Data are presented on the effects of the use of molasses and distillery slops in conjunction with sulfur for the reclamation of a saline-sodic and a sodic soil from southwestern Puerto Rico. Results show that, in a sodic Guánica clay soil, corn yields were higher under the molasses treatment in the first corn crop, sulfur-slops and sulfur molasses in the second corn crop, and molasses, sulfur-slops, and sulfur molasses in the third crop, namely, snapbeans. Hydraulic conductivity values were markedly increased in the sulfur-slops and sulfur molasses treatments and removal of harmful exchangeable sodium was possible throughout the three crops. This was probably because of better water movement and the fact that more Ca ions were brought into circulation to displace adsorbed sodium. The experiments conducted on the saline-sodic Fe (Faith) clay soil followed about the same pattern of crop yields, hydraulic conductivity, and removal of exchangeable sodium of the Guánica clay soil. On the check plots, however, replacement of adsorbed sodium was rather pronounced for several possible reasons. These are: The soil had excess soluble salts which, for some time at least, maintained the colloids in a flocculated state. The soil column was rather short, 6 inches, and the hydrolysis of fertilizer salts must have brought into circulation Ca ions in an amount such as to replace considerable adsorbed sodium. Since Thiobacillus thiooxidans derives its energy from the oxidation of sulfur alone it is believed that the enhanced oxidation of sulfur must have been caused by created aeration and somewhat acid conditions which favored the bacteria.

Data are presented on the effect, of the application of two levels of blackstrap molasses and of rum distillery slops on some soil physical conditions, and crop and nutrient yields of a poorly drained soil of New Jersey. A favorable lasting effect on soil aggregate stabilization with the application of a fourth of an acre-inch of distillery slops and blackstrap molasses was observed when these materials were applied to this soil. The effect persisted even altor the growth of four consecutive crops (snap beans, Sudan grass, wheat, and barley). The emergence of snap bean seedlings was favorably affected by the slops and molasses treatments, but the emergence of other crops was not influenced, hy these treatments. The uptake of P, K, and Ca by snap beans was increased by these treatments, as were the crop yields. Soil hydraulic-conductivity values also tended to increase with time in the check treatments. The values also tended to increase in the slops treatment, until the third crop, and slightly decreased after the removal of the fourth crop. Two possible explanations are offered for the decrease in hydraulic conductivity in contrast to the slight increase in aggregate stability with time. These are: First, aggregate stability was determined using 0.5- to 2-mm size aggregates separated from the soil by sieving. Since a breakdown of the macroaggregate was observed to occur after the last crop, the 0.5- to 2-mm sized aggregates which formed from these larger aggregates were quite stable. Further, since the smaller aggregates tend to create finer pores which retard water movement, the hydraulic conductivity values were reduced. The second possible explanation is that, since roots had been accumulating in the soil because of the growth of four crops, these probably plugged the macro- and micropores, thus sealing, to a certain extent, the channels that would have beenn available for the movement of water. The relatively high content of water-stable soil aggregates present, in the soil at the time of removal of the fourth crop is indicative of the resistance to decomposition of the organic cementing or bonding agents which are present in the slops and molasses, and are responsible for the formation of water-stable soil aggregates.

Data are presented on a laboratory study conducted to determine the effects of the use of blackstrap molasses and rum distillery slops on the reclamation of a highly saline-alkali heavy clay soil of southwestern Puerto Rico. The study revealed that even the lowest levels of distillery slops and diluted molasses, around 2.3 acre-inch, were sufficient to lower the conductivity of the soil-saturation extract from 67 mmhos/cm. to less than 3, and the exchangeable sodium percentage from 43 to less than 1 percent. It is believed that most of the Ca and Mg found in leachates of columns treated with the most slops or molasses may be attributed to the production of organic acids during the decomposition of slops and molasses. These organic acids rendered soluble the soil-free CaCO3 and MgCO3, widening the Ca and Mg:Na ratio to substitute the sodium by a mass action effect. Subjecting the soil to a dry period in between, the 6 and 7 acre-feet of water did not alter the movement of water and resulted in a complete soil reclamation.

The effect of water table depth on yield of sugarcane varieties PR 980, PR 1028, PR 1059, PR 1141, PR 64-610, PR 61-632 and PR 64-2705 was studied in lysimeter tanks in the field. Using plastic drains at varying distances and depths, variety PR 980 was studied on a 5-ha farm. Results obtained show that varieties differ in their response to water table conditions. Varieties PR 980, PR 1059, PR 64-610, PR 61-632 and PR 64-2705 yielded significantly more cane and sugar when the water table was lowered. Varieties PR 1028 and PR 1141 did not show statistically significant differences among treatment differentials. Under actual field conditions, using perforated plastic drains, variety PR 980 yielded significantly more sugar than in undrained plots. The results obtained in the lysimeter tanks are in accord with those observed under commercial production.

Data are presented in this paper on the availability of moisture in Catalina clay, an Oxisol, and Cialitos clay, an Ultisol. The soils are very high in clay content and fairly high in organic-matter content. Catalina clay is high in free iron oxides with 18.2 percent, while Cialitos clay has 13 percent. Striking differences are evident as to cation exchange capacity with values of over 20 meq. for Cialitos and only around 12 meq. for Catalina. Both soils have low available water-supplying power. However, when the individual aggregates are considered, the smaller ones retain larger volumes of available water than the larger ones. This is so because moisture retained at higher tensions decreases with decreasing aggregate size, while that retained at lower tensions increases with decreasing aggregate size. These results are explained on the basis of the larger volume of small pores in larger aggregates and the larger voids created in-between smaller aggregates.