Evaluation of application timing in fertilizer micro-dosing technology on millet production in Niger,West Africa

Micro-dosing technology has been developed by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) and its partners to help subsistence farmers in the Sahel improve inorganic fertilizer application. However, the ICRISAT's recommendations regarding fertilizer application through this technology are only applicable at sowing and do not allow any flexibility in terms of labor and/or capital management. In rural areas, fertilizer cannot always be applied at sowing due to financial and labor constraints. The purpose of this study was to evaluate the effect of the timing of fertilizer application on millet production. A 2-year on-station experiment and a 1-year on-farm field experiment were conducted in the western region of Niger, West Africa. Even under the heterogeneous climatic conditions of the region during our experimental period, the results showed that the trend was the same as observed in previous studies: millet production improved through fertilizer application compared to the control (without fertilizer). The harvest index was also higher compared to that of the control. This increased production was consistently the same for all application timings. The marginal value–cost ratio on the investment calculated using a budgeting analysis for the on-farm experiment showed that – regardless of application timing – millet farmers who fertilized their fields with inorganic fertilizer made more profit than those who did not (control). This was also true for farmers who were unable to fertilize at sowing – delayed application was still the more profitable option relative to the no fertilizer control. Our results indicate that small subsistence farmers can be offered more options for inorganic fertilizer application timing using the micro-dosing technology. Delayed inorganic fertilizer application can help small farmers who are often labor constrained at the sowing period improve their yields as well as their economic returns.

A farm-level evaluation of nitrogen and phosphorus fertilizer use and planting density for pearl millet production in Niger

Mineral fertilizer use is increasing in West Africa though little information is available on yield response in farmers' fields. Farmers in this region plant at low density (average 5,000 pockets ha^–1, 3 plants pocket^–1), which can affect fertilizer use efficiency. A study was conducted with 20 farmers in Niger to assess the response of pearl millet [Pennisetum glaucum (L.) R. Br.] to phosphorus and nitrogen fertilizers under farm conditions. In each field, treatments included control, single superphosphate (SSP) only, SSP plus N (point placed near plant), and either SSP or partially acidulated phosphate rock (PAPR) plus N broadcast. N and P were applied at 30 kg N ha^–1 and 30 kg P₂O₅ ha^–1. Farmers were allowed to plant, weed, etc., as they wished and they planted at densities ranging from 2,000 to 12,000 pockets ha^–1. In the absence of fertilizer, increasing density from 2,000 to 7,000 pockets ha^–1 increased yield by 400%. A strong interaction was found between fertilizer use and density. Farmers planting at densities less than 3,500 pockets ha^–1 had average yields of 317 kg grain ha^–1 while those planting at densities higher than 6,500 pockets ha^–1 showed average yields of 977 grain ha^–1. Though phosphate alone increased yields significantly at all densities, little response to fertilizer N was found at densities below 6,000 pockets ha^–1. Significant residual responses in 1987 and 1988 were found to P applied in high-density plots in 1986. Depending on fertilizer and grain prices, analysis showed that fertilizer use must be be combined with high plant density (10,000 pockets ha^–1) or no economic benefit from fertilizer use will be realized.     

Climatic constraints to crop production and fertilizer use

The alarming food deficits projected for sub-Saharan African from recent production figures make it mandatory that no effort be spared in reversing the trend of declining yields. Developing better understanding of such climate-related constraints as high intensity storms, inadequate rainfall or poor rainfall distribution, high temperatures and high evaporative demands, excessive rainfall and high erodibility of soils will result in measures that can overcome or mitigate these constraints.     

Alleviating fertilizer policy constraints to increased fertilizer use and increased food production in West Africa

In sub-Saharan Africa, sustainable economic growth and development, food security, and fair income distribution are possible only if there is sustained growth in agricultural production. The influx of commercially imported or donated foodgrains has helped many governments to maintain a policy of low food prices, usually for the benefit of the vocal urban dwellers. Such practices tend to kill the incentive for increased local production of foodgrains or for the increase in the use of inputs needed to improve the productivity of the farming systems.High degree of state control in the handling of fertilizers, existence of subsidies which put undue strain on national treasuries, lack of good infrastructures, relatively small markets and poorly developed research and extension systems are some of the constraints that prevent the optimal use of fertilizers in West Africa.Overcoming the constraints requires total commitment by governments, collaboration with the private sector as well as with the donor community and the development of carefully thought-out fertilizer policy instruments. The various measures needed for an effective policy are interrelated and must be undertaken simultaneously to ensure success.     

