The purpose of this study is to quantify the rice harvest losses in China and to evaluate the impacts of machinery and harvest outsourcing services on these losses,given the background of high-speed mechanization and ...The purpose of this study is to quantify the rice harvest losses in China and to evaluate the impacts of machinery and harvest outsourcing services on these losses,given the background of high-speed mechanization and outsourcing services.Data were collected from a national survey conducted in 2016 by the research team in conjunction with the Research Center for the Rural Economy of the Ministry of Agriculture and Rural Affairs of China.A non-parametric method was used to test whether combine harvesting and outsourcing services could significantly reduce harvest losses.Next,quantile regression was used to estimate the real effects of machinery and outsourcing services on harvest losses.The analysis yielded four main study outcomes.First,the harvest loss rate of rice in China was 3.65%.Second,mechanical reaping and winnowing caused greater losses than manual methods,while the opposite was true of field transportation.Third,combine harvesting increased the losses.Fourth,the effects of an outsourcing service on losses differed among the different harvesting methods.Outsourcing services increased losses in segmented harvesting but they reduced losses in combine harvesting.展开更多
Agricultural mechanization plays a pivotal role in the transition from subsistence to commercial agriculture, with a particular focus on labour-intensive activities like harvesting. This study assesses the operational...Agricultural mechanization plays a pivotal role in the transition from subsistence to commercial agriculture, with a particular focus on labour-intensive activities like harvesting. This study assesses the operational characteristics of the BRRI Whole Feed Combine Harvester (Model BRRI WCH2021) at the field level. Developed under the SFMRA project, the harvester’s technical performance and loss assessment were conducted during the Boro 2022 and Aman 2022 seasons in farmer fields in Bangladesh’s Rangpur region. The field efficiency of the harvester was determined to be 62.5% and 57.9% in the Boro and Aman seasons, respectively. Fuel consumption rates were recorded at 2.77 l/ha and 2.31 l/ha for the Boro and Aman seasons. The total harvesting losses, encompassing cutter bar, shatter, cylinder, and separation loss, averaged 0.56% and 0.48% in the Boro and Aman seasons, respectively. Mechanized harvesting with the BRRI Whole Feed Combine Harvester significantly reduced paddy losses by 5.81% compared to manual methods. The field evaluation results indicate the combine harvester’s satisfactory performance, highlighting its potential to alleviate labour demands during peak harvesting. The development of the BRRI WCH offers a sustainable solution for rice harvesting mechanization among progressive farmers. It paves the way for the broader adoption of advanced agricultural technology in Bangladesh.展开更多
China is one of the most important rapeseed producing countries in the world. Effective mechanical harvesting time for decreasing harvesting loss of winter oilseed rape has been becoming a critical factor. An elite cu...China is one of the most important rapeseed producing countries in the world. Effective mechanical harvesting time for decreasing harvesting loss of winter oilseed rape has been becoming a critical factor. An elite cultivar Zhongshuang 11 (Brassica napus L.) was employed in two rounds of field experiments from 2009 to 2011. Seeds were sown with machine, three combine harvesting times namely combine harvesting A, B, and C (CHA, CHB, and CHC) were designed and manual harvesting (MH) as control was performed at maturity. The harvesting treatments were determined according to color of pod and seed in the field. Seed yield loss and quality in different treatments were evaluated. Results showed that both seed yields and harvesting losses in 2009-2010 were higher than that in 2010-2011, whereas seed oil contents in 2010-2011 were higher than that in 2009-2010. The highest yield appeared in CHB, which was significantly higher than that in MH. Furthermore, harvesting loss in CHB were 50% that in MH. Seed oil content and chlorophyll exhibited no obvious difference between CHB and MH. Economic profit analysis demonstrated that mechanical sowing/combine harvesting (MS/CH) showed an input/output ratio of 1:1.6, and it was 1:1.2 in mechanical sowing/manual harvesting (MS/MH). Labor-cost accounted for more than 70% of the total cost in MS/MH, which led to low profitability to a great extent. Our results suggested that CHB was the optimum harvesting time for winter oilseed rape along the Yangtze River.展开更多
