Effects of Different Nutrient Management Systems and Cultivation Methods on Crop Yield and Soil Fertility

[Objective] The aim was to provide scientific basis for improving the middle and low yielding fields fertility and farmland productivity. [Method] A field experiment was carried out to study the effects of different management practices （including nutrient management systems and cultivation methods） on crop yield and soil fertility in winter wheat/summer maize rotation system. [Result] The crop yield in the treatment of the high yield and high efficiency system was remarkably higher than farmer conventional management practice. After five crop seasons experiment, the contents of soil organic matter for high yield and high efficiency system increased 2.72-3.01 g/kg, and that of soil total nitrogen increased 0.12-0.16 g/kg, the soil Olsen-P increased 5.2 mg/kg and the soil available K （NH4OAC-K） increased about 37.8 mg/kg. [Conclusion] Considering the yield and soil fertility comprehensively, the management system of high yield and high efficiency could effectively increase the crop yield and improve the soil fertility.

Sustainable Nutrient Management in Chinese Agriculture: Challenges and Perspective

China has to raise agricultural productivity in its limited and shrinking farmland to guarantee food security for its huge and ever-growing population. Sustainable soil nutrient management is of paramount importance to the world's most populous country. Critical challenges the country is facing in sustaining soil fertility and in alleviating the hazardous impact of intensive fertilizer use are discussed in this paper. It is emphatically pointed out that national strategies as well as area-specific action plans with respect to scientific nutrient management are urgently needed to balance productivity and sustainability in the future. Relevant proposals for addressing those challenges are also presented.

Rice (Oryza sativa L.) nutrient management using mycorrhizal fungi and endophytic Herbaspirillum seropedicae

Integrated nutrient management with biological and chemical fertilizers can improve rice （Oryza safiva L.） productivity, bio-fortification, soil health and fertility. Accordingly, this study was planned to evaluate the combined effects of biological fertilizers including arbuscular mycorrhizal （AM） fungi （Glomus mosseae） and free-living nitrogen-fixing bacteria （Herbaspi- rillum seropedicae）, as well as chemical fertilizers on the yield and nutrient contents of wetland rice under field conditions. Seedlings were inoculated with AM fungi and the bacteria in the nursery and were then transplanted to the field. The experi- ment was carried out as a split factorial design with three replicates. Treatments included three rates of nitrogen （N 1, N2 and N3） and phosphorous （P1, P2 and P3） fertilizers （100, 75 and 50% of the optimum level） in the main plots and mycorrhizal and bacterial treatments in the sub plots. The total of urea （g） used per plot was equal to N1=200, N2=150 and N3=100 at three different growth stages （seeding, tillering and heading） and the total of P （g） per plot used once at seeding using triple super phosphate including P1 =16, P2=13 and P3=10. Plant growth and yield as well as the concentration of nitrogen （N）, phosphorous （P）, potassium （K）, iron （Fe）, and zinc （Zn） were measured in the soil, straw and grains. N-fertilizer and biological fertilizers had significant effects on root, shoot and grain yield of rice, however, P-fertilizer just significantly affected root and shoot dry weights. Interestingly, analyses of variance indicated that biological fertilization significantly affected all the experimental treatments except straw N. AM fungi, N1 and P1 resulted in the highest rate of rice growth and yield. The interactions of chemical and biological fertilization resulted in significant effects on grain Zn, Fe, P, and N as well as soil Fe, K and N. The highest rate of grain nutrient uptake was resulted by the combined use of biological fertilization and the medium level of chemical fertilization. Interestingly, with decreasing the rate of chemical N fertilization, rice nutrient use efficiency increased indicating how biological fertilization can be efficient in providing plants with its essential nutrients such as N. However, the highest rate of soil and straw nutrient concentration was related to the combined use of biologicalfertilization and the highest rate of chemical fertilization. We conclude that biological fertilizer, （mycorrhizal fungi and H. seropedicae） can significantly improve wetland rice growth and yield （resulting in the decreased rate of chemical fertilizer）, espe- cially if combined with appropriate rate of chemical fertilization, by enhancing nutrient uptake （fortification） and root growth.