Phosphorus seed coating increases phosphorus uptake,early growth and yield of pearl millet (Pennisetum glaucum (L.) R. Br.) grown on an acid sandy soil in Niger,West Africa

In pot and field experiments conducted in 1990 and 1991 on an acid sandy, phosphorus (P) deficient soil in Niger, West Africa, the effect of seed coating on seedling emergence, early growth and grain yield of pearl millet (Pennisetum glaucum (L.) R. Br.) was studied. Seeds of pearl millet were coated with different rates (0; 0.5; 1.0; 2.0; 5.0; 10.0 mg P seed^–1) and types of P fertilizers (single superphosphate, ammonium dihydrogen phosphate; monocalcium phosphate, sodium dihydrogen phosphate and sodium triphosphate). Seedling emergence was generally reduced at coating rates higher than 0.5 mg P seed^–1 and prevented with single superphosphate and sodium triphosphate at rates higher than 5 mg P seed^–1. No correlation was found between the pH and osmomolity of the coatings and final emergence of millet seedlings. The most favourable effect on plant growth and P content was achieved with ammonium dihydrogen phosphate (AHP) as seed coating. This was attributed to the enhancement effect of ammonium on P uptake. Compared to the untreated control dry matter production at 20 days after planting (DAP) was increased by 280%, P content per plant by 330%, total biomass at maturity by 30% and grain yield by 45%. Although seed coating with AHP may be harmful to seedlings emergence, it represents a suitable method to enhance early growth and increase yield of pearl millet.     

Efficient fertilizer use for increased crop production: The humid Nigeria experience

Fertilizer use in Nigeria, though growing, is still very low especially if considered in relation to the growing food needs of the country. Efforts have been made through scientific investigations to find ways of increasing fertilizer use efficiency in the humid zone of the country. Investigations have been carried out mainly on nitrogen, phosphorus, potassium, mixed and compound fertilizers. The secondary nutrients sulphur, calcium and magnesium as well as the micronutrients have received comparatively little attention. In the Southeastern humid zone, a considerable effort has been made to solve the problem of soil acidity through liming. Interaction of the primary nutrients under field conditions has not been investigated sufficiently.Results of experiments carried out on comparisons of P sources, urea placement methods and interaction of N, P, K, S fertilizers in the Ultisols of Southeastern Nigeria show that single superphosphate was superior to Togo phosphate rock, partially acidulated Togo phosphate rock, and diammonium phosphate for the production of maize. Methods of application of urea did not significantly affect maize grain yield. There was no significant interaction of N, P, K, S in the Ultisol but S was limiting. An application of a minimum of 45 kg/N/ha appears to be threshold for positive response to P by maize stover. More effort is needed to understand nutrient interaction in the Ultisols which are dominant in the humid Southern zone of Nigeria.     

Nutrient cycling practices and changes in soil properties in the crop-livestock farming systems of western Niger Republic of West Africa

Pearl millet [Pennisetum glaucum R. (Br.) L.] is grown in West Africa on sandy, acid soils deficient in plant nutrients. In the mixed farming systems of western Niger, livestock graze millet stover by day and deposit dung and urine directly on cropland during overnight kraaling. Kraaling of livestock is perhaps the most important pathway to recycle nutrients and sustain soil fertility. Three tillage practices (immediate tillage, late tillage and no till) four amendment types (dung-plus-urine, dung alone, millet stover and millet stover ashes), and three fertilizer N rates (0, 15 and 30 kg N ha^–1) were factorially combined and arranged in a split plot design. Average millet grain yield in immediate till plots was 30% higher than in no-till plots and was 13% greater in plots amended with dung-plus-urine than in plots that received manure alone. The highest pH (5.8) and lowest bulk density 1.46 g/cm³ of surface soil were measured in plots amended with dung-plus-urine. Under the less nomadic livestock management system, where animals are mostly stall-fed, technology is needed to capture and transfer nutrients in animal urine to farmers' fields for cropping.     