The high harvest losses associated with the mechanical harvesting of maize in China are currently a major barrier to the adoption of this technology.This paper summarizes works of literature regarding harvest losses f...The high harvest losses associated with the mechanical harvesting of maize in China are currently a major barrier to the adoption of this technology.This paper summarizes works of literature regarding harvest losses from the combine harvesting of maize in China and abroad.The main findings are as follows:(1)In 2012-2019,2987 samples data obtained from the major maize production areas of China showed that the average harvest loss was 345.2 kg/hm2(3.5%of the average yield),with losses ranging from 0 to 9288.5 kg/hm2;(2)The harvest losses from combine harvesting are mainly caused by the dropping of ears.The ear losses include the pre-harvest loss caused by ear abscission,damage caused by maize borer,lodging,and the ear loss during combine harvesting,and the main pre-harvest loss is caused by lodging;(3)Harvest losses are affected by maize variety,planting mode,cultivation management,pests and diseases,weather conditions during harvesting,harvest date,combine harvester type,harvester adjustment,operator proficiency,and the terrain conditions of the maize field;(4)The harvest losses from combine harvesting are also related to the type of header,feeding and threshing methods,the adjustment of header stripping clearance,feeding amount,forward speed,cylinder or rotor speed,and the clearance between the cylinder and the concave of the harvester.However,the combine losses mainly come from header losses.In order to reduce the harvest losses,the following solutions were proposed:(1)Breed and select maize varieties which are resistant to lodging,especially during the field drying of mature grains,as well as those resistant to maize borer and stalk rot;(2)Select varieties suitable for grain harvest-which requires matching the accumulated-temperature demand of the maize hybrids,optimal plant density,row spacing,and irrigation and fertilizer management with the light and heat conditions of the production area while cultivating uniform populations and healthy plants-as well as preventing and controlling damage from maize borer,stalk rot,and ear rot,harvesting at the appropriate time;(3)Develop and select advanced maize combine harvesters,formulate standardized operating procedures for harvesting machinery,and standardize field operation;(4)select appropriate agricultural machinery and agronomic practices,and improve the training of maize producers and harvester operators.展开更多
Teak (Tectona grandis Linn. f.) ranks among the top five tropical hardwood species and is being promoted for use in plantations in its non-native range due to its high economic value. However, there is a general lac...Teak (Tectona grandis Linn. f.) ranks among the top five tropical hardwood species and is being promoted for use in plantations in its non-native range due to its high economic value. However, there is a general lack of data on ecosystem functioning of teak plantations. We aimed at understanding storage and flux of nutrients related to young plantations of teak. Cycling of nitrogen (N) and phosphorus (P) in a chronosequence of plantations (1, 5, 11, 18, 24 and 30 years) was studied in the Moist Deciduous Forest Region of North India with the objective of investigating the nutrient cycling pattern at younger age since the current trend of harvesting age of the species in several tropical countries is being drastically reduced for quick return from this high value crop. Standing state, nutrient uptake, nutrient return and nutrient retransloca-tion in these plantations were estimated by tree harvesting and chemical analysis methods. The range of total standing nutrient across all these plantations was 20.3 to 586.6 kg?ha-1 for N and 5.3 to 208.8 kg?ha-1 for P. Net uptake of N ranged from 19.4 to 88.9 kg?ha-1?a-1 and P from 3.8 to 18.1 kg?ha-1?a-1. Retranslocation of N and P among all the stands ranged from 8.7 to 48.0 kg?ha-1?a-1 and 0.01 to 3.5 kg?ha-1?a-1, respectively. Range of total nutrient return was 25.8 to 91.3 kg?ha-1?a-1 for N and 2.7 to 10.1 kg?ha-1?a-1 for P. N and P use efficiency was between 107.4 and 192.5 g dry organic matter (OM) g-1N, and 551.9 and 841.1 g OM g-1P, respec-tively. The turnover time ranged from 2.04-13.17 years for N and be-tween 2.40-22.66 years for P. Quantity of N and P in the soil nutrient pool ranged from 2566.8 to 4426.8 kg?ha-1 and 372 to 520 kg?ha-1, re-spectively. Storage and flux of components in different plant parts of different aged plantations were assessed and depicted in compartment models. Percentage storage in soil, litter and vegetation ranged from 82% to 99%, 0.6% to 2.4% and 0.5% to 15% for N, respectively, and from 63% to 98%, 0.5% to 2% and 1% to 35% for P, respectively. This infor-mation could be useful in managing external nutrient manipulation to crops of different ages for optimum biomass production or carbon se-questration.展开更多
