Regional distribution of wheat yield and chemical fertilizer requirements in China

Quantification of currently attainable yield and fertilizer requirements can provide detailed information for assessing the food supply capacity and offer data support for agricultural decision-making. Datasets from a total of 5 408 field experiments were collected from 2000 to 2015 across the major wheat production regions in China to analyze the spatial distribution of wheat yield, the soil nutrient supply capacity(represented by relative yield, defined as the ratio of the yield under the omission of one of nitrogen(N), phosphorus(P) and potassium(K) to the yield under the full NPK fertilizer application), and N, P and K fertilizer requirements by combining the kriging interpolation method with the Nutrient Expert Decision Support System for Wheat. The results indicated that the average attainable yield was 6.4 t ha~(-1), with a coefficient of variation(CV) of 24.9% across all sites. The yields in North-central China(NCC) and the northern part of the Middle and Lower reaches of the Yangtze River(MLYR) were generally higher than 7 t ha~(-1), whereas the yields in Southwest China(SWC), Northeast China(NEC), and the eastern part of Northwest China(NWC) were usually less than 6 t ha~(-1). The precentage of area having a relative yield above 0.70, 0.85, and 0.85 for N, P, and K fertilizers accounted for 52.3, 74.7, and 95.9%, respectively. Variation existed in N, P, and K fertilizer requirements, with a CV of 24.8, 23.9, and 29.9%, respectively, across all sites. More fertilizer was needed in NCC and the northern part of the MLYR than in other regions. The average fertilizer requirement was 162, 72, and 57 kg ha~(-1) for N, P_2O_5, and K_2O fertilizers, respectively, across all sites. The incorporation of the spatial variation of attainable yield and fertilizer requirements into wheat production practices would benefit sustainable wheat production and environmental safety.     

Early interspecific dynamics,dry matter production and nitrogen use in Kernza (Thinopyrum intermedium) – alfalfa (Medicago sativa L.) mixed intercropping

ABSTRACT

The global interest in growing perennial grain crops such as intermediate wheatgrass (Thinopyrum intermedium) (Kernza) for production of food and feed is increasing. Intercropping Kernza with legumes may be a sustainable way of supplying nitrogen to soil and associated intercrop. We determined the competitive interactions between intercropped Kernza (K) and alfalfa (Medicago sativa L.) (A) under three inorganic nitrogen (N) rates N0, N1, N2 (0, 200, 400 kg ha^?1) and five species relative frequencies (SRF) (100%K:0%A, 75%K:25%A, 50%K:50%A, 25%K:75%A and 0% K:100%A) in mixed intercrops (MI) in a greenhouse pot experiment. After 11 weeks of growth. Kernza dry matter yield (DM) and N accumulated (NACC) were low, but alfalfa DM and NACC high at 0 kg N ha^?1. 200 and 400 kg N ha^?1 fertiliser application increased the competitive ability (CA) of Kernza and reduced the CA of alfalfa. SRF had large impacts on alfalfa DM, NACC and NFIX only at 0 kg N ha^?1 fertiliser, and insignificant impacts on Kernza at all N fertiliser levels, indicating that adjustment of SRF may not be an effective way to modulate the interspecific competition of Kernza. Further research on the other factors that influence the interspecific competition are warranted.     