Effect of planting technique and amendment type on pearl millet yield, nutrient uptake, and water use on degraded land in Niger

Due to increased population pressure and limited availability of fertile land, farmers on desert fringes increasingly rely on marginal land for agricultural production, which they have learned to rehabilitate with different technologies for soils and water conservation. One such method is the indigenous zai technique used in the Sahel. It combines water harvesting and targeted application of organic amendments by the use of small pits dug into the hardened soil. To study the resource use efficiency of this technique, experiments were conducted 1999–2000, on-station at ICRISAT in Niger, and on-farm at two locations on degraded lands. On-station, the effect of application rate of millet straw and cattle manure on millet dry matter production was studied. On-farm, the effects of organic amendment type (millet straw and cattle manure, at the rate of 300 g per plant) and water harvesting (with and without water harvesting) on millet grain yield, dry matter production, and water use were studied. First, the comparison of zai vs. flat planting, both unamended, resulted in a 3- to 4-fold (in one case, even 19-fold) increase in grain yield on-farm in both years, which points to the yield effects of improved water harvesting in the zai alone. Zai improved the water use efficiency by a factor of about 2. The yields increased further with the application of organic amendments. Manure resulted in 2–68 times better grain yields than no amendment and 2–7 times better grain yields than millet straw (higher on the more degraded soils). Millet dry matter produced per unit of manure N or K was higher than that of millet straw, a tendency that was similar for all rates of application. Zai improved nutrient uptake in the range of 43–64% for N, 50–87% for P and 58–66% for K. Zai increased grain yield produced per unit N (8 vs. 5 kg kg⁻¹) and K (10 vs. 6 kg kg⁻¹) compared to flat; so is the effect of cattle manure compared to millet straw (9 vs. 4 kg kg⁻¹, and 14 vs. 3 kg kg⁻¹), respectively, Therefore zai shows a good potential for increasing agronomic efficiency and nutrient use efficiency. Increasing the rate of cattle manure application from 1 to 3 t ha⁻¹ increased the yield by 115% TDM, but increasing the manure application rate further from 3 to 5 t ha⁻¹ only gave an additional 12% yield increase, which shows that optimum application rates are around 3t ha⁻¹.     

Effect of intensive cropping and fertilizer use on the crop removal of sulphur and zinc and their availability in soil

In a long-term field experiment, involving multiple cropping (pearl millet-wheat-cowpea) and use of fertilizer based on soil tests for a slightly alkaline alluvial soil, an attempt has been made to examine the pattern of crop removal of sulphur and zinc and their availability in the soil during a 7 to 8 year period. Additions of nitrogen (N) and phosphorus (P) enhanced the sulphur uptake over the control and treatment N, by 60.8 and 23.4% respectively. Both sulphur (through superphosphate) and farm manure raised the removal of S to the same extent. NPK applied at 50, 100 and 150% of the optimum recommended dose showed an increase of 63.2, 26.5 and 17.1% respectively, over control, 50 and 100% level of application. Treatments N, NP and NPK promoted the uptake of zinc by 67.4, 23.4 and 14.0% over the control, treatment N and treatment NP respectively. An increase of 7.1 and 17.7% in Zn uptake was noticed with farm manure and zinc sulphate incorporations. As has been seen in the case of sulphur, graded doses of NPK showed respective increases of 49.8, 27.0 and 8.6% in Zn removal. There was a marked depletion by 54.8 to 67.1% in available S in soil in all the treatments except the one where sulphur was being supplied every year. Without zinc being added, the extent of decrease in Zn in soil ranged from 18.9 to 30.6%. Addition of zinc improved the availability by 128.0% over the initial status.     

Effects of phosphorus on yield of cowpea cultivars intercropped with pearl millet on Psammentic paleustalf in Niger

Phosphorus (P) is the most limiting soil nutrient in the sandy soils of Niger and farmers rarely use chemical fertilizers in producing pearl millet and cowpea. A 3-yr study was conducted in farmer's fields at two locations in South Western Niger to investigate yield response of six cowpea cultivars to applied P-fertilizer (0, 8, 16 kg ha^–1) when intercropped with millet. Significant yield differences were found between cultivars for their seed and dry fodder yield at all rates of applied P. Cultivars responded differently to the application of P. Millet grain was more than doubled with the addition of 8 to 16 kg P ha^–1. Cowpea cultivars did not have significant differential effect on millet yields. Cowpea cultivars differed significantly in the accumulation of P in fodder with the highest yielding cultivars taking up more P than the low yielding ones. The results have important implications for breeding and selection of cowpea cultivars that are adapted to a range of fertility levels.Submitted as Journal Article No. 1211 of ICRISAT.     

