Phosphorus use efficiency (PUE) is very low in alkaline calcareous soils; however, it can be improved by using suitable application methods along with farm manure (FM). The present field study was conducted to optimize phosphorus (P) levels and application methods in order to maximize wheat yield, PUE, and net returns on calcareous soils with and without FM application. Five P soil solution levels, i.e. 0.00, 0.05, 0.10, 0.20, and 0.30 mg P L -1 , were maintained according to the Freundlich model through the application of 0, 36, 61, 104, and 142 kg P 2 O 5 ha -1 , respectively. The calculated P (0, 36, 61, 104, and 142 kg P 2 O 5 ha -1 ) was applied by broadcasting, band-placement, and top-dressing, with or without 300 kg ha -1 well-rotted FM. The results revealed that the bandplacement technique at 104 kg P 2 O 5 ha -1 improved PUE and wheat output with and without FM application. Furthermore, wheat grain and straw P uptake was high at 142 kg P 2 O 5 ha -1 . In addition, protein content and Olsen P were high at 142 kg P 2 O 5 ha -1 . The band-placement technique at 104 kg P 2 O 5 ha -1 increased net returns and the cost/benefit ratio. FM application further augmented the productivity, PUE, and net returns under various P levels and application techniques. In conclusion, band-placement of P at 104 kg P 2 O 5 ha -1 with FM improved yield, PUE, and net returns of wheat sown on sandy clay loam calcareous soils.

No abstract

Tomato production in Pakistan faces significant problems of low yields due to various biotic and abiotic stresses primarily because of a narrow genetic base of the cultivars being used. Therefore, Introduction and evaluation of the exotic tomato germplasm has become necessary to acquire elite material to develop future breeding programs. To this end, the present study was conducted for the phenotypic characterization of twenty exotic tomato genotypes along with two locally grown cultivars in semi-arid subtropical climate. Data were collected for morphological, fruit quality and fruit yield traits. A significant (p<0.05) phenotypic variation was observed for all the studied traits. Maximum yield was obtained from “Rober” i.e., 1508.31 g per plant. The maximum shelf life was observed in the Cromco, with the least weight loss (2.45%) and loss in the firmness of fruit (22.61%) in 4 days. Correlation analyses revealed a strong genetic association among morphological and yield related traits. High estimates of the heritability (ranged from 79.77% to 95.01% for different traits), along with a high genetic advance (up to 34%) showed the potential usefulness of these traits and genotypes to develop breeding programs to improve the tomato yield and fruit quality.

No abstract

Understanding the dynamics of potassium (K) and its availability is fundamental in its efficient use as an important nutrient. The objectives of present study were to compare standard K extraction methods for extractable K and kinetics of K adsorption on five different textured soils. The soils were analyzed for physico-chemical properties, extractable K contents and kinetics of K adsorption. The soils had variable contents of soluble (8-52mg kg-1), exchangeable (13-215mg kg-1), fixed (488-1836mg kg-1), structural (2936-26362mg kg-1) and total K (3438-28517mg kg-1). Except soluble K, the amount of K in different forms was significantly (P?0.05) correlated with clay contents, electrical conductivity (EC), cation exchange capacity (CEC) and calcium carbonate in soils. Different methods variated the extracted K in different textured soils. Mehlich-III, ammonium acetate, AB-DTPA, and calcium chloride extracted K was maximum in sandy clay loam (298mg kg-1, 267mg kg?1, 226mg kg-1, and 113mg kg-1) and lowest was in loamy sand (33mg kg-1, 24mg  kg-1, 30mg kg-1, and 24mg   kg-1) respectively. Elovich and power function models best explained the K kinetics adsorption, as rate of adsorption constants were negatively correlated with sand contents in the soil type. Pearson correlation showed that the extractability of K by different methods and kinetics of K adsorption were dependent on soil texture EC, CEC and calcium carbonate contents. Hence, soil physico-chemical properties should be considered in recommending rate of K fertilization along with crop K demand and soil extractable K.