Field harvest loss is a common problem of maize grain mechanical harvesting in China and abroad.From 2012 to 2019,2987 groups of samples for the quality of mechanical grain harvesting in field were obtained in 21 majo...Field harvest loss is a common problem of maize grain mechanical harvesting in China and abroad.From 2012 to 2019,2987 groups of samples for the quality of mechanical grain harvesting in field were obtained in 21 major maize-producing provinces,cities,and regions of China.The analysis performed in this study showed that the average harvest loss of fallen ears was equivalent to 76.5%of the total harvest loss,indicating that the harvest loss in the mechanical harvesting of maize grain mainly came from the loss of fallen ears.Meanwhile,statistical analysis of the harvest loss in different ranges of grain moisture contents showed that,when the grain moisture content fell below 20%,the harvest loss rate of fallen ears and the total harvest loss rate both increased sharply,and the harvest loss of fallen ears increased faster than the harvest loss of fallen grain with a decreasing grain moisture content.Moreover,the results of multi-point experiments and harvest experiments in different periods showed that,during harvesting time,the harvest loss of fallen ears caused by lodging was the main reason for in-field harvest losses in the mechanical harvesting of maize grain.Apart from the above mentioned,the test results of 35 groups of harvesters for the in-field mechanical harvesting of maize grain showed that the harvester types and their operating parameters were important factors affecting the harvest loss in the mechanical harvesting of maize grain.Therefore,the principal paths to reduce harvest loss in the mechanical harvesting of maize grain are to breed lodging-resistant maize varieties,adopt reasonable planting densities,cultivate healthy plants,develop harvesters with low harvesting loss,intensify the training of operators,and harvest at an appropriate time.展开更多
The harvesting difficulty caused by corn lodging aggravated the loss of grain,especially in the regions where small harvesters were used as the main force for corn harvesting.An experimental study and analysis of harv...The harvesting difficulty caused by corn lodging aggravated the loss of grain,especially in the regions where small harvesters were used as the main force for corn harvesting.An experimental study and analysis of harvest loss of small harvesters on the root lodged corn were made to get the laws of lodged corn harvest loss.The experiment was conducted in different harvesting directions and at a range of harvesting speeds.A 4-row self-propelled corn harvester(JM-4Y),a 2-row crawler type self-propelled corn harvester(JM-2C),and a 2-row crawler-type corn harvester equipped with a spiral auxiliary feeding device for lodged stalks(JM-2CAF)were taken as the research objects and the grain loss per square meter and the ear loss quantity per 30 square meters were taken as the experiment indices.The results showed that the average grain loss masses of the JM-4Y harvester,the JM-2C harvester and the JM-2CAF harvester in different harvesting directions were 101.88g,285.72 g and 110.20 g,while the average corn ear losses were 10.08,33.54 and 9.28 pieces.The lowest harvest loss of the JM-4Y harvester appeared when the harvesting was the same as the lodging direction,while the JM-2CAF harvester caused the lowest harvest loss when the harvesting direction was opposite to the lodging direction.The different feeding demands of the ordinary harvester head and the auxiliary feeding devices made the harvesters have different feeding conditions.At different harvesting speeds,the average grain loss mass of the JM-4Y harvester,the JM-2C harvester and the JM-2CAF harvester were 139.06 g,453.42 g and 236.64 g while the average corn ear loss quantities were 15.12,52.52 and 34.80 pieces.The JM-4Y harvester had the lowest harvest loss at almost every harvesting speed,and the JM-2CAF harvester only had lower harvest loss when the harvesting speed was lower than 0.8 m/s.The insufficient time to lift and deliver the lodged stalk and the impact between the spiral blades and the stalks were the causes of harvest loss when harvesting speed got higher.This study provides practical and theoretical references for the loss reduction of lodged corn harvesting.展开更多
