A long-term soil fertility experiment in the rice-wheat system was initiated in 1980181 to evaluate the long-term effect of organic manure and inorganicfe rtilizers on grain yield and soil chemical properties. The experiment employed a randomized complete block design (RCBD) and was located on slightly acidic loam soil at Regional Agricultural Research Station (RARS), Parwanipur . The balanced application ofN-P20s-K20 (100-30-30) kglha in both rice and wheat along with 25 kg ZnSO/ha in rice produced the highest grain and straw yield sfor both crops. The combined effect of NPK verses minus PK, minus P and minus K treatments was more pronounced with the advancement of years in both rice and wheat. However, the effect of phosphorus was more pronounced in wheat than rice. The use of FYM alone was not sufficient to meet the nutrient requirement of either crops. However, the addition of 50 kg Niha enhanced the benefit of compost application. Furthermore, the use of 10 t FYM/ha plus 50 kg Niha in rice and residual FYM with NPK in wheat was superior to both FYM alone and imbalancedfertilizer application. A decreasing yield trend was observed for plots treated with imbalanced f ertilizers. The soil analysis results showed that the use of FYM alone or FYM/choppe d straw combined with inorganic fertilizer increased the organic carbon c.ontent of soil. The long-term use of N alone in theform_of urea decreased soil pH value. However, pH was maintained by long-term application of FYM. Similarly, continuous use of FYM alone or with 50 kg Nlha increased the total nitrogen and available phosphorus of the soil. The highest potassium content of wheat straw was obtained with the application of 10 I chopped strawlha plus 50-0-0 in rice season and 100-30-30 in wheat.

A long-term soil fertility experiment in the rice-wheat system was initiated in 1980181 to evaluate the long-term effect of organic manure and inorganicfe rtilizers on grain yield and soil chemical properties. The experiment employed a randomized complete block design (RCBD) and was located on slightly acidic loam soil at Regional Agricultural Research Station (RARS), Parwanipur . The balanced application ofN-P20s-K20 (100-30-30) kglha in both rice and wheat along with 25 kg ZnSO/ha in rice produced the highest grain and straw yield sfor both crops. The combined effect of NPK verses minus PK, minus P and minus K treatments was more pronounced with the advancement of years in both rice and wheat. However, the effect of phosphorus was more pronounced in wheat than rice. The use of FYM alone was not sufficient to meet the nutrient requirement of either crops. However, the addition of 50 kg Niha enhanced the benefit of compost application. Furthermore, the use of 10 t FYM/ha plus 50 kg Niha in rice and residual FYM with NPK in wheat was superior to both FYM alone and imbalancedfertilizer application. A decreasing yield trend was observed for plots treated with imbalanced f ertilizers. The soil analysis results showed that the use of FYM alone or FYM/choppe d straw combined with inorganic fertilizer increased the organic carbon c.ontent of soil. The long-term use of N alone in theform_of urea decreased soil pH value. However, pH was maintained by long-term application of FYM. Similarly, continuous use of FYM alone or with 50 kg Nlha increased the total nitrogen and available phosphorus of the soil. The highest potassium content of wheat straw was obtained with the application of 10 I chopped strawlha plus 50-0-0 in rice season and 100-30-30 in wheat.

A long-term fertility field experiment (1978179 - 1996/97) in rice-wheat-fallow cropping system was conducted at Regional Agriculture Research Station (RARS), Tarahara to evaluate the effict of organic and inorganic manure on the grain yield of rice and wheat as well as chemical properties of soil. The application of 100 kg nitrogenlha was found in negative relation with the grain yield of rice and wheat, while it had positive to the application of 50 kg nitrogenlha under Tarahara condition. Similarly the response of phosphorous in combination with nitrogen alone or with potash attained positive effect of grain yield showing 30 kg of phosphorous and potashlha were inadequate dose for rice crop. The positive response of both of phosphorous and potash indicated to be verified for their accurate combination and dose for optimum yield The application of 30 and 40 kg of phosphorous and potash in combination with sole nitrogen or with each other nutrients, the response was positive but not peifect. The effict on soil properties, the pH was found decreasing less in the field supplied with combination of nitrogen, phosphorous and potash than any single or double major nutrients applied plots. Organic matter increased even without any external supplementation of any nutrients and also the percentage of nitrogen was found increasing which was recorded as higher in the plots supplied with combined nutrient application rather than the application of any one or two major nutrients. Similarly the external supply of phosphorous and potash was found as not properly substituting the quantity that was removed by rice and wheat crops in the experiment.

