Paper Number 4

Plant nutrition management for better
farmer livelihood, food security and environment*

Salahuddin Solaiman
Agriculture and Food Section,
Planning and Development Division, Islamabad-Pakistan
and
Nisar Ahmad
National Fertilizer Development Centre, Islamabad-Pakistan

1. Introduction

Agriculture is the dominant sector of the economy and accounts for 23 percent to the Gross Domestic Product (GDP) of the country. It employs 42 percent of the total workforce. Agriculture serves as a major supplier of raw materials to the industry as well as market for the industrial products. It also contributes substantially to Pakistan’s export earning. Almost 67.5 percent of country’s population are living in rural areas and are directly or indirectly linked with agriculture for their livelihood. Agriculture sector has grown at an average rate of 4.5 percent per annum during the decade of the 1990s (GOP, Eco. Survey, 2005). However, in the first two years of the new millennium (2000-2002). Pakistan witnessed crippling drought which seriously affected agriculture lands and productivity. As a result, the overall agricultural growth turned negative for these two years but recovered gradually during the next two years (2002-2004) and witnessed a modest recovery.

A strong performance of agriculture has been one of the hallmarks of the fiscal year (FY) 2004-05, with growth reaching as high as 7.5 percent on account of unprecedented increase in cotton production (14.6 million bales) and a near bumper wheat crop of the size 21.1 million tonnes. Major crops account for 37.1 percent of agricultural value added, minor crops 12 percent and livestock 46.8 percent.

Greater reliance is placed in achieving higher per unit production within a water constrained environment. Another dimension to the whole scenario of agriculture performance is the climatic change that to a great extent will determine the type, magnitude and productivity of Pakistan’s agriculture. The economics and technical feasibility of high input-output agriculture will come to test when all these emerging trends are taken into account simultaneously. Besides availability of water, the other factors hampering growth of sector are low productivity, inefficient use of water, degradation of land resources, ineffective transfer of technology and inefficient and unbalanced use of fertilizers.

The current population of the country is about 153 million, increasing at 1.87 percent per annum. At this trend total population will reach 167 million by year 2011 and 194 million by 2020 (NIPS, 2005). Thus the main objectives of agriculture in the medium term development framework (MTDF, 2005-2010) is to achieve self-reliance in agriculture commodities, ensure food security and maintain average annual growth rate of 5.2 percent per annum. Among other strategies, the efficient, balanced and optimum use of chemical fertilizers along with organic and biosources will play a vital role to achieve crop production targets for food security and improving livelihood of small farmers.

2. Small farmers’ livelihood in Pakistan

Despite all developmental efforts, Pakistan is facing many difficult challenges. One third of the population still lives below the poverty line. The literacy rate is about 54 percent, access to quality education is limited, income and regional inequalities are widespread, skill shortages are taking a toll in the economy’s productivity including agriculture. Based on the last Pakistan Integrated Household Economic Survey (PIHES) 2000-2001, the official poverty line is estimated at Rs.748 consumption expenditure per month per capita. Poverty estimates based on official poverty line suggest that the poor accounted for 32.1 percent of Pakistan’s population in 2000-2001. Poverty estimates show a higher incidence of poverty in Pakistan’s rural areas. In 2000-2001, rural and urban poverty is estimated at 38.99 percent and 22.67 percent, respectively. The Government of Pakistan has set a target for reducing the overty up to 21 percent by 2009-2010 and 13 percent by the end of 2015. (Pakistan Millennium Development Goals 2005, Government of Pakistan).

Among all poor communities in Pakistan, the farmers and particularly small farmers are at worst in their livelihood. They are deprived of most of the basic facilities. The reasons for miserability of small farmers are having less land holding and consequently low income, in spite of getting the higher productivity.

The most serious inequities at present exist in the rural areas mainly because of the pattern of land ownership. Despite three land reforms (in 1959, 1972 and 1977), the land distribution in Pakistan is much skewed. The skewed distribution of landholdings has not only adversely affected the access of the rural poor to basic production resources, but also cropping intensity and consequently farm productivity. Farms less than 5 hectare in size account for about 85.7 percent of farmers’ owned only 43.4 percent of the total farm area. On the other hand, large farmers of more than 10 hectare comprised only 5.5 percent of all farmers account for 37.5 percent of the total farm area (Table 1).