Cassava is a major food crop for farmers and especially small holder farmers and cultivated under low input other than the irrigation.It is cultivated as mono crop or intercrop at early stage and cultivating throughou...Cassava is a major food crop for farmers and especially small holder farmers and cultivated under low input other than the irrigation.It is cultivated as mono crop or intercrop at early stage and cultivating throughout the year.It is harvested carefully because of cyanogenic glucosides and consumed with in day.Easy and un-damageable uprooting of the tuber mainly depends on soil moisture,texture and agronomic practices.The study was focused with the objectives of the assessment of soil loss due to the harvesting of cassava roots tubers under low input agriculture,and to estimate the amount of plant nutrients loss due to crop harvest for cassava.Also the observation was made the correlation between the soil loss and physical characters of the tuber,soil texture and agronomic practices.Average plant specific soil loss due to crop harvesting was 80.7 g root−1 and crop specific soil loss due to crop harvesting was 7.64 kg ha−1 harvest−1 loss in Valliagmam area in Jaffna,Sri Lanka.Soil moisture content at harvesting time was a significant factor that explained the variations in the soil lost at cassava harvesting.Soil moisture has linear positive relationship with average plant specific soil loss due to crop harvesting.Soil nutrient loss during cassava harvesting by removal of adhering soil with root tuber was 1.15 kg of N,1.99 kg of P and 2.91 kg of K ha−1 harvest−1.Application of fertilizer is important since considerable amount nutrient loss was observed due to soil loss due to crop harvest.展开更多
基金the 2015 Special Scientific Research Project of Grain Public Welfare Industry,China(201513004-2)the research grant from the Murata Science Foundation,JSPS KAKENHI,Japan(JP19H03063)the scholarship from China Scholarship Council(CSC201906350150)。
文摘The purpose of this study is to quantify the rice harvest losses in China and to evaluate the impacts of machinery and harvest outsourcing services on these losses,given the background of high-speed mechanization and outsourcing services.Data were collected from a national survey conducted in 2016 by the research team in conjunction with the Research Center for the Rural Economy of the Ministry of Agriculture and Rural Affairs of China.A non-parametric method was used to test whether combine harvesting and outsourcing services could significantly reduce harvest losses.Next,quantile regression was used to estimate the real effects of machinery and outsourcing services on harvest losses.The analysis yielded four main study outcomes.First,the harvest loss rate of rice in China was 3.65%.Second,mechanical reaping and winnowing caused greater losses than manual methods,while the opposite was true of field transportation.Third,combine harvesting increased the losses.Fourth,the effects of an outsourcing service on losses differed among the different harvesting methods.Outsourcing services increased losses in segmented harvesting but they reduced losses in combine harvesting.
文摘Agricultural mechanization plays a pivotal role in the transition from subsistence to commercial agriculture, with a particular focus on labour-intensive activities like harvesting. This study assesses the operational characteristics of the BRRI Whole Feed Combine Harvester (Model BRRI WCH2021) at the field level. Developed under the SFMRA project, the harvester’s technical performance and loss assessment were conducted during the Boro 2022 and Aman 2022 seasons in farmer fields in Bangladesh’s Rangpur region. The field efficiency of the harvester was determined to be 62.5% and 57.9% in the Boro and Aman seasons, respectively. Fuel consumption rates were recorded at 2.77 l/ha and 2.31 l/ha for the Boro and Aman seasons. The total harvesting losses, encompassing cutter bar, shatter, cylinder, and separation loss, averaged 0.56% and 0.48% in the Boro and Aman seasons, respectively. Mechanized harvesting with the BRRI Whole Feed Combine Harvester significantly reduced paddy losses by 5.81% compared to manual methods. The field evaluation results indicate the combine harvester’s satisfactory performance, highlighting its potential to alleviate labour demands during peak harvesting. The development of the BRRI WCH offers a sustainable solution for rice harvesting mechanization among progressive farmers. It paves the way for the broader adoption of advanced agricultural technology in Bangladesh.