A long-term fertility field experiment (1978179 - 1996/97) in rice-wheat-fallow cropping system was conducted at Regional Agriculture Research Station (RARS), Tarahara to evaluate the effict of organic and inorganic manure on the grain yield of rice and wheat as well as chemical properties of soil. The application of 100 kg nitrogenlha was found in negative relation with the grain yield of rice and wheat, while it had positive to the application of 50 kg nitrogenlha under Tarahara condition. Similarly the response of phosphorous in combination with nitrogen alone or with potash attained positive effect of grain yield showing 30 kg of phosphorous and potashlha were inadequate dose for rice crop. The positive response of both of phosphorous and potash indicated to be verified for their accurate combination and dose for optimum yield The application of 30 and 40 kg of phosphorous and potash in combination with sole nitrogen or with each other nutrients, the response was positive but not peifect. The effict on soil properties, the pH was found decreasing less in the field supplied with combination of nitrogen, phosphorous and potash than any single or double major nutrients applied plots. Organic matter increased even without any external supplementation of any nutrients and also the percentage of nitrogen was found increasing which was recorded as higher in the plots supplied with combined nutrient application rather than the application of any one or two major nutrients. Similarly the external supply of phosphorous and potash was found as not properly substituting the quantity that was removed by rice and wheat crops in the experiment.

A Long Term Soil FertWty experiment has heen conducted since 1987188 to study the sustainability ofsoilfertility and productivity of the rice-wheat system under Khajura (Western Terai) conditions. Response to supplement phosphorous (P) was seen in later years of the experiment in rice, whereas in wheat, response to P was observed from the initial years. A residual effect of FYM was seen in rice. The highest grain yield (3634kglha) of rice was observed in treatment 5(100:30:30 NPK) Treatment 5 also produced highest mean grain yield in wheat (2556 kg/ha. The main grain yields of T2 ( 100:00:0), T3(100:30:00) and T4 (100:00:30) NPK kglha were comparable in both rice and wheat. The combine effect ofP and K on wheat yield greater the effect of either. By comparison P and K application had no significant effect on rice yield Nitrogen is very important for both rice and wheat. Phosphorous and Potassium some what important for rice (at low nitrogen) Phosphorous and Potassium more important .for what (at all N levels). Role of the FYM in rice greater than F_YM in wheat. The similar results were obtained in mean straw yield, plant height , panicle length, grain/spike and no. c ftillers and 1000 grain weight. The average available P205 (83.8kglha) and K20 contain (60kglha) in soil was observed to decline over the study period Total nitrogen and organic matter content increased with the application of FYM/compost (I 0 tlha)

A Long Term Soil FertWty experiment has heen conducted since 1987188 to study the sustainability ofsoilfertility and productivity of the rice-wheat system under Khajura (Western Terai) conditions. Response to supplement phosphorous (P) was seen in later years of the experiment in rice, whereas in wheat, response to P was observed from the initial years. A residual effect of FYM was seen in rice. The highest grain yield (3634kglha) of rice was observed in treatment 5(100:30:30 NPK) Treatment 5 also produced highest mean grain yield in wheat (2556 kg/ha. The main grain yields of T2 ( 100:00:0), T3(100:30:00) and T4 (100:00:30) NPK kglha were comparable in both rice and wheat. The combine effect ofP and K on wheat yield greater the effect of either. By comparison P and K application had no significant effect on rice yield Nitrogen is very important for both rice and wheat. Phosphorous and Potassium some what important for rice (at low nitrogen) Phosphorous and Potassium more important .for what (at all N levels). Role of the FYM in rice greater than F_YM in wheat. The similar results were obtained in mean straw yield, plant height , panicle length, grain/spike and no. c ftillers and 1000 grain weight. The average available P205 (83.8kglha) and K20 contain (60kglha) in soil was observed to decline over the study period Total nitrogen and organic matter content increased with the application of FYM/compost (I 0 tlha)