This basic inequity in land holdings is clearly reflected in the differences in their respective economic and social positions as in the case in other economic sectors. The larger landowners have more access to water, credit, fertilizer and other resources.

Table 1. Land distribution by farm size

In contrast to this situation, when input use, particularly fertilizers and aggregate productivity at national level is viewed with respect to farm size, an inverse relationship is quite evident. Fertilizer use adoption by farm size is higher in small farmers in comparison to large farmers. It was found that small farms’ aggregate productivity in term of gross output value per cultivated hectare was higher (Fertilizer Use Survey at Farm Level in Pakistan, NFDC – March 2000).

Despite high use of inputs and better productivity the small farmers have little surplus to market and farm income not sufficient to sustain livelihood. There is need to diversify and tap other sources of income other than crop sector such as livestock, etc. Most of the small farmers are unable to use the facility of concessional credit because of cumbersome procedures for transacting a bank loan. Even within the small farmer category there is a case for improving the condition of the poorest of the poor.

3. Soil fertility status

The cultivated soils are calcareous and alkaline with pH 7.0 to 8.5. The data generated by public and private sector research organizations in the country reflect the general agreement about the deficiency of nitrogen (N) in all the soils. In case of phosphorus (P) more than 9 percent soils have inadequate soil phosphorus or can be called deficient. In case of potassium, the picture is not as clear as in case of N and P. The reports state the deficiency of potassium (K) exist up to 40 percent in soils, but crop responses to K are erratic and potash use is negligible. Among micronutrients, field-scale deficiencies of economic significance prevail in case of Zn, B, and Fe. The organic matter content of the majority of cultivated lands averages around 0.5 percent. About 84 percent soil samples analysed have shown that organic matter content is very low (Ahmed and Rashid, 2003).

4. Fertility supply

4.1 Domestic production

There are 14 fertilizer plants in the country. Of these, 8 are Urea plants, 2 of single superphosphate (SSP) and one each of Calcium Ammonium Nitrate (CAN), Nitrophos (NP), Diammonium Phosphate (DAP) and NPK. The present fertilizer production capacity and actual production is given in Table 2. Urea plants have performed well, producing 110.6 percent of capacity during 2004-05.

Table 2. Existing fertilizer capacity and actual production (’000 tonnes)

4.2 Imports

Despite a very large production base, the country is not able to meet its entire fertilizer requirement. Annual import of fertilizer products is around 1 352 thousand tonnes (Table 2). All fertilizer was imported by private sector except Urea. Imports in 2004-2005 are higher by 10.9 percent due to additional import of Urea.

Table 3. Fertilizer imports (’000 tonnes)

5. Fertilizer consumption

The nitrogen (N) consumption in Pakistan has increased more rapidly, than phosphate (P₂O₅) and potash (K₂O) fertilizers during last 40 years (Figure 1). This fast increase in nitrogen can be attributed to a variety of economic and technical factors. Urea which is the main source of nitrogen was cheaper, locally available and provides rapid crop response. Comaratively, phosphate and potash fertilizers were imported and expensive. This promoted imbalance use.

It is also important to look at the fertilizer products, through which the nutrients are supplied (Table 4). Total consumption (here the off take is used as an indicator for consumption) has increased rapidly over a relatively short period from 3.4 million tonnes in 1985/1986 to more than 7.0 million tonnes in 2004/05. Urea is the most important nitrogenous fertilizer (46 percent N) with a fast growing trend, reaching 5.1 million tonnes (product) consumption in 2004/2005 followed by DAP.

Figure 1. Total fertilizer nutrient consumption in Pakistan

Table 4. Fertilizer off take (equals consumption) by products in ’000 tonnes

5.1 Consumption per hectare of cropped area

The application of plant nutrients per hectare of cropped land gives an indication of the intensification of agricultural production. Increase in arable land has been very marginal due to the natural limitations and conditions. Increase in agricultural production had to be achieved through higher yields per hectare. One of the underlying factors was steady increase from a level of about 20 kg/ha in early 1970’s to 161 kg/ha in 2004-2005. The increase in total application can be attributed largely to nitrogen, and to a lesser degree of phosphates (Figure 2).