基金supported by the Special Funding for Modern Agricultural Technical System of China (Rapeseed)the National Natural Science Foundation of China (31071372)
文摘China is one of the most important rapeseed producing countries in the world. Effective mechanical harvesting time for decreasing harvesting loss of winter oilseed rape has been becoming a critical factor. An elite cultivar Zhongshuang 11 (Brassica napus L.) was employed in two rounds of field experiments from 2009 to 2011. Seeds were sown with machine, three combine harvesting times namely combine harvesting A, B, and C (CHA, CHB, and CHC) were designed and manual harvesting (MH) as control was performed at maturity. The harvesting treatments were determined according to color of pod and seed in the field. Seed yield loss and quality in different treatments were evaluated. Results showed that both seed yields and harvesting losses in 2009-2010 were higher than that in 2010-2011, whereas seed oil contents in 2010-2011 were higher than that in 2009-2010. The highest yield appeared in CHB, which was significantly higher than that in MH. Furthermore, harvesting loss in CHB were 50% that in MH. Seed oil content and chlorophyll exhibited no obvious difference between CHB and MH. Economic profit analysis demonstrated that mechanical sowing/combine harvesting (MS/CH) showed an input/output ratio of 1:1.6, and it was 1:1.2 in mechanical sowing/manual harvesting (MS/MH). Labor-cost accounted for more than 70% of the total cost in MS/MH, which led to low profitability to a great extent. Our results suggested that CHB was the optimum harvesting time for winter oilseed rape along the Yangtze River.
基金This work was supported by the National Key Research and Development Program of China(Grant No.2016YFD0300101,No.2016YFD03001010)the National Natural Science Foundation of China(Grant No.31371575)+1 种基金the China Agriculture Research System(CARS-02-25)the Agricultural Science and Technology Innovation Project of the Chinese Academy of Agricultural Sciences.
文摘The high harvest losses associated with the mechanical harvesting of maize in China are currently a major barrier to the adoption of this technology.This paper summarizes works of literature regarding harvest losses from the combine harvesting of maize in China and abroad.The main findings are as follows:(1)In 2012-2019,2987 samples data obtained from the major maize production areas of China showed that the average harvest loss was 345.2 kg/hm2(3.5%of the average yield),with losses ranging from 0 to 9288.5 kg/hm2;(2)The harvest losses from combine harvesting are mainly caused by the dropping of ears.The ear losses include the pre-harvest loss caused by ear abscission,damage caused by maize borer,lodging,and the ear loss during combine harvesting,and the main pre-harvest loss is caused by lodging;(3)Harvest losses are affected by maize variety,planting mode,cultivation management,pests and diseases,weather conditions during harvesting,harvest date,combine harvester type,harvester adjustment,operator proficiency,and the terrain conditions of the maize field;(4)The harvest losses from combine harvesting are also related to the type of header,feeding and threshing methods,the adjustment of header stripping clearance,feeding amount,forward speed,cylinder or rotor speed,and the clearance between the cylinder and the concave of the harvester.However,the combine losses mainly come from header losses.In order to reduce the harvest losses,the following solutions were proposed:(1)Breed and select maize varieties which are resistant to lodging,especially during the field drying of mature grains,as well as those resistant to maize borer and stalk rot;(2)Select varieties suitable for grain harvest-which requires matching the accumulated-temperature demand of the maize hybrids,optimal plant density,row spacing,and irrigation and fertilizer management with the light and heat conditions of the production area while cultivating uniform populations and healthy plants-as well as preventing and controlling damage from maize borer,stalk rot,and ear rot,harvesting at the appropriate time;(3)Develop and select advanced maize combine harvesters,formulate standardized operating procedures for harvesting machinery,and standardize field operation;(4)select appropriate agricultural machinery and agronomic practices,and improve the training of maize producers and harvester operators.
