Pub Date : 2023-01-20DOI: 10.1017/S0014479722000564
Rui Wang, Wei-Xiong Wu, Xiao Cheng, Wenli Peng
Summary Rationally higher population density is crucial for seeking a balance that meets lodging resistance and maximizes seed yield in mechanized direct-seeded winter canola. In this study, a split-plot experiment with two cultivars (Huayouza9 and Zhongshuang11) and eleven planting densities (12–105 plants m-2) was conducted in a two-season field experiment to evaluate the high planting density in this cropping system and improve its production efficiency. Seed yield noticeably increased in planting density up to 80 plants m-2 in Zhongshuang11 (2187 kg hm-2) and 60 plants m-2 in Huayouza9 (2943 kg hm-2). The seed yield of Huayouza9 did not differ significantly from the local target seed yield. Higher plant density curtailed the luxurious vegetative growth of individual canola plants at the density of no less than 60–80 plants m-2, and high seed yield was derived from the increased ratio of main raceme and branch seed weight in winter canola. An increase in plant densities contributed to the reinforced sunlight interception at the pod-filling stage, providing a larger canopy photosynthetic area for the rapid growth of more canola pods at higher densities (60–105 plants m-2). Lodging resistance and breaking resistance decreased sharply with the plant density increasing from 12 to 60 plants m-2 while remaining almost steady as it further increased from 60 to 105 plants m-2 for Huayouza9 and Zhongshuang11. Hence, the population density of 60 plants m-2 reached a balance between lodging resistance and maximized seed yield in mechanized direct-seeded winter canola in China.
合理提高种群密度是实现机械化直播冬油菜抗倒伏和产量最大化平衡的关键。本研究采用花油杂9号和中双11号2个品种和11个种植密度(12 ~ 105株m-2)的分畦试验，进行了2季田间试验，以评价该种植制度的高密度种植，提高其生产效率。种植密度显著提高种子产量，中双11和花油杂9分别达到80株m-2 (2187 kg hm-2)和60株m-2 (2943 kg hm-2)。花油杂9的种子产量与当地目标种子产量差异不显著。当密度不低于60 ~ 80株m-2时，较高的植株密度会抑制单株的营养生长，而高的种子产量则来自于冬季油菜主总状花序和分枝种子重量的增加。植株密度的增加有助于增强灌荚期的阳光拦截，在较高密度(60-105株m-2)下，为更多的油菜荚果的快速生长提供了更大的冠层光合面积。花油杂9号和中双11号的抗倒伏性和抗折性随株密度从12株m-2增加到60株m-2而急剧下降，但随株密度从60株m-2增加到105株m-2而基本保持稳定。因此，60株m-2的种群密度在中国机械化直播冬季油菜的抗倒伏性和最大种子产量之间达到了平衡。
{"title":"High plant density increases sunlight interception and yield of direct-seeded winter canola in China","authors":"Rui Wang, Wei-Xiong Wu, Xiao Cheng, Wenli Peng","doi":"10.1017/S0014479722000564","DOIUrl":"https://doi.org/10.1017/S0014479722000564","url":null,"abstract":"Summary Rationally higher population density is crucial for seeking a balance that meets lodging resistance and maximizes seed yield in mechanized direct-seeded winter canola. In this study, a split-plot experiment with two cultivars (Huayouza9 and Zhongshuang11) and eleven planting densities (12–105 plants m-2) was conducted in a two-season field experiment to evaluate the high planting density in this cropping system and improve its production efficiency. Seed yield noticeably increased in planting density up to 80 plants m-2 in Zhongshuang11 (2187 kg hm-2) and 60 plants m-2 in Huayouza9 (2943 kg hm-2). The seed yield of Huayouza9 did not differ significantly from the local target seed yield. Higher plant density curtailed the luxurious vegetative growth of individual canola plants at the density of no less than 60–80 plants m-2, and high seed yield was derived from the increased ratio of main raceme and branch seed weight in winter canola. An increase in plant densities contributed to the reinforced sunlight interception at the pod-filling stage, providing a larger canopy photosynthetic area for the rapid growth of more canola pods at higher densities (60–105 plants m-2). Lodging resistance and breaking resistance decreased sharply with the plant density increasing from 12 to 60 plants m-2 while remaining almost steady as it further increased from 60 to 105 plants m-2 for Huayouza9 and Zhongshuang11. Hence, the population density of 60 plants m-2 reached a balance between lodging resistance and maximized seed yield in mechanized direct-seeded winter canola in China.","PeriodicalId":12245,"journal":{"name":"Experimental Agriculture","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47673069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-09DOI: 10.1017/S0014479722000540
C. Pierozan Junior, J. L. Favarin, J. L. C. Baptistella, R. E. M. de Almeida, Silas Maciel de Oliveira, B. C. Lago, T. Tezotto
Summary In Brazil, high-yield soybean [Glycine Max (L). Merrill] – corn (Zea mays L.) double cropping system might be nitrogen (N)-limited and additional N fertilization can be beneficial. Early application of N in soybean reduces the symbiotic N fixation (SNF) efficiency and/or establishment. One alternative to avoid SNF impairment is to apply N between the beginning pod (R3) and seed-fill (R5) stages through the use of controlled release fertilizers. In this study, N was applied at 50 kg ha−1 as common urea (CU) or controlled release urea (CRU) with different lag periods until N release starts (30 days, 60 days, or 1:1 mix of both lag times) in a randomized complete blocks design with six treatments and four replicates under tropical and subtropical conditions. CU was applied after soybean emergence (VE) or at the beginning pod (R3), and CRU only at VE. Using urea labeled with 15N isotope, we analyzed the N source used by soybean (fertilizer, soil, or SNF) and SNF parameters. On average, CRU – 30 days, CRU – 1:1 mix (30 + 60 days) and CU applied at the R3 stage increased grain yield by 9.2% (354 kg ha−1) compared to the control. N derived from all fertilizer treatment were almost 35 kg N ha−1, a high N recovery efficiency of 68%. The SNF was not impaired by CU and CRU and accounted for 71% (220 kg N ha−1) of total N uptake. In the conditions of the experiments, fertilization of 50 kg N ha−1 as CRU was shown to be effective to supply N in late soybean demand (R3 stage), increasing yield without damaging the SNF process in high-yield environments.