The development in fertilizer consumption can be seen as a success. But what has been of concern is the fact that only the consumption of N has increased, leaving the use of other nutrients at a very low level. Since crops take the necessary nutrients mainly from soil resources, a depletion of these reserves could be termed as soil mining. In the long run, a decrease in soil fertility with additional negative effects on the environment is to be expected. Table 5 indicates the extent of stagnation in imbalance which has stayed over the past years. Balanced crop nutrition requires the proper supply of N, P and K plus other nutrients such as sulphur and micronutrients (Zn, B, Fe), as determined by soil analysis.

Figure 2. Application rate in kg per ha nutrients

The fertilizer consumption has grown at compound rate of 4.2 percent per annum, whereas growth in major crops was less than 2 percent. The N:P₂O₅ ratio did not change during the past 20 years. The application of potash was negligible.

Table 5. Fertilizer use and crop yields

5.2 Impacts of balanced fertilizer use

Balanced fertilizer use is a key for efficiency and crop productivity. The comparison of yield for major crops obtained from current farmer’s practices of fertilizer use and with balanced mix is given in Table 6.

Table 6. Crop yield comparison with current farmers' practices of fertilizer use vs obtained with balanced recommended level (kg/ha)

Thus, the present yield obtained by farmers is about 40-70 percent of that which can be obtained with recommended rates and balance use. It is, therefore, impotant to correct the balance.

6. Fertilizer demand

The quantum of fertilizer growth will depend upon water availability, and any increase in area and commodity prices received by farmers. In the next five years Urea imports may reach 1.4 million tonnes if no new capacity is added and DAP imports will be 1.6 million tonnes (Table 7). The proposal for BMR in the existing Urea plants and new investment is under consideration subject to availability of gas. However, it appears Urea and DAP imports will continue in the next 3-4 years.

Table 7. Future demand forecast ('000 tonnes)

7. Soil nutrient balance and flow analysis

A nutrient balance sheet gives the net changes in the crop environment over a given period: a season, a year, or longer. It is constructed by placing together all the additions to the crop environment and all the removals from that environment in the period studied. A comparison of additions and removals gives the nutrients balance. If the balance is positive it indicates that the crops produced, together with other removals are not depleting the soil. However, an excessive positive balance may represent over-fertilization, a waste of nutrients.

Negative balance means that the nutrients provided from all sources are not sufficient to support crop (and other) nutrient removal and therefore usually represent a drain on the soil. Repeated negative balances lead to real soil depletion to the point where crop yields decline. In such situation, restoration of soil fertility is indeed difficult.

Crops remove quantities of all nutrients, including the secondary and micronutrients, but additions often do not supply the whole range. In Pakistan, the two principal fertilizers Urea and DAP do not provide appreciable quantities of any nutrients other than N and P₂O₅. Farmyard Manure (FYM) contributes all nutrients to some extent. The green manure and biological sources only introduces N from external sources (air); all else comes from the soil. The balance sheet works out on these assumption: (FAO, 1996).

The present report considers fertilizer application to be reflected in off take data. FYM data are estimates based on limited livestock surveys, estimated FYM proportion (25 percent) recovered for manure (and not fuel or lost), dung and urine production. BNF has been calculated from measured N fixation by pulses, and the figure doubled to account for berseem clover, for which no N fixation data were found.

Irrigation water is an important aspect of crop nutrition in Pakistan, as it is actually a dilute solution of cations and anions. The K contribution in normal irrigation is substantial, overestimates of K supply, particularly when groundwater is major source.

Crop production figures were used to calculate nutrient removals in Pakistan. This is because all crop residues are normally used for animal feed, fuel, house roofing and other purposes. The set of conventional uptake efficiency percentages used in the calculations are set out below (FAO, 1998):

Based on these assumptions at national level there is negative balance of about 18 kg N, 25 kg P₂O₅ and 50 kg K₂O per ha. However, if data are further disaggregated there is positive balance of N in cotton zone. However, trend shows that depleting of soil is continuing despite improvement in fertilizer use.

