Effect of organic waste and NPK fertilizer on potato yield and soil fertility

A field experiment was conducted to examine the effect of organic waste and NPK fertilizers on macro and micronutrients concentration in potato straw and on yield at Nuclear Institute of food and Agriculture Peshawar, Pakistan during 2012. Fifteen treatments of various organic and inorganic fertilizers were applied to potato crop each replicated three times. After harvesting of the crop, potato yield was recorded. For soil fertility analysis 90 soil samples from two depths (015 and 15-30 cm) and 45 straw samples were also collected and analyzed. Fertilizer doses showed significant effect on potato yield and soil fertility parameter. The treatments (Filter cake + full NPK) and (Municipal solid waste + full NPK) showed high yield and significant effect on NPK and micronutrients concentrations in potato straw. The lowest concentrations of micronutrients in soil and potato straw were observed mainly in treatment (PK recommended dose) and control. It can be concluded from this experiment that the conjunctive use of inorganic fertilizers with organic waste further accelerated the beneficial effect of inorganic fertilizers on soil and plants. The treatments (Filter cake + full NPK) and (MSW + full NPK) seemed to be the appropriate dose for sustainable production of potato.


Introduction
Pakistan is basically an agricultural country.The soils are 100% deficient in organic matter (O.M less than 1%) and in major plant nutrients including nitrogen and phosphours.Soil organic matter plays a major role in maintaining soil quality and also effect the production of the crop [1].The beneficial effects of organic manures are manifested through increase in soil organic matter and humus over the period.Soil organic matter and humus acts in several ways; it serves as slow release source of plant nutrients to the crops and increases water holding capacity to maintain the water regime of the soil and acts as a buffer against change in soil pH [2].Using the residues of agricultural activities, municipal waste, improve soil physical and chemical properties and also the fertility and production capacity [3].Composts are important source to maintain and restore soil fertility particularly in those countries where the organic matter content of the soil is low.Nutritional stress including widespread nutrient deficiencies, low organic matter content, unbalanced use of fertilizers, poor physical condition and soil fertility are the major limiting factors causing low crop production in Pakistan [4].The balance application of chemial fertilizer is very nessery for valuable producation.However, their imbalance use, high rates,availability time is not properly manage and some nutrient has loses from the soil is the serious porblum for the farmers [5].Potato (Solanum tuberosum L.) belong to family solanaceae is the fourth most important food crop in the world on the basis of production, Its cultivation is quite intensive in northern west Punjab and north west Khyber Pakhtunkhwa.Three crops of potato can be grown in a year, a spring and an autumn crop in the plains and a summer crop in the hilly area at higher altitudes.The area under potato is 137.7 thousand hectares with production of 2554.2 thousand tonnes with average yield is 22.7 t ha -1 , In Khyber Pakhtunkhwa it is grown on the area of 9.2 thousand hectares and yield is 123.1 thousand tonnes with average yield of 13.1 t ha

Experimental design
The experiment was conducted to according randomize complete block (RCBD) with fifteen treatments and each treatment was replicated three times.Potato was sown on ridges made 30 cm high and 80 cm apart.Different treatments i.e.N, P2O5, K2O, FYM, MSW and filter cake were applied alone or in various combinations including control, farm yard manure, municipal solid waste, NPK full (250-120-120 kg ha -1 ), tomato residue + half NPK, filter cake + half NPK, tomato residue + full NPK, filter cake + full NPK, recommended PK, tomato residue alone, filter cake alone, FYM + half NPK, MSW + half NPK, FYM + full NPK and MSW + full NPK.The fertilizers were applied at the time of sowing; half of the nitrogen was applied at time of sowing and half at the time of earthing off.

Laboratory procedure
Total nitrogen in Potato straw samples was determined by kjeldhal method suggested by Bremner [9] while total Phosphorous, Potassium and micronutrients was determined by the standard procedure described by [10].

