Farmers' Fertilizer Practice Research Articles

Site Specific Nutrient Management for Maize on Ultisols Lampung

Site Specific Nutrient Management for Maize on Ultisols Lampung (A M Murni, JM Pasuquin, and C Witt): Lampung is the third major maize producing province in Indonesia after East Java and Central Java. In Lampung maize is cultivated mainly in upland areas with ultisols and only some cultivated on paddy field as a secondary crop in the dry season. The average maize yield in Lampung is still 3.4 Mg ha-1 bellow yield potential of 7-10 Mg ha-1. To increase the productivity of maize through site-specific nutrient management (SSNM), on-farm trials were conducted in five locations in Lampung i.e. four locations in Central Lampung District (Sidowaras, Binjai Ngagung, Watu Agung and Balai Rejo) and one location in South Lampung District (Trimulyo, Tegineneng Sub District) during the 2004/2005, 2005/2006 and 2006/2007 rainy seasons. The experimental setup followed a standard protocol at all sites and included nutrient omission plots (PK, NK, NP) to estimate indigenous nutrient supplies, an NPK plot to measure yield response to fertilizer application, and a farmers’ fertilizer practice (FFP) plot in each farmer’s field. An SSNM treatment plot was included in the second and third seasons. Each of the above treatments was paralleled by a plot with improved crop management practice (ICM), i.e. higher planting density, addition of lime, and addition of magnesium. Results showed that yield response to fertilizer N, P and K application in these sites were: N = 2.3-4.1 Mg ha-1; P = 0.6-2.0 Mg ha-1; K = 0.3-2.4 Mg ha-1. Attainable yield in the three seasons on average ranged from 7.6 Mg ha-1 to 10.6 Mg ha-1. Yield in the SSNM treatment (with or without ICM) was significantly higher than the FFP indicating great opportunities for farmers to increase productivity and profitability with improved nutrient and crop management.

Conservation agriculture and precision nutrient management practices in maize-wheat system: Effects on crop and water productivity and economic profitability

Excessive pumping of groundwater over the years to meet the high irrigation water requirement of rice-wheat system has resulted in over exploitation of groundwater in the Indo-Gangetic plains (IGP) of India. Replacement of traditional rice with less water crops such as maize under conservation agriculture (CA) based management (tillage, crop establishment and residue management) practices are required to promote sustainable intensification. Furthermore, inefficient nutrient management practices are responsible for low crop yields and nutrient use efficiencies in MW system. A 3-year field experiment was conducted in farmer’s participatory strategic research mode at Taraori, Karnal, India to evaluate the effects of tillage and crop establishment (TCE) methods, residue management, mungbean integration, and nutrient management practices on crop yields, water productivity and profitability of MW system. The main plot treatments included four combinations of TCE, residue and mungbean integration [conventional tillage (CT), conventional tillage with mungbean (CT + MB), permanent bed (PB) and permanent bed with MB (PB + MB] with three nutrient management practices [farmer’s fertilizer practice (FFP), recommended dose of fertilize (RDF) and site specific nutrient management (SSNM)] using Nutrient Expert® as sub plot treatments. System productivity, water use efficiency (WUE) and net returns under PB + MB were significantly increased by 28.2–30.7%, 27.8–31.0% and 36.8–40.5% compared to CT respectively, during three years of experimentation. Integration of MB in MW system contributed 24.9 and 27.6% increases in system productivity and net returns compared with no MB, respectively. SSNM based nutrient management increased the mean (averaged across 3 yrs) system productivity, WUE and net returns of MW system by 13.4%, 13.3% and 15.3% compared with FFP, respectively. Study showed that conservation agriculture based sustainable intensification (PB + MB) and SSNM approach provided opportunities for enhancing crop and water use efficiency, and profitability of MW system in North-West IGP of India.