Improving Rice-Based Cropping Pattern Through Soil Moisture and Integrated Nutrient Management in Mid-Tropical Plain Zone of Tripura, India

An experiment was conducted in three fallow paddy fields situated on the mid-tropical plain zone of a northeastern Indian state （Tripura） to provide rice fallow management options using leftover soil moisture and nutrients. The three experimental fields were managed by growing rice under the system of rice intensification as the rainy season crop and then groundnut, lentil, rapeseed and potato as the post-rainy season crops. Fertilization under the integrated nutrient management system and lifesaving irrigation at critical stages of each post-rainy season crop were provided. Results showed that the field water use efficiency values were 5.93, 2.39, 2.37 and 59.76 kg/（hm2.mm） and that the yield of these crops increased by approximately 20%, 34%, 40% and 20% after applying two lifesaving irrigations in groundnut, lentil, rapeseed and potato, respectively. Therefore, fallow paddy field can provide possible profitable crops during the post-rainy season by utilizing the residual moisture and minimum supplemental irrigation under improved nutrient management practices.

Elevation, Slope Aspect and Integrated Nutrient Management Effects on Crop Productivity and Soil Quality in North-west Himalayas, India

On farm bio-resource recycling has been given greater emphasis with the introduction of conservation agriculture specifically withclimate change scenarios in the mid-hills of the north-west Himalaya region（NWHR）. Under this changing scenario, elevation, slope aspect and integrated nutrient management（INM） may affect significantly soil quality and crop productivity. A study was conducted during 2009-2010 to 2010-2011 at the Ashti watershed of NWHR in a rainfed condition to examine the influence of elevation, slope aspect and integrated nutrient management（INM） on soil resource and crop productivity. Two years of farm demonstration trials indicated that crop productivity and soil quality is significantly affected by elevation, slope aspect and INM. Results showed that wheat equivalent yield（WEY） of improved technology increased crop productivity by -20%-37% compared to the conventional system. Intercropping of maize with cowpea and soybean enhanced yield by another 8%-17%. North aspect and higher elevation increased crop productivity by 15%-25% compared to south aspect and low elevation（except paddy）. Intercropping of maize with cowpea and soybean enhanced yield by another 8%-15%. Irrespective of slope, elevation and cropping system, the WEY increased by -30% in this region due to INMtechnology. The influence of elevation, slope aspect and INM significantly affected soil resources（SQI） and soil carbon change（SCC）. SCC is significantly correlated with SQI for conventional（R2 = 0.65＊）, INM technology（R2 = 0.81＊） and for both technologies（R2 = 0.73＊）. It is recommended that at higher elevation.（except for paddy soils） with a north facing slope, INM is recommended for higher crop productivity; conservation of soil resources is recommended for the mid hills of NWHR; and single values of SCC are appropriate as a SQI for this region.

Exploring Crop Yield Benefits of Integrated Water and Nutrient Management Technologies in the Desert Margins of Africa： Experiences from Semi-Arid Zimbabwe

The benefits of integrating locally adaptable water and nutrient management technologies were explored in semi-arid Zimbabwe. On-farm maize based experiments were set up on six farmers＇ fields in Ward 5, Shurugwi. Three tillage systems namely Post-Emergence Tied Ridging （PETR）, Rip ＆ Pot-Holing （RPH） and Conventional Mouldboard Ploughing （CMP） were integrated to three nutrient management regimes, i.e. a control with no fertility amelioration, pit-stored cattle manure band applied at 10 t/ha and the latter with an additional top dressing of ammonium nitrate （34.5% N） at 100 kg/ha. On each site the treatments were set up as a completely randomized split-plot block design replicated 3 times with tillage （water management） as the main treatment and fertility as the sub-treatment. CMP mimicked the farmers＇ common land preparation practice while PETR and RPH systems represented the improved water harvesting tillage techniques. Results revealed significant nutrient management effects right from the first season giving 3-year means of 1,298, 1,977 and 2,490 kg/ha for the control, manure and manure plus fertilizer treatments respectively. On the other hand, water harvesting tillage effects were insignificant initially （2003/4） but had beneficial effects in subsequent seasons （2004/5 and 2005/6） with 3-year grain yield means of 1,624, 2,032 and 2,108 kg/ha for CMP, PETR and RPH, respectively. Maximum yield benefits from integrating PETR and RPH with manure ＋ AN fertility ameliorants amounted to 218 and 261% respectively, compared to CMP with no fertility amendment. The results therefore showed increased benefits when in-situ water harvesting tillage techniques are integrated with appropriate nutrient ameliorants giving realizable food security benefits to the farmer.