在巴西，高产大豆[Glycine Max (L). Merrill] -玉米(Zea mays L.)双熟制可能是氮(N)有限的，额外施氮可能是有益的。大豆早期施氮降低了共生固氮(SNF)效率和(或)建立。避免SNF损害的一种替代方法是在开始荚果(R3)和灌种(R5)阶段之间施用氮肥，通过使用控释肥料。本研究采用随机完全区组设计，在热带和亚热带条件下，采用6个处理、4个重复，以50 kg ha - 1施用氮肥，分别作为普通尿素(CU)或控释尿素(CRU)，不同滞后期(30天、60天或两种滞后期的1:1混合)，直至氮素开始释放。CU在大豆出苗后(VE)或初豆荚(R3)施用，CRU仅在VE施用。利用15N同位素标记的尿素，分析了大豆氮素来源(肥料、土壤或SNF)和SNF参数。平均而言，在R3期施用CRU - 30天、CRU - 1:1混合(30 + 60天)和CU可使籽粒产量比对照提高9.2% (354 kg ha - 1)。所有施肥处理的氮素提取量均接近35 kg N ha - 1，氮素回收率高达68%。SNF不受CU和CRU的影响，占总氮吸收的71% (220 kg N ha - 1)。在本试验条件下，施用50 kg N ha - 1作为CRU可有效满足大豆后期(R3期)的氮素需求，在不破坏高产环境下SNF过程的情况下提高产量。
{"title":"Controlled release urea increases soybean yield without compromising symbiotic nitrogen fixation","authors":"C. Pierozan Junior, J. L. Favarin, J. L. C. Baptistella, R. E. M. de Almeida, Silas Maciel de Oliveira, B. C. Lago, T. Tezotto","doi":"10.1017/S0014479722000540","DOIUrl":"https://doi.org/10.1017/S0014479722000540","url":null,"abstract":"Summary In Brazil, high-yield soybean [Glycine Max (L). Merrill] – corn (Zea mays L.) double cropping system might be nitrogen (N)-limited and additional N fertilization can be beneficial. Early application of N in soybean reduces the symbiotic N fixation (SNF) efficiency and/or establishment. One alternative to avoid SNF impairment is to apply N between the beginning pod (R3) and seed-fill (R5) stages through the use of controlled release fertilizers. In this study, N was applied at 50 kg ha−1 as common urea (CU) or controlled release urea (CRU) with different lag periods until N release starts (30 days, 60 days, or 1:1 mix of both lag times) in a randomized complete blocks design with six treatments and four replicates under tropical and subtropical conditions. CU was applied after soybean emergence (VE) or at the beginning pod (R3), and CRU only at VE. Using urea labeled with 15N isotope, we analyzed the N source used by soybean (fertilizer, soil, or SNF) and SNF parameters. On average, CRU – 30 days, CRU – 1:1 mix (30 + 60 days) and CU applied at the R3 stage increased grain yield by 9.2% (354 kg ha−1) compared to the control. N derived from all fertilizer treatment were almost 35 kg N ha−1, a high N recovery efficiency of 68%. The SNF was not impaired by CU and CRU and accounted for 71% (220 kg N ha−1) of total N uptake. In the conditions of the experiments, fertilization of 50 kg N ha−1 as CRU was shown to be effective to supply N in late soybean demand (R3 stage), increasing yield without damaging the SNF process in high-yield environments.","PeriodicalId":12245,"journal":{"name":"Experimental Agriculture","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47427786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1017/s0014479723000182
Antoine Drouillard, Mathieu Léchaudel, Michel Génard, Anna Doizy, Isabelle Grechi
Summary Fruit quality is a key factor – beginning with the producer, continuing through the supply chain, and ending with the consumer. It is described by multiple indicators and varies during the growth and ripening of the fruit. This study focused on two main aspects of Cogshall mango ( Mangifera indica L.) quality: (i) the physical properties of the fruit with fresh mass (FM), pulp dry matter content (DMC), and pulp coloration; and (ii) the chemical properties with pulp sugar content and pulp acidity. These indicators were monitored on on-tree fruit, from about 60 days after bloom until full maturity. The same indicators were also monitored on fruit stored in cold storage rooms during ripening. The effects of leaf-to-fruit ratio (manageable by pruning or fruit thinning), maturity stage of fruit at harvest (manageable by harvest date), and storage temperature on the kinetics of quality traits of on-tree and stored fruit were assessed. In addition, a change-point analysis was applied to the sweetness index kinetics (used as a proxy of fruit ripening) to study fruit ripening induction. The leaf-to-fruit ratio mainly influenced fruit growth in terms of FM and pulp DMC, whereas it had less impact on the evolution of fruit chemical properties. The maturity stage of the fruit at harvest was a key factor in determining the potential quality at the ripe stage. Ripening occurs naturally at the mature green stage for on-tree fruit, but ripening at an earlier stage can be induced by harvesting the fruit. During the ripening phase, a low leaf-to-fruit ratio and a cold storage temperature tended to slow down the daily rate of sweetness increase. The use of cold temperatures during storage slowed down starch degradation and sucrose accumulation, while almost stopping the variation in fruit coloration and acidity.