Đánh giá phương pháp xác định nhu cầu phân bón NPK lên năng suất bắp lai trên đất phù sa bao đê và không bao đê tại An Phú - An Giang

The objectives of this study were to evaluate the methods to quantify the N, P and K fertilizer requirement for hybrid maize based on its yield in An Phu - An Giang. The research has been conducted in winter-spring crop in 2014-2015 and 2015 – 2016 included six treatments: (i) added NPKCaMg fertilizer (200N); (ii) without N fertilizer; (iii) without P fertilizer; (iv) without K fertilizer; (v) added NPKCaMg fertilizer (160N);(vi) farmers’ fertilizer practice (FFP). From the principle of SSNM, the method of determining the demand for fertilizer N is based on the recovery efficiency method (REN) with the dose of fertilizer to meet local demand for hybrid maize compared to using agronomic efficiency (AEN). For P and K fertilization, fertilizer demand for hybrid maize by fertilizer demand for the removed to grain and fertilizer demand for the expected grain yield response. The same yield (11-12 tons/ha), the higher demand of NPK fertilizer on the undeposited soil compared to the deposited soil. The capacity to provide soil N fertilizer is 45-50%, for P and K is> 80%, the capacity of NPK supplying from soil was ranked in order K>P>N. Indigenous NPK supplying of the undeposited soil was lower than the deposited soil and ranked in order of 51-80-91%; 54-86-91%, respectively.

Effects of precision conservation agriculture in a maize-wheat-mungbean rotation on crop yield, water-use and radiation conversion under a semiarid agro-ecosystem

In recent years, water resources have decreased and water saving has become an important issue in the Indo-Gangetic Plains (IGP) of South Asia. Maize-wheat-mungbean (MWMb), is an alternate to traditional rice-wheat cropping system, can mitigate the effects of the frequency, intensity, and duration of rainfall due to climate change on food security in the semi arid-region of north-western IGP. The objective of this research was to determine the productivity, water-use efficiency (WUE) and incident radiation conversation efficiency (IRCE) of MWMb cropping system under 3 tillage practices [zero tillage (ZT), permanent beds (PB) and conventional tillage (CT) and 4 nutrient management strategies [Control (unfertilized), farmers’ fertilizer practice (FFP), recommended dose of fertilizers (Ad-hoc) and a site specific nutrient management (SSNM” using the Nutrient Expert® decision support tool). Results of multi-year trial showed that among tillage practices, ZT and PB practices reduced the system irrigation water requirement by 140–200mmha−1 and 200–300mmha−1 respectively, compared to CT system, resulting an enhanced grain yield by 5.7–24.6%, biomass yield by 4.6–20.8%, WUE by 18.4–39.0%, and IRCE by 9.9–34.4%, respectively. Significant (P≤0.05) improvement in system WUE, grain and biomass yield, and IRCE (by 30.6–59.9, 38.3–80.5, 34.3–64.7 and 13.5–48.5%, respectively) was observed in SSNM compared to the unfertilized plots. Significant (P≤0.05) interactions between tillage practices and nutrient management strategies was measured with respect to water–use, WUE, grain and biomass yield, and IRCE of MWMb system. Combinations of ZT/PB practices+SSNM/Ad-hoc nutrient management strategies registered significantly (P<0.05) higher system WUE and IRCE, grain and biomass yield compared to CT+unfertilized/FFP. Results of present study showed that SSNM/Ad-hoc based nutrient application coupled with CA-based tillage practices in MWMb system has complementarity to attain higher system productivity, WUE and IRCE compared to the use of these crop management practices in isolation.

The rice production practices of high yield and high nitrogen use efficiency in Jiangsu, China

To face the great challenges of ensuring food security and environmental sustainability, agricultural production must be improved by high yield and high resource utilization efficiency (HYHE). We recently addressed this challenge and evaluated yield potential by surveying 735 farmers in 2008–2012 and then conducting 6 rice field experiments in 2008–2013 with large demonstration areas in 2010–2013 aimed to actualize the HYHE in Jiangsu Province, China. The survey result showed that the averaged N rate, grain yield and N partial factor productivity (PFPN) of the farmers were 336.7 kg ha−1, 8131.8 kg ha−1 and 24.2 kg kg−1, respectively. Through controlling total N rates and adjusting the application timing, the yield and the PFPN of optimal N managements (OPT) were increased by 5.9% and 37.6% with 31.4% reduction in N supply amounts for 6 experimental sites, and the yield increased by 5.6% for large demonstration areas compared with farmers’ fertilizer practices (FFP), respectively. In conclusion, although the soil properties of the different regions varied, HYHE could be achieved by regulating the N management practices, thus contributing to higher rice production and lower environmental costs from intensive agriculture in Jiangsu, China.