Effect of Integrated Nutrient Management on Growth and Productivity of Hybrid Rice

Sustaining rice （Oryza sativa L.） productivity at high level is a great challenge, particularly in areas where rice productivity declines in spite of following recommended nutrient management practices. Nutrient management by integrating organic manures, inorganic fertilizers and biofertilizers may play an important role in improving and sustaining rice productivity. In this study, the authors tried to evaluate the suitable proportion of organic manures and inorganic fertilizers along with biofertilizer to maximize growth and productivity of hybrid rice on sandy-loam lateritic soils of West Bengal, India. The crop having 50% recommended dose of fertilizer （RDF） ＋ 50% recommended dose of nitrogen （RDN） through mustard oil cake （MOC） and 75% RDF ＋ 25% RDN through MOC ＋ biofertilizer significantly increased plant height, number of tillers/m2, leaf area index （LAI）, dry matter accumulation （DMA） and crop growth rate （CGR） at initial and vital period of grain growth over those of 25% RDF ＋ 75% RDN through MOC and 100% RDN through MOC. The former two treatments also increased number of panicles/m2 and number of grains/panicle over those of only organic manuring （100% RDN） or only chemical fertilization （100% RDF） or 25% RDF ＋ 75% RDN through MOC. Crop with 75% RDF ＋ 25% RDN through MOC ＋ biofertilizer or 50% RDF ＋ 50% RDN through MOC produced 20.2%-33.8% higher grain yield and 11.0%-33.3% greater straw yield, and paid higher gross and net returns over other treatments. This study suggests growing hybrid rice with 75% RDF ＋ 25% RDN through MOC ＋ biofertilizer or 50% RDF ＋ 50% RDN through MOC for better growth, higher productivity and greater profit.

Nutrient Management in Fragrant Rice: A Review

Rice (Oryza sativa L.) is the most important cereal food grain crop and is consumed by the majority of the world’s human population. Among all cultivars, fragrant/aromatic rice is preferred by the better part of the human population because of its aroma, taste and cooking quality. But most of the fragrant rice varieties are low yielding and easily sensitive to the surrounding environmental condition. Among different agronomic performances, proper nutrient management can improve the yield of fragrant rice not only by giving the required amount of nutrients but also by maintaining the health of the soil and the quality of the produce. In most cases, traditional agricultural practices degraded soil health and increased environmental pollution which leads to inferior grain quality. On the other hand, excessive application of chemical fertilizers reduced the nutrient status of the soil and badly affected the soil productivity and environmental stability. Therefore, a suitable approach of nutrient management is required to keep the production of fragrant rice to a notable amount and increase the nutrient use efficiency of soil. Application of manures and fertilizers in an appropriate dose which is the main object of nutrient management is required for its utmost importance in the growth and development of the crop that finally results in better yield and grain quality. Therefore, nutrient management is an important aspect in aromatic rice production to attain sustainable grain yield and high economic return with better quality of produce.

Machine learning in nutrient management:A review

In agriculture,precise fertilization and effective nutrient management are critical.Machine learning(ML)has recently been increasingly used to develop decision support tools for modern agricultural systems,including nutrient management,to improve yields while reducing expenses and environmental impact.ML based systems require huge amounts of data from different platforms to handle non-linear tasks and build predictive models that can improve agricultural productivity.This study reviews machine learning based techniques for estimating fertilizer and nutrient status that have been developed in the last decade.A thorough investigation of detection and classification approaches was conducted,which served as the basis for a detailed assessment of the key challenges that remain to be addressed.The research findings suggest that rapid improvements in machine learning and sensor technology can provide cost-effective and thorough nutrient assessment and decision-making solutions.Future research directions are also recommended to improve the practical application of this technology.

Ecological fitness of brown planthopper, Nilaparvata lugens (Stål), to rice nutrient management