文摘Teak (Tectona grandis Linn. f.) ranks among the top five tropical hardwood species and is being promoted for use in plantations in its non-native range due to its high economic value. However, there is a general lack of data on ecosystem functioning of teak plantations. We aimed at understanding storage and flux of nutrients related to young plantations of teak. Cycling of nitrogen (N) and phosphorus (P) in a chronosequence of plantations (1, 5, 11, 18, 24 and 30 years) was studied in the Moist Deciduous Forest Region of North India with the objective of investigating the nutrient cycling pattern at younger age since the current trend of harvesting age of the species in several tropical countries is being drastically reduced for quick return from this high value crop. Standing state, nutrient uptake, nutrient return and nutrient retransloca-tion in these plantations were estimated by tree harvesting and chemical analysis methods. The range of total standing nutrient across all these plantations was 20.3 to 586.6 kg?ha-1 for N and 5.3 to 208.8 kg?ha-1 for P. Net uptake of N ranged from 19.4 to 88.9 kg?ha-1?a-1 and P from 3.8 to 18.1 kg?ha-1?a-1. Retranslocation of N and P among all the stands ranged from 8.7 to 48.0 kg?ha-1?a-1 and 0.01 to 3.5 kg?ha-1?a-1, respectively. Range of total nutrient return was 25.8 to 91.3 kg?ha-1?a-1 for N and 2.7 to 10.1 kg?ha-1?a-1 for P. N and P use efficiency was between 107.4 and 192.5 g dry organic matter (OM) g-1N, and 551.9 and 841.1 g OM g-1P, respec-tively. The turnover time ranged from 2.04-13.17 years for N and be-tween 2.40-22.66 years for P. Quantity of N and P in the soil nutrient pool ranged from 2566.8 to 4426.8 kg?ha-1 and 372 to 520 kg?ha-1, re-spectively. Storage and flux of components in different plant parts of different aged plantations were assessed and depicted in compartment models. Percentage storage in soil, litter and vegetation ranged from 82% to 99%, 0.6% to 2.4% and 0.5% to 15% for N, respectively, and from 63% to 98%, 0.5% to 2% and 1% to 35% for P, respectively. This infor-mation could be useful in managing external nutrient manipulation to crops of different ages for optimum biomass production or carbon se-questration.
基金This work was financially supported by the National Key Research and Development Program of China(Grant No.2016YFD0300101,No.2016YFD0300110)the National Natural Science Foundation of China(Grant No.31371575)+1 种基金the China Agriculture Research System(CARS-02-25)the Agricultural Science and Technology Innovation Project of the Chinese Academy of Agricultural Sciences.
文摘Field harvest loss is a common problem of maize grain mechanical harvesting in China and abroad.From 2012 to 2019,2987 groups of samples for the quality of mechanical grain harvesting in field were obtained in 21 major maize-producing provinces,cities,and regions of China.The analysis performed in this study showed that the average harvest loss of fallen ears was equivalent to 76.5%of the total harvest loss,indicating that the harvest loss in the mechanical harvesting of maize grain mainly came from the loss of fallen ears.Meanwhile,statistical analysis of the harvest loss in different ranges of grain moisture contents showed that,when the grain moisture content fell below 20%,the harvest loss rate of fallen ears and the total harvest loss rate both increased sharply,and the harvest loss of fallen ears increased faster than the harvest loss of fallen grain with a decreasing grain moisture content.Moreover,the results of multi-point experiments and harvest experiments in different periods showed that,during harvesting time,the harvest loss of fallen ears caused by lodging was the main reason for in-field harvest losses in the mechanical harvesting of maize grain.Apart from the above mentioned,the test results of 35 groups of harvesters for the in-field mechanical harvesting of maize grain showed that the harvester types and their operating parameters were important factors affecting the harvest loss in the mechanical harvesting of maize grain.Therefore,the principal paths to reduce harvest loss in the mechanical harvesting of maize grain are to breed lodging-resistant maize varieties,adopt reasonable planting densities,cultivate healthy plants,develop harvesters with low harvesting loss,intensify the training of operators,and harvest at an appropriate time.