Improving fertilizer recommendations for subsistance farmers in West Africa: The use of agro-economic analysis of on-farm trials

A large number of zero, half and full rate fertilizer trials were conducted on-farm in Southern Senegal with rainfed lowland rice (n = 24), maize (n = 48), and groundnuts (n = 18). Trial sites were located according to farmer selected criteria: soil texture in the case of rice; compound garden versus outer field in the case of maize; and, previous cropping history in the case of groundnuts. Quadratic fertilizer response curves using all the cases explained only 16–29% of the variance. Subsequent stratification of the fields by soil organic matter, texture, and pH permitted the identification of fertilizer responsive and non-responsive fields. Response curves using only the tests conducted on soils without a limiting constraint explained 36 to 47% of the variance. At half rate fertilization levels VCR's of 3.8 (maize), 5.8 (rice) and 6.9 (groundnuts) resulted. Within productive fields, level of weed control, percent barrenness and final stand at harvest explained much of the remaining variation in yields for rice (82%), maize (61%) and groundnuts (76%) respectively. Response curves were then used in an economic analysis to address on-farm fertilizer allocation issues. Based on survey results and field trial data, partial budgets for small and medium-sized farms were developed. This analysis showed marginal rates of return of 400 and 165 percent to half and full rate fertilization, respectively. This type of fertilizer validation program, conducted on farmer-selected sites, improved targeting of recommendations, and helped to identify agronomic practices that should result in reduced economic risk and increased fertilizer adoption by farmers.Research for this paper was conducted at the Institut Senegalais de Recherches Agricoles, and was supported by USAID Projects No. 685–0223 and No. 685–0205.     

Overcoming soil nutrient constraints to crop production in West Africa: Importance of fertilizers and priorities in soil fertility research

The Alfisols, Oxisols, Ultisols and Inceptisols which dominate the soils of West Africa have sustained crop growth for a very long time. As a consequence, their fertility has become perilously low and the task of increasing or even maintaining the productive capacity of these soils has become perhaps the greatest challenge to agricultural scientists in this latter half of the 20th century.Water is useful not only for the growth of plants but also for the efficient use of costly inputs such as fertilizers. On the other hand, fertilizers increase the water-use efficiency. Such interactions must be closely studied so as to maximize the impact of inputs of agricultural production.The nutrients in the soil are always in a state of flux, with additions and subtractions. Monitoring the dynamics of the nutrients would promote their efficient use by crops and prolong the productive life of the soils.Several models currently exist for the study of organic matter dynamics in soils. These models should be applied to the West African situation since it is vital to develop management practices that can promote efficient use of nutrients released during mineralisation of soil organic matter.Judicious fertilizer use in West Africa should be promoted as this practice will enhance agricultural production while protecting the fragile environment.     

Improving nutrient use efficiency from decomposing manure and millet yield under Plinthosols in Niger

To improve synchronicity between nutrients released from the decomposing manure with millet nutrient requirement under zaï technique, a 2-year field experiment was conducted at the International Crops Research Institute for the Semi-Arid Tropics Research Station, Sadoré, Niger. The treatments consisted of factorial combination of two rates of cattle manure (200 and 300 g per zaï hole), three periods of manure application (before planting, at planting and 15 days later) and two rates of mineral fertilizer [nitrogen (N), phosphorus (P) and potassium (K) 15–15–15] applied at 6 g per zaï hole and a control, without mineral fertilizer). Manure dry mass losses did not significantly differ among manure application periods in 2013. However, in 2014 the highest manure dry mass loss occurred when manure was applied before planting with 70% of manure applied being decomposed at millet maturity stage (115 days after litterbag installation) followed by manure applied at planting with almost 50% of dry mass losses. The quantities of N and P absorbed by millet at tillering stage represented, 61, 52 and 33% of N released and 15, 12 and 15% of P released at the same time when manure was applied before planting, at planting and 15 days after planting, respectively. Application of manure before planting increased on an average millet grain yield by 16 and 20% and N utilization efficiency by 25 and 31% compared to application of manure at planting and 15 days after planting respectively. Addition of mineral fertilizer induced a synergetic effect on millet grain yield (p = 0.002). Millet grain yields increased on average by 5, 17 and 57% when 6 g per zaï pit of NPK fertilizer were added to plots receiving manure application before planting, at planting and 15 days after planting, respectively. We conclude that application of manure prior to planting satisfies better millet nutrients demand, thereby increasing nutrient use efficiency and grain yield under zai pits.     