Introduction:The brown planthopper(BPH),Nilaparvata lugens(Stål)(Hemiptera:Delphacidae),is a notorious insect pest of rice.Nutrient supplementation can alter plant biochemical compositions which may indirectly affect on ecological fitness parameters of its insect pest.However,few findings are available on nutrient-induced ecological fitness of BPH and relationship of BPH fitness parameters with its host rice plant biochemical contents.Methods:We studied the main and interaction effects of nitrogen(N),phosphorus(P),and potassium(K)inputs on BPH fitness,as measured by the following variables:nymph survival,nymphal duration,adult body weight,and its survival.Brown planthopper fitness parameters were regressed as function of rice plant(Oryza sativa)biochemical composition.A completely randomized design with four replications in a factorial scheme was used considering N,P,and K levels as factors.Results:Nitrogen application to the host rice plants provided greater survival and enhanced body weight of BPH.The nymphal duration was found to decrease with N subsidy that caused shorter generation time of BPH.Nitrogenous compounds N and soluble protein(SP),total free sugar(TFS),and silicon(Si)content in rice plant tissue correlated strongly with all fitness traits of BPH.Nitrogen,SP,and TFS associated positively with BPH survival and body weight,while negatively with nymphal duration.In contrast,Si had negative correlation with BPH survival and body weight,but positive with nymphal duration.Phosphorus supplementation to host plant contributed to increase BPH body weight.Relationships of P with all parameters of BPH were weak except body weight which was highly significant and positive.Interaction between N and P inputs demonstrated significant effect on BPH body weight.Application of K had no significant effect on BPH survival and development.Regression analysis did not detect significant relationship of BPH fitness parameters with plant tissue content of K.Conclusions:The results suggest that BPH ecological fitness characters were improved after N and P fertilization to rice plants which are associated with biochemical content of rice plant.Therefore,N and P inputs should be used judiciously in rice cultivation to keep BPH ecological fitness potential at minimum level.

Combined Effects of Nutrient and Pesticide Management on Soil Microbial Activity in Hybrid Rice Double Annual Cropping System

Combined effects on soil microbial activity of nutrient and pesticide management in hybrid rice double annual cropping system were studied. Results of field experiment demonstrated significant changes in soil microbial biomass phospholipid contents, abundance of heterotrophic bacteria and proteolytic bacteria, electron transport system (ETS)/dehydrogenase activity, soil protein contents under different management practices and at various growth stages. Marked depletions in the soil microbial biomass phospholipid contents were found with the advancement of crop growth stages, while the incorporation of fertilizers and/or pesticides also induced slight changes, and the lowest microbial biomass phospholipid content was found with pesticides application alone. A decline in the bacterial abundance of heterotrophic bacteria and proteolytic bacteria was observed during the continuance of crop growth, while the lowest abundance of heterotrophic bacteria and proteolytic bacteria was found with pesticides application alone, which coincided with the decline of soil microbial biomass. A consistent increase in the electron transport system activity was measured during the different crop growth stages of rice. The use of fertilizers (NPK) alone or combined with pesticides increased it, while a decline was noticed with pesticides application alone as compared with the control. The soil protein content was found to be relatively stable with fertilizers and/or pesticides application at various growth stages in both crops undertaken, but notable changes were detected at different growth stages.

Sampling Size Requirements to Delineate Spatial Variability of Soil Properties for Site-Specific Nutrient Management in Rubber Tree Plantations

Site-specific nutrient management is an important strategy to promote sustainable production of rubber trees in order to obtain high yields of natural rubber. Making effective nutrient management decisions for rubber trees depend on knowing the spatial variations of soil fertility properties in advance. In this study the Kriging geostatistical method was used to examine the spatial variability of soil total nitrogen(TN), organic matter(OM), available phosphorus(AP) and available potassium(AK) in a typical hilly rubber tree plantation in Hainan, China. The spatial variability of the soils was small for the TN and OM and had medium variability for the AP and AK variables. Anisotropic semivariograms of all soil properties revealed that elevation and building contour ledge can profoundly affect the spatial variability of soil properties in the plantation, except for the AK variable. Soil samples had to be collected in alignment with the direction of elevation and perpendicular to the direction of building contour ledges, which was needed to obtain more reliable information within the study area in the rubber tree plantation. In formulating a sample scheme for AK, the distribution features of the soil’s parent material should be considered as the influence factor in the study field. The Kriging method used to guide the soil sampling for spatial variability dertermination of soil properties was about 2-5 times more efficient than the classic statistical method.

Nutrient Management for Eucalypt Plantations in South China

Eucalypts are very popular for revegetation in many parts of south China because of their capacity to tolerate degraded sites and unfertile soils,and their fast growth potential to coppice. This paper reviews a decade of field trials in china, undertaken as part of several bilateral researchprograms in plantation forestry, concerning the use of fertilizers, harvest residue management and inoculation with ectomycorrhizal fungi. One of the key questions addressed is whether the productivity of plantation ...