A long-term soil fertility experiment has been conducted at National Wheat Research Program/Regional Agricultural Research Station, Bhairahwa since 1988 to study the effect ofmineral fertilizers and/or manure   in soil fertility in rice-wheat system.  Response of P was seen in later years of the experiment in rice whereas in wheat response of P was observed from theinitial years. Faster yield decline (178.4 kg lhalyr.) was found in the treatment without Phosphorus. Sesbania increased the rice yield but no residual effect of Sesbania was observed inwheat. Residual effect of Farm Yard Manure (FYM) was also seen in rice. Farm Yard Manure (FYM) in combination with Nand P produced better yield of wheat than themineral fertilizers. All Preceiving treatment showed declining trend. Application f potassiumsignificantly increased the grain yield of wheat and thousand grain weight.  Olsen P was below the critical/eve! of 5 uglg soiI where P was not applied. Exchangeable potassium was also below the critical level of78 uglg soil in all treatments including the Farm Yard Manure (FYM).

A long-term soil fertility experiment has been conducted at National Wheat Research Program/Regional Agricultural Research Station, Bhairahwa since 1988 to study the effect ofmineral fertilizers and/or manure   in soil fertility in rice-wheat system.  Response of P was seen in later years of the experiment in rice whereas in wheat response of P was observed from theinitial years. Faster yield decline (178.4 kg lhalyr.) was found in the treatment without Phosphorus. Sesbania increased the rice yield but no residual effect of Sesbania was observed inwheat. Residual effect of Farm Yard Manure (FYM) was also seen in rice. Farm Yard Manure (FYM) in combination with Nand P produced better yield of wheat than themineral fertilizers. All Preceiving treatment showed declining trend. Application f potassiumsignificantly increased the grain yield of wheat and thousand grain weight.  Olsen P was below the critical/eve! of 5 uglg soiI where P was not applied. Exchangeable potassium was also below the critical level of78 uglg soil in all treatments including the Farm Yard Manure (FYM).

A long-term soil fertility experiment has been conducted at National Wheat Research Program/Regional Agricultural Research Station, Bhairahwa since 1988 to study the effect ofmineral fertilizers and/or manure   in soil fertility in rice-wheat system.  Response of P was seen in later years of the experiment in rice whereas in wheat response of P was observed from theinitial years. Faster yield decline (178.4 kg lhalyr.) was found in the treatment without Phosphorus. Sesbania increased the rice yield but no residual effect of Sesbania was observed inwheat. Residual effect of Farm Yard Manure (FYM) was also seen in rice. Farm Yard Manure (FYM) in combination with Nand P produced better yield of wheat than themineral fertilizers. All Preceiving treatment showed declining trend. Application f potassiumsignificantly increased the grain yield of wheat and thousand grain weight.  Olsen P was below the critical/eve! of 5 uglg soiI where P was not applied. Exchangeable potassium was also below the critical level of78 uglg soil in all treatments including the Farm Yard Manure (FYM).

A long-term soil fertility experiment has been conducted at National Wheat Research Program/Regional Agricultural Research Station, Bhairahwa since 1988 to study the effect ofmineral fertilizers and/or manure   in soil fertility in rice-wheat system.  Response of P was seen in later years of the experiment in rice whereas in wheat response of P was observed from theinitial years. Faster yield decline (178.4 kg lhalyr.) was found in the treatment without Phosphorus. Sesbania increased the rice yield but no residual effect of Sesbania was observed inwheat. Residual effect of Farm Yard Manure (FYM) was also seen in rice. Farm Yard Manure (FYM) in combination with Nand P produced better yield of wheat than themineral fertilizers. All Preceiving treatment showed declining trend. Application f potassiumsignificantly increased the grain yield of wheat and thousand grain weight.  Olsen P was below the critical/eve! of 5 uglg soiI where P was not applied. Exchangeable potassium was also below the critical level of78 uglg soil in all treatments including the Farm Yard Manure (FYM).