Statistical Analysis
The data were recorded and statistically analyzed by using analysis of variance techniques.Treatment means were tested by using least significant differences (LSD) at 5% level of probability [11].The maximum Cu concentration was observed (5.4 mg Kg -1 ) in the treatments (Filter cake + half NPK and F.Y.M + half NPK) at soil depths of (0-15 cm) and (15-30 cm) respectively.The highest concentration of Fe (448.6 and 402.6 mg Kg - 1 ) was observed in the treatment (FYM + half NPK) at soil depths of (0-15 cm) and (15-30 cm) respectively.High Mn concentrations (14.1 and 12.4 mg Kg -1 ) were observed in the treatment (Filter cake+ full NPK and FYM + half NPK) at soil depth (0-15 cm) and (15-30 cm) respectively.The lowest concentrations of Zn, Cu, Fe and Mn were observed in control presented in table.2 at 0-15 and 15-30 cm soil depth.The results was in line with those of Diacono et al., [12] who also reported that Zn, Cu, Fe and Mn concentration increase with applications of organic manure.Asiegbu et al. [13] Found that N, P and K fertilizers were more efficient than the organic manures in supplying N, P and K to the growing plant at least in the short run, further supported by Banin et al. [14] that FYM increase the uptake of N, Fe and Zn and also enhanced P uptake.

Effect of organic waste and NPK fertilizer on micro nutrients concentration in potato straw
The micronutrient concentration (Zn, Cu, Fe and Mn) in potato straw were significantly (P ≤ 0.05) increased with the organic waste and NPK fertilizers as compared to control and presented in Table .3.Highest zinc concentration (27.00 mg Kg -1 ) was observed in the treatment where only Tomato residue was treated which was significantly higher from rest of treatment and lowest zinc concentration was recorded (5.53 mg Kg -1 ) in control.Similarly maximum Cu concentration was noted (29.26 mg Kg -1 ) in the treatment where only Tomato residue was applied and the minimum concentration (11.46 mg Kg -1 ) was in control.The Fe concentration was in range (1314.0-1376.4mg Kg -1 ) and highest in treatment (Filter cake + full NPK) and lowest in control.The significant (P ≤ 0.05) highest concentration of Mn (3.16 mg Kg -1 ) was recorded on municipal solid waste treatment and lowest concentration was observed in control.Micronutrients concentrations of plants is directly associated with their concentrations in soils, their levels significantly differ with plant species, and even can also affected by genotypes within the same species [15].4).The highest P concentration was observed (0.27 g 100 g -1 ) in treatment where only Farm yard manure was applied and statistically similar to treatment where MSW + full NPK was treated and lowest Phosphorous concentration was noted in control (0.27 g 100 g -1 ).The K concentration was maximum (3.66 g 100 g -1 ) in treatment where FYM was applied and lowest in control (2.66 g 100 g - 1 ).Nitrogen, Phosphorus and Potassium uptake by plants increase with increase in FYM application [16].Phosphorus and FYM application had significant (P ≤ 0.05) effect on both tuber and shoot weight showing that there was positive interaction between Phosphorous and FYM on tuber and shoot weight.Effect of organic waste and NPK fertilizer on Yield and plant height of potato.The data regarding potato tuber yield is presented in table.5, the results indicated that the combined used of organic and inorganic fertilizer increased potato yield significantly (P ≤ 0.05) over control.Treatment where MSW + half NPK showed maximum yield (20.66 kg plot -1 ) and yield was decreased up to (10.16 kg plot -1 ) in control.Potato plant height was in range 33.80-54.46cm.The result was agreed with findings of Baishya [17] who observed that the highest tuber yield was obtained with the application of 50 %NPK of the recommended dose through inorganic fertilizers and remaining 50% from PM. Similar result were founded by Moshileh et al. [7] who revealed that the significant increased were noted in plant height and chlorophyll concentration with the increase of potash levels.Tikhonov et al. [18] found that NPK application increased yield and enhanced starch content when compared with NP and NK.

Conclusions
From the present research work it is concluded that combine application of organic waste and inorganic fertilizers could significantly improve soil fertility and nutrients concentration in potato straw.Application of Filter cake + Full NPK and Municipal solid waste + Full NPK could be recommended.The long term use of organic and inorganic fertilizers will be beneficial in achieving sustainable yields.

Authors' contributions
Conceived and designed the experiments: M Afzal, Performed the experiments: M Zahoor, M Ali & W Mohammad, Analyzed the data: N Khan & M Adnan, Contributed reagents /materials/ analysis tools: W