{"title":"Variations in mango fruit quality in response to management factors on a pre- and post-harvest continuum","authors":"Antoine Drouillard, Mathieu Léchaudel, Michel Génard, Anna Doizy, Isabelle Grechi","doi":"10.1017/s0014479723000182","DOIUrl":"https://doi.org/10.1017/s0014479723000182","url":null,"abstract":"Summary Fruit quality is a key factor – beginning with the producer, continuing through the supply chain, and ending with the consumer. It is described by multiple indicators and varies during the growth and ripening of the fruit. This study focused on two main aspects of Cogshall mango ( Mangifera indica L.) quality: (i) the physical properties of the fruit with fresh mass (FM), pulp dry matter content (DMC), and pulp coloration; and (ii) the chemical properties with pulp sugar content and pulp acidity. These indicators were monitored on on-tree fruit, from about 60 days after bloom until full maturity. The same indicators were also monitored on fruit stored in cold storage rooms during ripening. The effects of leaf-to-fruit ratio (manageable by pruning or fruit thinning), maturity stage of fruit at harvest (manageable by harvest date), and storage temperature on the kinetics of quality traits of on-tree and stored fruit were assessed. In addition, a change-point analysis was applied to the sweetness index kinetics (used as a proxy of fruit ripening) to study fruit ripening induction. The leaf-to-fruit ratio mainly influenced fruit growth in terms of FM and pulp DMC, whereas it had less impact on the evolution of fruit chemical properties. The maturity stage of the fruit at harvest was a key factor in determining the potential quality at the ripe stage. Ripening occurs naturally at the mature green stage for on-tree fruit, but ripening at an earlier stage can be induced by harvesting the fruit. During the ripening phase, a low leaf-to-fruit ratio and a cold storage temperature tended to slow down the daily rate of sweetness increase. The use of cold temperatures during storage slowed down starch degradation and sucrose accumulation, while almost stopping the variation in fruit coloration and acidity.","PeriodicalId":12245,"journal":{"name":"Experimental Agriculture","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135560183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1017/s0014479723000145
Oscar Iván Monsalve Camacho, Oscar Gonzalo Castillo-Romero, Carlos Ricardo Bojacá Aldana, Martha Cecilia Henao Toro
Summary A variety of established tools are available for agricultural sustainability assessment at global, regional, and farm geographical scales. However, no assessment has been reported in research literature to indicate their ability to provide insights about the most sustainable cropping system at plot level or experimental unit. Despite the environmental and social importance of soil in agricultural systems, many of the sustainability assessments use few or no indicators related to soil properties or processes. Hence, we propose a sustainability assessment methodology oriented to soil-associated agricultural experiments (SMAES) by defining its parameters through simulations and testing the methodology with real data from a fertilization tomato experiment with five treatments: chemical control (CR); organic control (OR); and organic:chemical ratios (OR) of 25:75, 50:50, and 75:25. The distance from the maximum, principal component analysis, and product of weighted indicator techniques were chosen for normalization, weighting, and aggregation in a single index process, respectively. Applying the SMAES methodology, the sustainability level of the treatments followed this sequence: CR (0.95) > O25:C75 (0.73) > O50:C50 (0.60) > O75:C25 (0.55) > OR (0.45). The proposed SMAES methodology allows soil researchers to define the best treatment through the interaction of the environmental, social, and economic dimensions of agricultural systems.