Effect of nitrogen root zone fertilization on rice yield, uptake and utilization of macronutrient in lower reaches of Yangtze River, China

Improper application of nitrogen (N) has led to high N losses and low N use efficiency in the lower reaches of Yangtze River in China. An effective method to solve such problems is the deep fertilized N in root zone (RZF). Limited information is available on the effect of RZF on the uptake of macronutrients (N, P and K) and rice yield. Field experiments, conducted from 2014 to 2015, compared the farmer fertilizer practice (FFP, with 225 kg ha−1 of N, split into three doses) and RZF using the same rate but placing N 5 cm away from rice roots in holes 10 cm deep (RZF10) or 5 cm deep (RZF5) as a single application. The highest mean yield (10.0 t ha−1) was obtained in RZF10, which was 19.5% more than that in FFP. Root zone fertilization of urea (whether 10 cm deep or 5 cm deep) resulted in greater accumulation of N, P and K in stem, leaf sheaths, leaf blades and grains compared to that in FFP in sandy and in loam soils. The uptake of N, P and K was the highest in RZF10 (average at 176.7, 66.2 and 179.1 kg ha−1, respectively), higher than that in FFP by 45.0, 17.0 and 22.6%, respectively. N apparent recovery efficiency was markedly higher in RZF10 (53.1%) than in FFP (27.5%). RZF10 significantly increased the N, P, K uptake compared with FFP under different N rates in both sandy and loam soils. These results suggest that the N, P and K input amount should be re-determined under RZF.

Effect of N Fertilization Pattern on Rice Yield, N Use Efficiency and Fertilizer-N Fate in the Yangtze River Basin, China.

High N loss and low N use efficiency (NUE), caused by high N fertilizer inputs and inappropriate fertilization patterns, have become important issues in the rice (Oryza sativa L.) growing regions of southern China. Changing current farmer fertilizer practice (FFP, 225 kg ha–1 N as three applications, 40% as basal fertilizer, 30% as tillering fertilizer and 30% as jointing fertilizer) to one—time root—zone fertilization (RZF, 225 kg ha–1 N applied once into 10 cm deep holes positioned 5 cm from the rice root as basal fertilizer) will address this problem. A two—year field experiment covering two rice growing regions was conducted to investigate the effect of urea one—time RZF on rice growth, nutrient uptake, and NUE. The highest NH4+–N content for RZF at fertilizer point at 30 d and 60 d after fertilization were 861.8 and 369.9 mg kg–1 higher than FFP, respectively. Rice yield and total N accumulation of RZF increased by 4.3–44.9% and 12.7–111.2% compared to FFP, respectively. RZF reduced fertilizer—N loss by 56.3–81.9% compared to FFP. The NUEs following RZF (mean of 65.8% for the difference method and 43.7% for the labelled method) were significantly higher than FFP (mean of 35.7% for the difference method and 14.4% for the labelled method). In conclusion, RZF maintained substantial levels of fertilizer—N in the root—zone, which led to enhanced rice biomass and N uptake during the early growth stages, increased fertilizer—N residual levels and reduced fertilizer—N loss at harvest. RZF produced a higher yield increment and showed an increased capacity to resist environmental threats than FFP in sandy soils. Therefore, adopting suitable fertilizer patterns plays a key role in enhancing agricultural benefits.

Polyaspartate Urea and Nitrogen Management Affect Nonstructural Carbohydrates and Yield of Rice

In rice (Oryza sativa L.), nonstructural carbohydrates (NSC) play an important role in grain yield. To investigate the effects of urea type (polyaspartate urea versus conventional urea) and N management method (farmer's fertilizer practice and optimized N management) on NSC accumulation and remobilization in rice, field experiments were conducted in Wenjiang, China, in 2014 and 2015. Grain yield, effective panicles, and total number of spikelets were positively related to NSC accumulation in aboveground parts and remobilization of stored NSC (RSN) in the stem plus sheath from 20 d after heading to maturity. Polyaspartate urea, in place of conventional urea, increased NSC accumulation in the leaf lamina and the stem plus sheath at the heading stage and promoted RSN in the stem plus sheath from 20 d after heading to maturity, improving grain yield and total aboveground biomass. Compared with farmer's fertilizer practice, optimized N management showed a 5% reduction in NSC accumulation in the stem plus sheath from planting to heading and a 22% decrease in RSN in the stem plus sheath from heading to 20 d after. Optimized N management increased RSN in the stem plus sheath from 20 d after heading to maturity, increasing NSC accumulation in the panicle and grain yield. Using polyaspartate urea with optimized N management may indeed be a practical and feasible way to enhance grain yield of rice in subtropical humid monsoon climates.