A long-term soil fertility experiment was conducted in alluvial soil to study the effect of FYM and inorganic fertiliser In rice-wheat cropping system at Khumaltar condition. Cultivation .of rice­ wheat rotations was monitored from 1993 to 1997. The Chianung 242 rice and Annapurna-1 wheat varieties were used in the experiment for all the five · years. The results show that significantly higher yields of rice and wheat were obtained through the application of balanced fertilisers.Application of 100 kg N/ha alone sustained the rice yields of 7.4 t/ha. No response to phosphorus or potassium was observed in either rice or wheat crops. Additionally no significant changes in soil pH, organic matter, total nitrogen, available phosphorus or potassium were observed either with the application of a balanced fertiliser or organic manure. The efficiency of fertilisers and manure was influenced by the amount of rain fall received. Rice and wheat yielded better in higher rainfall years. These results confirm that rice and wheat yields in rice-wheat system cannot be sustained by the application of organic manure alone.

A long-term soil fertility experiment was conducted in alluvial soil to study the effect of FYM and inorganic fertiliser In rice-wheat cropping system at Khumaltar condition. Cultivation .of rice­ wheat rotations was monitored from 1993 to 1997. The Chianung 242 rice and Annapurna-1 wheat varieties were used in the experiment for all the five · years. The results show that significantly higher yields of rice and wheat were obtained through the application of balanced fertilisers.Application of 100 kg N/ha alone sustained the rice yields of 7.4 t/ha. No response to phosphorus or potassium was observed in either rice or wheat crops. Additionally no significant changes in soil pH, organic matter, total nitrogen, available phosphorus or potassium were observed either with the application of a balanced fertiliser or organic manure. The efficiency of fertilisers and manure was influenced by the amount of rain fall received. Rice and wheat yielded better in higher rainfall years. These results confirm that rice and wheat yields in rice-wheat system cannot be sustained by the application of organic manure alone.

A long-term fertility trial was initiated in 1992 to study the effects of manures and fertilizers onthe productivity of maize-toria (mustard) rotation. The response of maize in the first year to the treatments under study (manure, lime and fertilizers) was found   to be non-significant. However, from the second year the grain yield of toria and from the third year the grain yield ofmaize were found to be consistently declining. From third year both maize and toria have beenshowing a gradual decline in grain yields during the succeeding years till 1998. The difference in response to calcite and dolomite   lime was found non significant. Biotic and abiotcconstraints could be the reason for declining the yield of both crops. The sharp decline in thegrain yield suggests laboratory investigation and treatments modification.

A long-term fertility trial was initiated in 1992 to study the effects of manures and fertilizers onthe productivity of maize-toria (mustard) rotation. The response of maize in the first year to the treatments under study (manure, lime and fertilizers) was found   to be non-significant. However, from the second year the grain yield of toria and from the third year the grain yield ofmaize were found to be consistently declining. From third year both maize and toria have beenshowing a gradual decline in grain yields during the succeeding years till 1998. The difference in response to calcite and dolomite   lime was found non significant. Biotic and abiotcconstraints could be the reason for declining the yield of both crops. The sharp decline in thegrain yield suggests laboratory investigation and treatments modification.

A long-term soil fertility experiment was initiated at the Regional  Agriculture  Research  Station(RARS), Hill  Crop Research Programme (HCRP) in Kabre, Dolakha  since  1993/94-1997/98. The main  objectives of  this  experiment was  to  study  the  effects  of  continuous  applications  oforganic and  inorganic fertilizers on  crop yields  in a  maize/millet  cropping pattern.   For  millet,the highest grain yields  (1689 kg/ha)  were  obtained  in plots  treated  with  recommended  rates oforganic manure  (FYM  30 t/ha). By contrast, the highest maize grain yields (5284 kg/ha)   wereobtained in plots   treated with recommended   rates of inorganic fertilizers    (NPK 120:60:40).Overall decreasing yield   trend was found   in maize yield   over years.   The  highest  combined(maize +millet) total grain yield  was obtained from  NPK  120:60:40 kg/ha  (6501 kg/ha) followedby  the  use  of NPK  80:60:40  kg/ha  4435  kg/ha)  and  compost  10  ton  + NPK  60:30:20  kg/ha(5949 kg/ha) (Table 1).