多效唑对杂交中稻不同密肥群体产量和抗倒伏性的影响

为探究高产稻田中防止倒伏发生的早期诊断技术,2015-2016年,以大面积推广的杂交中稻高产新品种蓉18优1015为试验材料,设计3因素完全因子试验,研究不同密肥群体下喷施多效唑对稻谷产量和抗倒伏性的影响。结果表明,随着施氮量和移栽密度的增加,稻谷产量提高,植株抗倒力下降,以施氮量150 kg·hm^-2和移栽密度18.75 万穴·hm^-2的产量较高。不同密肥群体下施用多效唑对产量和植株抗倒伏性有显著影响,施用多效唑后植株抗倒力增强,但产量因穗粒数下降而减少。不同密肥处理下施用多效唑对产量影响各异。于水稻最高苗期施用多效唑使植株重心高度、弯曲力矩、倒伏指数显著降低,折断弯矩则明显提高,穗粒数平均减少5.24~7.87粒。多效唑对产量的影响表现为低施氮量下因穗粒数减少而减产;中施氮量下产量差异不显著;高施氮量下植株未倒伏、籽粒灌浆结实正常,因结实率和千粒重高而增产。综上所述,肥力水平和施氮量高的稻田于最高苗期施用多效唑有利于水稻产量提高和控制后期倒伏。本研究为指导大面积水稻高产稳产提供了科学依据。     

高油酸花生品种开农1760产量及其构成的可视化分析

分析高油酸小粒花生品种开农1760的产量及其与农艺性状的关系,为高产优质育种提供有效指导。本研究以开农1760参加的2014-2015年河南省小粒花生区试数据为基础,运用GGE (genotype+genotype-by-environment interaction)双标图评价其丰产性和稳产性,利用R语言进行可视化的相关分析和通径分析。结果显示,开农1760的丰产稳产性综合排名第一,出米率的变异系数最小,饱果率与产量呈极显著正相关,百果重、单株生产力、百仁重、主茎高、侧枝长和结果枝数与产量呈显著正相关,结果枝数的直接通径系数最大,是影响开农1760荚果产量的关键性状。综上所述,开农1760丰产性好、稳定性强,适合在河南省大面积推广利用;在选育小粒花生新品种时可侧重做好对结果枝数的选择。     

The priority of management factors for reducing the yield gap of summer maize in the north of Huang-Huai-Hai region,China

Understanding yield potential, yield gap and the priority of management factors for reducing the yield gap in current intensive maize production is essential for meeting future food demand with the limited resources. In this study, we conducted field experiments using different planting modes, which were basic productivity(CK), farmer practice(FP), high yield and high efficiency(HH), and super high yield(SH), to estimate the yield gap. Different factorial experiments(fertilizer, planting density, hybrids, and irrigation) were also conducted to evaluate the priority of individual management factors for reducing the yield gap between the different planting modes. We found significant differences between the maize yields of different planting modes. The treatments of CK, FP, HH, and SH achieved 54.26, 58.76, 65.77, and 71.99% of the yield potential, respectively. The yield gaps between three pairs: CK and FP, FP and HH, and HH and SH, were 0.76, 1.23 and 0.85 t ha~(–1), respectively. By further analyzing the priority of management factors for reducing the yield gap between FP and HH, as well as HH and SH, we found that the priorities of the management factors(contribution rates) were plant density(13.29%)fertilizer(11.95%)hybrids(8.19%)irrigation(4%) for FP to HH, and hybrids(8.94%)plant density(4.84%)fertilizer(1.91%) for HH to SH. Therefore, increasing the planting density of FP was the key factor for decreasing the yield gap between FP and HH, while choosing hybrids with density and lodging tolerance was the key factor for decreasing the yield gap between HH and SH.     

Associations between postpartum diseases and milk yield and changes in body condition between drying off and parturition of dairy cows in Argentina

ABSTRACT

Aims: To assess the change in body condition score (BCS) during the early and late dry periods and its association with postpartum diseases and milk yield in grazing dairy cows from central Argentina.

Methods: BCS assessments during the dry period, and cow health and milk production records up to 90 days in milk (DIM), were collated for cows from 28 farms at monthly visits between 2007 and 2008. Cows were categorised into four groups; those in Group 1 (n=7,067) maintained or gained BCS during the early and late dry periods; Group 2 (n=2,615) maintained or gained BCS during the early dry period and lost BCS during the late dry period; Group 3 (n=1,989) lost BCS during the early dry period and maintained or gained BCS during the late dry period; and Group 4 (n=5,144) lost BCS during the early and late dry periods.

