PRACTICAL, PRODUCTIVE ANDENVIRONMENT FRIENDLYUTILIZATION OF SALT AFFECTEDSOILS IN PAKISTANBy:Farooq et al; PAEC,Islamabad, Pakistan
The topic of soil salinity is so wide anddiversified that probably every bodysitting in this hall has his/her own salinityProblems,Perception,Solutions and the way ofUtilizationHence every effort in its own perspective has to bepractical and productive and probablyenvironment friendly tooINTRODUCTION
In Pakistan• Climatic conditions are arid and semi arid• Very high temperature in central and Southernparts• Frost in central and Northern parts• Mini. rainfall of 250 mm in 68% ofgeographical area• Maxi. rainfall of 550 mm in 24% ofgeographical area• Monsoon* rain in July and August• Winter rains** in Northern and Western part*,** Now scanty and rare, respectively
Major Problems1. Drought: Created by low precipitation,high heat and evapo-transpiration andshortage of irrigation water;2. Salinity: Created by seepage of waterfrom canals, and rivers and highevaporation which has affected 6.3 Mhaof land
The entire 6.3 Mha of saline soils are divided intothree general types i.e.i) Saline soils in irrigated areas,ii) Saline soils in water deficit and /or dry areas, andiii) Saline soil in desert areas.Type-i soils possess electrical conductivity (EC) inthe range of 10 to 15 dSm-1, are found saline sodicthrough out root zone, can be easily drained, andpossess good physical qualities. The extent of thesesoils is 4.79 Mha of which one Mha is under wheatcultivation and require salt tolerant wheat genotypes
Type-ii soils, that are in water deficit/dry areas, arealso beset with desertification such as those located inSouthern Punjab and some parts of Sind Province.The average temperature during wheat season in theseareas ranges between 19-32 0C and average annual rainfall between 0.19-35mm.These soils possess EC in the range of 6-10 dS m-1andexist as patches. The extent of such soils in Pakistan is1.5 Mha and can be cultivated with high yielding salttolerant genotypes that may also tolerate waterdeficiency and high temperature.
Type-iii soils, which are present in desert areas arepeculiar to semi arid zones comprising Cholistan,Thar, and Kharan.These soils are beset with high rate of evaporationand strong summer winds. Water is most critical andlimiting factor that prohibits using such areas foragricultural production.These soil requires genotypes that can be grownwithout much water, can sustain strong winds andprovide green cover to barren lands therebyprotecting it from the wind erosion.
The problem however, is that all these soils are notsimilar in nature. There are highly significantdifferences ini.Composition, type and quantity of predominant saltsin a particular area,ii.Climatic conditions, availability and type ofirrigation water andiii.Co-existence of salinity with desertification.Hence, it is imperative to tailor plantsspecifically suitable to such conditions andothers as well
MATERIAL S AND METHODSMaterial used in this studycomprised short stature line(SSt), drought tolerant line(DTL), and “DURUGEN” whichcombines both salt and droughttolerance.
DTL was produced by crossingWL-1076 with a waterdeficiency tolerant accession ofAegilops geneculata. F1 wasback crossed with recurrentwheat parent and selfed 6 timesbefore DTL was tested in thefield for salt tolerance.
RUSULTSSSt was produced for type-i saline soils present in thedistricts of Rahim Yar Khan in Southern and Kamaliain the central Punjab where wheat-cotton rotation isbeing practiced. It was sown at the end of January afterpicking last lint of cotton. In 90-100 DAS, SSt plants onthe average attained•18 inches of height,• produce 24-30 productive tillers, and• grain yield of about 3000 kg ha-1instead of 1000kg ha-1of commercial cultivar.Getting this much yield in 100 days compared to 155-160 days ofcommercial cultivars was never possible without SSt.
Typical SSt plant with short stature and heavy tillersTypical SSt plant with short stature and heavy tillers
DTL was developed for type-ii saline soils located indistricts of Bahawalpur, and Rahim Yar Khan in thesouthern Punjab and some parts of Sind Province.These areas have twin problems of salinity andwater deficiencyAt Rahim Yar Khan,genotype on the average possess• 100 cm long plant height,• >21 productive tillers plant-1and• grain yield of 4000 kg ha-1which is 10% higher thanthe yield obtained from the local check.
16A typicalA typicalDTLDTLplantplantHeavy waxHeavy waxcan be seencan be seenon theon theleaves andleaves andstemsstems
DURUGEN was developed for type-iiisaline soils that are coupled withdesertification, high temperature,strong winds, and are mostly locatedin Thal, Thar, and Kharan,The conditions there are so harsh that theinhabitants have largely been migrated toother places in search of livelihood.
Simulated field trials of first generation“DURUGEN” produced• 6-26 tillers,• 4-20 spikes,• 60-90cm plant height,• 55-90 grams of plant weight,• 15-23 grain spike-1and• 2.2-6.3 grams grain weightspike-1.The second generation plants when tested using 50% less irrigationwater and salinity of EC 15dS m-1indicated significantly lowerreduction (10-12%) in biomass and (5-8 %) and in grain yield thanthat (37% and 23%, respectively) observed in check varieties grownunder similar conditions.
DISCUSSIONIt is generally believed that solutionto salinity depends upon: Gravity of the situation, Resources of the country, Priority of the agriculture sectors, Environmental conditions, and Social acceptance of the approachin term of economic benefits
Gravity of situation in Pakistan 6.3 Mha of land is affected by salinity One of the priorities of agriculture sector isachieving wheat production target of 26.50 Mtons There are about 4.1 million small farmerswatching their land being degraded due tosalinity, drought, and/or water deficiency, Water is 35-40% less than it was availablepreviously, Most of the water deficient areas are also besetwith high temperatureFarmers want to see their lands productive with minimuminvestment in order to ensure food security to their families
Added to this is•Pakistan’s current population which is over 156 M,•Current figure of undernourished people which is between 35-40%•Require more food calories to reduce the number, and hence needto increase wheat production (major staple cereal) from23.4 MT to 26.50 MTwhich is possible by using saline landsFor example, SSt was developed for saline areas that are canalirrigated and are used for wheat-cotton rotation. The extent of suchsoils in Pakistan is 4.79Mha of which 2.89 Mha became saline due toirrigation provided by subsurface saline water.If SSt can be cultivated on only one Mha of this area, it wouldproduce approximately 3 MT of extra wheat which can increaseconsumption of calories by the poor inhabitant of saline lands.
DTL is an improved version of low input WL-1076 which possessproven potential to be cultivated on saline/water deficit areas ofBahawalpur, Rahim Yar Khan, and Multan where farmers canprovide only 2-3 irrigations (instead of at-least 5 given tocommercial cultivars)In Bahawalpur region, farmers obtained grain yield of 4000 kg ha-1that was 10% higher than the commercial wheat cultivar that isinput intensive and the resource deficient farmer can not afford tocultivate this due to shortage of water and inadequate andexpensive fertilizers which are largely imported.
Potential of DURUGEN has indicatedthat if cultivated in desert areas, thefarmer at-least can get green cover onthe barren lands which can preventerosion caused by strong windsthereby improving the desertenvironment.It can also provide some fodder for theanimals which is enough attraction for re-habilitating these soil and their owners to