8. Integrated Plant Nutrient Management (IPNM) concept

The basic concept underlying the principle of Integrated Plant Nutrient Management (IPNM) is the maintenance and possibly increase of soil fertility for sustaining increased crop productivity through optimizing of all possible sources, organic and inorganic, of plant nutrients required for crop growth and quality in an integrated manner appropriate to each cropping systems and farming situation within its ecological social and economic possibilities (FAO, 1995; Tandon and Roy, 2004).

Integrated Plant Nutrition System is a conceptual approach and is imbedded on a philosophy of social, economical, environmental and technological considerations, while Integrated Plant Nutrient Management (IPNM) is actually the technical and managerial aspects of achieving the objectives of IPNS under farm situation. Soil fertility improvement following the IPNS approaches will:

• Raise soil productivity and food production, and will ensure food security at local level;
• Enhance resilience of the land to erosion and degradation;
• Enhance soil and agrobiodiversity;
• Enhance soil capacity to sequestrate carbon and mitigate the effect of climate change; and
• Ensure prosperity and healthy environment for the future generation. (Roy, 2000)

9. Components and technology

Agricultural research contributes towards component and technologies governing principle of crop production and of plant nutrition. Field research fills gaps and generates knowledge which is translated into extension messages and disseminated to farmers. The main components of integrated plant nutrient management are (i) soil (ii) balance and efficient use of mineral fertilizers (iii) organic fertilizer sources (iv) green manures (v) biofertilizers, and (vi) industrial waste and city garbage. These are briefly discussed in the follow up sections with their relevance to Pakistan conditions.

9.1 Soil resources

Soil supplies all the known essential plant nutrients. However, due to crop intensification and cultivation of soils over the years there is continuous mining of the essential plant nutrients from the soil. Most of the soils in Pakistan have poor status of available plant nutrients and can not supply optimum level for crop productivity. Soil fertility is dpleting due to mining of essential plant nutrients. However, through good tilth and physical condition of soil, the nutrient availability can be improved.

9.2 Chemical fertilizers

Balance and adequate use of chemical fertilizers is very important component of technology. It has been discussed in detail in Section 5.0.

9.3 Farmyard Manure (FYM)

FYM consists of materials collected from animal droppings, beddings, and domestic sweep. The value of animal manures has been recognized since ancient times. Based on number of animals, the estimated contribution is shown in Table 8. However, it may be stated that about 50 percent of animal dropping is not collected. Of the collected about 50 percent is used as fuel. Thus, nutrients recycled to crops are about 1/4^th of the total droppings.

Table 8. Livestock population, production of manure, and nutrient potential of manure in Pakistan

9.4 Green manures

Green manuring with N-fixing leguminous crops improves soil fertility (Buresh et al., 1993) and enhances availability of other nutrients (Hundal et al., 1988; Nagarajah et al; 1989). The prominent cropping systems in Pakistan are:

1. Rice-wheat
2. Cotton-wheat
3. Mixed cropping (sugarcane-maize-wheat-cotton)
4. Oilseed-pulses-wheat

The three cropping systems i) rice-wheat, ii) cotton-wheat and iii) mixed cropping are very exhaustive. The cropping intensity is over 150 percent. The use of only nitrogenous and phosphatic fertilizers is causing potash, sulphur and micronutrient deficiencies restricting the yield potential. The sandwiching of green manuring crops in these tight cropping patterns is considered not only an excellent source of nitrogen, but the intervention improves physical condition of soil and availability of other nutrients. The studies have shown that the contribution of green manure legumes was quite high at low level of nitrogen application through fertilizers and dropped with increase in rates (RRI, 1998; Mian et al., 1988 and Bhatti et al., 1985). The studies of pre-rice green manuring of three years showed a significant impact on yield of next wheat crop and reducing its N requirements. The studies further concluded that green manure production technology along with zero tillage (Conservation Agronomy) can benefit the exhaustive rice-wheat cropping system through N fertilizer saving and increase in grain yields (Mann, 2000, Zia et al., undated). Major green manure crops are dhaincha/jantar (Sesbania aculeatea) and guar (Cyamopsis tetragonolaba). However, trials on sun hemp (Crotalaria juncea) and tropical jantar (Sesbania rostrata) have also been conducted. The nitrogen contribution from all these sources have been quantified from 70 to 100 kg/ha (Hussain, 1996). In wheat-cotton system, there is generally no time for green manure except to try relay cropping. The farmers are also not prepared to sacrifice main crop.