Evaluation of the grain yield and nitrogen nutrient status of wheat (Triticum aestivum L.) using thermal imaging

Nitrogen (N) supply significantly influences plant growth and crop yields. To investigate the dynamic process of wheat plant responses to nitrogen management, digital infrared thermography was used to detect canopy average temperature (CAT) during different wheat growth stages in three field management experiments, including N applied rates, N application methods and cultivation approaches, which were conducted in 2013–2014 in southeast China. The CAT was reduced with increased N rates, compared to the control (0N), applications of 300kgNha−1 reduced CAT by 14.0%, 10.7% and 9.2% at the tillering, heading and milking stages, respectively. The CAT was also sensitive to N application methods, in which the CAT of the farmers’ fertilizer practice (FFP) was lower and higher than that of the optimal N management (OPT) before the heading stage and after the heading stage, respectively. Considering the cultivation approaches, the effects of deep tillage (NC-DP) on the CAT was more efficient than normal cultivation (NC) in wheat production. Lower CAT was observed for higher wheat biomass and yield, as a result of the CAT being somewhat negatively correlated with leaf N content. The wheat yield could be estimated by monitoring the CAT based on the response curves of the grain yield and CAT to the N addition rate, which was associated with stomatal conductance and transpiration rate. In conclusion, our results indicated that canopy temperature may provide an effective tool for dynamical monitoring of wheat growth and yields.

Effects of slow/controlled release urea on annual CH4 and N2O emissions in paddy field.

Present study examined the influence of different types of slow/controlled release urea on rice yield and annual greenhouse gas emissions in a paddy field, and assessed the greenhouse gas intensity (GHGI, equivalent to global warming potential GWP/rice yield). The results indicated that the optimized fertilization (OPT) treatment recorded the similar yield with reduced nitrogen fertilizer (21.4%) supply compared with the farmers' fertilizer practice (FFP) treatment, and decreased the annual emissions of CH4 (12.6%) and N2O (12.5%) during the rice season, and N2O emission (33.3%) during the fallow period. Application of controlled release urea (CRU) reduced CH4 emission by 28.9% during the rice-growing season with respect to OPT treatment, and showed negligible CH4 emission during the fallow season. However, nitrification inhibitor (DMPP) treatment was found to reduce the CH4 emissions by 41.6% and 76.9%, and N2O emissions by 85.7% and 6.5%, during the rice growing season and fallow season, respectively, compared with OPT treatment. In the fallow season, the N2O emissions accounted for 76.8%-94.9% of annual N2O emissions, which was clearly a key point for evaluation of greenhouse gas emissions in paddy. The average values of GHGI in OPT, CRU and DMPP treatments were 0.50, 0.41 and 0.33 kg·kg-1, respectively. Considering the benefits of higher rice yield and lower annual greenhouse gas emissions, combined application of urea and nitrification inhibitor could be the best combination in paddy fields.

Site‐Specific Nutrient Management for Cassava in Southern India

Cassava (Manihot esculenta Crantz.) yield in the major growing environments of India has been stagnating despite the development of high yielding varieties and increasing use of chemical fertilizers. On farm experiments were conducted to evaluate the performance of site‐specific nutrient management (SSNM). Field and crop specific NPK rates were calculated using quantitative evaluation of fertility of tropical soils (QUEFTS) model. The average 2‐yr yield advantage of SSNM over farmer fertilizer practice (FFP) was 7 Mg ha−1. The N agronomic efficiency increase of SSNM over FFP was 32 kg kg−1, the N recovery efficiency of SSNM was 0.14 kg kg−1 greater than that of FFP and the N physiological efficiency of SSNM was 54 kg kg−1 greater than that of FFP, whereas the partial factor productivity of SSNM was 148 kg less than that of FFP. Use of SSNM led to a reduction of fertilizer costs by an average of US$10 ha−1 crop−1 and an increase in gross return above fertilizer costs by $254 ha−1 crop−1 compared with FFP. Zone NPK recommendation maps and customized fertilizer blends were also developed. The results showed the potential of SSNM in significantly increasing yield and nutrient use efficiency of cassava. Future research is needed to validate the customized fertilizer blends and fine tune zone NPK recommendation maps which will help reduce the need for field specific modeling and intensive crop monitoring.