A long-term soil fertility experiment was initiated at the Regional  Agriculture  Research  Station(RARS), Hill  Crop Research Programme (HCRP) in Kabre, Dolakha  since  1993/94-1997/98. The main  objectives of  this  experiment was  to  study  the  effects  of  continuous  applications  oforganic and  inorganic fertilizers on  crop yields  in a  maize/millet  cropping pattern.   For  millet,the highest grain yields  (1689 kg/ha)  were  obtained  in plots  treated  with  recommended  rates oforganic manure  (FYM  30 t/ha). By contrast, the highest maize grain yields (5284 kg/ha)   wereobtained in plots   treated with recommended   rates of inorganic fertilizers    (NPK 120:60:40).Overall decreasing yield   trend was found   in maize yield   over years.   The  highest  combined(maize +millet) total grain yield  was obtained from  NPK  120:60:40 kg/ha  (6501 kg/ha) followedby  the  use  of NPK  80:60:40  kg/ha  4435  kg/ha)  and  compost  10  ton  + NPK  60:30:20  kg/ha(5949 kg/ha) (Table 1).

A long-term soil fertility experiment under maize-wheat cropping pattern was conducted from 1994/95 to 1997/98 at the Agricultural Research Center, Surkhet in order to study the long-term effects of balanced and unbalanced fertilizers application for maize and wheat on crop yields and soil chemical properties. The highest yield was obtained from plots receiving recommended levels of N, P and K in both wheat and maize. Yields remained almost from the first to fourth year for organic manure treated plots.  While both inorganic and organic treated plot showed the consistent increase in maize yield from year one to four.  The lowest yields  of maize and· wheat  were  observed  in plots fertilized   according  to farmers'  practice   (3.7 t/ha FYM)  soil chemical  analysis  revealed  a decreasing  trend  in available phosphorus  and  organic  matter content and an increasing trend in total nitrogen and available potassium  over the study period Continuation of the experiment for  an additional four  to five years  is needed to strengthen the findings from  this long-term study.

A long-term soil fertility experiment under maize-wheat cropping pattern was conducted from 1994/95 to 1997/98 at the Agricultural Research Center, Surkhet in order to study the long-term effects of balanced and unbalanced fertilizers application for maize and wheat on crop yields and soil chemical properties. The highest yield was obtained from plots receiving recommended levels of N, P and K in both wheat and maize. Yields remained almost from the first to fourth year for organic manure treated plots.  While both inorganic and organic treated plot showed the consistent increase in maize yield from year one to four.  The lowest yields  of maize and· wheat  were  observed  in plots fertilized   according  to farmers'  practice   (3.7 t/ha FYM)  soil chemical  analysis  revealed  a decreasing  trend  in available phosphorus  and  organic  matter content and an increasing trend in total nitrogen and available potassium  over the study period Continuation of the experiment for  an additional four  to five years  is needed to strengthen the findings from  this long-term study.

Field experiments in three systems; rice-wheat in bunded terraces (Chambas, 465m and Pakuwa850m asl), upland rice-blackgram in rainfed upland and unbunded gentle slope terraces (Dor DorTar, 550m asl) and maize-finger millet in rainfed upland unbunded gentle slope terrace (Dor Dor village, 850m asl) in the western hills of Nepal were conducted during 1997-98 to determine theresponse of cereal crops (rice, wheat, maize and upland rice) to the application of manure orfertilizer or a combination of both and their residual effects on a succeeding crop of blackgram inupland rice-blackgram system and finger-millet in the maize-finger millet system. Data from  thefirst year showed  that the application of  farmers'  practice  of inorganic fertilizers  (50:15:15 kgN:P:K/ha in rice, 40:15:15 kg N:P:K in upland rice, 90:30:30 kg N:P:K/ha in maize and 80:15:15 kg N:P:K/ha in wheat) gave a significantly higher grain yield of rice, upland rice, maize and wheatthan the control. Yield responses to N supplied through organic manure was less in all cropscompared to the same dose supplied through inorganic fertilizer. Significant residual effect of manure or fertilizer or combination of both was not observed on crops of blackgram and finger­ millet after upland rice and maize crops respectively.