Changes in Soil Physicochemical Properties under Selected Climate-Smart Agricultural Practices in Central African Republic

Soil nutrient depletion as a result of continuous cultivation with insufficient external nutrient replenishment is a major challenge in sub-Saharan Africa (SSA). A trial using the organic and mineral fertilizer was established in the cassava cropping system of the Pissa and Damara areas to address the declining soil fertility. The study aimed to evaluate the effect of cow manure and mineral fertilizer in combination or sole application on soil physico-chemical properties and macronutrients. The experimental trial adopted a randomized complete block design (RCBD) replicated four times. The treatments comprised of;T1 (Control), T2 (Peasant practice), T3 (sole NPK), and T4 (Cow manure + NPK). The data on soil physicochemical analysis was subjected to a one-way analysis of variance in SAS 9.4 and the mean was separated by Tukey’s HSD test at p < 0.005. The soil pH values ranged from 4.20 to 4.91;and 4.53 to 5.28 in Pissa and Damara respectively. According to the treatments, a low pH value is observed in T3 (4.13) in the Pissa. Combined use of cow manure and the mineral fertilizer resulted in higher Mg K and N in the Pissa region and higher soil pH in Damara. The use of sole NPK (T3) gave a higher soil carbon and CN ratio. In the Pissa region the CEC, Cu, Fe, and Zn were higher in the treatments with mineral fertilizer compared to the control. Conclusively, the use of mineral fertilizer and cow manure can be used with optimum rates to improve soil physico-chemical properties on a sustainable basis.

Nitrogen deposition as an important nutrient from the environment and its impact on ecosystems in China

As an example of atmospheric nitrogen(N) deposition,the paper summarizes the definition,form and amount of nutrient from the environment(NFE) and the relationship between NFE and anthro-pogenic reactive N emission.Based on our own study and published articles,we find that N wet and dry deposition has been an important nutrient resource in agricultural and natural ecosystems in China.The total amount of N deposition and other environment-derived N in China was up to 18 Tg N/a,equal to ap-proximately 60% of the national N fertilizer consumption.Nitrogen deposition is expected to contribute substantially to nutrient cycling and net primary productivity in various ecosystems.Therefore,it is crucial to utilize this environment-derived nutrient resource by integrated nutrient resource management in order to realize the sustainable development of both agricultural and non-agricultural ecosystems.

Impacts of soil fertility management on productivity and economics of rice and fodder intercropping systems under rainfed conditions in Odisha,India

Under small and marginal farm conditions,allocation of land exclusively for forages is not possible.Hence,integration of forages in existing crop geometry can ensure production of grain and fodder,simultaneously under rainfed conditions.Afield experiment was conducted to study the effect of different nutrient management practices on rice and fodder intercropping systems under rainfed conditions during 2015-2017.The intercropping system comprised(i)sole rice(R),(ii)rice and cowpea(5:2)(CP)and(iii)rice and ricebean(5:2)(RB)whereas the different nutrient management practices comprised(i)application of farm yard manure(FYM)at 5t ha^(-1)(farmers'practice)(N_(1)),(ii)application of inorganic fertilizer(recommended dose of fertilizer(RDF)of rice,60:30:30 kg ha^(-1) of N:P_(2)O_(5):K_(2)O)(N_(2))and(iii)application of both FYM at 5t ha^(-1) and 50%of RDF inorganic fertilizer(N3).The results of the experiment revealed that the growth attribute such as leaf area was influenced significantly when fodder crops were taken as intercrops because rice plant was getting more nitrogen from soil due to nitrogen fixation of leguminous fodder crops.Among the nutrient management practices,significant differences in leaf area were found beween N2 and and between N_(3)and N_(1)treatments.However,regarding total number of effective tillers,significant differences were found neither between nutrient management practices nor between cropping systems.The rice equivalent yield(REY)based on price(REY_(P))was found to be significantly lower in CP(2615 kg ha^(-1);-6.4%)and RB intercropping systems(2571 kg ha^(-1);-8.0%)than in R monocropping system(2794 kg ha^(-1)).However,the REY based on energy(REY_(E))of CP(2999 kg ha^(-1);+7.3%)and RB(2960 kg ha^(-1);+5.9%)were found to be significantly higher than that of R(2794 kg ha^(-1))irrespective of nutrient management practices.Between different nutrient management practices,the N3 treatment recorded the highest REY_(P)and REY_(E)which was at par with the N_(2)treatment and significantly higher than the N1 treatment irrespective of cropping systems.The combined application of both organic and inorganic sources of nutrients helped to supply nutrients throughout the growing season,which led to improved growth parameters and rice yield.The R monocropping system resulted in more income and rain water use efficiency(RWUE)closely followed by rice and fodder intercropping systems.However,the REYe and energy use efficiency(EUE)of rice and fodder intercropping systems were higher than those of R.Also,fodder helped to meet the requirement of cattle feeding in the off-season.Hence,the intercropping system is advocated in the study zone.Further study can be done on ecosystem services and carbon sequestration potential of the intercropping system,as well as the system's coping ability in response to short drought through observing periodic soil moisture regime in root zone.