9.5 Crop residues

A huge quantity of crop residues such as wheat straw, cotton sticks, sugarcane trash/tops and rice husk, etc., are available. But due to some economic compulsions such as need for animal fodder and fuel, the crop residues are partially recycled in the soil, or burned to clear field for next crop otherwise these may contribute in improving organic matter in the soil and thus keep it productive. Kallar grass is recognized as a salt tolerant grass capable of producing a good amount of biomass on degraded soils in summer.

9.6 Filter cake and stillage

Pakistan sugar industry is producing about 1 million tonnes of filter cake every year, which is a rich source of organic matter, micro and macronutrients. Some sugar mills have molasses-based distillery plants, which produce stillage that contains nutrients especially potassium. The major portion of filter cake is sold to the brick baking industry and stillage is drained out thus causing loss of plant nutrients and environmental pollution. If all these materials are recycled by composting back to soil, it will provide essential plant nutrients for crop growth.

9.7 Sewage sludge, city garbage, industrial wastewater etc.

Sewage sludge, city garbage, industrial wastewater and effluents are also good source of plant nutrients. However, these materials require proper treatment to remove the toxic heavy metals before application to crops. It is estimated that the urban areas of Pakistan generate about 55 thousand tonnes of solid waste daily or about 20 million tonnes per annum (GOPa, 2005). However, this solid waste is not being properly managed and recycled fo different useful purposes including pre-treatment and composting for crop nutrition. Sewage water is partially used for raising vegetables near the urban areas without any pre-treatment. If adequate treatment of above waste materials is managed before their application, they will not only supplement the chemical fertilizers but the chance of environmental pollution will also be minimized.

9.8 Biofertilizers

A broad term used for products (carrier or liquid based) containing living or dormant microorganisms like bacteria, fungi, actinomycetes, algae alone or in combination which on application help in fixing atmospheric nitrogen or solubilise/mobilize soil nutrients in addition to secretion of growth promoting substances for enhancing crop growth. ‘Bio’ means living and ‘fertilizer’ means a product which provide nutrients in usable form. Biofertilizers are also known as bio-inoculants or microbial cultures. Biofertilizers can be broadly classified into four categories.

• Nitrogen fixing biofertilizers: (Thizobium, Azotobacter, Azospirillum, Acetobacter BGA, Azolla)
• Phosphorus solubilising/mobilising biofertilizers (PSB or PSM): (P-solubilising e.g. Bacillus Pseudomonas, Aspergillus etc. P-mobiliser e.g. VA-mycorrhiza).
• Composting accelerators (i) Cellulolytic (Trichoderma), (ii) Lignolytic (Humicola). Plant growth promoting rhizobacteria: (Species of Pseudomonas).

The Pakistan Agriculture Research Council (PARC), National Institute of Biotechnology and Genetic Engineering (NIBGE) and Provincial Agricultural Research Institutes are carrying out work on biological fertilization. All these institutions are isolating strains of rhizospheric bacteria, which have potential for mobilizing atmospheric N, both on legumes and non-legumes. In greenhouse, field and laboratory studies, effective microorganisms, in combination with NPK, green manure and FYM, have been shown to give yield responses of 18.3 percent in rice and 39 percent in wheat. Significant responses have also been reported in maize, peas and potatoes. NARC in collaboration with Engro Chemical Pakistan Limited (ECPL) commercialized rhizobium specific for chickpea in the name of Biozot. One packet of 500 gms was sold at Rs.50 to farmers. The project continued for three years (1996 to 1998) covering an area of one thousand acre each year. On the average, yield improvement of 25-40 percent was recorded (personal communication with Biological Section). However, it could not sustain.

