The Himalayan region is a known hot spot of crop diversity. Traditional varieties (usually called primitive cultivars or landraces), having withstood the rigors of time (including harsh climatic conditions as well as ...The Himalayan region is a known hot spot of crop diversity. Traditional varieties (usually called primitive cultivars or landraces), having withstood the rigors of time (including harsh climatic conditions as well as attacks of insects, pests and diseases), can still be found in crop fields in rural parts of Indian Central Himalaya (ICH). These landraces harbor many desired traits from which, for example, varieties that are tolerant/resistant to abiotic/biotic stresses could be developed. In addition to the above benefits, landraces provide a basis for food security and a more varied and interesting diet. Some landraces are also known to be of medicinal value. These, along with some lesser known hill crops, are often referred to by different names such as under exploited crops, crops for marginal lands, poor person crops, and neglected mountain crops. The Himalayan region continues to be a reservoir of a large number of landraces and cultivars whose economic and ecological potential is yet to be fully understood and/or exploited. Indians have had a history of rice cultivation since ancient times. Farmers, including tribals inhabiting the IHR, still cultivate a plethora of landraces of rice and thus directly contribute towardson-farm conservation of valuable germplasm and help in the preservation of crop diversity. The present paper looks at the on-farm conservation of rice germplasm, which is still practised in the Kumaun region of ICH.展开更多
Evaluation and demonstration study was conducted at Kemo-Gerbi kebele of Adami Tulu Jidokombolcha district on two to three year old Borana bulls with the objectives of evaluation and demonstration of bulls fattening t...Evaluation and demonstration study was conducted at Kemo-Gerbi kebele of Adami Tulu Jidokombolcha district on two to three year old Borana bulls with the objectives of evaluation and demonstration of bulls fattening technologies at on-farm level.One farmer’s research extension group(FREG)was formed for fattening the bulls.Twenty bulls were purchased from Borana zone by farmers for the fattening trials.Two feeding treatments(T1=crushed maize grain(20%)+wheat bran(45%)+35%Noug cake and T2=wheat bran(65%)+cotton seed cake(35%))were evaluated at on-farm.Eight hour grazing was common for both treatments.The animals were randomly assigned for dietary rations and data on live weight change of the animals were taken using weight chart tape(developed by JICA project).Finishing weights,total weight gain and daily weight gain of the bulls were not different(P>0.05)between the treatments.Bulls fed on treatment one attained an average daily weight gain of 0.83 kg per bull;while bulls fed on treatment two gained 0.76 kg per bull per day.Total gross margin of treatment one(53,154.5 ETB)was higher than treatment two(49,467.75 ETB).Cost-benefit analysis showed that feeding option number one(T1)is more profitable than feeding option number two(T2).However,fatteners can use any of the feeding options depending on availability of the ingredients in their area.展开更多
Constraints and probable pathway towards increasing tree density and diversity within farmlands as a means of reducing human dependency on Mt. Marsabit forest for wood are addressed. The forest provides a carbon sink ...Constraints and probable pathway towards increasing tree density and diversity within farmlands as a means of reducing human dependency on Mt. Marsabit forest for wood are addressed. The forest provides a carbon sink to counteract the risks and hazards associated with climate change. A structured questionnaire was administered to a sample of 205 respondents that were selected from a population of 3075 farming households using a systematic random sampling procedure. While majority of the farms （53%） had low tree density （1-10 trees）, only 8% of the farms had high density （≥ 20 trees）. About 50% and 15% farms had Grevelia robusta and Eucalyptus cammudelensis, which were grown for timber production, respectively. Broad leafed trees, like Croton megalocarpus and Moringa stenoptella had been established in 17% of the farmlands, respectively. With only 20% of the households having a fence around the crop fields, coupled by widely inter-household sharing of crop residues for grazing, tree browsing by livestock was a constraint to tree establishment. The challenges present an opportunity to establish governance structures and processes for communal responsibility and management of tree resources in the farms. A plausible approach entails the Adaptive Collaborative Management （ACM） as a process that facilitates to experiential learning and negotiation for probable actions and policies in management of natural resources.展开更多