Site-Specific Nutrient Management under Rice-Based Cropping Systems in Indo-Gangetic Plains: Yield, Profit and Apparent Nutrient Balance

High fertilizer use efficiency in rice (Oryza sativa L.)-based cropping systems in Indo-Gangetic Plains (IGP) is not achieved because farmers’ fertilizer practices (FFP) and blanket state recommendations (BSR) do not take into account the site-specific variability of nutrient availability in the soil. We evaluated the site-specific nutrient management (SSNM) option against existing FFP, blanket state recommendation (BSR), improved BSR (IBSR i.e., 25 % higher than BSR), and state soil testing laboratory recommendation (STLR) in six pre-dominant rice-based cropping systems namely wheat–rice (W–R), mustard–rice (M–R), potato–rice (P–R), garlic–rice (G–R), chickpea–rice (C–R) and berseem fodder–rice (B–R) in terms of yield gain, economics, nutrient harvest index, soil fertility, and apparent nutrient balances. System rice equivalent yield (SREY) improved by 15.7, 9.5, 13.9 and 30 %, in SSNM over BSR, IBSR, STLR and FFP, respectively. SSNM involved additional cost of ₹ 2940–5291 ha−1 over BSR and ₹ 5492–10120 ha−1 over FFP under different cropping systems but contributed higher added net return of ₹ 23236–75056 ha−1 and ₹ 39577–143899 ha−1 over BSR and FFP, respectively. The output: input ratio and nutrient harvest index for N, P, K were also highest in SSNM. At the end of the experiment, soil available N, Olsen-P and available K content were either maintained or improved over their initial values in SSNM treatments, whereas soil available K in FFP declined by −1.65 % and increased over initial content in BSR and STLR in 0–15 cm soil profile depth. After three crop cycles, apparent N and P balances were positive in all the cropping systems and fertilizer treatments; only exception was a negative N balance in C–R and B–R systems in different fertilizer treatments. The apparent K balances were negative in all the cropping systems irrespective of nutrient management options. But, the magnitude of negative balance was lower in plots received SSNM treatment as compared to other nutrient management strategies, indicating a potential for improving yields, nutrient use efficiency and farm profit without deteriorating soil fertility in different rice based systems in IGP.

Site-Specific Nutrient Management for Rainfed Maize in Western Mid-Hills of Nepal

On-farm experiment was conducted in eight farmers’ field, of Khasyoli village development committee (952 to 1415 masl), Nepal, from April to September, 2011 to address the major constraint (nutrient management) to maize production through site-specific nutrient management (SSNM) as this approach is popular among scientists. The experiment comprised three nutrient omission plots (0N, 0P, and 0K), an ample NPK plot, and a farmers’ fertilization practice (FFP) plot, arranged in randomized complete block design. Farmers planted open pollinated variety (Manakamana-3) and managed in their way. Field-specific NPK application rates were calculated by considering nutrient demand, indigenous NPK supply and recovery efficiency of fertilizers. Grain yield in FFP (2.32 Mg/ha) and 0N (1.79 Mg/ha) plots differed significantly from each other and rest of the treatments, but was statistically similar among 0P (3.18 Mg/ha), 0K (3.40 Mg/ha) and ample NPK (3.38 Mg/ha) plots. Post-harvest grain and stover analysis revealed that indigenous NPK supply (20-71 kg N, 19-68 kg P2O5 and 51-164 kg K2O/ha) of soil vary among the farmers’ field. Moreover, soil was poor in indigenous N supply (42 kg/ha), but rich in indigenous P2O5 (35 kg/ha) and K2O (90 kg/ha) supply, on an average. As per the principles of SSNM, the initial fertilizer recommendation made can vary from 40-222 kg N, 0- 93 kg P2O5, and 0-50 kg K2O/ha. On an average, farmers may apply no or lower dose of P2O5 (18 kg/ha) and K2O (3 kg/ha) but need to significantly increase dose of N (143 kg/ha) fertilizer for enhancing soil and maize productivity.Int J Appl Sci Biotechnol, Vol 3(2): 227-231 DOI: http://dx.doi.org/10.3126/ijasbt.v3i2.12538

