This study examined effect of potassium drip fertigation on the growth and

fruit yield of tomato under field conditions at western Libyan conditions, in two

consecutive seasons. The soil texture sites was sandy, pH around 8.0. the soil potassium

was extracted and estimated by flam photometer at 766 μm. The rate of potassium fertilizer

were F1: 0; F2: 150; F3: 300 kg K2O ha-1 as potassium chloride form in three replicates.

The experimental site was designed in randomized complete block (RCBD). and I1: 75%

ET𝑐; I2: 100% ET𝑐; I3: 125% ET𝑐 levels for irrigation. The interactions for both potassium

fertilization levels and irrigation treatments with fruit yield were found. The single

treatments of potassium fertilization or irrigation significantly affected the tomato fruit

yield, where fertilization and irrigation applications increased the fruit weight from 13.99 t

ha-1 to 34.47 t ha-1 t/ha minimum in F1I1 and maximum in F3I3. Application of different Kfertilizers

and irrigations had significant effect in PFP (partial factor productivity), and

AUE (agronomic use efficiency) as compared to K-control plots of tomato. The average of

PFP for K and irrigation in two treatments were 65.65 kg kg-1 in F2I3, and 59.43 kg kg-1 in

F3I3 which are greater than the values of control, F1I1, F1I2, and F1I3 treatments

Factorial field experiment was conducted to evaluate relationship between two genotypes of local wheat (Triticum aestivum) and phosphorus soil test values. The M 0.5 NaHCO₃ based (Olsen phosphorus) extractant was carried out on soils taken from the plots. The experiment was conducted at western region of Libya. Soil pH at the experimental site was 8.1 and the texture is sandy. The experiment was performed using a randomized complete block design (RCBD) method with three replicates for each treatment of phosphate fertilizer at concentrations of 0, 60, and 120 kg P₂O₅ ha^-1 for both genotypes. Results were expressed by relative values (Relative Yield). Relative yield (RY) of the two wheat cultivars showed similar significant responses to both soil test values and the grain yield. Linear relationship between relative yield and the grain yield at 0 kg P2O5 ha^-1 for both genotypes was found, whereas, non-linear relationship was noticed among treatments that received 120 kg P₂O₅ ha^-1. Both the linear and non- linear relationship have explained by tendency curves and showed how both genotypes response to phosphate fertilizer.

Field experiment was conducted to evaluate the correlation relationship between the yield of two localized wheat genotypes (Triticum aestivum,) Acsad 901 and Salamboo and Olsen phosphorus soil test (0.5 M of NaHCO3 at pH 8.5) values. The experimental site was run at west sector of Libya. The experimental site pH was 8.4 and the texture is sandy The experiment consisted of three replicates and three phosphate fertilizer rates which equivalent, (0, 60, and 120) kg P2O5 ha-1 for both genotypes. The results of grain yield of the experiment were expressed by relative values (Relative Yield). The relative yield (RY) illustrated the relationship between soil test values and the grain yield clearly. Very close correlation relationship (r = 0.98 ) between relative yield of grain and the soil test values of Salamboo was found whereas Acsad genotypes was achieved less correlation( r =0.69) at 0 kg P2O5 ha-1 for both genotypes. The similarity between the two genotypes was very close (r = 0.99 ) for treatments that received high phosphate rate.

Factorial field experiment was done to estimate agronomic phosphorus use efficiency (APE) and partial factor productivity (PFP). The experiment was run in a private farm in Janzour area which is located west of Tripoli Libya in 2018. Two localized wheat genotypes (L1, and L2) and three rates of triple super phosphate fertilizer (0, 60, and 120) kg P2O5 ha-1 were used. The results indicated that both genotypes have good response to phosphate fertilization. APE and PFP achieved positive relationship with only 60 kg P2O5 ha-1 rate for both genotypes. Moreover, APE calculation showed positive relationship with increasing soil phosphorus test values, meanwhile, APE values was kept steady at 120 kg P2O5 ha-1 .