Sweet chestnut （Castanea sativa Mill.）, the only native species of Castanea genus in Europe, occupies over 12,000 ha in Andalusia （South of Spain）. From 2000 until now, we have carried out different activities foc...Sweet chestnut （Castanea sativa Mill.）, the only native species of Castanea genus in Europe, occupies over 12,000 ha in Andalusia （South of Spain）. From 2000 until now, we have carried out different activities focused on the location and cataloguing of the different chestnut groves in the region and the evaluation of the genetic variability contained in this germplasm. Two different types of chestnut groves were detected： one of clonal nature （varieties obtained by grafting） and another of open pollination （trees from seed）. In the first case, the aim of our study was to identify and characterise the main chestnut traditional varieties. High levels of genetic variability were detected in clonal orchards by means of morphological and molecular analysis. A total of 38 varieties were identified： 12 in Huelva and 26 in Malaga regions. Moreover, we reported data about the presence of synonymies and homonymies. Our results indicate that chestnut production in this region is a traditional system that uses varieties developed in situ, constituting a genuine system of ＇on farm＇ conservation. Nevertheless, their preservation is seriously threatened in most zones due to the varietal substitution, the low profit or the abandonment, which determines the urgent necessity to safeguard these genetic resources. Furthermore, preliminary results for chestnut populations indicated a high degree of genetic variation.展开更多
The culture of African sharptooth catfish(Clarias gariepinus)in most developing countries lacks suitable diets for semi-intensive production.The present study evaluated the growth performance,survival,nutrient utiliza...The culture of African sharptooth catfish(Clarias gariepinus)in most developing countries lacks suitable diets for semi-intensive production.The present study evaluated the growth performance,survival,nutrient utilization,hepatosomatic index(HSI),body composition,yield and feeding cost of African catfish fed on semi-intensive feeds 1(SMF1)and semi-intensive feed 2(SMF2)produced on-farm and an industrially manufactured(IM)feed as a control.Two hundred fish(14.95±0.24 g)were stocked in triplicate earthen ponds and fed the three diets at 5%of the body weight for eight weeks.The final weight,specific growth rate and yield of fish fed the SMF2 diet was significantly lower than SMF1 and IM diets.However,no significant differences were revelead in final weight,specific growth rate and yield between fish fed SMF1 and IM diets.The survival rate,feed conversion ratio and protein efficiency ratio of fish did not differ among the diets.Apparent net protein utilization was significantly higher on fish fed the SMF2 and SMF1 diets than IM diet.The HSI of fish fed the IM diet was significantly higher and the livers were yellow-coloured compared to smaller and brownish/reddish livers of fish fed the SMF1 and SMF2 diets.The fish fed the IM diet had statistically lower ash content than SMF1 diet.The incidence cost of fish fed the IM diet was 35%higher,while its profit index was 31%lower than fish fed the SMF1 and SMF2 diets.Taken together,African catfish farmers can reduce feed cost up to 30%by using on-farm produced feeds when formulated properly and blended without affecting fish growth performance,survival and yield while obtaining better protein retention and healthier fish.展开更多
The study aimed at identifying the determinants of household’s choice of livelihood diversification strategies. The result of the study based on a total of 384 sample respondents selected using multistage sampling pr...The study aimed at identifying the determinants of household’s choice of livelihood diversification strategies. The result of the study based on a total of 384 sample respondents selected using multistage sampling procedures. Furthermore the study employed bivariate Probit econometric model to identify factors affecting household’s choice of livelihood diversification strategies. The result of the descriptive statistics showed that households in the study area were engaged in four types of combination of livelihood diversification strategies: on-farm only, on-farm plus off-farm, on-farm plus non-farm, and on-farm plus off-farm plus non-farm with their respective share of 34.9, 11.5, 47.9 and 5.7 percent respectively. The econometric model result showed that wealth, sex, education level, livestok holding, and training were negatively and significantly determined households choice of off-farm livelihood strategies;whereas past erosion hazard and distance to market were positively and significantly determined their choice of off-farm livelihood strategies. On the other hand, wealth, dependency ratio, past erosion hazard, market availability, yield loss/reduction due to drought, distance to credit source, distance to market, frequency of extension contact, and ICT ownership (Radio, TV and/or Mobile phone) positively determine household’s choice of non-farm livelihood strategies whereas access to irrigation and distance to credit negatively determined their choice of non-farm livelihood strategies.展开更多