{"title":"Sustainability assessment methodology oriented to soil-associated agricultural experiments","authors":"Oscar Iván Monsalve Camacho, Oscar Gonzalo Castillo-Romero, Carlos Ricardo Bojacá Aldana, Martha Cecilia Henao Toro","doi":"10.1017/s0014479723000145","DOIUrl":"https://doi.org/10.1017/s0014479723000145","url":null,"abstract":"Summary A variety of established tools are available for agricultural sustainability assessment at global, regional, and farm geographical scales. However, no assessment has been reported in research literature to indicate their ability to provide insights about the most sustainable cropping system at plot level or experimental unit. Despite the environmental and social importance of soil in agricultural systems, many of the sustainability assessments use few or no indicators related to soil properties or processes. Hence, we propose a sustainability assessment methodology oriented to soil-associated agricultural experiments (SMAES) by defining its parameters through simulations and testing the methodology with real data from a fertilization tomato experiment with five treatments: chemical control (CR); organic control (OR); and organic:chemical ratios (OR) of 25:75, 50:50, and 75:25. The distance from the maximum, principal component analysis, and product of weighted indicator techniques were chosen for normalization, weighting, and aggregation in a single index process, respectively. Applying the SMAES methodology, the sustainability level of the treatments followed this sequence: CR (0.95) > O25:C75 (0.73) > O50:C50 (0.60) > O75:C25 (0.55) > OR (0.45). The proposed SMAES methodology allows soil researchers to define the best treatment through the interaction of the environmental, social, and economic dimensions of agricultural systems.","PeriodicalId":12245,"journal":{"name":"Experimental Agriculture","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135402173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Summary To clarify the combined effects of the cutting time and cutting height on ratooning ability and rice grain yield of the ratoon crop in the novel ratoon rice cropping, a field experiment was carried out to investigate the combined effects of harvesting time and the stubble-cutting height of the main crop on the growth duration, ratooning ability and grain yield of the ratoon crop. The growth period was shortened by 3.5 days on average when the harvesting time was 10 days ahead of time. On average, the growth duration was prolonged by 7 days per each decrease of 10 cm stubble height. Early harvesting and increasing stubble-cutting height greatly increased the grain yield of the ratoon crop. The highest grain yield was achieved at 10 days after flowering stage and a stubble height of 30 cm, which were 6916 kg·hm −2 for XLY900 and 7262 kg·hm −2 for YY4149, averaged across years. High rice yield of the ratoon crop was mainly depended on panicle numbers and grain-filling percentage, rather than spikelets per panicle. Increasing cutting height and the cutting time of the main crop ahead maintain more stubble biomass and nitrogen content. A significant positive correlation was observed between stubble nitrogen content and tillers-to-stubble ratio (TSR), as well as a significant positive relation was found between panicle-to-stubble ratio and TSR. Therefore, cutting 10 days after flowering stage of the main crop with 30 cm stubble-cutting height enhances ratooning ability due to higher stubble biomass and nitrogen content, and then increases rice yield of the ratoon crop.
{"title":"Early harvesting and increasing stubble-cutting height enhance ratoon rice yield","authors":"Yuanwei Chen, Huabin Zheng, Weiqin Wang, Qiyuan Tang","doi":"10.1017/s0014479723000157","DOIUrl":"https://doi.org/10.1017/s0014479723000157","url":null,"abstract":"Summary To clarify the combined effects of the cutting time and cutting height on ratooning ability and rice grain yield of the ratoon crop in the novel ratoon rice cropping, a field experiment was carried out to investigate the combined effects of harvesting time and the stubble-cutting height of the main crop on the growth duration, ratooning ability and grain yield of the ratoon crop. The growth period was shortened by 3.5 days on average when the harvesting time was 10 days ahead of time. On average, the growth duration was prolonged by 7 days per each decrease of 10 cm stubble height. Early harvesting and increasing stubble-cutting height greatly increased the grain yield of the ratoon crop. The highest grain yield was achieved at 10 days after flowering stage and a stubble height of 30 cm, which were 6916 kg·hm −2 for XLY900 and 7262 kg·hm −2 for YY4149, averaged across years. High rice yield of the ratoon crop was mainly depended on panicle numbers and grain-filling percentage, rather than spikelets per panicle. Increasing cutting height and the cutting time of the main crop ahead maintain more stubble biomass and nitrogen content. A significant positive correlation was observed between stubble nitrogen content and tillers-to-stubble ratio (TSR), as well as a significant positive relation was found between panicle-to-stubble ratio and TSR. Therefore, cutting 10 days after flowering stage of the main crop with 30 cm stubble-cutting height enhances ratooning ability due to higher stubble biomass and nitrogen content, and then increases rice yield of the ratoon crop.","PeriodicalId":12245,"journal":{"name":"Experimental Agriculture","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135601328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1017/s0014479723000194