Results: Cows in Group 1 had reduced odds of having retained fetal membranes (RFM), metritis, and clinical mastitis up to 90 DIM than cows in Group 2 (p<0.001), but the odds of disease were similar to cows in Group 3. The odds of having RFM or clinical mastitis tended to be lower in cows in Group 1 than cows in Group 4 (p=0.08). The odds of cows being culled or dying during the first 90 DIM were lower for cows in Group 1 than for those in Groups 2, 3, and 4 (p≤0.05). Mean accumulated milk yield up to 90 DIM was higher in cows in Group 1 than Group 2 and Group 4 (p<0.001), but was similar to that of cows in Group 3 (p=0.28).

Conclusions and clinical relevance: Cows that lost BCS during the late dry period had increased odds of being diagnosed with several postpartum diseases and had decreased milk yield compared to cows that maintained or gained BCS during the entire dry period. Loss of BCS during any stage of the dry period was also associated with increased incidence of culling or death during the first 90 DIM. These results should raise awareness among dairy cattle producers of the importance of properly managing cow body condition during the dry period, especially during the late dry period.     

陇薯系列高淀粉马铃薯品种的淀粉产量及品质性状综合评价

为了评价高淀粉马铃薯品种的综合品质性状,本研究以甘肃省农业科学院育成的15个马铃薯品种(系)为参试材料,2011-2018年连续8年定点田间试验,测定了块茎产量、营养品质(干物质、淀粉、维生素C、粗蛋白)含量和矿物质元素(钾、钙、铁、锌)含量。结果表明,参试材料的块茎产量和营养品质含量均存在显著的基因型、环境及基因型与环境的互作效应,其中块茎产量、淀粉产量、干物质含量、淀粉含量性状的基因型效应大于环境效应,而营养品质中的维生素C、粗蛋白和还原糖含量的环境效应大于基因型效应。参试材料的块茎产量24 549~50 140 kg·hm^-2,淀粉产量4 271~9 298 kg·hm^-2,干物质含量21.07%~30.18%,淀粉含量14.63%~21.83%,维生素C含量12.20~18.95 mg·100g^-1,粗蛋白含量2.17%~2.71%,还原糖含量0.18%~0.43%,钾含量4 316~5 368 mg·kg^-1,钙含量85.10~138.40 mg·kg^-1,铁含量10.17~24.50 mg·kg^-1,锌含量2.45~3.80 mg·kg^-1。大西洋的衍生品种陇薯8号、陇薯9号、陇薯12号、陇薯14号、L0527-2、L08104-12、LZ111和L1149-2淀粉含量均超过18%,其中,L1149-2总体表现优异,其平均块茎产量50 140 kg·hm^-2、淀粉产量9 298 kg·hm^-2、干物质含量26.75%、淀粉含量19.30%、维生素C含量14.62 mg·100g^-1、粗蛋白含量2.52%、还原糖含量0.28%、钾含量5 297 mg·kg^-1、钙含量138.40 mg·kg^-1、铁含量20.40 mg·kg^-1、锌含量3.20 mg·kg^-1;而陇薯5号淀粉产量及营养品质较差。本研究为合理利用陇薯系列高淀粉马铃薯品种提供了科学依据,对改良高淀粉马铃薯品种产量和品质具有指导意义。     

不同播期对黄秋葵长势、抗病性和产量的影响

为在河北省推广种植黄秋葵,在安国、保定、邯郸、衡水和石家庄5个试验点进行黄秋葵分期播种试验,研究了不同播期对石秋葵1号、红玉和五福3个品种生长势、抗病性和产量的影响。结果表明:播期对石秋葵1号、红玉和五福生长势、抗病性和产量具有较大的影响,随着播期的推迟,3个品种的茎粗大致呈逐渐增高的趋势,株高呈先降后升的趋势(除2018年的红玉外),单株结果数则先增加后减少,单果质量(除五福外)逐渐增大;以4月20日、25日和30日为播期,得到的黄秋葵单株产量和折合667 m~2产量较高。综合得出,河北省黄秋葵种植以4月20日、25日、30日为播期最为适宜。     