Field experiments in three systems; rice-wheat in bunded terraces (Chambas, 465m and Pakuwa850m asl), upland rice-blackgram in rainfed upland and unbunded gentle slope terraces (Dor DorTar, 550m asl) and maize-finger millet in rainfed upland unbunded gentle slope terrace (Dor Dor village, 850m asl) in the western hills of Nepal were conducted during 1997-98 to determine theresponse of cereal crops (rice, wheat, maize and upland rice) to the application of manure orfertilizer or a combination of both and their residual effects on a succeeding crop of blackgram inupland rice-blackgram system and finger-millet in the maize-finger millet system. Data from  thefirst year showed  that the application of  farmers'  practice  of inorganic fertilizers  (50:15:15 kgN:P:K/ha in rice, 40:15:15 kg N:P:K in upland rice, 90:30:30 kg N:P:K/ha in maize and 80:15:15 kg N:P:K/ha in wheat) gave a significantly higher grain yield of rice, upland rice, maize and wheatthan the control. Yield responses to N supplied through organic manure was less in all cropscompared to the same dose supplied through inorganic fertilizer. Significant residual effect of manure or fertilizer or combination of both was not observed on crops of blackgram and finger­ millet after upland rice and maize crops respectively.

Two long-term experiments,  one in rice - wheat system and another one in maize/finger millet system were conducted at Pakhribas Agricultural Centre (PAC) (1450 masl) for  8 (1989 to 1996) and 6 years (1989 to 1994) respectively.   The objectives of both the experiments were to find  out the long-term response of organic and inorganic fertilizers  singly or in combination with crop yields and soil properties.  In case of wheat-rice system, the additional objectives were to know the residual effect on rice yields when organic and inorganic fertilizers were applied to the preceding wheat crop and also to estimate nutrients uptake by rice and wheat crops. Application of 60:30:30 kg N:P2 O5:K2O/ha plus  15 t compost/ha gave higher grain yields  (3.52 to 5.01  t/ha) in all years. Response of K was recorded when applied with N. The residual effect of compost on rice yield was noted but no residual effect from chemical fertilizer. However, chemical fertilizers increased exchangeable acidity upto 1.2 to 2.0 cmol/kg in both the system. Available phosphorus       in soil decreased as much as 12.2 mg/kg with chemical fertilizers and increased 26.4 to 30.8 mg/kg with compost plus N top-dressing.  Available K in soil significantly increased to 92.9 m/kg with the application of 25 t compost/ha in maize/finger millet system but such high response was not noted in wheat-rice system. Application  of  2  t  lime/ha  in  each  year   increased  pH   to  6.2  and exchangeable Ca to 11.1 cmol/kg. Cation exchange capacity, micronutrient (Fe, Mn, Cu and Zn)and physical properties (bulk density, moisture % at field capacity, wilting point and water holding capacity) were not affected by the treatments. Nitrogen, P and K uptake by rice and wheat crops were higher in the treatment of 15 t compost plus balanced fertilizer (60:30:30 kg N:P2 O5.K2O/ha) thereby producing more crop  yields.

Two long-term experiments,  one in rice - wheat system and another one in maize/finger millet system were conducted at Pakhribas Agricultural Centre (PAC) (1450 masl) for  8 (1989 to 1996) and 6 years (1989 to 1994) respectively.   The objectives of both the experiments were to find  out the long-term response of organic and inorganic fertilizers  singly or in combination with crop yields and soil properties.  In case of wheat-rice system, the additional objectives were to know the residual effect on rice yields when organic and inorganic fertilizers were applied to the preceding wheat crop and also to estimate nutrients uptake by rice and wheat crops. Application of 60:30:30 kg N:P2 O5:K2O/ha plus  15 t compost/ha gave higher grain yields  (3.52 to 5.01  t/ha) in all years. Response of K was recorded when applied with N. The residual effect of compost on rice yield was noted but no residual effect from chemical fertilizer. However, chemical fertilizers increased exchangeable acidity upto 1.2 to 2.0 cmol/kg in both the system. Available phosphorus       in soil decreased as much as 12.2 mg/kg with chemical fertilizers and increased 26.4 to 30.8 mg/kg with compost plus N top-dressing.  Available K in soil significantly increased to 92.9 m/kg with the application of 25 t compost/ha in maize/finger millet system but such high response was not noted in wheat-rice system. Application  of  2  t  lime/ha  in  each  year   increased  pH   to  6.2  and exchangeable Ca to 11.1 cmol/kg. Cation exchange capacity, micronutrient (Fe, Mn, Cu and Zn)and physical properties (bulk density, moisture % at field capacity, wilting point and water holding capacity) were not affected by the treatments. Nitrogen, P and K uptake by rice and wheat crops were higher in the treatment of 15 t compost plus balanced fertilizer (60:30:30 kg N:P2 O5.K2O/ha) thereby producing more crop  yields.