D. A. Salve, M. L. Maydup, G. A. Salazar, E. A. Tambussi, M. Antonietta
Summary In highlands, the increase in altitude results in a drastic decrease in temperature (T) that delays phenological development of maize, decreasing light interception during the cycle. This could be partially overcome by increasing plant density, but information is scarce for designing specific management options. The objective of this work was to describe changes in canopy development, photosynthetic performance, biomass and yield of maize grown at contrasting plant densities (5.7 plants m −2 , locally used, and 8.7 plants m −2 , 50% higher). Three experiments were carried out in two high-altitude environments within the Argentinean Andean region, Hornillos (HOR, 2380 masl, 2019–20 and 2020–21) and El Rosal (ERO, 3350 masl, 2019–20), and complementary data were obtained from samplings in 8 farmer’s fields (from 2400 to 3400 masl, 2022–23). In the experiments, mean T during the first 150 days of the cycle was 33% lower at ERO, which implied 39 extra days but 25% shorter thermal time to achieve silking. The higher plant density significantly increased leaf area index and light interception at ERO, whereas at HOR, this was only evident during the second season. At the leaf level, plants grown at ERO had thicker leaves with higher chlorophyll (+36%) and nitrogen (40%) content. Photosynthetic electron transport rate at full irradiance was +20% higher at ERO but significantly varied throughout the day with lowest values in the morning, which was not observed at HOR and was not related to light intensity or stomatal conductance. At HOR, the increase in plant density did not improve light interception, nor yield in 2019–20 (with average yields of 6356 kg ha −1 ) but it did improve both in 2020–21 when generally lower yields were attained (4821 kg ha −1 ). Across farmer’s fields, increasing densities consistently reduced yield per plant ( r 2 = 0.57***) but improved yield per area basis, which was maximised at 10 pl m −2 as a result of a steady increase in kernel number m −2 (up to 15 pl m −2 ). Thus, in these high-altitude environments, increasing plant density beyond recommended (6 pl m −2 ) is a promising approach for improving yield, with major penalties of supra-optimum densities being related to kernel weight. Further work is needed to explore the effect of different factors limiting kernel growth, over plant density responses.
在高原地区，海拔的升高导致温度(T)的急剧下降，延缓了玉米的物候发育，减少了周期中的光截获。这可以通过增加植物密度来部分克服，但是缺乏设计具体管理方案的信息。本研究的目的是描述不同植物密度(5.7株m−2，本地使用，8.7株m−2，高50%)下玉米生长的冠层发育、光合性能、生物量和产量的变化。在阿根廷安第斯地区Hornillos (HOR, 2380 masl, 2019-20和2020-21)和El Rosal (ERO, 3350 masl, 2019-20)两个高海拔环境中进行了三项实验，并从8个农民的农田(2400 - 3400 masl, 2022-23)取样获得了补充数据。在实验中，发丝周期前150天的平均T值在低温下降低33%，这意味着发丝所需的时间增加了39天，但发丝所需的时间缩短了25%。较高的密度显著提高了低密度稻的叶面积指数和光截获量，而高密度稻只在第二季表现明显。在叶片水平上，在ERO条件下生长的植株叶片较厚，叶绿素含量(+36%)和氮含量(40%)较高。全光照下的光合电子传递速率在低光照条件下比低光照条件下高20%，但全天变化显著，在早晨最低，这在高光照条件下没有观察到，也与光强和气孔导度无关。在HOR条件下，植株密度的增加并没有提高2019-20年的光截获率和产量(平均产量为6356 kg ha - 1)，但在产量普遍较低的2020-21年(4821 kg ha - 1)，密度的增加确实提高了两者。在农民的田地中，增加密度持续降低单株产量(r 2 = 0.57***)，但提高了单株产量，由于籽粒数m - 2的稳定增加(高达15 pl m - 2)，单株产量在10 pl m - 2时达到最大。因此，在这些高海拔环境中，将植物密度增加到推荐值(6 pl m−2)以上是提高产量的一种有希望的方法，而超最佳密度的主要惩罚与粒重有关。需要进一步研究不同因素对籽粒生长的限制对植株密度响应的影响。
{"title":"Canopy development, leaf traits and yield in high-altitude Andean maize under contrasting plant densities in Argentina","authors":"D. A. Salve, M. L. Maydup, G. A. Salazar, E. A. Tambussi, M. Antonietta","doi":"10.1017/s0014479723000194","DOIUrl":"https://doi.org/10.1017/s0014479723000194","url":null,"abstract":"Summary In highlands, the increase in altitude results in a drastic decrease in temperature (T) that delays phenological development of maize, decreasing light interception during the cycle. This could be partially overcome by increasing plant density, but information is scarce for designing specific management options. The objective of this work was to describe changes in canopy development, photosynthetic performance, biomass and yield of maize grown at contrasting plant densities (5.7 plants m −2 , locally used, and 8.7 plants m −2 , 50% higher). Three experiments were carried out in two high-altitude environments within the Argentinean Andean region, Hornillos (HOR, 2380 masl, 2019–20 and 2020–21) and El Rosal (ERO, 3350 masl, 2019–20), and complementary data were obtained from samplings in 8 farmer’s fields (from 2400 to 3400 masl, 2022–23). In the experiments, mean T during the first 150 days of the cycle was 33% lower at ERO, which implied 39 extra days but 25% shorter thermal time to achieve silking. The higher plant density significantly increased leaf area index and light interception at ERO, whereas at HOR, this was only evident during the second season. At the leaf level, plants grown at ERO had thicker leaves with higher chlorophyll (+36%) and nitrogen (40%) content. Photosynthetic electron transport rate at full irradiance was +20% higher at ERO but significantly varied throughout the day with lowest values in the morning, which was not observed at HOR and was not related to light intensity or stomatal conductance. At HOR, the increase in plant density did not improve light interception, nor yield in 2019–20 (with average yields of 6356 kg ha −1 ) but it did improve both in 2020–21 when generally lower yields were attained (4821 kg ha −1 ). Across farmer’s fields, increasing densities consistently reduced yield per plant ( r 2 = 0.57***) but improved yield per area basis, which was maximised at 10 pl m −2 as a result of a steady increase in kernel number m −2 (up to 15 pl m −2 ). Thus, in these high-altitude environments, increasing plant density beyond recommended (6 pl m −2 ) is a promising approach for improving yield, with major penalties of supra-optimum densities being related to kernel weight. Further work is needed to explore the effect of different factors limiting kernel growth, over plant density responses.","PeriodicalId":12245,"journal":{"name":"Experimental Agriculture","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135658884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1017/s0014479723000169