Assessment of Farmer’s Practices on the Rubber Nursery Management Using Growing Medium and Varietal Selection in Mon State

Rubber is an economically important perennial crop in Myanmar for latex production. As the rubber plantation area increases yearly, the requirement of vigorous rubber seedlings for its establishment plays a central role. The success of rubber plantations depends on some farming practices such as using different compost or other materials in the potting soil-medium, varietal selection for stock and scion in the budding process, and fertilizer application methods. The objective of this study was to assess the farmer’s practices in the establishment of rubber nurseries in mostly rubber planted areas in Myanmar. The survey interviewed 60 respondents from three townships in Mon State, namely Mudon, Kyaikmaraw, and Thanbyuzayat. The response data were analyzed through the descriptive method. This survey exposed the potentially active operators (middle age of 30 - 60 years) in rubber nursery production. Local experienced farmers usually raised the budded seedlings with 15 cm × 23 cm polyethylene bag in all study regions. Most farmers selected multi-clonal seed for stock and BPM 24 for scion according to the local market demand and high latex yield. All survey areas used both organic and inorganic fertilizers for nutrient management. Compost is a chief component of growing medium in their nursery production. However, making compost and high demand of the compost were local constraints. Therefore, this survey suggested improving the proper composting method for rubber nursery establishment.

Mitigation strategies for soil acidification based on optimal nitrogen management

Soil acidification is a serious constraint to food production worldwide.This review explores its primary causes,with a focus on the role of nitrogen fertilizer,and suggests mitigation strategies based on optimal N management.Natural acidification is determined by the leaching of weak acid mainly caused by climate and soil conditions,whereas the use of ammonium-based fertilizers,nitrate leaching and removal of base cations(BCs)by crop harvesting mostly accounts for anthropogenic acidification.In addition,low soil acid buffering capacity,mainly determined by soil parent materials and soil organic matter content,also accelerates acidification.This study proposes targeted mitigation strategies for different stages of soil acidification,which include monitoring soil carbonate content and p H of soils with p H>6.5(e.g.,calcareous soil),use of alkaline amendments for strongly acidic soils(p H<5.5)with aluminum toxicity risk to p H between 5.5 and 6.5,and decreasing acidification rates and supplementing BCs to maintain this optimal p H range,especially for soils with low acid buffering capacity.Effective mitigation involves optimizing the rate and form of N fertilizers used,regulating N transformation processes,and establishing an integrated soil–crop management system that balances acid production and soil buffering capacity.

Recent Advances on the Technologies to Increase Fertilizer Use Efficiency

To increase fertilizer use efficiency （FUE） and to minimize its negative impact on environment have been the focal points in the world for a long time. It is very important to increase FUE in China for its relatively low FUE and serious losses of nutrients. Recent advances of the technologies to increase FUE are reviewed in this article. These include site-specific and real-time nitrogen management, non-destructive quick test of the nitrogen status of plants, new types of slow release and controlled release fertilizers, site-specific nutrient management, and use of urease inhibitor and nitrification inhibitor to decrease nitrogen losses. Future outlook in technologies related to FUE improvement is also discussed.

Research,Extension,and Good Farming Practices Improve Water Quality and Productivity

Agriculture in southeastern Oregon and southwestern Idaho known collectively as the Treasure Valley has depended on furrow irrigation using heavy inputs of water and nitrogen （N） fertilizer. Crop rotations include onion, corn, wheat, sugar beet, potato, bean, and other crops. By 1986 groundwater had become contaminated with nitrate and residues of the herbicide chlorthal-dimethyl （DCPA）; an official groundwater management area was established by the Oregon Department of Environmental Quality along with an action plan and well monitoring network. The action plan allowed for a trial period to see whether voluntary changes would improve trends. Researchers, producers, and agencies cooperated to develop production options that had the possibility of being both environmentally protective and cost effective. Options were tested to improve irrigation practices, increase N fertilizer use efficiency on several rotation crops, and find a cost effective replacement for DCPA. Research demonstrated the opportunity for increased productivity through both irrigation scheduling and the adoption of drip and sprinkler systems. Fertilizer research demonstrated that smaller, more frequent N applications were more efficient than a single large application. Effective, lower cost herbicides replaced DCPA. Research results were effectively delivered through many means and voluntarily adopted. Both groundwater nitrate and DCPA residues are declining. Productivity has increased.