Efficiency Test of IRRI Fertilizing Recommendations on Rainfed Low Land Rice Field in West Kalimantan

Fertilizing recommendation for lowland rice field in West Kalimantan is still in national scale and tends to be excessive. It is less relevant due to various factors such as the test method competence, the carrying capacity of the land, and the diverse condition of rice field agro-ecosystem. Site-specific nutrient management (SSNM) is an approach for rice fertilizing on paddy plot based on science, history of land fertilization, and nutrient sources surrounding the area which can affect soil fertility level and soil conservation.This study was aimed to examine fertilizing efficiency of N, P, and K and the increased productivity of rice by utilizing software (website) of the IRRI. The study was conducted in farmers fields in two villages, i.e. Anjongan and Pak Bulu, Pontianak Regency, West Kalimantan. The results showed that the SSNM fertilization on rice increased yields by the average of 0.62 t ha-1 (13.47%) per growing season. The efficiency of SSNM fertilization was on the average of 22.05% N, 48.25% P2O5, and 31.50% K2O. The additional profits obtained from the SSNM recommendation was on the average of IDR 1,886,317 per ha pergrowing season compared to the profits from the FFP (farmer fertilizer practice).Keywords: Fertilizing efficiency, low land, rice, site specific fertilization [How to Cite: Muhammad H, M Syam and DP Widiastuti. 2014. Efficiency Test of IRRI Fertilizing Recommendations on Rainfed Low Land Rice Field in West Kalimantan. J Trop Soils 19: 25-33. Doi: 10.5400/jts.2014.19.1.25]

Effect of site-specific nutrient management on yield, profit and apparent nutrient balance under pre-dominant cropping systems of Upper Gangetic Plains

A field experiment was conducted on a Typic Ustochrept soil at Project Directorate for Farming Systems Research Modipuram (2904' N, 77046' E, 237m asl), for three consecutive years (2007-08 to 2009-10) to evaluate the sitespecific nutrient management (SSNM) option against existing farmers fertilizer practices (FFP), state recommendation (SR), improved SR (ISR) (i.e. 25% higher than SR), and soil testing laboratory recommendation (STLR) in six predominant wheat based cropping systems of Upper Gangetic Plains, in terms of yield gain, economics, nutrient harvest index, soil fertility, and apparent nutrient balances. SSNM improved system wheat equivalent yield over SR, ISR, STLR and FFP by 19%, 8%, 17% and 29%, respectively. SSNM involved additional cost of Rupees 5 097 to 7 938 /ha over SR and FFP under different cropping systems but it gave higher added net return of Rupees 13 649 to 58 776 /ha and Rupees 25 030 to 68 980 /ha over SR and FFP, respectively. The output: input ratio and nutrient harvest index were also highest in SSNM. At the end of the experiment, soil available N, Olsen-P and available K content were either maintained or improved over its initial values in SSNM treatments, whereas these parameters declined or marginally increased over the initial contents under FFP and SR in 0-15 cm soil profile depth. After 03-crop cycles, apparent N and P balances were positive in most of the cropping systems and fertilizer treatments, except a negative N balance was noticed in pigeonpea [Cajanus cajan (L.) Millsp]–wheat (Triticum aestivum L.) and groundnut (Arachis hypogaea L.)–wheat systems under SR and SSNM treatments. The apparent K balances were negative across all the cropping systems and nutrient management options but the magnitude was lower under SSNM.