The traditional rice-fish farming system is selected as a ＂globally important agricultural heritage system＂ （GIAHS） by the Food and Agriculture Organization （FAO）,United Nations Development Programme （UNDP）,an...The traditional rice-fish farming system is selected as a ＂globally important agricultural heritage system＂ （GIAHS） by the Food and Agriculture Organization （FAO）,United Nations Development Programme （UNDP）,and Global Environment Facility （GEF）,etc.In Zhejiang Province of China,where the pilot site for this GIAHS farming system is located,we compared the use of traditional rice varieties in rice-fish co-culture and rice monoculture.Further,we determined how traditional rice varieties were performed in this rice-fish system.Only 19% of the farmers who practiced rice monoculture planted traditional varieties while 52% of farmers who practiced rice-fish co-culture planted traditional varieties.Traditional varieties represented 13% of the total land cultivated under rice in the rice-fish system but only 2% in the rice monoculture system.In the rice-fish system,yield was lower for traditional rice varieties than hybrid varieties but application of fertilizers and pesticides was also lower.In a field experiment in the rice-fish system without pesticides,rice planthopper numbers and sheath blight incidence were lower from three traditional varieties than one hybrid variety;yields were 8 to 32% lower from the traditional varieties than the hybrid.Our results showed that traditional rice varieties can be preserved through conserving GIAHS rice-fish co-culture.Our study also indicated that traditional rice varieties can survive in the rice-fish system because these varieties are helpful to the whole system and beneficial to the farmers.展开更多
Although Cambodia might have achieved self-sufficiency and an exported surplus in rice production,its rice-based farming systems are widely associated with low productivity,low farmer income and rural poverty.The stud...Although Cambodia might have achieved self-sufficiency and an exported surplus in rice production,its rice-based farming systems are widely associated with low productivity,low farmer income and rural poverty.The study is based on a questionnaire village survey in 14 communes containing 97 villages of Kampong Chhnang Province from March to June,2011.It analyzes the prevailing rice-based cropping systems and evaluates options for their improvement.Differences in cropping systems depend on the distance from the Tonle Sap water bodies.At distances greater than 10 km,transplanted wet-season rice cropping system with low productivity of about 1.6 t/hm 2 prevails.This deficiency can be primarily attributed to soils with high coarse sand fractions and low pH （〈 4.0）,use of ＇late＇ cultivars,and exclusive use of self-propagated seeds.To improve this cropping system,commercial ＇medium＇ cultivars help prevent crop failure by shortening the cultivation period by one month and complementation of wet-season rice with non-rice crops should be expanded.Areas adjacent （≤ 1 km） to the water bodies become inundated for up to seven months between July until January of each year.In this area,soils contain more fine sand,silt and clay,and their pH is higher （〉 4.0）.Farmers predominantly cultivate dry-season recession rice between January and April.Seventy-nine percent of the area is sown directly and harvested by combines.Adoption ratio of commercial rice seeds is 59% and yields average 3.2 t/hm 2.Introduction of the second dry-season rice between April and July may double annual yields in this rice cropping system.Besides upgrading other cultivation technologies,using seeds from commercial sources will improve yield and rice quality.Along with rice,farmers grow non-rice crops at different intensities ranging from single annual crops to intensive sequences at low yields.展开更多
Although agriculture is not the only contributor of excess nutrients to US waters, agriculture is an important contributor and should do its part to reduce nutrient loading. One important step in reducing agricultural...Although agriculture is not the only contributor of excess nutrients to US waters, agriculture is an important contributor and should do its part to reduce nutrient loading. One important step in reducing agricultural contribution is to accurately account for all sources of plant available nutrients so that only needed nutrients are applied. In this study, three fertilizer rate treatments were evaluated: no fertilizer (control), traditional rate, and reduced rate based on a recently-developed enhanced soil test methodology. For each of nine sites in Texas, fertilizer data (formulation, rate, cost, and application date) and crop data (yield, price, and harvest date) were recorded, and economic throughput (profit) was determined. In this four year study, fertilizer rates were reduced 30%-50% (and fertilizer costs reduced 23%-39%) based on enhanced soil test methodology recommendations for wheat, corn, oats, and grain sorghum, but yields