基金This research was financially supported by the National Natural Science Foundation of China(51705193,52105257)Jilin Province Science and Technology Development Project(20190701055GH).
文摘The harvesting difficulty caused by corn lodging aggravated the loss of grain,especially in the regions where small harvesters were used as the main force for corn harvesting.An experimental study and analysis of harvest loss of small harvesters on the root lodged corn were made to get the laws of lodged corn harvest loss.The experiment was conducted in different harvesting directions and at a range of harvesting speeds.A 4-row self-propelled corn harvester(JM-4Y),a 2-row crawler type self-propelled corn harvester(JM-2C),and a 2-row crawler-type corn harvester equipped with a spiral auxiliary feeding device for lodged stalks(JM-2CAF)were taken as the research objects and the grain loss per square meter and the ear loss quantity per 30 square meters were taken as the experiment indices.The results showed that the average grain loss masses of the JM-4Y harvester,the JM-2C harvester and the JM-2CAF harvester in different harvesting directions were 101.88g,285.72 g and 110.20 g,while the average corn ear losses were 10.08,33.54 and 9.28 pieces.The lowest harvest loss of the JM-4Y harvester appeared when the harvesting was the same as the lodging direction,while the JM-2CAF harvester caused the lowest harvest loss when the harvesting direction was opposite to the lodging direction.The different feeding demands of the ordinary harvester head and the auxiliary feeding devices made the harvesters have different feeding conditions.At different harvesting speeds,the average grain loss mass of the JM-4Y harvester,the JM-2C harvester and the JM-2CAF harvester were 139.06 g,453.42 g and 236.64 g while the average corn ear loss quantities were 15.12,52.52 and 34.80 pieces.The JM-4Y harvester had the lowest harvest loss at almost every harvesting speed,and the JM-2CAF harvester only had lower harvest loss when the harvesting speed was lower than 0.8 m/s.The insufficient time to lift and deliver the lodged stalk and the impact between the spiral blades and the stalks were the causes of harvest loss when harvesting speed got higher.This study provides practical and theoretical references for the loss reduction of lodged corn harvesting.
文摘Cassava is a major food crop for farmers and especially small holder farmers and cultivated under low input other than the irrigation.It is cultivated as mono crop or intercrop at early stage and cultivating throughout the year.It is harvested carefully because of cyanogenic glucosides and consumed with in day.Easy and un-damageable uprooting of the tuber mainly depends on soil moisture,texture and agronomic practices.The study was focused with the objectives of the assessment of soil loss due to the harvesting of cassava roots tubers under low input agriculture,and to estimate the amount of plant nutrients loss due to crop harvest for cassava.Also the observation was made the correlation between the soil loss and physical characters of the tuber,soil texture and agronomic practices.Average plant specific soil loss due to crop harvesting was 80.7 g root−1 and crop specific soil loss due to crop harvesting was 7.64 kg ha−1 harvest−1 loss in Valliagmam area in Jaffna,Sri Lanka.Soil moisture content at harvesting time was a significant factor that explained the variations in the soil lost at cassava harvesting.Soil moisture has linear positive relationship with average plant specific soil loss due to crop harvesting.Soil nutrient loss during cassava harvesting by removal of adhering soil with root tuber was 1.15 kg of N,1.99 kg of P and 2.91 kg of K ha−1 harvest−1.Application of fertilizer is important since considerable amount nutrient loss was observed due to soil loss due to crop harvest.