Nutrient release dynamics from decomposing organic materials and their mulching-effect on pearl millet yields in a low-input Sahelian cropping system

Organic material inputs for increased crop yields are insufficient in the Sahelian West Africa. There is a need for diversifying organic amendment sources for improved nutrient supply in low-input cropping system. The 2-year study aimed to (1) explore the rates of mass losses and nutrient release dynamics from Acacia tumida prunings (AT) and millet straw (MS) under field conditions, (2) assess termite’s contribution to the decomposition of AT and MS, and (3) ascertain the mulching-effect of these organic materials on pearl millet yields. The study was conducted in Niger using field experiment and litterbag methodology and the data modelled using single exponential decay equations. Under field conditions, mulching with AT and MS increased millet grain yield by 35 and 33%, respectively compared to control. The harvest index (HI) in 2014 increased by 21% compared to that obtained in 2013 with the highest HI being recorded for the AT mulched treatment. The results from litterbag experiment indicated a greater dry mass losses from MS decomposition in 2013 whereas relatively higher mass losses were recorded from AT decomposition in 2014. The differences in mass losses among the organic materials could be related to the interaction of soil moisture dynamics and termites’ population which are positively correlated with mass losses. The contribution of termites to the decomposition was estimated to be 36% for MS and 8% for AT. In 2013, at 126 days after litterbags placement, the amounts of N, P, and K released from MS were 16, 1, and 25 kg ha^?1 of initial nutrient applied, respectively compared with the 22, 1, and 23 kg ha^?1 recorded from AT treatment. During the same period in 2014, the total amounts of N, P and K released from MS were 15, 0.6, and 29 kg ha^?1, respectively compared to the 32 kg ha^?1 of N, 1 kg ha^?1 of P, and 29 kg ha^?1 of K released from the AT treatment. The intrinsic organic material quality could explain markedly the variation in nutrient released among the organic material. These results indicate that Acacia tumida prunings have a potential to provide nutrient through mineralization for enhanced crop yield in the Sahel.     

Leaching of nitrate,calcium and magnesium under maize cultivation on an oxisol in Togo

In tropical regions, crop yields generally decrease with time, partly due to a decline in the levels of exchangeable bases linked to acidification of the upper layers of the soil. Nitrogen, calcium and magnesium balances were studied on an oxisol in southern Togo under continuous maize cropping with mineral fertilization and crop residue return, by measuring inputs and outputs.The balance was near equilibrium for nitrogen (urea dressing, 120 kg N ha^–1 y^–1) and negative for calcium and magnesium. Leaching represented between 29% and 85% of the total output for nitrogen and accounted for practically all the calcium and magnesium outputs.In the upper horizons, nitrate, calcium and magnesium contents in the soil solution were correlated. This was interpreted as an exchange between the calcium and magnesium ions adsorbed on the soil and the protons released by the transformation of ammonium into nitrate. The nutrient content of the soil solution increased in the case of no potassium fertilization, probably because of a lower nitrogen immobilization by microorganisms, the crop residue yield being reduced by the induced deficiency. An insufficient potassium fertilization increases leaching losses of calcium, magnesium and nitrogen.In the deeper horizons, the nitrate content of the soil solution was not correlated with the calcium and magnesium contents. Nitrogen was probably taken up by roots and some calcium and magnesium ions exchanged during their transport through the soil.     

Efficient fertilizer use for increased crop production: The Liberia experience

Work on soil fertility in Liberia (situated between 4° and 9° N Latitude and 7° and 12° West Longitude) since 1954 has been reviewed. The dominant soils in Liberia are highly leached and acidic Ultisols. Nitrogen and phosphorus, in that order, are the two most limiting nutrients in these soils which are dominated by 1.1 lattice clays. Many of the earliest trials showed that crops responded positively to the use of fertilizers. However, little or no work was done on the economics of fertilizer use in Liberia. Results of field trials conducted in collaboration with the International Fertilizer Development Center at two locations showed significant response to phosphorus. More work is necessary in order to study the residual effects of different P fertilizer sources as well as the economic optimum levels for P fertilizer application. Inspite of the fact that the soils are very acid, lime applied at the rate of 2t/ha had no effect on crop yield. Because of the heavy rainfall, leaching of nitrates is suspected. However, there is need to conduct research on ways to improve N-use efficiency of both upland and lowland crops.     