were not significantly reduced (0%-6%) and oat yields actually increased 5%. Profit decreased -18% for wheat, oats, and grain sorghum with reduced fertilizer rates. Although these changes were not statistically significant, they do represent benefit through increased profit potential and decreased input cost and production risk. In only 6% of the time was the traditional fertilizer rate the most profitable, compared to 51% for the unfertilized treatment and 43% for the enhanced soil test treatment. These results do not indicate that fertilizer application should be avoided but that fertilizer rates should be carefully chosen considering all sources of plant available nutrients (e.g., mineralization, irrigation water, nutrients deeper in the soil profile) to ensure that fertilizer is applied at the optimal rate.展开更多
文摘The Himalayan region is a known hot spot of crop diversity. Traditional varieties (usually called primitive cultivars or landraces), having withstood the rigors of time (including harsh climatic conditions as well as attacks of insects, pests and diseases), can still be found in crop fields in rural parts of Indian Central Himalaya (ICH). These landraces harbor many desired traits from which, for example, varieties that are tolerant/resistant to abiotic/biotic stresses could be developed. In addition to the above benefits, landraces provide a basis for food security and a more varied and interesting diet. Some landraces are also known to be of medicinal value. These, along with some lesser known hill crops, are often referred to by different names such as under exploited crops, crops for marginal lands, poor person crops, and neglected mountain crops. The Himalayan region continues to be a reservoir of a large number of landraces and cultivars whose economic and ecological potential is yet to be fully understood and/or exploited. Indians have had a history of rice cultivation since ancient times. Farmers, including tribals inhabiting the IHR, still cultivate a plethora of landraces of rice and thus directly contribute towardson-farm conservation of valuable germplasm and help in the preservation of crop diversity. The present paper looks at the on-farm conservation of rice germplasm, which is still practised in the Kumaun region of ICH.
文摘Evaluation and demonstration study was conducted at Kemo-Gerbi kebele of Adami Tulu Jidokombolcha district on two to three year old Borana bulls with the objectives of evaluation and demonstration of bulls fattening technologies at on-farm level.One farmer’s research extension group(FREG)was formed for fattening the bulls.Twenty bulls were purchased from Borana zone by farmers for the fattening trials.Two feeding treatments(T1=crushed maize grain(20%)+wheat bran(45%)+35%Noug cake and T2=wheat bran(65%)+cotton seed cake(35%))were evaluated at on-farm.Eight hour grazing was common for both treatments.The animals were randomly assigned for dietary rations and data on live weight change of the animals were taken using weight chart tape(developed by JICA project).Finishing weights,total weight gain and daily weight gain of the bulls were not different(P>0.05)between the treatments.Bulls fed on treatment one attained an average daily weight gain of 0.83 kg per bull;while bulls fed on treatment two gained 0.76 kg per bull per day.Total gross margin of treatment one(53,154.5 ETB)was higher than treatment two(49,467.75 ETB).Cost-benefit analysis showed that feeding option number one(T1)is more profitable than feeding option number two(T2).However,fatteners can use any of the feeding options depending on availability of the ingredients in their area.
文摘Constraints and probable pathway towards increasing tree density and diversity within farmlands as a means of reducing human dependency on Mt. Marsabit forest for wood are addressed. The forest provides a carbon sink to counteract the risks and hazards associated with climate change. A structured questionnaire was administered to a sample of 205 respondents that were selected from a population of 3075 farming households using a systematic random sampling procedure. While majority of the farms （53%） had low tree density （1-10 trees）, only 8% of the farms had high density （≥ 20 trees）. About 50% and 15% farms had Grevelia robusta and Eucalyptus cammudelensis, which were grown for timber production, respectively. Broad leafed trees, like Croton megalocarpus and Moringa stenoptella had been established in 17% of the farmlands, respectively. With only 20% of the households having a fence around the crop fields, coupled by widely inter-household sharing of crop residues for grazing, tree browsing by livestock was a constraint to tree establishment. The challenges present an opportunity to establish governance structures and processes for communal responsibility and management of tree resources in the farms. A plausible approach entails the Adaptive Collaborative Management （ACM） as a process that facilitates to experiential learning and negotiation for probable actions and policies in management of natural resources.