Mekdim D. Regassa, Philip K. Miriti, Mequanint B. Melesse
Summary Understanding farmers’ preferences and willingness to pay for different traits is critical for demand-driven varietal development and designing targeted strategies that stimulate adoption of varieties by farmers. This study uses choice experiment data from a random sample of 1299 Tanzanian farmers to analyze their preferences for traits of groundnut varieties, investigate trade-offs involved in valuation of attributes, and explore heterogeneity in preferences. Results reveal that farmers have strong preferences for groundnut varieties that are high yielding, tolerant to environmental stresses, early-maturing, red-colored, and fetching high sale prices in grain markets. Farmers are willing to pay the highest premium for high-yielding attributes, closely followed by the tolerance trait. Further, a latent class analysis identifies four distinct classes of farmers, confirming considerable heterogeneity in farmers’ preferences for various groundnut traits. A specific distinction is notable between preferences of consumption-oriented and market-oriented farmer classes. Our results have important implications for demand-driven variety development and targeted dissemination of improved varieties.
{"title":"Farmers’ heterogeneous preferences for traits of improved varieties: Informing demand-oriented crop breeding in Tanzania","authors":"Mekdim D. Regassa, Philip K. Miriti, Mequanint B. Melesse","doi":"10.1017/s0014479723000169","DOIUrl":"https://doi.org/10.1017/s0014479723000169","url":null,"abstract":"Summary Understanding farmers’ preferences and willingness to pay for different traits is critical for demand-driven varietal development and designing targeted strategies that stimulate adoption of varieties by farmers. This study uses choice experiment data from a random sample of 1299 Tanzanian farmers to analyze their preferences for traits of groundnut varieties, investigate trade-offs involved in valuation of attributes, and explore heterogeneity in preferences. Results reveal that farmers have strong preferences for groundnut varieties that are high yielding, tolerant to environmental stresses, early-maturing, red-colored, and fetching high sale prices in grain markets. Farmers are willing to pay the highest premium for high-yielding attributes, closely followed by the tolerance trait. Further, a latent class analysis identifies four distinct classes of farmers, confirming considerable heterogeneity in farmers’ preferences for various groundnut traits. A specific distinction is notable between preferences of consumption-oriented and market-oriented farmer classes. Our results have important implications for demand-driven variety development and targeted dissemination of improved varieties.","PeriodicalId":12245,"journal":{"name":"Experimental Agriculture","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135440833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-22DOI: 10.1017/S0014479722000527
Naliharilala Miora Rakotoarivelo Njaramanana, Volatsara Baholy Rahetlah, J. Trap, P. Autfray
Summary In Madagascar, upland rice cropping is constrained by soil acidity and low phosphorus (P) bioavailability. Given their role in plant P nutrition, arbuscular mycorrhizal fungi (AMF) may improve crop yield in nutrient-poor tropical soils. In the Vakinankaratra region, a field experiment was conducted at 908 m asl on an acidic Ferralsol during the 2019–2020 growing season. The aim was to test the ability of four promoted rice varieties to respond to AMF seed-coating inoculation with a commercial strain of Rhizophagus irregularis in the absence or presence of P fertilizer (20 kg ha−1 of P2O5) under no expected nitrogen (N) limitation. In absence of P fertilization, both at tillering and at maturity and irrespective of the rice varieties, AMF inoculation significantly improved plant performance and finally grain yield, grain N, and grain P amounts by an average of 28%, 30%, and 39%, respectively. In contrast, when P fertilizer was supplied, no significant effect of AMF inoculation was observed. Rice growth variables were significantly higher with the application of P fertilizer than with AMF inoculation both at tillering and at maturity. P fertilizer without inoculation provided an average grain yield improvement of 85%. At tillering, mycorrhizal parameters for root colonization assessment were not positively linked with rice growth variables suggesting an early effect of AMF inoculation. We concluded that, with no P fertilization, AMF seed coating inoculation at the field scale significantly improved upland rice plant performance in a limited soil P environment. Our rice genetic variability did not interfere significantly both with mycorrhizal parameters and crop AMF inoculation benefits.
