21435元·hm-2和34804元·hm-2;与水溶肥处理相比,分别增产7.2％和9.1％,增收25337元·hm-2和25413元·hm-2;同时,果实品质有所改善.

Soil moisture is an important indicator for agricultural planting and agricultural water management. People have been trying to guide crop cultivation, formulate irrigation systems, and develop intelligent agriculture by knowing exactly what the soil moisture is in real time. This paper considers the impact of meteorological parameters on soil-moisture change and proposes a soil-moisture prediction method based on the Gene Expression Programming (GEP) algorithm. The prediction model is tested on datasets from Shunyi, Yanqing and Daxing agricultural farms, Beijing. The results show that the GEP model can predict soil moisture with a maximum correlation coefficient of 0.98, and the root-mean-square errors in three different farms were below 2.32.

With the rapid development of economy and people's living standards, people's demands for crops have changed from quantity to quality. The rise and rapid development of remote sensing technology provides an effective method for crop monitoring. Accurately predicting wheat quality before harvest is highly desirable to optimize management for farmers, grading harvest and categorized storage for the enterprise, future trading price, and policy planning. In this research, the main producing areas of winter wheat (Henan, Shandong, Hebei, Anhui and Jiangsu provinces) were chosed as the research areas, with collected 898 samples of winter wheat over growing seasons of 2008, 2009 and 2019. A Hierarchical Linear model (HLM) for estimating grain protein content (GPC) of winter wheat at heading-flowering stage was constructed to estimate the GPC of winter wheat in 2019 by using meteorological factors, remote sensing imagery and gluten type of winter wheat, where remote sensing data and gluten type were input variables at the first level of HLM and the meteorological data was used as the second level of HLM. To solve the problem of deviation in interannual and spatial expansion of GPC estimation model, maximum values of Enhanced Vegetation Index (EVI) from April to May calculated by moderate-resolution-imaging spectroradiometer were computed to represent the crop growth status and used in the GPC estimation model. Critical meteorological factors (temperature, precipitation, radiation) and their combinations for GPS estimation were compared and the best estimation model was used in this study. The results showed that the accuracy of GPC considering three meteorological factors performed higher accuracy (Calibrated set: R2 = 0.39, RMSE = 1.04%; Verification set: R2 = 0.43, RMSE = 0.94%) than the others GPC model with two meteorological factors or single meteorological factor. Therefore, three meteorological factors were used as input variables to build a winter wheat GPC forecast model for the regional winter wheat GPC forecast in this research. The GPC estimation model was applied to the GPC remote sensing estimation of the main winter wheat-producing areas, and the GPC prediction map of the main winter wheat producing areas in 2019 was obtained, which could obtain the distribution of winter wheat quality in the Huang-Huai-Hai region. The results of this study could provide data support for subsequent wheat planting regionalization to achieve green, high-yield, high-quality and efficient grain production.