不同吸附特性的稻草生物炭对稻田氨挥发和水稻产量的影响

秸秆生物炭具有改善土壤生态环境、土壤蓄水保肥和减少温室气体排放等正效应,但其石灰效应会加大稻田氨挥发损失。为充分发挥生物炭吸铵特性,降低其石灰效应的不利影响,对不同热解温度(300、500、700℃)和酸化水平(pH值=5、7、9)稻草生物炭处理下的田面水NH_4~+-N浓度、氨挥发和水稻产量进行了研究。结果表明:偏酸性(pH值=5)、中性(p H值=7)生物炭处理在基肥期和分蘖肥期均能显著降低田面水NH_4~+-N峰值浓度(P0.05),降幅达16.90%～35.60%。全生育期稻田氨挥发损失占施氮量的15.14%～26.05%(2019年)、15.10%～19.00%(2020年)。稻田增施热解温度为700℃、酸化水平为5(p H值=5)的生物炭(C700P5)降氨效果最好,两年氨挥发分别显著降低22.93%、12.61%(P0.05)。高温热解配合偏酸性、中性生物炭(C700P5、C700P7)增产效果显著,增产率达9.92%～13.50%,结构方程模型表明,其增产原因是生物炭酸化处理降低了稻草生物炭的石灰效应,而热解温度调整提高了生物炭阳离子交换量(CationExchange Capacity,CEC),进而降低了田面水NH_4~+-N浓度和氨挥发损失,最终提高了水稻地上部氮素积累和水稻产量。研究可揭示不同热解温度和酸化水平制备的生物炭在稻田中的应用潜力,并为稻田合理施用生物炭和减少化肥施用量提供理论依据。     

Influence of Aguamiel (Agave atrovirens) as a Natural Feed Additive on Cecal Fermentation Kinetics of Some Forage Species in Horse Feeding

This study aimed to evaluate the effect of different dose levels of aguamiel (Agave atrovirens) on in vitro cecal gas, methane (CH₄), and carbon dioxide (CO₂) productions of five forage species (Avena sativa [hay]), Moringa oleifera, Caesalpinia coriacea, Salix babylonica, and Eichhornia crassipes using inocula from the horse. The forage samples were incubated with three doses of aguamiel: 0, 34, and 68 μg of aguamiel/g dry matter (DM) of substrate. Cecal inocula were collected from four adult female Criolla horses (3–4 years of age and weighing 300 ± 15.0 kg) grazed on native grasses for about 8 hours without supplementation. Forage type affected (P < .001) cecal asymptotic, rate and lag time of gas, CH₄ and CO₂ productions (mL/g DM), pH and DM degradability. Aguamiel dose had linear and quadratic effects (P < .05) on the asymptotic and rate of CH₄ productions and rate and lag time of CO₂ productions (mL/g DM). Forage type × aguamiel dose interactions were significant (P < .05) for asymptotic, rate and lag time of gas, and CH₄ and CO₂ productions (mL/g DM). Forage species effects were pronounced (P < .05) on CH₄ and CO₂ productions (mL/g incubated and degraded DM) and proportional CH₄ production at all hours of incubation, except for CO₂ production (mL/g incubated DM). Aguamiel dose affected (P < .05) CO₂ production (mL/g incubated DM) and proportional CO₂ production at the incubated hours. Forage type × aguamiel dose interactions were observed (P < .05) for CO₂ production (mL/g incubated DM) and proportional CO₂ production at the incubated hours but had no impact on CH₄ production. It is concluded that addition of aguamiel to five forage species affected fermentation kinetics of gas production resulting in different in vitro cecal gas, CH₄ and CO₂ productions from these substrates.