Site-specific nutrient management in a bamboo forest in Southeast China

Site-specific nutrient management (SSNM) provides a field-specific approach for dynamically applying nutrients to crops on an as-needed basis. The demand for bamboo in China cannot be met despite increases in domestic production and yield in recent years. Further increases in bamboo yield and improve ecological environment, with good economic returns, are feasible in most favorable growth environments of China through relatively straightforward adjustments in crop and nutrient management. We created a SSNM system for bamboo forestry starting in 2009. The influence of SSNM on nutrient availability and characteristics of soil microorganisms in comparison to the current farmer fertilizer practice (FFP) in a bamboo (Phyllostachys pubescens) forest was investigated from January to December 2011. The results showed that SSNM, in comparison to FFP, increased the average bamboo yield by approximately 4.3%. Fertilizer N, P, and K levels, however, decreased by 55%, 8%, and 16%, respectively. Higher resin N, P, and K availability by using FFP compared to SSNM indicated an accumulation of inorganic nutrients during periods when the bamboo demand for nutrients is low. These nutrients were, therefore, prone to large losses via runoff. Resin nutrient availability was shown to be a good indicator of plant nutrient uptake but not yield. Moreover, the addition of chemical fertilizer altered the microbial biomass C and N, the total amount of PLFA was higher via SSNM (295nmol/g) than those via FFP (262nmol/g), indicating SSNM also increased soil microbial activity. Overall, the SSNM system was found to reduce nutrient release to the environment while maintaining bamboo yields and soil ecological environment.

Optimizing nutrient management strategies for rice–wheat system in the Indo-Gangetic Plains of India and adjacent region for higher productivity, nutrient use efficiency and profits

Rice (Oryza sativa L.)–wheat (Trititicum aestivum L.) system (RWS) in South Asia is under stress, as nutrient removals by crops are higher than their replenishment through fertilizers. We evaluated improved nutrient management strategies at 10 different locations across the Indo-Gangetic Plains (IGP) of India and adjacent regions during 2003–04 to 2005–06, and compared the improved practices in terms of yield gain, nutrient use efficiency and economic returns, with existing farmers fertilizer practices (FFP), and state recommended fertilizer rates by the government departments (SR). Improved N–P–K application rates were calculated by accounting for the indigenous nutrient supply (INS), yield target and crop nutrient demand as a function of the interactions between N, P and K. Compared with the SR and FFP, improved practices increased average grain yield from 0.32 to 3.03 t ha−1 and 1.37–3.69 t ha−1 in rice, and 0.49–1.17 t ha−1 and 0.71–2.26 t ha−1 in wheat across the locations, respectively. Added net return (in US$) from improved practices over FFP and SR under RWS ranged from 219.6 to 804.9 and from 104.3 to 599 ha−1, respectively. Compared to improved practices, PFPN under SR and FFP were lower by 18.9 and 38.3% in rice, and 18.5 and 39.5% in wheat, respectively. Omission of P and K from improved nutrient management schedule resulted in yield loss of 0.6–2.8 t ha−1 in rice, and 0.43–1.84 t ha−1 in wheat, respectively. The annual removal of native P and K in the respective omission plots ranged from 21.8 to 46.1 kg P ha−1 and from 158.4 to 349.1 kg K ha−1. Application of 26 kg P and 99 kg K ha−1 under improved practices had synergistic effect on nutrient use efficiencies viz. PFPN, AEP, AEK, REP and REK. Results suggested that optimised nutrient supplies considering crop nutrient needs and INS have potential for improving yields, nutrient use efficiency and profits in RWS. The improved nutrient management strategy used in this study could be used in larger domains for improving cereal productivity, nutrient use efficiency and farm profits.

Effect of fertilizer management on rice yield, soil organic carbon and total nitrogen based on utilizing the milk vetch

A four-year(2008–2011) long term experiment was carried out to study the effects of different chemical fertilizer management on rice yield,paddy economic benefits,total nitrogen(N) accumulation,soil carbon(C) and nitrogen under the utilization of milk vetch(22 500 kg/hm2).The results were as follows: ①Compared with farmers’ fertilizer practice(FFP),fertilizers application delayed appropriately could increase rice yields.Among all treatments,treatments of 20% or 40% chemical fertilizer cut down could only increase 2.37% and 3.34% grain yield respectively than that of combined treatment of basal fertilizer + tillering fertilizer + panicle fertilizer(the ratio was 3∶4∶3)(Treat1),which was followed by the treatment of basal fertilizer + tillering fertilizer + panicle fertilizer(the ratio was 0∶7∶3)(Treat2).②The appropriate postponed fertilizers application could increase rice output value.Treat1 could increase 3.0% average annual output value,followed by Treat2.③The fertilizers application time postponed could improve total nitrogen accumulation in rice(TNA),N grain production efficiency(NGPE),N partial factor productivity(NPF) and N harvest index(NHI).Treat1was the best one in improving TNA,NGPE,NPF and NHI among all treatments.④The retarded fertilizers application could also increase the content of soil organic carbon(SOC) and soil total nitrogen(TN).Treat1 had the best effect in improving SOC and TN.Through the above comparison,the appropriate retarded use of combined fertilizers,which was composed of 30% basal fertilizer + 40% tillering fertilizer and 30% panicle fertilizer was a better approach for increasing rice yield and for enhancing soil fertility under the condition of utilizing milk vetch.