文摘Sweet chestnut （Castanea sativa Mill.）, the only native species of Castanea genus in Europe, occupies over 12,000 ha in Andalusia （South of Spain）. From 2000 until now, we have carried out different activities focused on the location and cataloguing of the different chestnut groves in the region and the evaluation of the genetic variability contained in this germplasm. Two different types of chestnut groves were detected： one of clonal nature （varieties obtained by grafting） and another of open pollination （trees from seed）. In the first case, the aim of our study was to identify and characterise the main chestnut traditional varieties. High levels of genetic variability were detected in clonal orchards by means of morphological and molecular analysis. A total of 38 varieties were identified： 12 in Huelva and 26 in Malaga regions. Moreover, we reported data about the presence of synonymies and homonymies. Our results indicate that chestnut production in this region is a traditional system that uses varieties developed in situ, constituting a genuine system of ＇on farm＇ conservation. Nevertheless, their preservation is seriously threatened in most zones due to the varietal substitution, the low profit or the abandonment, which determines the urgent necessity to safeguard these genetic resources. Furthermore, preliminary results for chestnut populations indicated a high degree of genetic variation.
基金funded by the World Bank through the University of Dar es Salaam,under the project“Higher Education Science and Technology(HEST)”component CIA:5.1.
文摘The culture of African sharptooth catfish(Clarias gariepinus)in most developing countries lacks suitable diets for semi-intensive production.The present study evaluated the growth performance,survival,nutrient utilization,hepatosomatic index(HSI),body composition,yield and feeding cost of African catfish fed on semi-intensive feeds 1(SMF1)and semi-intensive feed 2(SMF2)produced on-farm and an industrially manufactured(IM)feed as a control.Two hundred fish(14.95±0.24 g)were stocked in triplicate earthen ponds and fed the three diets at 5%of the body weight for eight weeks.The final weight,specific growth rate and yield of fish fed the SMF2 diet was significantly lower than SMF1 and IM diets.However,no significant differences were revelead in final weight,specific growth rate and yield between fish fed SMF1 and IM diets.The survival rate,feed conversion ratio and protein efficiency ratio of fish did not differ among the diets.Apparent net protein utilization was significantly higher on fish fed the SMF2 and SMF1 diets than IM diet.The HSI of fish fed the IM diet was significantly higher and the livers were yellow-coloured compared to smaller and brownish/reddish livers of fish fed the SMF1 and SMF2 diets.The fish fed the IM diet had statistically lower ash content than SMF1 diet.The incidence cost of fish fed the IM diet was 35%higher,while its profit index was 31%lower than fish fed the SMF1 and SMF2 diets.Taken together,African catfish farmers can reduce feed cost up to 30%by using on-farm produced feeds when formulated properly and blended without affecting fish growth performance,survival and yield while obtaining better protein retention and healthier fish.
文摘The study aimed at identifying the determinants of household’s choice of livelihood diversification strategies. The result of the study based on a total of 384 sample respondents selected using multistage sampling procedures. Furthermore the study employed bivariate Probit econometric model to identify factors affecting household’s choice of livelihood diversification strategies. The result of the descriptive statistics showed that households in the study area were engaged in four types of combination of livelihood diversification strategies: on-farm only, on-farm plus off-farm, on-farm plus non-farm, and on-farm plus off-farm plus non-farm with their respective share of 34.9, 11.5, 47.9 and 5.7 percent respectively. The econometric model result showed that wealth, sex, education level, livestok holding, and training were negatively and significantly determined households choice of off-farm livelihood strategies;whereas past erosion hazard and distance to market were positively and significantly determined their choice of off-farm livelihood strategies. On the other hand, wealth, dependency ratio, past erosion hazard, market availability, yield loss/reduction due to drought, distance to credit source, distance to market, frequency of extension contact, and ICT ownership (Radio, TV and/or Mobile phone) positively determine household’s choice of non-farm livelihood strategies whereas access to irrigation and distance to credit negatively determined their choice of non-farm livelihood strategies.