摘要在马达加斯加，旱地水稻种植受到土壤酸度和低磷生物利用度的限制。考虑到丛枝菌根真菌在植物磷营养中的作用，它们可以提高营养不良热带土壤的作物产量。在Vakinankaratra地区，在2019-2020年的生长季节，在海拔908米的酸性Ferralsol上进行了一项田间试验。目的是测试四个推广的水稻品种在不存在或存在磷肥（20 kg ha−1 P2O5）的情况下，在没有预期氮（N）限制的情况下对用商业菌株非规则根噬菌体接种AMF种子包衣的反应能力。在没有施磷的情况下，无论是在分蘖期还是成熟期，无论水稻品种如何，接种AMF都能显著提高植株性能，最终使产量、籽粒氮和籽粒磷含量分别平均提高28%、30%和39%。相反，当施用磷肥时，AMF接种没有观察到显著的效果。在分蘖期和成熟期，施用磷肥的水稻生长变量均显著高于接种AMF的水稻。不接种磷肥的平均粮食产量提高了85%。在分蘖期，用于根系定殖评估的菌根参数与水稻生长变量没有正相关，这表明AMF接种的早期效果。我们得出的结论是，在不施磷的情况下，在有限的土壤磷环境下，田间规模的AMF种衣剂接种显著提高了旱稻的植株性能。我们的水稻遗传变异性对菌根参数和作物AMF接种效益都没有显著干扰。
{"title":"Field arbuscular mycorrhizal inoculation increased plant performance without phosphorus fertilizer supply of four promoted upland rice varieties in Madagascar","authors":"Naliharilala Miora Rakotoarivelo Njaramanana, Volatsara Baholy Rahetlah, J. Trap, P. Autfray","doi":"10.1017/S0014479722000527","DOIUrl":"https://doi.org/10.1017/S0014479722000527","url":null,"abstract":"Summary In Madagascar, upland rice cropping is constrained by soil acidity and low phosphorus (P) bioavailability. Given their role in plant P nutrition, arbuscular mycorrhizal fungi (AMF) may improve crop yield in nutrient-poor tropical soils. In the Vakinankaratra region, a field experiment was conducted at 908 m asl on an acidic Ferralsol during the 2019–2020 growing season. The aim was to test the ability of four promoted rice varieties to respond to AMF seed-coating inoculation with a commercial strain of Rhizophagus irregularis in the absence or presence of P fertilizer (20 kg ha−1 of P2O5) under no expected nitrogen (N) limitation. In absence of P fertilization, both at tillering and at maturity and irrespective of the rice varieties, AMF inoculation significantly improved plant performance and finally grain yield, grain N, and grain P amounts by an average of 28%, 30%, and 39%, respectively. In contrast, when P fertilizer was supplied, no significant effect of AMF inoculation was observed. Rice growth variables were significantly higher with the application of P fertilizer than with AMF inoculation both at tillering and at maturity. P fertilizer without inoculation provided an average grain yield improvement of 85%. At tillering, mycorrhizal parameters for root colonization assessment were not positively linked with rice growth variables suggesting an early effect of AMF inoculation. We concluded that, with no P fertilization, AMF seed coating inoculation at the field scale significantly improved upland rice plant performance in a limited soil P environment. Our rice genetic variability did not interfere significantly both with mycorrhizal parameters and crop AMF inoculation benefits.","PeriodicalId":12245,"journal":{"name":"Experimental Agriculture","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2022-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45147055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-22DOI: 10.1017/S0014479722000539
José Francisco Valle, E. Arnaud, P. Marimo, Jacob van Etten
Summary User-oriented research is important in breeding improved genotypes, for developing and validating product concepts (mostly involving trait prioritisation), as well as evaluating breeding products in use situations (mostly involving participatory variety evaluation). This paper examines key aspects that enable cumulative learning in user-oriented research for root, tuber and banana (RTB) crop breeding. We reviewed empirical user-oriented studies on RTB crops published between 1996 and 2020. We examined the ability of user-oriented research to foster cumulative learning by examining four key aspects: spatial and temporal coverage; gender aspects; the range of traits considered and publishing practices as evident in reports and datasets. We conclude that user-oriented studies have received attention in RTB breeding but fall short of enabling cumulative learning. Substantial investments in methodology development and capacity are needed to bring greater coherence to this field and enable cumulative learning about user perspectives to iteratively increase the fit between improved genotypes and user preferences.