Closing yield gaps in maize production in Southeast Asia through site-specific nutrient management

Rising incomes and changing dietary requirements are swiftly transforming maize (Zea mays L) in Southeast Asia from a food staple into an important industrial commodity. Increased maize production is required to meet rising demands, but additional production should come from the sustainable intensification of existing farmlands to minimize the undesirable effects of agriculture on the environment. We hypothesize that maize yields, profit, and N use efficiencies can be significantly increased through site-specific nutrient management (SSNM), thereby reducing yield gaps in the region. Through a combined approach of simulation modeling and on-farm research in at least 65 sites in 13 major maize-producing domains across Indonesia, Vietnam and the Philippines from 2004 to 2008, we were able to (a) quantify maize yield gaps and yield responses to fertilizer application, (b) evaluate the agronomic and economic performance of SSNM, and (c) evaluate the incremental profitability of SSNM in various production and grain and fertilizer price scenarios. The average exploitable yield gap between the attainable yield and current farmers’ yield in Southeast Asia was about 0.9tha−1. Yield responses to fertilizer application across the region followed the order N>>P>K. Yield response to N was higher in irrigated sites than in rainfed sites (6tha−1 versus 2tha−1), while P and K fertilizer responses were similar across production systems (<2tha−1). Yield with SSNM was 1.0tha−1 (+13%) higher than the current farmers’ fertilizer practice (FFP) measured in the same cropping seasons. Yield increases were associated with a 10% decrease in the average N rate, but with increased application of K at sites where the previous K rates were low. Average N use efficiency increased by 42%, mainly by adjusting the rates and timing of N application to the stages of crop development. Across all sites and seasons, profitability increased by US$167ha−1 per crop, which was equivalent to15% of the total average net return. Opportunities for achieving higher income over the FFP (≥US$100ha−1 season) were greatest in highly favorable rainfed environments; less favorable rainfed areas were vulnerable to unfavorable market prices. We conclude that SSNM has the potential to close existing yield gaps in the maize production systems of Southeast Asia by improving yield, nutrient use efficiency, and profitability.

Fertilizer Management For Wheat Crop In The Himalayan Piedmont Soil

An experiment was conducted at the farmers’ fields in the Himalayan Piedmont soil to evaluate the soil test based (STB) fertilizer dose on wheat crop practicing in the rice – wheat cropping sequence during the Rabi season 2002-2003. Three fertilizer treatments: (i) no fertilizer (control), (ii) local farmers’ fertilizer management practice (FP) and (iii) soil test based fertilizer dose (STB) were tested in 10 farmers’ fields. The soils of the test fields were acidic and light textured. Results showed that the control plot produced a mean yield of 1.54 t/ha, which increased to 3.96 t/ha with FP and 4.98 t/ha with STB fertilizer dose. The STB fertilizer dose also increased the nitrogen, P, K and S uptake by wheat. Wheat yield showed a strong linear relationship with N, P, K, and S uptake. Partial factor productivity (PFP) of fertilizer (sum of N, P, K and S) was 25.2 kg/kg in FP and that in STB was 24.6 kg/kg. Slightly lower PFP in STB than that of FP may be attributed to the higher dose of N and K in the former. However, the significant yield increase in STB compared with FP encouraged farmers to practice STB fertilizer application for wheat cultivation. Bangladesh J. Agril. Res. 38(2): 241-246, June 2013 DOI: http://dx.doi.org/10.3329/bjar.v38i2.15887