At NIBGE, isolates were tested for their ability to produce indole acetic acid (IAA) in the rhizosphere and it was found that certain Pseudomonas spp. were most active. IAA, like 2:4D, can produce nodule-like excrescence on wheat roots and has been shown to mobilize atmospheric N thereby. Thus the prospects of providing partial N nutrition of wheat by inoculation of soil with isolates of Pseudomonas appear promising (Malik, et al., 1993). NIBGE based on its facilities including different capacity fermenters has already marketed its bio-fertilizer for rice under the name biopower. This product has been used over 10 000 acres of rice growing areas, and response of farmers has been excellent (Malik, K.A., 1997). Rashid et al., 1998 at Ayub Agricultural Research Institute reported that diazotroph bacterial inoculum increased wheat yield from 0 to 35 percent with low to high nitrogen application.

NIBGE has also been carrying out experimentation with Azolla for rice nutrition. An earlier problem, that Azolla would not survive the summer temperatures of Pakistan, has been overcme and there are now several heat-tolerant strains available. Azolla has been combined with N fertilizer and rice rhizospheric diazotrophic bacteria in field trials, from which it was found that an Azolla cover with 30 kg/ha N gave maximum rice yield, although biological nitrogen fixation (BNF) assisted in providing N to the rice plants.

At PARC, another important biological fertilization study is being conducted on microorganisms, which solubilize soil P. It has been found that strains of Aspergillus niger and Penicillium spp. have some solubilizing properties, not only in soil but also of P from rock phosphate.

At University of Agriculture, Faisalabad, Effective Microorganisms (EM) technology is being advocated, where claim has been made that this co-existing culture of five major types of beneficial microorganism has the potential to increase nutrient availability in the soil and thus crop productivity. However, many scientists have expressed their reservations about the product due to bio-safety concerns and lack of scientific evidence.

10. Limitations in the adoption of IPNM

10.1 Package of technology

Technology has not been developed to suit different farms and farming systems. There is need of commitment at research extension and national level for bottom up participatory approach and leadership. More allocation of resources is required to develop state of art technology.

10.2 Low availability of FYM

Amount of FYM available for use in the field is low and insufficient for meeting the requirements of crops. Farmers lack proper knowledge about the preparation of FYM and composting. Most used as fuel. Alternate sources of energy are to be made available to farmers.

10.3 Limitations in use of green manuring

• Small size of holdings;
• High demand for fodder;
• Lack of proper knowledge about green manuring and legumes; and
• Lack of organized research

10.4 Limitation in use of crop residues

• The price of straw and stalks is very high and the farmers are not willing to leave crop residues on the soil surface or incorporate into the soil as they fetch a good income from straw and stalks;
• Farmers dry crop residues and feed their cattle during winter when there is a shortage of fodder;
• Farmers use crop residues as fuel energy source as they do not have access to other sources of energy;
• Crop residues are used as a construction material in mud houses or cattle sheds.

10.5 Limitation in use of biofertilizers

• Application techniques and efficiency of strain
• Packing the product in marketable form
• Shelf life
• Specified minimum population of concerned microbes
• Good quality

11. Conclusion

Integrated Plant Nutrient Management (IPNM) through balanced use of mineral fertilizers, combined with organics and biosources may usher into new era for sustainable crop production to achieve food security, improving livelihood of small farmers and poverty reduction. The combined use of all these sources can lead to new green revolution. However, the national research institutions, universities, agriculture extension, private sector and government at policy level, all have to play their relevant role for technology development, its transfer and adoption at farm level in different ecological regions. The future approach will be to shift from increased use of fertilizer towards optimizing integrated management of all sources to address issues of low productivity, efficiency, soil nutrient depletion and environmental concerns. Government of Pakistan in Medium Term Development Framework (MTDF/2005-10) has emphasized the importance of IPNM in fertilizer use and crop production strategies. It will get due attention at policy level.

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