{"title":"Enabling cumulative learning in user-oriented research for root, tuber and banana crop breeding","authors":"José Francisco Valle, E. Arnaud, P. Marimo, Jacob van Etten","doi":"10.1017/S0014479722000539","DOIUrl":"https://doi.org/10.1017/S0014479722000539","url":null,"abstract":"Summary User-oriented research is important in breeding improved genotypes, for developing and validating product concepts (mostly involving trait prioritisation), as well as evaluating breeding products in use situations (mostly involving participatory variety evaluation). This paper examines key aspects that enable cumulative learning in user-oriented research for root, tuber and banana (RTB) crop breeding. We reviewed empirical user-oriented studies on RTB crops published between 1996 and 2020. We examined the ability of user-oriented research to foster cumulative learning by examining four key aspects: spatial and temporal coverage; gender aspects; the range of traits considered and publishing practices as evident in reports and datasets. We conclude that user-oriented studies have received attention in RTB breeding but fall short of enabling cumulative learning. Substantial investments in methodology development and capacity are needed to bring greater coherence to this field and enable cumulative learning about user perspectives to iteratively increase the fit between improved genotypes and user preferences.","PeriodicalId":12245,"journal":{"name":"Experimental Agriculture","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2022-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45486302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-05DOI: 10.1017/S0014479722000515
Kudzayi Janhi, C. Chiduza, John Fisher Mupangwa, L. Muzangwa
Summary Management strategies such as nitrogen (N) topdressing and clipping can be used to optimize a cover crop for the dual purpose of soil cover and forage. The present study tested oat (Avena sativa) for a holistic provision of soil cover and forage under various levels of clipping frequency and N topdressing. Effects on root and above-ground biomass, acid detergent fiber, neutral detergent fiber, and crude protein (CP) were evaluated. Clipping frequency had four levels, namely clipped only at termination (C1), clipped at 28 days after emergence (DAE) and termination (C2), clipped at 28, 42 DAE, and termination (C3), and clipped at 28, 42, 56 DAE, and termination (C4). Nitrogen topdressing had two levels, namely with (N1) and without (N0) the recommended N topdressing. Increasing clipping frequency reduced the root and aerial biomass and did not affect the forage quality harvested before termination. However, N topdressing increased biomass and CP content across the clipping frequencies. Results suggest clipping thrice combined with N topdressing (C4 + N1) provides the best option to satisfy both soil cover and livestock demands. The treatment (C4 + N1) gave > 2 t ha−1 of biomass during the growing period and 6 t ha−1 at termination which can be used for livestock forage and soil cover, respectively. Clipping thrice without N topdressing (C4 + N0) was the best option for resource-constrained farmers.
氮肥追肥和修剪等管理策略可用于优化覆盖作物，以实现土壤覆盖和饲料的双重目的。本研究对不同刈割频率和氮素追肥水平下燕麦(Avena sativa)整体提供土壤覆盖物和饲料进行了试验。评价其对根系和地上部生物量、酸性洗涤纤维、中性洗涤纤维和粗蛋白质(CP)的影响。剪断频率分为4个级别，即仅在终止时剪断(C1)、在出蛹后28天剪断(DAE)并终止(C2)、在28、42天剪断并终止(C3)、在28、42、56天剪断并终止(C4)。施氮量分为施(N1)和不施(N0)两个水平。刈割频率的增加减少了根生物量和地上生物量，但不影响刈割前收获的牧草质量。然而，在各个刈割频率上，追肥均增加了生物量和CP含量。结果表明，3次修剪配合C4 + N1追肥是满足土壤覆盖和牲畜需求的最佳选择。处理(C4 + N1)在生育期和终止期分别提供了2 t ha - 1和6 t ha - 1的生物量，可分别用于家畜饲料和土壤覆盖。对于资源受限的农户，3次刈割不施氮(C4 + N0)是最佳选择。
{"title":"Optimizing the clipping frequency and nitrogen topdressing in a dual-purpose oat used for fodder and cover cropping","authors":"Kudzayi Janhi, C. Chiduza, John Fisher Mupangwa, L. Muzangwa","doi":"10.1017/S0014479722000515","DOIUrl":"https://doi.org/10.1017/S0014479722000515","url":null,"abstract":"Summary Management strategies such as nitrogen (N) topdressing and clipping can be used to optimize a cover crop for the dual purpose of soil cover and forage. The present study tested oat (Avena sativa) for a holistic provision of soil cover and forage under various levels of clipping frequency and N topdressing. Effects on root and above-ground biomass, acid detergent fiber, neutral detergent fiber, and crude protein (CP) were evaluated. Clipping frequency had four levels, namely clipped only at termination (C1), clipped at 28 days after emergence (DAE) and termination (C2), clipped at 28, 42 DAE, and termination (C3), and clipped at 28, 42, 56 DAE, and termination (C4). Nitrogen topdressing had two levels, namely with (N1) and without (N0) the recommended N topdressing. Increasing clipping frequency reduced the root and aerial biomass and did not affect the forage quality harvested before termination. However, N topdressing increased biomass and CP content across the clipping frequencies. Results suggest clipping thrice combined with N topdressing (C4 + N1) provides the best option to satisfy both soil cover and livestock demands. The treatment (C4 + N1) gave > 2 t ha−1 of biomass during the growing period and 6 t ha−1 at termination which can be used for livestock forage and soil cover, respectively. Clipping thrice without N topdressing (C4 + N0) was the best option for resource-constrained farmers.","PeriodicalId":12245,"journal":{"name":"Experimental Agriculture","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2022-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44722694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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