基金supported by the National Basic Research Program of China (2011CB100406)the Science and Technology Department of Zhejiang Province,China(2008C12064)+2 种基金the Ministry of Environment Protection of China (201090020)the Wenzhou Bureau of Science and Technology of Zhejiang Province,China(N20080024)the Key Laboratory of Non-Point Sources Pollution Control,Ministry of Agriculture of China (KYJD09021)
文摘The traditional rice-fish farming system is selected as a ＂globally important agricultural heritage system＂ （GIAHS） by the Food and Agriculture Organization （FAO）,United Nations Development Programme （UNDP）,and Global Environment Facility （GEF）,etc.In Zhejiang Province of China,where the pilot site for this GIAHS farming system is located,we compared the use of traditional rice varieties in rice-fish co-culture and rice monoculture.Further,we determined how traditional rice varieties were performed in this rice-fish system.Only 19% of the farmers who practiced rice monoculture planted traditional varieties while 52% of farmers who practiced rice-fish co-culture planted traditional varieties.Traditional varieties represented 13% of the total land cultivated under rice in the rice-fish system but only 2% in the rice monoculture system.In the rice-fish system,yield was lower for traditional rice varieties than hybrid varieties but application of fertilizers and pesticides was also lower.In a field experiment in the rice-fish system without pesticides,rice planthopper numbers and sheath blight incidence were lower from three traditional varieties than one hybrid variety;yields were 8 to 32% lower from the traditional varieties than the hybrid.Our results showed that traditional rice varieties can be preserved through conserving GIAHS rice-fish co-culture.Our study also indicated that traditional rice varieties can survive in the rice-fish system because these varieties are helpful to the whole system and beneficial to the farmers.
基金the Asian Development Bank (ADB)for financial support (Loan No. 2376 CAM/Grant No.0092 CAM)funding of project personnel and the Management of the Tonle Sap Lowlands Rural Development Project (TS-LRDP)for their support
文摘Although Cambodia might have achieved self-sufficiency and an exported surplus in rice production,its rice-based farming systems are widely associated with low productivity,low farmer income and rural poverty.The study is based on a questionnaire village survey in 14 communes containing 97 villages of Kampong Chhnang Province from March to June,2011.It analyzes the prevailing rice-based cropping systems and evaluates options for their improvement.Differences in cropping systems depend on the distance from the Tonle Sap water bodies.At distances greater than 10 km,transplanted wet-season rice cropping system with low productivity of about 1.6 t/hm 2 prevails.This deficiency can be primarily attributed to soils with high coarse sand fractions and low pH （〈 4.0）,use of ＇late＇ cultivars,and exclusive use of self-propagated seeds.To improve this cropping system,commercial ＇medium＇ cultivars help prevent crop failure by shortening the cultivation period by one month and complementation of wet-season rice with non-rice crops should be expanded.Areas adjacent （≤ 1 km） to the water bodies become inundated for up to seven months between July until January of each year.In this area,soils contain more fine sand,silt and clay,and their pH is higher （〉 4.0）.Farmers predominantly cultivate dry-season recession rice between January and April.Seventy-nine percent of the area is sown directly and harvested by combines.Adoption ratio of commercial rice seeds is 59% and yields average 3.2 t/hm 2.Introduction of the second dry-season rice between April and July may double annual yields in this rice cropping system.Besides upgrading other cultivation technologies,using seeds from commercial sources will improve yield and rice quality.Along with rice,farmers grow non-rice crops at different intensities ranging from single annual crops to intensive sequences at low yields.
文摘Although agriculture is not the only contributor of excess nutrients to US waters, agriculture is an important contributor and should do its part to reduce nutrient loading. One important step in reducing agricultural contribution is to accurately account for all sources of plant available nutrients so that only needed nutrients are applied. In this study, three fertilizer rate treatments were evaluated: no fertilizer (control), traditional rate, and reduced rate based on a recently-developed enhanced soil test methodology. For each of nine sites in Texas, fertilizer data (formulation, rate, cost, and application date) and crop data (yield, price, and harvest date) were recorded, and economic throughput (profit) was determined. In this four year study, fertilizer rates were reduced 30%-50% (and fertilizer costs reduced 23%-39%) based on enhanced soil test methodology recommendations for wheat, corn, oats, and grain sorghum, but yields were not significantly reduced (0%-6%) and oat yields actually increased 5%. Profit decreased -18% for wheat, oats, and grain sorghum with reduced fertilizer rates. Although these changes were not statistically significant, they do represent benefit through increased profit potential and decreased input cost and production risk. In only 6% of the time was the traditional fertilizer rate the most profitable, compared to 51% for the unfertilized treatment and 43% for the enhanced soil test treatment. These results do not indicate that fertilizer application should be avoided but that fertilizer rates should be carefully chosen considering all sources of plant available nutrients (e.g., mineralization, irrigation water, nutrients deeper in the soil profile) to ensure that fertilizer is applied at the optimal rate.