Alleviating soil fertility constraints to increased crop production in West Africa: The experience in the Sahel

Lack of moisture limits crop production in semi-arid west Africa but poor soil fertility is a more serious constraint in the long run. Work done by IFDC and ICRISAT showed that phosphorus is the most limiting nutrient although response by millet to nitrogen when moisture and P are non-limiting can be substantial. A summary of the results of field trials in Niger showed that the sufficiency level for P estimated by regression analysis on the basis of Bray 1 extractable P is 7.9µg P/g of soil for 90% of maximum yield of millet. Application of 15–20 kg P/ha was usually adequate for optimum yields. Matam phosphate rock (PR) from Senegal, Tilemsi PR from Mali and Tahoua PR from Niger which are medium reactive were found to be suitable for direct application while partial acidulation (50% with sulfuric acid) of the less reactive phosphate rocks resulted in products with similar agronomic effectiveness as commercial superphosphates. Tests conducted by farmers showed that millet yields can be increased by more than 250% by the use of fertilizers. The need for constant monitoring of the crop needs for sulfur and potassium under continuous cultivation was highlighted.     

Impact of inorganic fertilizer availability on land use and agricultural production in the Fifth Region of Mali

An interactive multiple goal linear programming model has been developed for analysis of agricultural development options in a semiarid region in Mali. Natural and human resources have been quantified, constraints identified and the relations between agricultural activities described explicitly at both regional level and the level of agro-ecological zones.Animal husbandry and cropping system have been defined in a target-oriented way taking into account quantified aspects of sustainability. For crops this implies the requirement that the amounts of the macronutrients N, P and K in the rootable layer of the soil are safeguarded in the long run by nutrient applications. External inputs to realize predetermined target yields have been specified to compile quantitative input-output tables.Goals and goal-variables to be optimized in the model have been defined after consultations with various stakeholders in the region. Goal restrictions have been established through the interactive approach of the model.     

Crop residue,manure and fertilizer in dryland maize under reduced tillage in northern China: I grain yields and nutrient use efficiencies

The rapidly increasing population and associated quest for food and feed in China has led to increased soil cultivation and nitrogen (N) fertilizer use, and as a consequence to increased wind erosion and unbalanced crop nutrition. In the study presented here, we explored the long-term effects of various combinations of maize stover, cattle manure and nitrogen (N) and phosphorus (P) fertilizer applications on maize (Zea mays L.) yield and nutrient and water use efficiencies under reduced tillage practices. In a companion paper, we present the effects on nutrient balances and soil fertility characteristics. The ongoing factorial field trial was conducted at Shouyang Dryland Farming Experimental Station in northern China from 1993 onwards. The incomplete, determinant-optimal design comprised 12 treatments, including a control treatment, in duplicate. Grain yields and N, P, and potassium (K) uptakes and N, P and K use efficiencies were greatly influenced by the amount of rain during the growing season (GSR), and by soil water at sowing (SWS). There were highly significant interactions between GSR and added stover and manure, expressed in complex annual variations in grain yield and N, P and K use efficiencies. Annual mean grain yields ranged from 3,000 kg ha⁻¹ to 10,000 kg ha⁻¹ and treatment mean yields from 4,500 kg ha⁻¹ to 7,000 kg ha⁻¹. Balanced combination of stover (3,000–6,000 kg), manure (1,500–6,000 kg) and N fertilizer (105 kg) gave the highest yield. Stover and manure were important for supplying K, but the effects differed greatly between years. Overall mean N recovery efficiency (NRE) ranged from 28% to 54%, depending on N source. NRE in wet years ranged from 50% to 90%. In conclusion, balanced combinations of stover, manure and NP fertilizer gave the highest yield and NRE. Reduced tillage with adding stover and manure in autumn prior to ploughing is effective in minimizing labor requirement and wind erosion. The potentials of split applications of N fertilizer, targeted to the need of the growing crop (response farming), should be explored to further increase the N use efficiency.